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THE MECHANISM OF LIFE 



THE 

MECHANISM OF LIFE 



DR. STEPHANE LEDUC 

PKOFKSSKUK A L'lVoLF, I)E MKDK.CINK D1C NANTES 



TRANSLATED BY 



w. DEANE BUTCIIKR 



J OK THR 
OF .MKUICINE 



" La nature a forme 1 , ct forme tons 
Ics jours Ics ctres les plus simples par 
gene-ration spontandc, LAMARCK.' 




LONDON 
WILLIAM HEINEMANN 



First Impression . . . March 
Second Impression . . . January 



All Rights Reserved 



TRANSLATOR'S PREFACE 

PROFESSOR LEI-MIC'S Thvorie Phtiaico-chlmlquc de la Vie et 
Generations Spontancefi has excited a good deal of attention, 
and not a little opposition, on the Continent. As recently 
as 1907 the Academic des Sciences excluded from its Comptes 
Kendus the report of these experimental researches on diffusion 
and osmosis, because it touched too closely on the burning 
question of spontaneous generation. 

As the author points out, Lamarck's early evolutionary 
hypothesis was killed by opposition and neglect, and had to 
be reborn in England before it obtained universal acceptance 
as the Darwinian Theory. Not unnaturally, therefore, he 
turns for an appreciation of his work to the free air and 
wide hori/xm of the English-speaking countries. 

He has entitled his book "The Mechanism of Life," 
since however little we may know of the origin of life, 
we may yet hope to get a glimpse of the machinery, and 
perhaps even hear the whirr of the wheels in Nature's work- 
shop. The subject is of entrancing interest to the biologist 
and the physician, quite apart from its bearing on the 
question of spontaneous generation. Whatever view may 
be entertained by the different schools of thought as to the 
nature and significance of life, all alike will welcome this 
new and important contribution to our knowledge of the 
mechanism by which Nature constructs the bewildering variety 
of her forms. 

There is, I think, no more wonderful and illuminating 
spectacle than that of an osmotic growth, a crude lump 
of brute inanimate matter germinating before our very eyes, 
putting forth bud and stem and root and branch and leaf 
and fruit, with no stimulus from germ or seed, without even 

vii 



viii TRANSLATOR'S PREFACE 

the presence of organic matter. For these mineral growths 
are not mere crystallizations as many suppose ; they increase 
by intussusception and not by accretion. They exhibit the 
phenomena of circulation and respiration, and a crude sort 
of reproduction by budding ; they have a period of vigorous 
youthful growth, of old age, of death and of decay. They 
imitate the forms, the colour, the texture, and even the 
microscopical structure of organic growth so closely as to 
deceive the very elect. When we find, moreover, that the 
processes of nutrition are carried on in these osmotic pro- 
ductions just as in living beings, that an injury to an osmotic 
growth is repaired by the coagulation of its internal sap, and 
that it is able to perform periodic movements just as an 
animal or a plant, we are at a loss to define any line of 
separation between these mineral forms and those of organic 
life. 

In the present volume the author has collected all the 
data necessary for a complete survey of the mechanism of 
life, which consists essentially of those phenomena which are 
exhibited at the contact of solutions of different degrees 
of concentration. Whatever may be the verdict as to the 
author's case for spontaneous generation, all will agree that 
the book is a most brilliant and stimulating study, founded 
on the personal investigation of a born experimenter. 

The present volume is a translation of Dr. Leducs French 
edition, but it is more than this, the work has been translated, 
revised and corrected, and in many places re- written, by the 
author's own hand. I am responsible only for the English 
form of the treatise, and can but regret that I have been 
able to reproduce so imperfectly the charm of the original. 

W. DEANE BUTCHER. 

EALING. 



PREFACE TO THE ENGLISH EDITION 

CV.sT par Tinitiative clu Dr. Deane Butcher que cette 
ouvrage est presents aux leeteurs anglais, a la race qui a 
dote rimmanite de tant de decouvertes originales, genial es 
et d\me portee tres generalc. 

Com me un etre vivant, unc idee exige pour naitre et se 
developper Ic germe et le milieu de devcloppement, II est 
incleniable que le peuple anglo-americain constitue un milieu 
particulicrcment favorable a la naissance et an developpement 
des idees nouvelles. 

Pendant notre collaboration le Dr. Deane Butcher a ete un 
critique judicieux et eclaire, tons les changements dans Tedition 
anglaise sont dus a ses observations. II s^est assimile Touvrage 
pour le traduire, et dans beaucoup de parties, il a mis plus de 
clarte et de concision qiTil n'y en avait dans le texte original. 

STEPHANE LEDUC. 

NANTES, 1911. 



TABLE OF CONTENTS 

PACK 

TRANSLATOR'S PREFACE , . . . vii 

AUTHOR'S PREFACE . . , . . . . ix 

INTRODUCTION . . xiii 

I. LIFE AND LIVING BEINGS ..... i 

II. SOLUTIONS . . . . . . 14 

III ELECTROLYTIC SOLUTIONS . . . . .24 

IV. COLLOIDS ....... 36 

V. DIFFUSION AND OSMOSIS . . . . -43 

VI. PERIODICITY ....... 67 

VI I, COHESION AND CRYSTALLIZATION . . . .78 

VIII. KARYOKINESIS . . . . . .89 

IX. ENERGETICS . . . . . . -97 

X. SYNTHETIC BIOLOGY . . . . . .113 

XI. OSMOTIC GROWTH : A STUDY IN MORPHOGENESIS . 123 

XII. THE PHENOMENA OF LIFE AND OSMOTIC PRODUCTIONS: 

A STUDY IN PHYSIOGENESIS . . . -147 

XIII. EVOLUTION AND SPONTANEOUS GENERATION . . 160 



INTRODUCTION 

LIFK was formerly regarded as a phenomenon entirely separated 
from the other phenomena of Nature, and even up to the 
present time Science has proved wholly unable to give a 
definition of Life ; evolution, nutrition, sensibility, growth, 
organization, none of these, not even the faculty of repro- 
duction, is the exclusive appanage of life. 

Living things are made of the same chemical elements as 
minerals ; a living being is the arena of the same physical 
forces as those which affect the inorganic world. 

Life is difficult to define because it differs from one living 
being to another ; the life of a man is not that of a polyp or 
of a plant, and if we find it impossible to discover the line 
which separates life from the other phenomena of Nature, it is 
in fact because no such line of demarcation exists the 
passage from animate to inanimate is gradual and insensible. 
The step between a stalagmite and a polyp is less than that 
between a polyp and a man, and even the trained biologist is 
often at a loss to determine whether a given borderland form 
is the result of life, or of the inanimate forces of the mineral 
world. 

A living being is a transformer of matter and energy both 
matter and energy being uncreateable and indestructible, i.e. 
invariable in quantity. A living being is only a current of 
matter and of energy, both of which change from moment to 
moment while passing through the organism. 

That which constitutes a living being is its form ; for a 
living thing is born, develops, and dies with the form and 
structure of its organism. This ephemeral nature of the living 
being, which perishes with the destruction of its form, is in 



xiv INTRODUCTION 

marked contrast to the perennial character of the matter and 
the energy which circulate within it. 

The elementary phenomenon of life is the contact 
between an alimentary liquid and a cell. For the essential 
phenomenon of life is nutrition, and in order to be assimilated 
all the elements of an organism must be brought into a state 
of solution. Hence the study of life may be best begun by the 
study of those physico-chemical phenomena which result from 
the contact of two different liquids. Biology is thus but a 
branch of the physico-chemistry of liquids; it includes the 
study of electrolytic and colloidal solutions, and of the 
molecular forces brought into play by solution, osmosis, 
diffusion, cohesion, and crystalli/ation. 

In this volume I have endeavoured to give as much of the 
science of energetics as can be treated without the use of 
mathematical formulae ; the conception of entropy and 
Garnet's law of thermodynamics are also discussed. 

The phenomena of catalysis and of diastatic fermentation 
have for the first time been brought under the general laws of 
energetics. This I have done by showing that catalysis is only 
one instance of the general law of the transformation of potential 
into kinetic energy, vix. by the intervention of a foreign 
exciting and stimulating energy which may be infinitely 
smaller than the energy it transforms. This conception 
brings life into line with other catalytic actions, and shows us 
a living being as a store of potential energy, to be set free 
by an external stimulus which may also excite sensation. 

In a subsequent chapter I have dealt with the rise of 
Synthetic Biology, whose history and methods I have described. 
It is only of late that the progress of physico-chemical science 
has enabled us to enter into this field of research, the final one 
in the evolution of biological science. 

The present work contains some of the earliest results of 
this synthetic biology. We shall see how it is possible by 
the mere diffusion of liquids to obtain forms which imitate 
with the greatest accuracy not only the ordinary cellular 
tissues, but the more complicated striated structures, such as 
muscle and mother-of-pearl. We shall also see how it is 



INTRODUCTION xv 

possible by simple liquid diffusion to reproduce in ordered and 
regular succession complicated movements like those observed 
in the karyokinesis of the living cell. 

The essential character of the living being is its Form. 
This is the only characteristic which it retains during the 
whole of its existence, with which it is born, which causes its 
development, and disappears with its death. The task of 
synthetic biology is the recognition of those physico-chemical 
forces and conditions which can produce forms and structures 
analogous to those of living beings. This is the subject of the 
chapter on Morphogenesis. 

The last chapter deals with the doctrine of Evolution. 
The chain of life is of necessity a continuous one, from the 
mineral at one end to the most complicated organism at the 
other. We cannot allow that it is broken at any point, or that 
there is a link missing between animate and inanimate nature. 
Hence the theory of evolution necessarily admits the physico- 
chemical nature of life and the fact of spontaneous generation. 
Only thus can the evolutionary theory become a rational one, 
a stimulating and fertile inspirer of research. We seek for the 
physico-chemical forces which produce forms and structures 
analogous to those of living beings, and phenomena analogous 
to those of life. We study the alterations in environment 
which modify these forms, and we seek in the past history of 
our planet for those natural phenomena which have brought 
these physico-chemical forces into play. In this way we may 
find the road which will, we hope, lead some day to the 
discovery of the origin and the evolution of life upon the 
earth. 



THE MECHANISM OF LIFE 

CHAPTER I 
LIFE AND LIVING BEINGS 

PRIMITIVE man distinguished but two kinds of bodies in nature, 
those which were motionless and those which were animated. 
Movement was for him the expression of life. The stream, the 
wind, the waves, all were alive, and each was endowed with all 
the attributes of life will, sentiment, and passion. Ancient 
Greek mythology is but the poetic expression of this primitive 
conception. 

In the evolution of the intelligence, as in that of the body, 
the development .ofjthc individual is but a repetitipn of the 
development of tlie^race. Even now children attribute life to 
everything that moves. For them a little bird still lives in the 
inside of a watch, and produces the tick-tick of the wheels. 
In modern times, however, we have learnt that everything 
in nature nioyes^ so thcOl^motionof^ itself cannot be considered 
as flic characteristic of [life. 

Heraelitus aptly compares life to a flame. Aristotle says, 
" Life is nutrition, growth, and decay, having for its cause a 
principle which has its end in itself, namely e^rsXg^g/a. This 
principle is itself in need of definition, and Aristotle only 
substitutes one unknown epithet for another. 

Bichat defined life as the ensemble of the .functions, jvhjch 
resist death. This is to define life in terms of death, but 
death is but the end of life, and cannot be defined without 
first defining life. Claude Bernard rejects jJL.defiilition 
of life as insufficient, and incompatible with experimental 
science. 



2 THE MECHANISM OF LIFE 

Some modern physiologists regard sensibility, others 
irritability, as the characteristic of life, and define life as the 
faculty of responding, by some sort of change, to an external 
stimulus. As in the case of movement, we have found by 
more attentive observation that this faculty also is universal 
in nature. There is no action without reaction ; an elastic 
body repels the body that strikes it. Every object in nature 
dilates with heat, contracts with cold, and is modified by the 
light which it absorbs. Everything in nature responds to 
exterior action by a change, and hence this faculty cannot be 
the characteristic of life. 

A distinguished professor of physiology was accustomed to 
teach that the disproportion between action and reaction was_ 
the characteristic of life. " Allow a gramme weight to fall on 
a nerve, and the muscle will raise a weight of ten grammes. 
This disproportion is the characteristic of life." But there is a 
much greater disproportion between action and reaction when 
the friction of a match blows up a powder factory, or the 
turning of a switch lights the lamps and animates the tram- 
ways and the motors of a great city. The disproportion 
between action and reaction is therefore no characteristic 
of life. 

The essential characteristic of life is often said to be 
nutrition the phenomenon by which a living organism 
absorbs matter from its environment, subjects it to chemical 
metamorphosis, assimilates it, and finally ejects the destructive 
products of metamorphosis into the surrounding medium. 
But this characteristic is also common to a great number of 
ordinary chemical reactions, so that we cannot call it peculiar 
to life. Consider, for instance, a fragment of calcium 
chloride immersed in a solution of sodium carbonate. It 
absorbs the carbonic ion, incorporates it into a molecule of 
calcium carbonate, and ejects the chlorine ion into the 
surrounding medium. 

It may be argued that this is merely a chemical process, 
since the substance which determines the reaction is also 
modified, the chloride of calcium changing into carbonate of 
calcium. But every living thing is also changing its chemical 



LIFE AND LIVING BEINGS 3 

constitution during every moment of its existence, it is this 
change which constitutes the process of senile involution. 
The substance of the child is other than that of the ovum, 
and the substance of the adult is not that of the child. Hence 
we cannot regard nutrition as the exclusive characteristic 
of life. 

Other authorities regard growth and organization as the 
essentials of life. But crystals also grow. It was said that the 
growth of a crystal differed from that of a living thing, in that 
the former grew by the addition of material from without 
the juxtaposition of bricks, as it were while the latter grew by 
intussusception, an introduction of fresh material into the 
substance of the organism. A crystal, moreover, was homo- 
geneous, while the tissues of a living being were differentiated 
such differentiation constituting the organization. At the 
present time, however, we recognize the existence of a great 
variety of purely physical productions, the so-called " osmotic 
growths, 1 ' which increase by a process of intussusception, and 
develop therefrom a marvellous complexity of organization and 
of form. Hence growth and organization cannot be considered 
as the essential characteristics of life. 

Since, then, we are totally unable to define the exact 
boundary which separates life from the physical phenomena of 
nature, we may fairly conclude that no such separation exists. 
This is in conformity with the " law of continuity, 11 the 
principle which asserts that all the phenomena of nature are 
continuous in time and space. Classes, divisions, and separa- 
tions are all artificial, made not by nature but by man. All 
the forms and phenomena of nature are united by insensible 
transition ; it is impossible to separate them, and in the 
distinction between living and non-living things we must 
content ourselves with relative definitions, which arc far from 
being precise. 

Life can only be defined as the sum of all phenomena 
exhibited by living beings, and its definition thus becomes 
a mere corollary to the definition of a living being. 

The true definition of a living being is that it is a trans- 
former of energy, receiving from its environment the energy 



4 THE MECHANISM OF LIFE 

which it returns to that environment under another form. All 
living organisms arc transformers of energy. 

A living organism is also a transformer of matter. It 
absorbs matter from its environment, transforms it, and 
returns it to its environment in a different chemical condition. 
Living things are chemical transformers of matter. 

Living beings are also transformers of form. They com- 
mence as a very simple form, which gradually develops and 
becomes more complicated. 

The matter of which a living organism is constituted con- 

c5 O 

sists essentially of certain solutions of crystalloids and colloids. 
To this we may add an osmotic membrane to contain the 
liquids, and a solid skeleton to support and protect them. 
Finally, it would seem that a colloid of one of the albuminoid 
groups is a necessary constituent of every living being. 

We may say, then, that a living being is a transformer of 
energy and of matter, containing certain albuminoid sub- 
stances, with an evolutionary form, the constitution of which 
is essentially liquid. 

A living being has but a limited duration. It is born, 
develops, becomes organized, declines and dies. Through all 
the metamorphoses of form, of substance, and of energy, 
informing the whole course of its existence, there is a certain 
co-ordination, a certain harmony, which is necessary for the 
conservation of the individual. This harmony we call Life. 
Discord is disease, the total cessation of the harmony is Death. 
When the form is profoundly altered and the substance changed, 
the transformation of energy no longer follows its regular course, 
the organism is dead. 

After death the colloids which have constituted the form 
of the living thing pass from their liquid state as " sols " into 
their coagulated state as "gels." The metamorphoses of 
form, substance, and energy still continue, but no longer 
harmoniously for the conservation of the individual, but in 
dis-harmony for its dissolution. Finally, the form of the 
individual disappears, the substance and the energy of the 
living being is resolved and dispersed into other bodies and 
other phenomena. 



LIFE AND LIVING BEINGS 5 

The results hitherto obtained from the study of life seem 
but inconsiderable when compared with the time and labour 
devoted to the question. Max Verworn exclaims, " Are we 
on a false track ? Do we ask our questions of Nature amiss, 
or do we not read her answers aright ? " 

Each branch of science at its commencement employs only 
the simpler methods of observation. It is purely descriptive. 
The next step is to separate the different parts of the object 
studied to dissect and to analyse. The science has now 
become analytical. The final stage is to reproduce the sub- 
stances, the forms, and the phenomena which have been the 
subject of investigation. The science has at last become 
synthetical. 

Up to the present time, biology has made use only of the 
first two methods, the descriptive and the analytical. The 
analytical method is at a grave disadvantage in all biological 
investigations, since it is impossible to separate and analyse 
the elementary phenomena of life. The function of an organ 
ceases when it is isolated from the organism of which it forms 
a part. This is the chief cause of our lack of progress in the 
analysis of life. 

It is only recently that we have been able to apply the 
synthetic method to the study of the phenomena of life. Now 
that we know that a living organism is but the arena for the 
transformation of energy, we may hope to reproduce the 
elementary phenomena of life, by calling into play a similar 
transformation of energy in a suitable medium. 

Organic chemistry has already obtained numerous victories 
in the same direction, and the rapid advance in the produc- 
tion of organic bodies by chemical synthesis may be considered 
the first-fruits of synthetic biology. 

A phenomenon is determined by a number of circumstances 
which we call its causes, and of which it is the result. Every 
phenomenon, moreover, contributes to the production of other 
phenomena which are called its consequences. In order there- 
fore to understand any phenomenon in its entirety, we must 
determine all its causes both qualitatively and quantitatively. 

Phenomena succeed one another in time as consequences 



6 THE MECHANISM OF LIFE 

one of another, and thus form an uninterrupted chain from 
the infinite of the past into the infinite of the future. A 
living being gathers from its entourage a supply of matter and 
of energy, which it transforms and returns. It is part and 
parcel of the medium in which it lives, which acts upon it, 
and upon which it acts. The living being and the medium 
in which it exists are mutually interdependent. This medium 
is in its turn dependent on its entourage, and so on from 
medium to medium throughout the regions of infinite 
space. 

One of the great laws of the universe is the law of 
continuity in time and space. We must not lose sight of this 
law when we attempt to follow the metamorphoses of matter, 
of energy and of form in living beings. Evolution is but the 
expression of this law of continuity, this succession of 
phenomena following one another like the links of a chain, 
without discontinuity through the vast extent of time and 
space. 

The other great universal law, that of conservation, applies 
with equal force to living and to inanimate things. This law 
asserts the uncreateability and the indestructibility of matter 
and of energy. A given quantity of matter and of energy 
remains absolutely invariable through all the transformations 
through which it may pass. 

We need not here discuss the question of the possible trans- 
formation of matter into ether, or of ether into ponderable 
matter. Such a transformation, if it exists, would have but 
little bearing on the phenomena of life. Moreover, it also 
will probably be found to conform to the law of conservation 
of energy. 

In marked contrast to the permanence of matter and of 
energy is the ephemeral nature of form, as exhibited by living 
beings. Function, since it is but the resultant of form, is 
also ephemeral. All the faculties of life are bound up with 
its form, a living being is born, exists, and dies with its 
form. 

The phenomena of life may in certain cases slow down 
from their normal rapidity and intensity, as in hibernating 



LIFE AND LIVING BEINGS 7 

animals, or be entirely suspended, as in seeds. This state of 
suspension of life, of latent life as it were, reminds us of a 
machine that has been stopped, but which retains its form 
and substance unaltered, and may be started again whenever 
the obstacle to its progress is removed. 

During the whole course of its life a living being is 
intimately dependent on its entourage. For example, the 
phenomena of life are circumscribed within very narrow limits 
of temperature. A living organism, consisting as it does 
essentially of liquid solutions, can only exist at temperatures 
at which such solutions remain liquid, i.e. between C. and 
100 C. Certain organisms, it is true, may be frozen, but their 
life remains in a state of suspension so long as their substance 
remains solid. Since the albuminoid substances which are a 
necessary component of the living organism become coagulated 
at 44 C., the manifestations of life diminish rapidly above this 
temperature. The intensity of life may be said to augment 
gradually as the temperature rises from to 40, and then to 
diminish rapidly as the temperature rises above that point, 
becoming nearly extinct at 60 C. 

Another condition indispensable to life is the presence of 
oxygen. Life, compared by Heraclitus to a flame, is a com- 
bustion, an oxydation, for which the presence of oxygen at a 
certain pressure is indispensable. There are, it is true, certain 
anaerobic micro-organisms which apparently exist without 
oxygen,, but these in reality obtain their oxygen from the 
medium in which they grow. 

Life is also influenced by light, by mechanical pressure, by 
the chemical composition of its entourage, and by other 
conditions which we do not as yet understand. In each case 
the conditions which are favourable or noxious vary with the 
nature of the organism, some living in air, some in fresh water, 
and others in the sea. 

Formerly it was supposed that the substance of a living 
being was essentially different from that of the mineral world, 
so much so that two distinct chemistries were in existence 
organic chemistry, the study of substances derived from bodies 
which had once possessed life, and inorganic chemistry, dealing 



8 THE MECHANISM OF LIFE 

with minerals, metalloids, and metals. We now know that a 
living organism is composed of exactly the same elements 
as those which constitute the mineral world. These are 
carbon, oxygen, hydrogen, nitrogen, phosphorus, calcium, iron, 
sulphur, chlorine, sodium, potassium, and one or two other 
elements in smaller quantity. It was formerly supposed that 
the organic combinations of these elements were found only 
in living organisms and could be fashioned only by vital 
forces. In more recent times, however, an ever increasing 
number of organic substances have been produced in the 
laboratory. 

Organic bodies may be divided into four principal groups. 

(1) Carbohydrates, including the sugars and the starches, all 
of which may be considered as formed of carbon and water. 

(2) FatSj which may be considered chemically as the ethers of 
glycerine, combinations of one molecule of glycerine and 
three molecules of a fatty acid, with elimination of water. 

(3) Albuminoids, substances whose molecules are complex, con- 
taining nitrogen and sulphur in addition to carbon, oxygen, 
and hydrogen. The albuminoid of the cell nucleus also 
contains phosphorus, and the haemoglobin of the blood 
contains iron. (4) Minerals or inorganic elements, such as 
chloride of sodium, phosphate of calcium, and carbonic acid. 
This group also includes water, which is the most important 
constituent, since it forms more than a moiety of the sub- 
stance of all living creatures. 

Wohler in 1828 accomplished the first synthesis of an 
organic substance, urea, one of the products of the decom- 
position of albumin. Since then a large number of organic 
substances have been prepared by the synthesis of their 
inorganic elements. The most recent advance in this direction 
is that of fimile Fischer, who has produced polypeptides having 
the same reactions as the peptones, by combining a number of 
molecules of the amides of the fatty acids. 

In the further synthesis of organic compounds the problems 
we have before us are of the same order as those already 
solved. There is no essential difference between organic and 
inorganic chemistry; living organisms are formed of the 



LIFE AND LIVING BEINGS 9 

same elements as the mineral world, and the organic com- 
binations of these elements may be realized in our laboratories, 
just as in the laboratory of the living organism. 

Not only so, but a living being only borrows for a short 
time those mineral elements which, after having passed through 
the living organism, are returned once again to the mineral 
kingdom from which they came. 

All matter has life in itself or, at any rate, all matter 
susceptible of incorporation in a living cell. This life is 
potential while the element is in the mineral state, and actual 
while the element is passing through a living organism. 

Mineral matter is changed into organic matter in its passage 
through a vegetable organism. The carbonic acid produced by 
combustion and respiration is absorbed by the chlorophyll of 
the leaves under the stimulus of light the oxygen of the 
carbonic acid being returned to the air, while the carbon is 
utilized by the plant for the formation of sugar, starch, 
cellulose, and fats. 

Thus plants are fed in great part by their leaves, taking 
an important part of their nourishment from the air, while 
by their roots they draw from the earth the water, the 
phosphates, the mineral salts, and the nitrates required for 
the formation of their albuminoid constituents. A vegetable 
is a laboratory in which is carried out the process of organic 
synthesis by which mineral materials are changed into organic 
matter. The first synthetic reaction is the formation of a 
molecule of formic aldehyde, CH 2 O, by the combination of a 
molecule of water with an atom of carbon. 

From this formic aldehyde, or formol, we may obtain all 
the various carbohydrates by simple polymerization, i.e. by 
the association of several molecules, with or without elimi- 
nation of water. Thus two molecules of formol form one 
molecule of acetic acid, 2CH 2 O C 2 H 4 O 2 . Three molecules 
of formol form a molecule of lactic acid, 3CH 2 O = C 3 H 6 O S . 
Six molecules of formol represent glucose and levulose, 
6CII 2 O = C 6 H 12 O 6 . Twelve molecules of formol minus one 
molecule of water form saccharose, lactose, cane sugar, and 
sugar of milk, l#CH 2 = C 12 II 22 O n + II 2 O 5 n times six mole- 



10 THE MECHANISM OF LIFE 

i cules of forinol minus one molecule of water, ??(C 6 H 10 O 6 ), 

i form starch and cellulose. 

Animals derive their nourishment from vegetables either 
directly, or indirectly through the flesh of herbivorous animals. 
The mineral matter, rendered organic in its passage through a 
vegetable growth, is finally returned by the agency of animal 
organisms to the mineral world again, in the form of carbonic 
acid, water, urea, and nitrates. Thus vegetables may be 
regarded as synthetic agents, and animals and microbes as 
_?L_ d^ony^itimi. Here also the difference is only 



_ 
relative, for in certain cases vegetables produce carbonic acid, 

while some animal organisms effect synthetic combinations. 
Moreover, there are intermediary forms, such as fungi, which 
possessing no chlorophyll are nourished like animals by 
organic matter, and yet like vegetables are able to manu- 
facture organic matter from mineral salts. 

The work of combustion begun by the animal organism 
is finished by the action of micro-organisms, who complete 
the oxydation the rc-mincralizatioii of the chemical substances 
drawn originally from the inorganic world by the agency of 
plant life. 

To sum up. Vegetables ^>btai n^ Jjiej r^ jiourisl imgnt. from 
mineral substances, which they reduce^ dc-oxydi/c 2 and ^charge 
with_ so^r_energy. Anin^j3iga^sms oij_the contrary oxydi/e, 
and micro-organisms complete the oxydation of these sub- 

. ______ . ______________ -n__ ----- . ------ JL---, ------------------------------ J. ------------------ ....... _ .. - - . - - 

stances, returning _them to the mineral world as watej, 
carbonates, .nitrate^ and sulphates. 

Thus matter circulates eternally from the mineral to the 
vegetable, fiom the vegetable to the animal world, and back 
again. The matter which forms our structure, which is to-day 
part and parcel of ourselves, has formed the structure of an 
infinite number of living beings, and will continue to pursue 
its endless reincarnation after our decease. 

Tll!?-S!^^ ss c y c k f Hfkjs ^k? an endless cycle of energy. 
The combination of carbon with water carried out by the 
agency of chlorophyll can only take place with absorption of 
energy. This energy comes directly from the sun, the red and 
orange light radiations b^HlJ-LJ 1 ^ 



LIFE AND LIVING BEINGS 1 1 

The arrest of vegetation during the winter months is due not 
so much to the lowering of temperature as to the diminution 
of the radiant energy received from the sun. In the same 
way shade is harmful to vegetation, since the radiant energy 
required for growth is prevented from reaching the plant. 

The energy radiated by the sun is accumulated and stored 
in the plant tissues. Later on, animals feed on the plants and 
utilize this energy, excreting the products of decomposition, 
i.e. the constituents of their food minus the energy contained 
in it. Thus the_ whole of the energy which animates living 



from the sun. To the sun also we owe all artificial heat, the 
energy stored up in wood and coal. We are all of us children 
of the sun. 

The radiant energy of the sun is transformed by plants 
into chemical energy. It is this chemical energy which 
feeds the vital activity of animals, who return it to the 
external world under the form of heat, mechanical work, 
and muscular contraction, light in the glow-worm, electricity 
in the electric eel. 

There is a marked difference between the forms affected 
by organic and inorganic substances. The forms of the 
mineral world are those of crystals geometrical forms, 
bounded by straight lines, planes, and regular angles. Livmg 
organisms, on the contrary, affect forms which are less regular 
curve( l surfaces and rounded aiigles. The physical reason 
for this difference in form lies in a difference of consistency, 
crystals being solid, whereas living organisms are liquids or 
semi - liquids. The liquids of nature, streams and clouds 
and dewdrops, affect the same rounded forms as those of 
living organisms. 

Living beings for the most part present a remarkable 
degree of symmetry. Some, like radiolarians and star-fish, 
have a stellate form. In plants the various organs often 
radiate from an axis, in such a manner that on turning the 
plant about this axis the various forms are superposed thrice, 
four, or more often five times in one complete revolution. 
It is remarkable how often this number five recurs in the 



12 THE MECHANISM OF LIFE 

divisions and parts of a living organism. In other cases the 
similar parts are disposed symmetrically on either side of a 
median line or plane, giving a series of homologous parts 
which are not superposable. 

The most important characteristic of a living being is 
its form. This is implicitly admitted by naturalists, who 
classify animals and plants in genera and species according 
to the differences and analogies of their form. 

All living beings are composed of elementary organizations 
called cells. In its complete state, a cell consists of a 
membrane or envelope containing a mass of protoplasm, in 
the centre of which is a nucleus of differentiated protoplasm. 
This nucleus may in its turn contain a nucleolus. In some 
cases the cell is merely a protoplasmic mass without a visible 
envelope, so that a cell may be defined as essentially a mass 
of protoplasm provided with a nucleus. 

A living organism may consist merely of a single cell, 
which is able alone to accomplish all the functions of life. 
Most living beings, however, consist of a collection of in- 
numerable cells forming a cellular association or community. 
When a number of cells are thus united to constitute a 
single living being, the various functions of life are divided 
among different cellular groups. Certain cells become 
specialized for the accomplishment of a single function, and 
to each function corresponds a different form of cell. It is 
thus easy to recognize by their form the nerve cells, the 
muscle cells which perform the function of movement, and 
the glandular cells which perform the function of secretion. 
The cells of a living being arc microscopic in size, and it 
is remarkable that they never attain to any considerable 
dimensions. 

In order that life may be maintained in a living organism, 
it is necessary that a continual supply of aliment should be 
brought to it, and that certain other substances, the waste- 
products of combustion, should be eliminated. In order to 
be absorbed and assimilated, the alimentary substances must 
be presented to the living organism in a liquid or gaseous 
state. Thus the essential condition necessary for the 



LIFE AND LIVING BEINGS 13 

maintenance ofMife _is__the J?Jltoet 2.? JL-liYljlS 5^lL-wlth 

? | i r i^ i it_5^ '_!ML\? id. r JQi e j^i 1 !*: ui^y-T- 4?iij^i^LlMU2iiiii ( ?. i L .of 

life _is the coiitact_ of t\vo different liquids. This is the 
necessary condition which renders possible the chemical ex- 
changes and the transformations of energy which constitute 
life. It is in the study of the phenomena of liquid contact 
and diffusion that we may best hope to pierce the secrets 
of life. The physics of vital action are the physics of the 
phenomena which occur in liquids, and the study of the 
physics of a liquid must be the preface and the basis of all 
inquiry into the nature and origin of life. 



CHAPTER II 

SOLUTIONS 

WK have seen that living beings are transformers of energy 
and of matter, evolutionary in form and liquid in consistency ; 
that they are solutions of colloids and crystalloids separated 
by osmotic membranes to form microscopic cells, or consisting 
merely of a gelatinous mass of protoplasm, Avith a nucleus 
of slightly differentiated material. The elementary pheno- 
menon of life is the contact of two different solutions. This 
is the initial physical phenomenon from which proceed all 
the other phenomena of life in accordance with the ordinary 
chemical and physical laws. Thus the basis of biological 
science is the study of solution and of the phenomena which 
occur between two different solutions, either in immediate 
contact or when separated by a membrane. 

A solution is a homogeneous mixture of one or more solutes 
in a liquid solvent. Before solution the solute or dissolved 
substance may be solid, liquid, or gaseous. 

Soliites ? or substances capable of solution, may^ be divided 
into t wo jjjissfis substances which are cjy^ble^jof crystal- 
. r 5II^U?J4s au d those which are incapable^ of 
n^ the jcpllqids. Crystalloids may be divided 

again into two classes, those whose solutions arc ioni/ablc and 

T p ._ .. 7 -- 

therefore conduct electricity, chJefly jj^ 
and those whose solutions are non-ioni/able and are there- 
fore non-conductors. These latter are for the most part 
crystalli/able substances of organic origin, such as sugars, 
urea, etc. 

Avogadro's law asserts that under similar conditions of 
temperature and pressure, equal volumes of various gases 



SOLUTIONS 1 5 

contain an equal number of molecules. Under similar 
conditions, the molecular weights of different substances have 
therefore the same ratio as the weights of equal volumes of 
their vapours. Hence if we fix arbitrarily the molecular 
weight of any one substance, the molecular weight of all 
other substances is thereby determined. The molecular weight 
of hydrogen has been arbitrarily fixed as two, and hence the 
molecular weight of any substance will be double its gaseous 
density when compared with that of hydrogen. 

Gramme- Molecule. A gramme-molecule is the molecular 
weight of a body expressed in grammes. Occasionally 
for brevity a gramme-molecule is spoken of as a " molecule. 1 ' 
Thus we may say that the molecular weight of oxygen is 
16 grammes, meaning thereby that there are the same 
number of molecules in 16 grammes of oxygen as there are 
atoms in 1 gramme of hydrogen. 

Concentration-. The concentration of a solution is the 
ratio between the quantity of the solute and the quantity of 
the solvent. The concentration of a solution is expressed 
in various ways. (a) The weight of solute dissolved in 
100 grammes of the solvent, (b) The weight of solute 
present in 100 grammes of the solution. (c) The weight 
of solute dissolved in a litre of the solvent, (d) The weight of 
solute in a litre of the solution. The most usual method is to 
give the concentration as the weight of solute dissolved in 
100 grammes or in one litre of the solvent. 

Molecular Concentration. Many of the physical and 
biological properties of a solution are proportional, not to 
its mass or weight concentration, but to its molecular con- 
centration, i. e. to the number of gramme-molecules of tlie. 
S( Zk l J*L Contained in a litre of the solution. Many physical 
properties are quite independent of the nature of the solute, 
depending only on its degree of molecular concentration. 

Normal Solution. A iigi;imxl_solutioii is one which contains 

j )er Ufare. A decinormal 



solution contains one-tenth of a gramme-molecule of the 
solute per litre, and a centi normal solution one-hundredth of 
a gramme -molecule. A normal solution of urea, for example, 



1 6 THE MECHANISM OF LIFE 

contains 60 grammes of urea per litre, while a normal 
solution of sugar contains 34 grammes of sugar per litre. 

The Dissolved Substance is a Gas. Van t' HofF, using the 
data obtained by the botanist Pfeffer, showed that the 
dissolved matter in a solution behaved ^exactly as if it were 
a gas. The analogy is complete in every respect. Like the 
gaseous molecules, the molecules of a solute are mobile with 
respect to one another. Like those of a gas, the molecules 
of a solute tend to spread themselves equally, and to fill 
the whole space at their disposal, i.e. the whole volume of 
the solution. The. 1 surface of the solution represents the 
vessel containing the gas, which confines it within definite 
limits and prevents further expansion. 

Osmotic Pressure. Like the molecules of a gas, the mole- 
cules of a solute exercise pressure on the boundaries of the 
space containing it. This osmotic pressure follows exactly the 
same laws jas jjaseous pressure. It has the same constants, and 
all the notions acquired by the study of gaseous pressure 
are applicable to osmotic pressure. Osmotic pressure is in fact 
the jgascous pressure of the molecules of the solute. 

When a gas dilates and increases in volume, its temperature 
falls, and cold is produced. Similarly, when a soluble substance 
is dissolved, it increases in volume, and the temperature of the 
liquid falls. This phenomenon is well known as a means of 
producing cold by a refrigerating mixture. 

The i_ phenomena of 'life are governed by the laws of gaseous 
pressure, since all these _pjienpnieii_a take place in solutions. 
The fLmdamental laws of biology are those of the distribution 
of subsj:ances_in solution, which is regulated by the laws of 
gaseous pressure, since all these laws are applicable also to 
osmotic pressure. 

Boyle's Law. When a gas is compressed its volume is 
diminished. If the pressure is doubled, the volume is reduced 
to one-half. The quantity V X P, that is the volume multiplied 
by the pressure, is constant. 

Gay-Lussac's Law. For a difference of temperature of 
a degree Centigrade all gases dilate or contract by ^f 3 of 
their volume at Centigrade. 



SOLUTIONS 1 7 

Daltoii's Law. In a gaseous mixture, the total pressure 
is equal to the sum of the pressures which each gas would exert 
if it alone filled the whole of the receptacle. 

Pressure proportional to Molecular Concentration. The 
above laws are completely independent of the chemical nature 
of the gas, they depend only on the number of gaseous 
molecules in a given space, i.e. on the molecular concentration. 
If we double the mass of the gas in a given space, we double 
the number of molecules, and we also double the pressure, 
whatever the nature of the molecules. We may also double 
the pressure by compressing the molecules of a gas, or of 
several gases, into a space half the original size. The 
molecular concentration of a gas, or of a mixture of gases, 
is the ratio of the number of molecules to the volume they 
occupy. The pressure of a gas or of a mixture of gases 
is proportional to its molecular concentration. This is a 
better and a shorter way of expressing both Boyle^s law 
and Daltoifs law. 

One gramme-molecule of a gas, whatever its nature, con- 
densed into the volume of 1 litre, has a pressure of 22*35 
atmospheres. Similarly one gramme-molecule of a solute, 
whatever its nature, when dissolved in a litre of water, has 
the same pressure, viz, 22 '35 atmospheres. 

Absolute Zero. According to Gay-Lussac's law, the volume 
of a gas diminishes by -g-j^ of its volume at C. for each 
degree fall of temperature. Thus if the contraction is the 
same for all temperatures, the volume would be reduced to 
zero at 273 C. This is the absolute zero of temperature. 
Temperatures measured from this point are called absolute 
temperatures, and are designated by the symbol T. If t 
indicates the Centigrade temperature above the freezing point 
of water, then the absolute temperature is equal to 2 + 273. 

The Gaseous Constant. Consider a mass of gas at C. 
under a pressure P o , with volume V . At the absolute 
temperature T, if the pressure be unaltered, the volume of 

V T 

this gas will be P~. Therefore the constant PV, the product 



"P V 

of the pressure by the volume, will be represented by 



273 



1 8 THE MECHANISM OF LIFE 

At the same temperature, but under another pressure 
P', the gas will have a different volume V'. Since, accord- 
ing to Boyle's law, PV is constant (P'V' = P V ), it will 

P V T P V 

still equal ~fr- - Therefore ~b~ is also constant. This 

f^tltJ """" """* /w I O - - "" 

quantity is called "the gaseous__ constant, 11 and if we 
represent it by the symbol R, we obtain the general formula 

PV = RT for all gases, or -^ = R. 

Suppose, for instance, we have a gramme-molecule of a 
gas at C. in a space of 1 litre. It has a pressure of 
22'35 atmospheres at 0C., or 273 absolute temperature. 

PV 1 v QQ'IZ 
Since PV = RT, R = ^===i^Jl ) ==-0819. This number 



'0819 is the numerical value of the constant R for all gases, 
volume being measured in litres and pressure in atmospheres. 

Substances in sol iition behave exactly like ^ases, they 
follow the same laws and have the same constants. All 
the conceptions which have been acquired by the study of 
gases are applicable to solutions, and therefore to the 
phenomena of life. The osmotic pressure ^f_jx__sj2lutiQn_js 
the force with which the molecules of the^ solute, like gaseous, 
molecules, strive to diffuse into space, and press on the limits 
which confine them, the containing vessel being represented 
by the surfaces of the solution. Osmotic pressure is measured 
in exactly the samc__wa^jj^jrag^ To measure 

steam pressure we insert a manometer in the walls of the 
boiler. In the same way we may use a manometer to measure 
osmotic pressure. We attach the tube to the walls of the 
porous vessel, allow the solvent to increase in volume under 
the pressure of the solute, and measure the rise of the liquid 
in the manometer tube. 

Pfcffer's Apparatus. Pfeffer has designed an apparatus 
for the measurement of osmotic pressure. It consists of a 
vessel of porous porcelain, the pores of which are filled with 
a colloidal solution of ferrocyanide of copper. This forms a 
semi-permeable membrane which permits the passage of water 
into the vessel, but prevents the passage of sugar or of any 



SOLUTIONS 19 

colloid. The stopper which hermetically closes the vessel is 
pierced for the reception of a mercury manometer. The 
vessel is filled with a solution of sugar and plunged in a bath 
of water. The volume of the solution in the interior of the 
vessel can vary, since water passes easily in either direction 
through the pores of the vessel. The boundary of the solvent 
has become extensible, and its volume can increase or diminish 
in accordance with the osmotic pressure of the solute. Under 
the pressure of the sugar water is sucked into the vessel like 
air into a bellows, the solution passes into the tube of the 
manometer, and raises the column of mercury until its pressure 
balances the osmotic pressure of the sugar molecules. 

Osmotic Pressure follows the Laws of Gaseous Pressure. 
This osmotic pressure is in fact gaseous pressure, and may 
be measured in millimetres of mercury in just the same way. 
We may thus show that osmotic pressure follows the laws 
of gaseous pressure as defined by Boyle, Dalton, and Gay- 
Lussac. The coefficient of pressure variation for change of 
temperature is the same for a solute as for a gas. The 
formula PV = RT is applicable to both. The numerical value 
of the constant 11 is also the same for a solute as for a gas. 
being "0819 for one gramme-molecule of either, when the 
volume is expressed in litres and the pressure in atmospheres. 
The formula PV = RT shows that for a given mass, with the 
same volume, th_Jrcs^^ 
absolute ten ipcra t irre. 

Osmotic Pressure of Sugar. A normal solution of sugar., 
containing 342 grammes of sugar per litre, has a pressure of 
22*35 atmospheres, and it may well be asked why such an 
enormous pressure is not more evident. The reason will be 
found in the immense frictional resistance to diffusion. 
Frictional resistance is proportional to the area of the surfaces 
in contact, and this area increases rapidly with each division 
of the substance. When a solute is resolved into its com- 
ponent molecules, its surface is enormously increased, and 
therefore the friction between the molecules of the solute and 
those of the solvent. 

Isotonic Solutions. Two solutions which have the same 



20 THE MECHANISM OF LIFE 

o^^tic j)r^sure are said to be isp-osmotic or isotonic. 
When comparing two solutions of different concentration, the 
solution with the higher osm otic grcssurc_ is said to be Ivy per - 
tqnic, and that with^ jhe jower osmotic pressure Irypotonic. 

Lowering of the Freezing Point. Pure water freezes at 
C. Haoult showed that the introduction of a non-iqnizable 
substance, such as .sugar or alcohol, lowers the freezing^omt 
of a solution in proportion to the molecular concentration o_f 
the solute. One gramme-molecule of the solute introduced 
into one litre of the solution lowers its temperature of 
congelation by 1'85C. Thus a normal solution of _any n on - 
ipnizablc substance in water freezes aj>^ 1 '85 C. The measure- 
ment of this lowering of the freezing point is called Cryoscopy, 
a method which is becoming of great utility in medicine. 

Cryoscopy of Blood. In order to determine the osmotic 
pressure of the blood at 37 C., i.e. 98*6 F., the normal 
temperature, we proceed as follows. On freezing the blood, 
we find that it congeals at "56. Its molecular concentration 

'56 

is therefore ----- = '30, or about one-third of a gramme- 

1 *oO 

molecule per litre. Its osmotic pressure at C. is therefore 
'3 x 2&'35 = 6 '7 atmospheres. The increase of pressure with 
temperature is the same as for a gas, viz. ^, or '00367 of its 
pressure at for every degree rise of temperature. The 
increase of pressure at 37 is therefore '00367 X 37 X 6*7= '9 
atmospheres. The total osmotic pressure at 37 is therefore 
6*7 + '9 = 7*6 atmospheres. 

Rise of Boiling Point. Water under atmospheric pressure 
boils at a temperature of 100 C. The addition of a solute 
whose solution does not conduct electricity, such as sugar, 
causes a rise in the boiling point proportional to the molecular 
concentration of that solute. 

Lowering of the Vapour Tension. Th^j^oi^jtoisioi^of 
a liquid is lowered by the addition of a solute. A liquid boils 
at the temperature at which its vapour tension equals thaj; 
of__the atmosphere. Since an aqueous solution of sugar at 
atmospheric pressure does not begin to boil at 100 C., it is 
manifest that its vapour tension is then less than that of the 



SOLUTIONS 2 1 

atmosphere. The addition of a solute such as sugar, whose 
solution is not ionizable, and therefore does not conduct 
electricity, lowers the vapour tension of the solution in 
proportion to the molecular concentration of the solute. 

Corresponding Values. We have thus found five properties 
of a solution which vary proportionally, so that from the 
measurement of any one of them we can determine the 
corresponding values of all the others. These are 

1. The Molecular Concentration. 

2. The Osmotic Pressure. 

3. The Diminution of Vapour Tension. 

4. The Raising of the Boiling Point. 

5. The Lowering of the Freezing Point. 

Cryoscopy. The usual method employed for the deter- 
mination of the molecular concentration and osmotic 
pressure of a solution is by cryoscopy the measurement of 
its temperature of congelation. A very sensitive thermometer 
is used, the scale of which extends over only 5 and is divided 
into hundredths of a degree. The liquid under examination is 
placed in a test tube, in which the bulb of the thermometer 
is plunged, and this is supported in a second tube with an air 
space all round it. The whole is then suspended to the under 
side of the cover of the refrigerating vessel, which may be 
cooled either by filling it with a freezing mixture, or by the 
evaporation of ether. During the whole of the operation the 
liquid is agitated by a mechanical stirrer. The first step is 
to determine the freezing point of distilled water. As the 
water cools the mercury gradually descends in the stem of 
the thermometer till it reaches a point below the zero mark 
at C. As soon as ice begins to form the mercury rises, at 
first rapidly and then more slowly, reaches a maximum, and 
finally descends again. This maximum reading is the true, 
point of congelation. The inner tube is then emptied, care 
being taken to leave a few small ice crystals to serve as centres 
of congelation for the subsequent experiment, thus avoiding 
supercooling of the solution. The process is then repeated 
with the solution under examination. The difference between 



22 THE MECHANISM OF LIFE 

/ rccx J 11 K PQJ n -t- s ..A 8 . th required " Jo \veri tig of the 



freezing point. " 

Cryoscopy is the method most used in biological research 
to determine molecular concentration. It has, however, some 
grave defects. It necessitates several cubic centimetres of the 
liquid under examination. It gives us the constants of the 
solution at the temperature of free/ing, which is far below 
that of life. Organic liquids are easily altered and are 
extremely sensible to minute differences of temperature, 
cryoseopy therefore gives us no information as to the con- 
stitution of solutions under normal conditions. It is desirable 
to have some other method of determining molecular con- 
centration and the other interdependent constants at the 
normal temperature of life. A much better method, were it 
possible, would be the direct determination of the vapour 
tension of the solutions under normal conditions of temperature 
and pressure. 

Molecular Lowering* of the Freezing Point. For every 
substance whose solution is not ionized and therefore does 
not conduct electricity, the lowering of the free/ing point is 
the same, vi/. 1'85 C. for each gramme-molecule of the solute 
per litre of the solution. 

Determination of the Molecular Concentration. In order 
to obtain the molecular concentration of a non-ionizable 
substance, we have only to determine the lowering of the 
freezing point. Let A be the lowering of the freezing point 
of any solution. Orijdividnig it by 1'85 ...(the lowering of the 
freezing point for a normal .solution), we obtain the lumibcr of 
in a litre of the solution. If n be the 



A 

number of gramme-molecules per litre, then n=- ------ . 

1 *Ot) 

Determination of the Osmotic Pressure. The osmotic 
pressure P of a solution may be obtained by multiply- 
ing its molecular concentration n_ by 22*35 atmospheres. 

P = n x 22-35 = -A: x 22-35. 
loo 

Determination of Molecular Weight. The lowering of the 
freezing point also enables us to calculate the molecular 



SOLUTIONS 23 

weight of any non-ionizable solute. Thus Bouchard has been 
able to determine by means of cryoscopy the mean molecular 
weight of the substances eliminated by the urine. A_wejjght x 
of the subs taiice is dissolved in a litre of .wateiy and _ thejowgr- 
ing of the free/ing point is observed. The vajue thus found 
divided by 1/85 gives us n, the number of gi'aninie-mplecules 
per_Jitre. The molecular weight M may be determined by 
dividing the original weight x by n. 

The study of osmotic pressure was begun by the Abbe 
Nollet ; and one of his disciples, Parrot, at an early date thus 
described its importance : " It is a force analogous in all 
respects to the mechanical forces, a force able to set matter in 
motion, or to act as a static force in producing pressure. It 
is this force which causes the circulation of heterogeneous 
matter in the liquids which serve as its vehicle. It is this 
force which produces those actions which escape our notice by 
their minuteness and bewilder us by their results. It is for 
the infinitely small particles of matter what gravitation is for 
heavy masses. It can displace matter in solution upwards 
against gravity as easily as downwards or in a horizontal 
direction. 1 " 

Thus the recognition of the fact that a substance in solution 
is really a gas, has at a single stroke put us in possession of 
the laws of osmotic pressure laws slowly and laboriously 
discovered by the long series of investigations on the pressure 
of gases. 

Osmotic pressure plays a most important role in the arena 
of life. It is found at work in all the phenomena of life. 
When osmotic pressure fails, life itself ceases^ 



CHATTER III 
ELECTROLYTIC SOLUTIONS 

Solutions wliicli conduct Electricity. The laws of solution 
which we have studied in the previous chapter apply only to 
those solutions, chiefly of organic origin, which do not conduct 
electricity. Solutions of electrolytes such as the ordinary 
salts, acids, and bases, which are ionized on solution, give values 
for the various constants of solution which do not accord with 
those required by theory. If, for instance, we take a gramme- 
molecule of an electrolyte such as chloride of sodium, and 
dissolve it in a litre of water, we find that the lowering of the 
free/ing point is nearly double the theoretical value of 1'85. 
The same holds good for the osmotic pressure, and for all the 
constants which are proportional to the molecular concentra- 
tion of the solute. The solution behaves, in each case, as if it 
contained more than one gramme-molecule of sodium chloride 
per litre. It behaves, in fact, as if it contained i times the 
number of molecules of solute originally introduced into it. 
If n be the original number of molecules, then it will apparently 
contain ri = m molecules. This law is universal for all 
electrolytic solutions; the theoretical value for their concen- 
tration, osmotic pressure, and all the proportional physical 

constants must be multiplied by this quantity, =-, which is 

n 

the ratio of the apparent number of the molecules present 
to the number originally introduced. 

A similar dissociation of the molecule is observed in the 
case of many gases. The vapour of chloride of ammonium, 
for instance, is decomposed by heat, and it may be shown 
experimentally that the increase of pressure on heating above 



ELECTROLYTIC SOLUTIONS 25 

that which theory demands, is due to an increase in the 
number of the gaseous molecules present. Some of the 
vapour particles are dissociated into two or more fragments, 
each of which plays the part of a single molecule. 

Arrhenius, in 1885, advanced the hypothesis that the 
apparent increase in the number of molecules of an electrolytic 
solution was also due to dissociation. This interpretation 
at once threw a Hood of light on a number of phenomena 
hitherto obscure. 

Coefficient of Dissociation. We have seen that in order 
to obtain values which accord with experiment we have to 
multiply the number of gramme-molecules of the solute 
by the coefficient i, which is called the Coefficient of Dis- 
sociation. 

This coefficient of dissociation, i, may be found by observing 
the lowering of the freezing point of a normal solution, and 

dividing it by T85. = _~ . 

The coefficient of dissociation varies with the degree of 
concentration of the solution, rising to a maximum when the 
solution is sufficiently diluted. 

If we know /, the coefficient of dissociation for a given 
solute, contained in a solution of a definite concentration, 
we can find n' 9 the number of particles present in a solution 
containing n gramme-molecules of the solute per litre, since 
n' = in. On the other hand, if from a consideration of its 
free/ing point and other constants we find that an electrolytic 
solution appears to contain ri gramme-molecules per litre, 

the real number of chemical gramme-molecules in one litre 

/ 

of the solution will be only =n. 

i 

Very concentrated solutions do not conform to these laws. 
In this they resemble gases, which as they approach their 
point of condensation tend less and less to conform to the 
laws of gaseous pressure. 

Electrolysis. If we take a solution of an acid, a salt, or a 
base, and dip into it two metallic rods, one connected to the 
positive and the other to the negative pole of a battery, we 



26 THE MECHANISM OF LIFE 

find that the metals or metallic radicals of the solution are 
liberated at the negative pole, while the acid radicals of the 
salts and acids and the hydroxyl of the bases are liberated at 
the positive pole. The liberated substances may either be dis- 
charged unchanged, or they may enter into new combinations, 
causing a series of secondary reactions. 

Electrolytes. Solutions which conduct electricity are called 
Electrolytes, and the conducting metallic rods dipping into 
the solution are the Electrodes. Faraday gave the names 
of Ions to the atoms or atom -groups liberated at either 
electrode. The ions liberated at the positive electrode are the 
Anions, and those at the negative electrode are the Cations. 
The only solutions which possess any notable degree of 
electrical conductivity are the aqueous solutions of the various 
salts, acids, and bases, and in these solutions only do we meet 
with those phenomena of dissociation which arc evidenced by 
anomalies of osmotic pressure, free/ing point and the like, 
anomalies which show that the solution contains a greater 
number of molecules than that indicated by its molecular 
concentration. These anomalies are due to dissociation, the 
division of some of the molecules into fragments, each of 
which plays the part of a separate molecule, contributing its 
quota to the osmotic tension and vapour pressure of the 
solution, in fact to all the phenomena which are dependent 
on the degree of molecular concentration. The electrical 
conductivity of a solution is therefore proved to be dependent 
on its molecular dissociation. 

Arrheniufi' Theory of Electrolysis. In 1885, Arrhenius 
brought forward his theory of the transport of electricity by 
an electrolyte. According to this hypothesis, the electric 
current is carried by the ions, the positive charges by the 
cations, and the negative charges by the anions. In virtue 
of the attraction between charges of different sign, and 
repulsion between charges of like sign, the cations are 
repelled by the positive charge on the anode, and attracted 
by the negative charge on the cathode. Similarly the 
anions are repelled by the cathode and attracted by the 
anode. 



ELECTROLYTIC SOLUTIONS 27 

An electrolytic solution contains three varieties of particles, 
positive ions or cations, negative ions or anions, and un- 
dissociated neutral molecules. The molecular concentration 
of such a solution, with the corresponding constants, depends 
on the total number of these particles, I.e. the sum of the ions 
and the undissociated neutral molecules. We may indicate 

an ion by placing above it the sign of its electrical charge, one 

+ - 

sign for each valency. Thus Na and Cl indicate the two ions 

++ 
of a salt solution ; Cu and S() 4 the two ions of a solution 

of sulphate of copper. A point is sometimes substituted for 
the -|- sign, and a comma for the sign. Thus Na' and (T ; 
Cu'-and SO 4 " 

My friend T)r. Lewis Jones has given a very vivid picture 
of the processes which go on in an electrolytic solution 
when an electric current is passing. He compares an electro- 
lytic cell to a ballroom, in which are gyrating a number of 
dancing couples, representing the neutral molecules, and a 
number of isolated ladies and gentlemen representing the 
anions and cations respectively. If we suppose a mirror 
at one end of the ballroom and a buffet at the other, 
the ladies will gradually accumulate around the mirror, and 
the gentlemen around the buffet. Moreover, the dancing 
couples will gradually be dissociated in order to follow this 
movement. 

Degree of Dissociation. The degree of dissociation is the 
fraction of the molecules in the solution which have under- 
gone dissociation. Let n be the total number of molecules of 
the solute, and n the number of dissociated molecules. Then 

~ will represent the degree of dissociation. Let Jc be the 



n 



number of ions into which each molecule is split. Then 

a = 71 , i.e. the degree of dissociation is the ratio of the 
nk 

number of ions actually present in a solution to the number 
which would be present if all the molecules of the solute were 
dissociated. 

Let n be the total number of particles present in a solution 



28 THE MECHANISM OF LIFE 

containing n molecules, each of which is composed of Jc ions. 
Then if a is the degree of dissociation, 



- = 1 + (*-!) = . 
n 

We thus obtain i the coefficient of dissociation, in terms 
of the degree of dissociation a and the number of ions in 
each molecule k. 

If there is no dissociation, i.e. if = (), then n' = n, and 
i = 1. If all the molecules are dissociated, a = 1, and i = k. 

Faraday's Law. Faraday found that the quantity of 
electricity required to liberate one gramme-molecule of any 
radical is 96*537 coulombs for each valency of the radical. 

Electrochemical Equivalent. The electrochemical equivalent 
of a radical is the weight liberated by one coulomb of electricity. 
It is equal to the molecular weight of the ion, divided by 
96'537 times its valency. 

Electrolytic Conductivity. The conductivity of an electro- 

lyte is the inverse of its resistance. C= ~. 

For a given difference of potential the conductivity of 
an electrolyte is proportional to the number of ions in unit 
volume, the electrical charge on each ion, and the velocity of 
the ions. 

The specific conductivity A of an electrolyte is the 
conductivity of a cube of the solution, each face of which is 
one square centimetre in area. The molecular conductivity of 
an electrolyte is the conductivity of a solution containing one 
gramme-molecule of the substance placed between two parallel 
conducting plates, one centimetre apart. The molecular 
conductivity is independent of the volume occupied by the 
gramme-molecule of the solute, depending only on the degree 
of dissociation. The molecular conductivity U is equal to the 
product of V, the volume of the molecule, by A, its specific 

conductivity. U = VA. Whence A=- r , i.e. the specific 



ELECTROLYTIC SOLUTIONS 29 

conductivity equals the molecular conductivity divided by 
the volume. 

The conductivity of an electrolyte is proportional to the 
number of ions in a volume of the solution containing one 
gram me- molecule. Let M w be the conductivity for complete 
dissociation and M v the molecular conductivity at the volume 

V. Then - = l ' =~-=a, the degree of dissociation. This 
M^ -iik n 

is OstwaWs law, which says that the degree of dissociation is 
equal to the ratio of conductivity when the gram me- molecule 
occupies a volume V, to its conductivity when the solution is 
so dilute that dissociation is complete. Hence the degree 
of dissociation may also be determined by comparing the 
electrical conductivities of two solutions of different degrees 
of concentration. 



SO, SO, SO, 

+ 4- +4- + + 

Cu Cu Cu 



SO, SO, S0 4 



Cu Cu Cu 



FIG. i. Before the passage of the current. 



SO 4 

++ 

Cu Cu Cu Cu 



S0 4 S0 4 SO 4 S0 4 SO. 

++ ++ 
Cu Cu 



FIG. 2. After the passage of the current. 

Velocity of the Ions. If the electrolytic cell is divided into 
two segments by means of a porous diaphragm, we shall find 
after a time an unequal distribution of the solute on the two 
sides. For instance, with a solution of sulphate of copper, 
after the current has passed for some time there will be a 
diminution of concentration in the liquid on both sides of the 
diaphragm, but the loss will be very unequally divided. Two- 
thirds of the loss of concentration will be on the side of the 
negative electrode and only one-third on the positive side. 
In 1853, Hittorf gave the following ingenious explanation of 
this phenomenon : 



30 THE MECHANISM OF LIFE 

Fig. 1 represents an electrolytic vessel containing a solution 
of sulphate of copper, the vertical line indicating a porous 
partition separating the vessel into two parts. Fig. 2 shows 
the same vessel after the passage of the current. The acid 
radical has travelled twice as fast as the metal. For each 
copper ion which has passed through the porous plate towards 
the cathode two acid radicals have passed through it towards 
the anode. Three ions have been liberated at either electrode, 
but in consequence of the difference of velocity with which 
the positive and the negative ions have travelled, the negative 
side of the vessel contains only one molecule of copper sulphate 
and has lost two-thirds of its molecular concentration, while 
the positive side contains two molecules of copper sulphate 
and has only lost one-third of its concentration. This proves 
clearly that the ions move in different directions with different 
velocities. Let u be the velocity of the anions, and v the 
velocity of the cations. Let n be the loss of concentration at 
the cathode, and 1 n the loss of concentration at the anode. 

Then - = --, i.e. the loss of concentration at the cathode is 
v 1 n 

to the loss of concentration at the anode as the velocity of 
the anions is to that of the cations. Hence by measuring the 
loss of concentration at the two electrodes, we have an easy 
means of determining the comparative velocity of different ions. 
In 1876, Kohlrausch compared the conductivity of the 
chlorides, bromides, and iodides of potassium, sodium, and 
ammonium respectively. He found that altering the cation 
did not affect the differences of conductivity between the 
three salts, thus showing that these differences of conductivity 
were dependent on the nature of the anion only, and not on 
the particular base with which it was combined. The difference 
of conductivity between an iodide and a bromide, for example, 
is the same whether potassium, sodium, or ammonium salts 
are compared. A similar experiment has been made with a 
scries of cations combined with various anions. The difference 
of conductivity of the salts in the series is the same whichever 
anion is used, i.e. the difference of conductivity between potas- 
sium chloride and sodium chloride is the same as that between 



ELETCROLYTJC SOLUTIONS 31 

potassium bromide and sodium bromide. Hence we may con- 
clude that the conductivity of any salt is an ionic property. 

KohlrauscK's law may be expressed by the formula c = 
r/(?/ + t>), where c is the conductivity of the salt, d the degree 
of dissociation, i.e. the fraction of the electrolyte broken up 
into ions, and u and v the velocity of the anions and cations 
respectively. When all the molecules of the electrolyte arc 
dissociated, </ = !, and the formula becomes c m = ii + v. 

As we have already seen, a salt is formed by the union of 
a metal M with an acid radical R. Potassium sulphate, K 2 SO 4 , 
consists of the metal K 2 and the acid radical SO 4 . Ammonium 
chloride, NII 4 C1, consists of the basic radical NII 4 and the 
acid radical Cl. The various acids may be considered as salts 
of the metal hydrogen. Thus sulphuric acid, II 2 SO 4 , is the 
sulphate of hydrogen. Bases may be considered as salts 
with the hydroxyl group, OH, replacing the acid radical. 
Thus potash, KOH, is the hydroxyl of potassium. The various 
electrolytic combinations may be represented by the following 
symbols : 

Salts = Mil. 
Acids = 1111. 
Bases = MOH. 

The various chemical reactions of an electrolyte arc all 
ionic reactions, the chemical activity of an electrolytic solution 
being proportional to its electric conductivity, i.e. the degree 
of dissociation of its ions. The acidity of an electrolytic 

solution is due to the presence of the dissociated ion II, and 
its strength is determined by the concentration of these free 
hydrogen ions. Hence the greater the degree of dissociation 
the stronger the acid. 

The basic character of a solution is determined by the 

presence of the hydroxyl radical OH. The greater the con- 
centration of the hydroxyl ions, i.e. the greater the dissociation, 

the stronger is the base. 

+ - 

The ions H and OH are of special importance, since they 

are the ions of water, H 2 O = H + OH. The degree of dissocia- 



32 THE MECHANISM OF LIFE 

tion of pure water is but small. Water is, however, the most 
important of all the various agents in the chemical reactions 
of life, since a large number of organic substances are de- 
composed by water by a process of hydrolysis, and a vast 
number of organic substances are but combinations of carbon 

with the ions H and OH, their diversity being due to variations 
in the relative proportions and grouping. 

The Chemical, Therapeutic, and Toxic Actions of Ions. The 
chemical, therapeutic, antiseptic, and toxic actions of electro- 
lytic solutions are almost exclusively due to ioni/ation. Take, 
for instance, a solution of nitrate of silver in which the addition 
of chlorine produces a white precipitate of chloride of silver. 
This precipitate occurs only when the solution added is one 

such as NaCl, where the chlorine is present as the free ion Cl. 
No such precipitate is produced in a solution of chlorate of 
potassium or chloracetic acid, where the chlorine is entangled 
in the complex ion C1O 3 or C 2 IT 3 C1O 2 . 

Since, then, the toxic and pharmacological properties of an 
electrolyte depend entirely on the ionic grouping, it behoves 
the physician and the biologist to study the structure and 
grouping of the ions in a molecule, rather than that of the 
atoms. Consider for a moment the totally different properties 
of the phosphides and the phosphates. The former are ex- 
tremely toxic, while the latter are perfectly harmless. There 
is not the slightest analogy between their actions on the 
living organism. On the other hand, all the phosphides pro- 
duce the same toxic and therapeutic effects, whatever the 
cation with which they are united. Their toxic properties 

are derived from the presence of the free phosphorus ion P. 
The phosphates contain phosphorus in the same proportion 
as the phosphides, but this phosphorus is harmlessly entangled 

in the complex ion PO 4 , whose properties are absolutely 

different from those of the ion P. 

The above considerations apply equally to the chlorides 
and chlorates, the iodides and iodates, the sulphides and 
sulphates, and in general to all chemical salts. 



ELECTROLYTIC SOLUTIONS 33 

The question has an intimate bearing on practical pharma- 
cology. When we prescribe a cacodylate or an amylarsinate, 
we are not prescribing an arsenical treatment whose effects 
can be compared with those of an arsenide, an arsenite, or 
an arsenate. This fact is sufficiently indicated by the difference 
in the toxic doses of the different salts. Each variety of 
arsenical ion has its own special physiological and therapeutic 
properties. We do not expect to obtain the results of a 
ferruginous treatment from the administration of a ferrocyanide 
or a ferricyanide. Both contain iron, it is true, but neither 

+ -H- 

possess the properties of the cation Fe, but rather those of the 
complex anion of which they form a part. 

We have already said that most of the therapeutic, toxic, 
and caustic actions of an electrolyte arc due to ionic action, 
and the substances can therefore have no toxic action unless 
they are dissociated. Many of the solvents employed in 
medicine, such as alcohol, glycerine, vaseline, and chloroform 
dissolve the electrolytes but do not dissociate them into ions, 
and these solutions therefore do not conduct electricity. Such 
solutions have no therapeutic action. With the absence of 
dissociation all the ionic toxic and caustic effects also disappear 
entirely, and only re-appear as the water of the tissue is able 
slowly to effect the necessary dissociation. 

Carbolic acid dissolved in glycerine is hardly caustic and 
but very slightly toxic. We have met with several instances 
in which a tablcspoonful of carbolized glycerine, in eq ual parts, 
has been swallowed without any ill effect, either caustic or 
toxic, whereas the same dose dissolved in water would have 
been fatal. This absence of dissociation has enabled the 
surgeon Menciere to inject carbolic and glycerine in equal 
proportions into the larger joints, the part being subsequently 
washed out with pure alcohol. Thus by employing vaseline, 
oil, or glycerine as a solvent, and avoiding the access of water, 
we are able to use electrolytic antiseptics in very concen- 
trated form. Their action is brought out very slowly, as the 
water of the organism effects the necessary dissociation of the 
electrolyte. 
3 



34 THE MECHANISM OF LIFE 

Since all chemical, toxic, and therapeutic actions are ionic, 
they are proportional to the degree of ionic concentration, i.e. 
to the number of ions in a given volume. The only point of 
importance, that which determines their activity, whether 
chemical or therapeutic, is the degree of ionization or dissocia- 
tion. For example, all acids have the same cation H. They 
have all identical properties, but they differ widely in the 
intensity of their action. There are weak acids such as 
acetic acid, and strong acids like sulphuric acid. The 
stronger acids are those which are more thoroughly dissociated, 

and in which the ion H is very concentrated ; whereas the 

feeble acids are but slightly dissociated, so that the ion H is 
less concentrated. 

Paul and Kronig have shown that the bactericidal action 
of different salts also varies with their degree of dissociation, 
i.e. with the concentration of the active ions. They made a 
series of observations on the bactericidal action of various 
salts of mercury, the bichloride, the bibromide, and the 
bicyanide, on the spores of Bacillus anihracls. The following 
results were obtained from a comparison of solutions con- 
taining 1 gramme-molecule of the salt in 64 litres of water. 
With the bichloride solution, after exposure to the solution 
for twenty minutes, only 7 colonies of the bacillus were 
developed. After exposure to a similar solution of the 
bibromide the number of colonies was 34. The antiseptic 
action of the bichloride was therefore five times as great as 
that of the bibromide. The bicyanide of mercury, however, 
even when four times as concentrated, permitted the growth 
of an enormous number of colonies, showing that it had no 
appreciable antiseptic action whatever. Nevertheless, the 
proportion of Hg is the same in all the solutions, and if there 
were any difference one would naturally expect that the 

ion Cy would be more toxic than Cl or Br. The real 
condition which varies in these solutions and determines their 
activity is the degree of dissociation. The whole of the 

antiseptic property resides in the ion Hg. This ion is very 



ELECTROLYTIC SOLUTIONS 35 

concentrated in the highly dissociated solution HgCl 2 , less 
concentrated in the less ionized solution HgBr 2 , and exceed- 
ingly dilute in the HgCy 2 , which is hardly ionized at all. 

What is true of the bactericidal action of the salts of 
mercury is equally true of their therapeutic effect. It is a great 
mistake to estimate the medicinal activity of a solution of a 
salt of mercury, or indeed of any electrolytic solution, simply 
by its degree of molecular concentration. The important 
point is the degree of dissociation, which is the only true 
measure of its activity. In the intramuscular injection of 
mercury salts it is by no means a matter of indifference what 
salt we employ. A salt should be used such as the bichloride 
or the biniodide, which is easily dissociated. Other salts are 
often employed because they occasion less pain at the site of 
injection ; but the pain is a sign of the degree of activity of 
the preparation. The pain, it is true, may be avoided by 
using a salt which is less easily dissociated, or in which the 
mercury is bound up in a complex ion, but by so doing we 
diminish the efficacy of the remedy. It is moreover quite easy 
to diminish, or even entirely to suppress, the pain, by using a 
very dilute solution of an active ionized salt. A one-half per 
cent, or even one-quarter per cent, solution of the bichloride 
or biniodide of mercury may be injected very slowly in 
sufficient quantity without producing the slightest discomfort. 
Local action depends entirely on ionic concentration. One 
drop of pure sulphuric acid will destroy the skin, whereas the 
same amount if diluted in a tumblerful of water will furnish 
a refreshing drink. 



CHAPTER IV 

COLLOIDS 

As we have already seen, living organisms are formed essentially 
of liquids. These liquids are solutions of crystallizable sub- 
stances or crystalloids, and non-crystalli/able substances or 
colloids a classification which we owe to Graham. 

The liquids are the most important constituents of a 
living organism, since they are the seat of all the chemical 
and physical phenomena of life. The junction of two liquids 
of different concentration is the arena in which takes place 
both the chemical transformation of matter and the correlative 
transformation of energy. In a former chapter we have passed 
in review the class of crystalloids, we will now turn our attention 
to the characteristic properties of colloids. 

Colloids. Colloids differ from crystalloids in that they 
do not form crystals from solution, being completely 
amorphous when in the solid state. The solution of a 
colloid solidifies in the same form which it possessed in the 
liquid state, the solvent being enclosed in the meshes of a sort 
of network formed by the solute. This form is approximately 
retained even after the water has evaporated by drying, the 
passage from the liquid state of solution to the solid state being 
effected through a series of intermediary states, such as a clot, 
coagulum, or jelly. This passage from the state of solution 
into a state of jelly is called coagulation. Some colloids, such 
as gelatine, coagulate with cold ; while others, such as egg- 
albumin, coagulate with heat. Some, like the cascine of milk, 
require the addition of certain chemical substances to set up 
coagulation ; while still others, such as the fibrin of blood, appear 
to coagulate spontaneously. The physical phenomena of 



COLLOIDS 37 

coagulation are still but little understood. In some cases it 
is a reversible phenomenon, thus gelatine coagulated by cold is 
redissolved by heat ; whereas with other colloids the process 
is irreversible, albumin coagulated by heat is not redissolved 
on cooling. 

Colloids in a state of coagulation have a vacuolar or sponge- 
like structure. The solvent is imprisoned in the vacuoles of 
the clot, and is expelled little by little by its retraction. 
Colloids diffused in water are usually called colloidal solutions, 
but they are not true solutions. Such a pseudo-solution of a 
colloid is called a " sol," while a colloid in a state of coagula- 
tion is called a "gel." Colloidal solutions spread but little, 
diffuse very slowly in the liquids of the body, and cannot 
penetrate organic membranes. 

Colloidal solutions diffuse light, unlike crystalloid solutions, 
which are transparent. We all know how the trajectory of a 
beam of sunlight through a darkened room is rendered visible 
by the particles of dust. In the same way if a colloidal solution 
is illuminated by a transverse ray of light, the light is diffused 
by the molecules of the colloid in semi-solution, and the liquid 
appears faintly illuminated on a dark background. The light 
diffused by a colloidal solution is polarized, which shows that 
it is reflected light. 

Siedentopf and Sigmondy have applied this principle of 
lateral illumination on a dark background to the construction 
of the ultra-microscope. With the aid of this instrument 
we may not only see, but count the particles in a colloidal 
solution, which is in reality merely a pseudo-solution or 
suspension, in contradistinction to the true solution of a 
crystalloid. 

Colloidal solutions possess only a very feeble osmotic 
pressure. The lowering of the freezing point and the other 
corresponding constants are also quite insignificant. This 
arises from the fact that the molecules of a colloid are 
extremely large when compared with those of a crystalloid. 
For example let us take colloidal substance whose molecular 
weight is 2000. A solution containing 40 grammes per litre 
would have an osmotic pressure only one-fiftieth of that of a 



38 THE MECHANISM OF LIFE 

solution of similar strength of a crystalloid whose molecular 
weight was 40. 

Not only so, but on measuring the molecular concentration, 
the osmotic pressure, and the other constants of a colloidal 
solution, we find values even lower than those which we should 
expect from a consideration of its molecular weight. This is 
probably due to the tendency of a colloid to polymerization, 
i.e. to form groups or associations of molecules. Suppose, for 
instance, that the molecules of a colloidal solution are aggregated 
into groups of ten. Since each group plays the part of a 
simple molecule, the osmotic pressure will be ten times less 
than that corresponding to the quantity of the solute present. 
Such a group of molecules is called by Naegeli a " micella." 

Similar phenomena of aggregation may be observed in the 
molecules of many inorganic substances. The molecule of 
iodine, for example, is monatomic at 1200 C., but becomes 
diatomic at the ordinary temperature. Sulphur at 860 C. is 
a gas with a vapour density of Q '%, while at 500 C. its vapour 
density rises to 6 '6. In both of these cases two or more 
molecules of the element have been condensed into one as a 
result of the fall of temperature. 

We frequently find that two successive cryoscopic observa- 
tions on the freezing point of the same colloidal solution 
will vary. This is due to the extreme sensitiveness of the 
micellae, which absorb or abandon their extra molecules under 
the slightest influence. This mobility in the constitution 
of the micellae appears to be one of the principal causes of 
the peculiar properties of colloidal solutions. 

The phenomenon of polymerization appears to be reversible. 
The micellae are formed under certain conditions, and are 
disintegrated when these conditions are removed. The 
osmotic pressure varies in the same manner, diminishing with 
polymerization and augmenting with the disintegration of the 
micellae. One may easily understand what an important role 
is played by this alternate polymerization and disintegration 
in the phenomena of life. 

Most colloidal substances are precipitated from their solu- 
tions by the addition of very small quantities of electrolytic 



COLLOIDS 39 

solutions. Non-electrolytic solutions do not appear to provoke 
this precipitation. This is not a chemical action, for an 
exceedingly small quantity of an electrolyte is able to 
precipitate an indefinite cjuantity of the colloid. The pre- 
cipitation is probably due to the electric charges carried by 
the dissociated ions of the electrolytes. 

When an electric current is passed through a colloid 
solution, the course of the molecules of the colloid is some- 
times towards the cathode and sometimes towards the anode, 
according to the nature of the colloid and of the solvent. 

o 

This displacement would appear to indicate a difference of 
electric potential between the molecules of the colloid and 
those of the solvent. Hardy has shown that in an alkaline 
solution the molecules of albumin travel towards the anode, 
while in an acid solution they travel towards the cathode. 

Metallic Colloids. Carey Lea and afterwards Crede suc- 
ceeded in obtaining silver in colloidal solution by ordinary 
chemical means. Professor Bredig has introduced a more 
general method of obtaining a number of metals in colloidal 
solutions in a state of great purity. He causes an electric 
arc to pass between two rods of the metal immersed in 
distilled water. The cathode is thus pulverized into a very 
fine powder which rests in suspension in the liquid, constitut- 
ing a colloidal solution. Bredig has in this way prepared 
sols of platinum, palladium, iridium, silver, and cadmium. 

Catalytic Properties of Colloids. Catalysis is the property 
possessed by certain bodies of initiating chemical reaction. 
The mass of the catalyzing body has no definite proportion to 
that of the substances entering into the reaction, and the 
appearance of the catalyzer is in no way altered by the 
reaction. 

Ostwald has shown that catalysis consists essentially in the 
acceleration or retardation of chemical reactions which would 
take place without the action of the catalyzer, but more 
slowly. 

Catalytic reactions are very numerous in chemistry. The 
inversion of sugar by acids, the etherization of alcohol by 
sulphuric acid, the decomposition of hydrogen peroxide by 



40 THE MECHANISM OF LIFE 

platinum black are all instances of catalysis. Fermentation 
by means of a soluble ferment or diastase, a phenomenon 
which may almost be called vital, is also a catalytic action. 
The action of pepsin, of the pancreatic ferment, of /ymase, and 
of other similar ferments has a great analogy with the purely 
physical phenomenon of catalysis. The diastases are all 
colloids, and so are many other catalyzers. 

A cataly/er is a stimulus which excites a transformation of 
energy. The cataly/er plays the same role in a chemical 
transformation as does the minimal exciting force which sets 
free the accumulation of potential energy previous to its 
transformation into kinetic energy. A cataly/cr is the friction 
of the match which sets free the chemical energy of the 
powder maga/ine. 

Bredig has studied the catalytic decomposition of hydrogen 
peroxide by metallic colloids prepared by his electric method. 
He found that 1 atom -gram me of colloidal platinum gives 
a sensible catalytic effect when diluted with 70 million 
litres of water. Caustic soda and other chemical substances 
inhibit the catalytic action of colloidal platinum in the same 
way as they inhibit the fermenting action of diastase. The 
curve of decomposition of hydrogen peroxide by colloidal 
platinum may be compared with the curve of fermentation by 
emulsin. Both are equally affected by the addition of an 
alkali. Many other chemical and physical agents have a 
similar inhibitory action on the catalysis of colloidal metals 
and on diastasic fermentation. Thus a mere trace of sul- 
phuretted hydrogen or hydrocyanic acid will paralyse the 
action of a colloidal metal, just as it does that of a ferment. 
This is what Bredig calls the poisoning of metallic ferments. 

We may hope that the further study of catalysis, a purely 
physico-chemical phenomenon, may throw more light on the 
mechanism of diastasic fermentation, which is essentially a vital 
reaction. 

It must not be forgotten that all classification is artificial 
and arbitrary, and only to be used as long as it facilitates 
study. This observation is particularly applicable to the 
classification of substances into crystalloids and colloids. 



COLLOIDS 41 

There is no sharp line between the two groups, the passage is 
gradual, and it is impossible to say where one group ends and 
the other begins. Many colloids such as haemoglobin are 
crystalli/able, and many cry stalli /able substances are coagul- 
able. Many substances appear at one time in the crystalloid 
state and at another time in the colloidal state, so that instead 
of dividing substances into colloids and crystalloids, we should 
rather consider these expressions as denoting different phases 
assumed by the same substance. 

In order to define clearly our various classes and divisions, 
we are apt to exaggerate slight differences of properties or 
composition. We say that colloids have no osmotic pressure, 
whereas in fact the osmotic pressure of the colloids though 
feeble plays a very important part in the phenomena of life. 

So in other departments of science a factor which is 
almost infinitesimal may yet exercise a vast influence on the 
results. It is by infinitesimal variations of pressure, a 
thousandth of a millimetre or less, that we obtain the various 
degrees of penetration in the Rontgen rays. 

The division into solutions and pseudo-solutions or sus- 
pensions is also an arbitrary one. A true solution is also 
a suspension of the molecules of the solute. There is no 
essential difference between a solution and a suspension, but 
only a difference in the si/e of the molecules, or agglomerations 
of molecules, in one case so small as to be transparent, and in 
the other case just big enough to diffuse light. There are 
moreover many properties common to colloidal solutions and 
suspensions of fine powders, such as kaolin, mastic, charcoal, or 
Indian ink. These particles in suspension are precipitated by 
solutions of electrolytes in a manner similar to the coagulation 
of colloids. 

The surface of every liquid is covered by a very thin layer, 
a sort of membrane slightly differentiated from the rest 
of the liquid. This membrane may be a chemical one, a 
pellicular precipitate like that which is formed by the contact 
of two membranogenous liquids. On the other hand, the 
membrane may not differ from the subjacent liquid in 
chemical composition, but only in physical properties. If we 



42 THE MECHANISM OF LIFE 

consider the molecules in the middle of a liquid, each molecule 
is subjected to the cohesive attraction of molecules on every 
side, attractions which neutralize one another. At the surface 
of the liquid, however, there are quite other conditions of 
equilibrium. There each molecule is drawn downwards 
towards the centre of the liquid, and there is no compensating 
attraction in an opposite direction. The resultant pressure 
is normal to the surface of the liquid, and is mechanically 
equivalent to an elastic membrane which tends to diminish 
the surface, and hence the volume of the liquid. We may 
therefore regard this surface tension as acting the part of a 
veritable physical membrane. 

There is a still further differentiation of the surface of a 
liquid. When the liquid is not a simple one, but complex 
as in a solution, we find that the concentration of the solute 
is greater at the surface than in the interior. This is the 
so-called phenomenon of " adsorption," which is another cause 
for the production of a physical membrane covering the 
surface of a liquid. 

Substances in a colloidal state have a great tendency to 
form these chemical or physical membranes at the point of 
contact between the colloidal solute and the solvent. This 
is probably the reason why the coagulum of a colloidal liquid 
usually presents a vacuolar or spongy structure. 



CHAPTER V 
DIFFUSION AND OSMOSIS 

Diffusion and Osmosis. If we place a lump of sugar in the 
bottom of a glass of water, it will dissolve, and spread by slow 
degrees equally throughout the whole volume of the liquid. 
If we pour a concentrated solution of sulphate of copper into 
the bottom of a glass vessel, and carefully pour over it a layer 
of clear water, the liquids, at first sharply separated by their 
difference of density, will gradually mix, so as to form a 
solution having exactly the same composition in all parts 
of the jar. The process whereby the sugar and the copper 
sulphate spread uniformly through the whole mass of the 
liquid in opposition to gravity is called Diffusion. This 
diffusion of the solute is a phenomenon exactly analogous to 
the expansion of a gas. It is the expression of osmotic 
pressure, or rather of the difference of the osmotic pressure of 
the solute in different parts of the vessel. The molecules of the 
solute move from a place where the osmotic pressure is greater 
towards a position where the osmotic pressure is less. The 
water molecules on the other hand pass from positions where 
the osmotic pressure of the solute is less towards positions 
where it is greater. As a consequence of this double circula- 
tion the osmotic pressure tends to become equalized in all 
parts of the vessel. 

Diffusion appears to be the fundamental physical pheno- 
menon of life. It is going on continually in the tissues of all 
living beings, and a study of the laws of diffusion and osmosis 
is therefore absolutely necessary for a just conception of vital 
phenomena. 

Coefficient of Diffusion. The coefficient of diffusion has 

43 



44 THE MECHANISM OF LIFE 

been defined by Fick as the quantity of a solute which in one 
second traverses each square centimetre of the cross section of 
a column of liquid 1 centimetre long, between the opposite 
sides of which there is unit difference of concentration. Nernst 
in his definition substitutes " unit difference of osmotic pressure " 
for " unit difference of concentration." 

Until recently it was generally believed that diffusion took 
place in colloids and plasmas just as in pure water. This is, 
however, by no means the case : the differences are considerable. 
When a solute is introduced into a colloidal solution, the 
greater the concentration of the colloid the slower will be 
the diffusion. This may be shown by a simple experiment. 
Several glass plates are prepared, by spreading on each a 
solution of gelatine of different concentration, to which a few 
drops of phenol phthalein have been added. If now a drop 
of an alkaline solution be placed on each plate, we can see 
that the drop diffuses more slowly through the more con- 
centrated gelatine solution, since the presence of the alkali is 
rendered visible by the coloration of the phenol phthalein. 
A similar demonstration may be made by allowing drops of 
acid to diffuse through solutions of gelatine made slightly 
alkaline and coloured with phenol phthalein. In general, 
we find on experiment that when similar drops of any 
coloured or colouring solution are left for an equal time on 
plates of gelatine of different degrees of concentration, the 
greater the concentration of the gelatine the smaller will be 
the circle of coloration obtained. 

We may show that the rapidity of diffusion diminishes 
as the gelatinous concentration increases, by another experi- 
ment. If we put side by side on our gelatine plate a drop of 
sulphate of copper and another of ferrocyanide of potassium, 
the point of contact of the two fluids will be sharply marked 
by a line of precipitate. We find that under similar conditions 
the time between the sowing of the drops and the formation 
of this line of precipitate is longer when the gelatine is more 
concentrated. 

Osmosis. In 1748, FAbbc Nollet discovered that when a 
pig's bladder filled with alcohol was plunged into water, the 



DIFFUSION AND OSMOSIS 45 

water passed into the bladder more rapidly than the alcohol 
passed out ; the bladder became distended, the internal pressure 
increased, and the liquid spirted out when the bladder was 
pricked by a pin. This passage of certain substances in 
solution through an animal membrane is called Osmosis, and 
membranes which exhibit this property are called osmotic 
membranes. 

Precipitated Membrane*. In 1867, Traube of Breslau dis- 
covered that osmotic membranes could be made artificially. 
Certain chemical precipitates such as copper ferrocyanide can 
form membranes having properties analogous to those of 
osmotic membranes. With these precipitated membranes 
Traube made a number of interesting experiments. These 
have lately been collected in the volume of his memoirs 
published by his son. 

Osmotic Membrane*. Osmotic membranes were formerly 
called semi-permeable membranes, being regarded as membranes 
which allow water to pass through them, but arrest the passage 
of the solute. This definition is inexact, since no membrane 
permeable to water is absolutely impermeable to the solutes. 
All we can say is that certain membranes are more permeable 
to water than to the substances in solution, and are moreover 
very unequally permeable to the various substances in solution. 
As a rule a membrane is much more permeable to a solute 
whose molecule is of small dimensions. Molecules of salt, for 
instance, pass through such a membrane much more quickly 
than do those of sugar. The term "osmotic membrane" 
should therefore in all cases replace that of " semi-permeable 
membrane/' 

Osmotic membranes behave exactly like colloids. The 
resistance which they oppose to the passage of different 
substances varies with the nature of the liquid or solute 
concerned. There is no real difference between the passage 
of a solution through an osmotic membrane and its diffusion 
through a colloid. The protoplasm of a living organism, 
being a colloid, acts exactly like an osmotic membrane so 
far as regards the distribution of solutions and substances in 
solution. 



46 THE MECHANISM OF LIFE 

The diffusion of molecules through a colloid, a plasma, or 
a membrane is governed by laws precisely analogous to Ohm's 
law, which governs the transport of electricity. The intensity 
or rapidity of diffusion is proportional to the difference of 
osmotic pressure^ and varies inversely with the resistance. 

In the case of molecular diffusion, however, the rapidity of 
diffusion depends also on the size and nature of the molecules 
of the diffusing substance. The theory of the resistance of 
the various plasmas and membranes to diffusion has been 
but little understood ; we can discover hardly any reference 
to it in the literature of the subject. 

The laws of diffusion apply equally to the diffusion of ions. 
Nernst has shown that there is a difference of electric potential 
at the surface of contact of two electrolytic solutions of different 
degrees of concentration. Both the positive and negative ions 
of the more concentrated solution pass into the less concen- 
trated solution, but the ions of one sign will pass more rapidly 
than those of the other sign, because being smaller, they meet 
with less resistance. 

The resistance of the medium plays a most important part 
in all the phenomena of diffusion. When two solutions of 
different concentration come into contact, the interchange of 
molecules and ions which occurs is unequal owing to the 
differences in resistance. Hence both solutions become modified 
not only in concentration but also in composition. It has 
long been known that diffusion can cause the decomposition 
of certain easily decomposed substances, and it would appear 
probable that diffusion is also capable of producing new 
chemical combinations. 

The separation of the liberated ions in consequence of the 
unequal resistance which they meet with in the medium they 
traverse often determines chemical reaction. This ionic 
separation is a fertile agent of chemical transformation in the 
living organism, and may be the determinant cause in those 
chemical reactions which constitute the phenomena of nutrition. 

When different liquids come into contact there are two 
distinct series of phenomena, those due to osmotic pressure 
and those due to differences of chemical composition. Even 



DIFFUSION AND OSMOSIS 47 

with isotonic solutions there will be a transfer of the solutes 
if these are of different chemical constitution. Take, for 
instance, two isotonic solutions, one of salt and another of 
sugar. When these are brought into contact there is no 
transference of water from one solution to the other, but 
there is a transference of the solutes. In the salt solution 
the osmotic pressure of the sugar is zero. Hence the difference 
of osmotic pressure of the sugar in the two solutions will 
cause the molecules of sugar to diffuse into the salt solution. 
For the same reason the salt will diffuse into the sugar 
solution. 

A disregard of this fact, that a solute will always pass 
from a solution where its osmotic pressure is high, into oiiv 
where its osmotic pressure is low, is a frequent source of 
error. Thus it is said to be contrary to the laws of 
osmosis that solutes should pass from the blood, with its 
low osmotic pressure, into the urine, where the general osmotic 
pressure is higher; the more so because in consequence of 
the exchange the osmotic pressure of the urine is still 
further increased. Such an exchange, it is argued, is contrary 
to the ordinary laws of physics, and can therefore only be 
accomplished by some occult vital action. This, however, is 
not the fact, as is proved by experiment. 

Consider an inextensible osmotic cell containing a solution 
of sugar, the walls of the cell being impermeable to sugar 
but permeable to salt. Let us plunge such a cell into a 
solution of salt, which has a lower osmotic pressure than 
the sugar solution. Since the walls of the cell are inex- 
tensible, the quantity of water in the cell cannot increase. 
The salt, however, will pass into the cell, since the osmotic 
pressure of the salt is greater on the outside than on the 
inside, and the walls are permeable to the molecules of salt. 
This passage will continue until the osmotic pressure of the 
salt is equal inside and outside the cell ; at the same time 
the total osmotic pressure within the cell will have increased, 
in spite of its being originally greater than the osmotic 
pressure outside. 

Plasmolysls. We all know that a cut flower soon dries 



48 THE MECHANISM OF LIFE 

up and fades. When, however, we place the shrivelled flower 
in water, the contracted protoplasm swells up again and 
refills the cells, which become turgid, and the flower revives, 
This phenomenon is due to the fact that vegetable protoplasm 
holds in solution substances like sugars and salts which have 
a high osmotic pressure. Consequently water has a tendency 
to penetrate the cellular walls of plants, to distend the 
cells and render them turgescent. De Vries has used this 
phenomenon for the measurement of osmotic tension. He 
employs for this purpose the turgid cells of the plant 
Tradescautia discolor. The cells are placed under the micro- 
scope and irrigated with a solution of nitrate of soda. On 
gradually increasing the concentration of the solution there 
comes a moment when the protoplasmic mass is seen to 
contract and to detach itself from the walls of the cell. 
This phenomenon, which is known as plasmolysis, occurs at 
the moment when the solution of nitrate of soda begins to 
abstract water from the protoplasmic juice, i.e. when the 
osmotic tension of the nitrate of soda becomes greater than 
that of the protoplasmic liquid. So long as the osmotic 
tension of the soda solution is less than that of the protoplasm, 
there will be a tendency for water to penetrate the cell wall 
and swell the protoplasm. When the osmotic tension of 
the solution which bathes the cell is identical with that of 
the cellular juice, there is no change in the volume of the 
protoplasm. In this way we are able to determine the 
osmotic pressure of any solution. We have only to dilute 
the solution till it has no effect on the protoplasm of the 
vegetable cells. Since the osmotic tension of this protoplasm 
is known, we can easily calculate the osmotic tension of the 
solution from the degree of dilution required. 

Red Blood Corpuscles as Indicators of Isotony. In 1886, 
Hamburger showed that the weakest solutions of various 
substances which would allow the deposition of the red 
blood cells, without being dilute enough to dissolve the 
haemoglobin, were isotonic to one another, and also to the 
blood serum, and to the contents of the blood corpuscles. 
This is Hamburger's method of determining the osmotic 



DIFFUSION AND OSMOSIS 49 

tension of a liquid. The diluted solution is gradually increased 
in strength until, when a drop of blood is added to it, the 
corpuscles are just precipitated, and no haemoglobin is 
dissolved. 

The Hcematocnte. In 1891, Hedin devised an instrument 
for determining the influence of different solutions on the 
red blood corpuscles. This instrument, the haematocrite, is 
a graduated pipette, designed to measure the volume of 
the globules separated by ccntrifugation from a given volume 
of blood under the influence of the liquid whose osmotic 
pressure is to be measured. The method depends on the 
principle that solutions isotonic to the blood corpuscles and 
to the blood serum will not alter the volume of the blood 
corpuscles, whereas hypertonic solutions decrease that volume. 

Action of Solutions of Different Degrees of Concentration on 
Living Cells. We have just seen that a living cell, whether 
vegetable or animal, is not altered in volume when immersed 
in an isotonic solution that does not act upon it chemically. 
When immersed in a hypertonic solution, it retracts ; in a 
slightly hypotonic solution it absorbs water and becomes 
turgescent, while in a very hypotonic solution it swells up 
and bursts. In a hypertonic solution the red blood cells retract 
and fall to the bottom of the glass, the rapidity with which 
they are deposited depending on the amount of retraction. 
In a hypotonic solution they swell up and burst, the haemo- 
globin dissolving in the liquid and colouring it red. This is 
the phenomenon of hsematolysis. According to Hamburger, 
the serum of blood may be considerably diluted with water 
before producing haematolysis. Experimenting with the 
blood of the frog, he found that the globules remained 
intact in size and shape when irrigated with a salt solution 
containing *64< per cent, of salt, this solution being isotonic 
with the frog's blood serum. On the other hand, they did not 
begin to lose their haemoglobin till the proportion of salt was 
reduced to below *22 per cent. Thus frog's serum may be 
diluted with 200 per cent, of water before producing haema- 
tolysis. In mammals the blood corpuscles remain invariable 
in a salt solution of about *9 per cent., and begin to lose their 
4 



SO THE MECHANISM OF LIFE 

haemoglobin approximately in a *6 per cent, solution. A 
solution of '9 per cent, of NaCl is therefore isotonic to the 
contents of the red blood corpuscles, to the serum of the blood, 
and to the cells of the tissues. It by no means follows that 
the cells of the blood and tissues undergo no change when 
irrigated with a '9 per cent, solution of chloride of sodium. 
They do not lose or gain water, it is true, and they retain 
their volume and their specific gravity. But they do undergo 
a chemical alteration, by the exchange of their electrolytes 
with those of the solution. Hamburger has pointed out that 
in mammals the shape of the red corpuscles is altered in every 
liquid other than the blood serum ; even in the lymph of the 
same animal there is a diminution of the long diameter, and 
an increase of the shorter diameter, while the concave discs 
become more spherical. 

All the cells of a living organism are extremely sensitive to 
slight differences of osmotic pressure the cells of epithelial 
tissue and of the nervous system as well as the blood cells. For 
instance, the introduction of too concentrated a saline solution 
into the nasal cavity will set up rhinitis and destroy the 
terminations of the olfactory nerves. Pure water, on the other 
hand, is itself a caustic. There is a spring at Gastein, in the 
Tyrol, which is called the poison spring, the " Gift-Brunnen." 
The water of this spring is almost absolutely pure, hence it 
has a tendency to distend and burst the epithelium cells of the 
digestive tract, and thus gives rise to the deleterious effects 
which have given it its name. Ordinary drinking water is 
never pure, it contains in solution salts from the soil and gases 
from the atmosphere. These give it an osmotic pressure 
which prevents the deleterious effects of a strongly hypotonic 
liquid. During a surgical operation it is of the first importance 
not to injure the living surfaces by flooding, them with 
strongly hypertonic or hypotonic solutions. This precaution 
becomes still more important when foreign liquids are brought 
into contact with the delicate cells of the large surfaces of the 
serous membranes. Gardeners are well aware of the noxious 
influence of a low osmotic pressure. They water the soil 
around the roots of a plant, so that the water may take up 



DIFFUSION AND OSMOSIS 51 

some of the salts from the soil before being absorbed by the 
plant. Pure water poured over the heart of a delicate plant 
may burst its cells owing to its low osmotic pressure. In many 
medical and surgical applications, on the other hand, a low 
osmotic pressure is of advantage. Thus, in order to remove 
the dry crusts of ec/eina and impetigo, the most efficacious 
application is a compress of cotton wool soaked in warm 
distilled water. Under the influence of such a hypotonic 
solution the dry cells rapidly swell up, burst, and are 
dissolved. 

Cooking is also very much a question of osmotic pressure. 
If salt is put into the water in which potatoes arid other 
vegetables are boiled, osmosis is set up and a current of water 
passes from the vegetable cells to the salt water. The cellular 
tissue of the vegetable becomes contracted and dried, and the 
membranes become adherent, the vegetable loses weight and 
becomes difficult of digestion, in consequence of its hard and 
waxy consistency, which prevents the action of the digestive 
juices. Vegetables should be cooked in soft water, and should 
be salted after cooking. When so treated, a potato absorbs 
water, the cells swell up, the skin bursts, the grains of starch 
also swell up and burst, and the pulp becomes more friable. 
The digestive juice is thus able to penetrate the different parts 
of the vegetable rapidly, and digestion is facilitated. Any one 
can easily prove for himself that a potato boiled in salt water 
diminishes in weight, whilst its weight increases when it is 
cooked in soft water. 

The method of cryoscopy is also of considerable service in 
forensic medicine. As shown by Carrara, the cryoscopy of the 
blood is an important aid in determining the question whether 
a body found in the water was thrown in before or after death. 
In the former case the concentration of the blood will be much 
diminished. In certain experiments on dogs the cryoscopic 
examination of the blood showed a freezing point of *6 C. 
The dog was then drowned, when the free/ing point of the 
blood in the left ventricle was increased to '9 C., and that 
in the right ventricle to '4 C. On the other hand, when 
a dog was killed before being thrown into the water, the 



52 THE MECHANISM OF LIFE 

osmotic pressure of the blood was hardly decreased even after 
an immersion of 72 hours. In the case of persons or animals 
drowned in sea water, a similar alteration of the point of 
congelation is observed, but in the reverse direction. In this 
case the osmotic pressure is raised considerably in those who are 
drowned, whereas no such rise is observed in those who are 
thrown into the sea after death. 

The circulation of the sap in plants and trees is also in 
great part due to osmotic pressure. The aspiration of the 
water from the soil is due to the intracellular osmotic 
pressure in the roots, which causes the sap to rise in the stem 
of a plant as it would in the tube of a manometer. From a 
knowledge of the osmotic pressure of the intracellular liquid 
of the roots, we may calculate the height to which the sap can 
be raised in the trunk of a tree, i.e. the maximum height to 
which the tree can possibly grow. Suppose, for instance, the 
plasma of the rootlets has an osmotic pressure of six atmo- 
spheres, corresponding to that of a 9 per cent, solution of 
sugar. A pressure of six atmospheres is equal to the weight 
of a column of water 6 X '76 X 13-596 = 61 '95 metres high. 
This, then, is the maximum height to which this osmotic 
pressure is able to lift the sap. That is to say, a tree whose 
rootlets contain a solution of sugar of 9 per cent, concentration, 
or its equivalent, can grow to a height of 62 metres. 

Cryoscopy is also of great use in practical medicine, more 
especially for the examination of the urine. The free/ing point 
of urine varies from 1 '26 C. to 2*35. Koryani has studied 
the ratio of the point of congelation of urine to that of a 
solution containing an equal quantity of chloride of sodium. 

TT n i ,1 , ,1 , freezing point of urine . , 

He finds that the ratio . r . . VT ^ increases when 

freezing point of NaCl 

the circulation through the tubules of the kidney is diminished. 

Hans Koeppe has shown that the hydrochloric acid of the 

gastric juice is produced by the osmotic exchanges between the 

blood and the gastric contents. The ion Na of the salt in 

the stomach contents exchanges with an ion H of the mono- 
basic salts of the blood, NaIIC0 3 + NaCl = HC1 + Na 2 C0 8 . 



DIFFUSION AND OSMOSIS 53 

Influence of Muscular Contraction on the Intramuscular 
Osmotic Pressure. When a muscle is immersed in an isotonic 
salt solution it does not change in weight. In a hypertonic 
solution it loses weight in consequence of a loss of water, which 
passes from the muscle into the solution to equalize the 
osmotic pressure. It gains weight in a hypotonic solution, the 
water current setting towards the point of higher concentra- 
tion. It is easy, therefore, to tell whether the osmotic pressure 
in a muscle is above or below that of a given solution, by 
observing whether the muscle gains or loses weight when 
immersed in it. Thus we may measure the osmotic pressure 
in a muscle by finding a salt solution in which the muscle 
neither gains nor loses weight. In this way we have been able 
to prove that the osmotic pressure of a tired muscle is higher 
than that of the normal muscle. Our experiments were 
carried out on the muscles of frogs. After having pithed the 
frog, one of the hind legs is removed by a single stroke of the 
scissors. The leg is skinned, dried with blotting paper, and 
weighed. It is then placed in a salt solution whose freezing 
point is *53 C. At 15 C. such a solution has an osmotic 
pressure of 6*6 atmospheres. We next proceed to determine 
the osmotic pressure of the corresponding leg after it has been 
tired by muscular work. For this it is stimulated by an inter- 
mittent faradic current passing once a second for five minutes. 
The leg is then skinned, dried, weighed, and placed in the same 
salt solution. After eight hours' immersion the legs are weighed 
again. The following are the results of six experiments, the 
numbers representing fractions of the original weight : 

Change of weight of untired leg 

After 8 hours - '000. 
After 16 hours - '000. 
After 24 hours - '006. 

Change of weight of stimulated leg 

After 8 hours + '050. 
After 16 hours + '080. 
After 24 hours + '101, 



54 THE MECHANISM OF LIFE 

This result shows that muscular work provoked by electric 
stimulation noticeably increases the osmotic pressure of the 
muscle. 

In order to discover the exact osmotic pressure in the 
stimulated muscles we repeated the series of experiments, using 
more and more concentrated solutions. In a solution whose 
freezing point was '57, we obtained the following values : 

Change of weight of untired leg 

After 8 hours - '000. 
After 16 hours - '004. 
After C M hours - -006. 

Change of weight of stimulated leg 

After 8 hours + "039. 
After 16 hours + '073. 
After 24 hours +'099. 

Finally, in a solution freezing at '72, i.e. with an osmotic 
pressure at 15 C. of 9 '176 atmospheres, we obtained the 
following mean values for the untired leg : 

After 8 hours -1)4. 
After 16 hours - '05. 
After 24 hours '05. 

In this solution, free/ing at '72 C., some of the stimu- 
lated muscles showed no diminution in weight, while others 
showed a very small diminution, and others again a slight 
augmentation, the maximum increase being '085 of the 
initial weight. The solution is therefore practically isotonic 
with the stimulated muscle. 

In this case the elevation of the intramuscular osmotic 
pressure produced by the electrical excitation and the muscular 
contractions was therefore 2*5 atmospheres, or more than %'G 
kilogrammes per square centimetre of surface. 

I made further experiments in order to discover whether 
the variation in osmotic pressure depended on the duration of 



+ 026 


+ 084 


+ 094 


+ 034 


+ 065 


+ 093 


+ 045 


+ '079 


+ 097 


+ 037 


+ 070 


+ 095 


+ 032 


+ 072 


+ 096 



DIFFUSION AND OSMOSIS 55 

the muscular contraction. For this purpose I used a solution 
freezing at *58 C. and immersed in it untired muscles, and 
muscles which had been electrically excited for two, four, and 
six minutes respectively. The following are the results : 

Untired muscles. Muscles stimulated once a second during 

2 Minutes. 4 Minutes. 6 Minutes. 

000 . 
+ 001 . 
+ 005 . 

000 . 

000 . 

Mean of all the observations 

+ 0012 . . +-0348 +-074 +'095 

These experiments show clearly that the osmotic intra- 
muscular pressure rises in proportion to the duration of the 
electrical stimulation. 

In order to determine the influence of the work ac- 
complished by the muscle on the elevation of the osmotic 
pressure, I made the following experiment. The two hind 
legs of a frog were submitted to the same electrical excitation, 
one leg being left at liberty, and the other being stretched by 
a hundred-gramme weight, acting by a cord and pulley. After 
exciting them electrically for five minutes, the legs were 
immersed for twenty-four hours in a saline solution freezing at 
53 C. The free limb showed an augmentation of *085 of the 
initial weight, and the stretched limb an increase of *106 of 
the initial weight. It is evident, therefore, that the osmotic 
pressure increases with the amount of work done by a muscle. 

Briefly, then, the results of our experiments are as follow : 

1. Muscular contraction electrically produced causes an 
increase of the osmotic pressure in a muscle. 

2. The intramuscular osmotic pressure may reach, or even 
exceed, 2*5 atmospheres, or 2'6 kilogrammes per square 
centimetre of surface. 

3. When a muscle is made to contract once a second, the 



56 THE MECHANISM OF LIFE 

elevation of the osmotic pressure increases with the number of 
contractions. 

4. The intramuscular osmotic pressure increases with the 
work done by the muscle. 

5. Fatigue is caused by the increase of osmotic pressure in 
a contracting muscle. 

The Field of Diffusion. Just as Faraday introduced the 
conception of a field of magnetic force and a field of electric 
force to explain magnetic and electrical phenomena, so we may 
elucidate the phenomena of diffusion by the conception of a 
field of diffusion, with centres or poles of diffusive force. If we 





FIG. 3. Fields of diffusive force. 

(a) Monopolar field of diffusion. A drop of blood in a saline solution of higher 

concentration. 

(b] Bipolar field of diffusion. Two poles of opposite signs. On the right a grain 

of salt forming a hypertonic pole of concentration, on the left a drop oi 
blood forming a hypotonic pole of dilution. 

consider a solution as a field of diffusion, any point where the 
concentration is greater than that of the rest may be considered 
as a centre of force, attractive for the molecules of water, and 
repulsive for the molecules of the solute. In the same way 
any point of less concentration may be regarded as a centre 
of attraction for the molecules of the solute, and a centre of 
repulsion for the molecules of water. 

A field of diffusion may be monopolar or bipolar. A 
bipolar field has a hypertonic pole or centre of concentration, 
and a hypotonic pole or centre of dilution. By analogy 
with the magnetic and electric fields we may designate the 
hypertonic pole as the positive pole of diffusion, and the 
hypotonic as the negative pole. 




DIFFUSION AND OSMOSIS 57 

The positive and negative poles and the lines of force in 
the field of diffusion may be illustrated by the following 
experiment. A thin layer of salt water is spread over an 
absolutely horizontal plate of glass. If now we take a drop 
of blood, or of Indian ink, and drop it carefully into the 
middle of the salt solution, we shall find that the coloured 
particles will travel along the lines of diffusive force, and thus 
map out for us a monopolar 
field of diffusion, as in Fig. 
3 a. Again, if we place two 
similar drops side by side in 
a salt solution, their lines 
of diffusion will repel one 
another, as in Fig. 4. 

Now let us put into the 

solution, side by side, one FIG. 4. Two drops of blood in a more 

drop Of less concentration concentrated solution, showing a field of 

, L . diffusion between two poles of the same 

and another of greater con- 
centration than the solution. 

The lines of diffusion will pass from one drop to the other, 
diverging from the centre of one drop and converging to- 
wards the centre of the other (Fig. 36). In this manner we 
are able to obtain diffusion fields analogous to the magnetic 
fields between poles of the same sign and poles of opposite signs. 
The conception of poles of diffusion is of the greatest 
importance in biology, throwing a flood of light on a number 
of phenomena, such as karyokinesis, which have hitherto been 
regarded as of a mysterious nature. It also enables us to 
appreciate the role played by diffusion in many other 
biological phenomena. Consider, for example, a centre of 
anabolism in a living organism. Here the molecules of the 
living protoplasm are in process of construction, simpler 
molecules being united and built up to form larger and more 
complex groups. As a result of this aggregation the number 
of molecules in a given area is diminished, i.e. the concentra- 
tion and the osmotic pressure fall, producing a hypotonic 
centre of diffusion. We may thus regard every centre of 
anabolism as a negative pole of diffusion. 



58 THE MECHANISM OF LIFE 

Consider, on the other hand, a centre of catabolism, where 
the molecules are being broken up into fragments or smaller 
groups. The concentration of the solution is increased, the 
osmotic pressure is raised, and we have a hypertonic centre of 
diffusion. Every centre of catabolism is therefore a positive 
pole of diffusion. Similar considerations as to the formation 
and breaking up of the molecules in anabolism and catabolism 
apply to polymerization. 

The diffusion field has similar properties to the magnetic 
and the electric field. Thus there is repulsion between poles of 
similar sign, and attraction between poles of different signs. 
A simple experiment will show this. A field of diffusion is 
made by pouring on a horizontal glass plate a 10 per cent, 
solution of gelatine to which 5 per cent, of salt has been 
added. The gelatine being set, we place side by side on its 
surface two drops, one of water, and one of a salt solution of 
greater concentration than 5 per cent. We have thus two 
poles of diffusion of contrary signs, a hypotonic pole at the 
water drop, and a hypertonic pole at the salt drop. Diffusion 
immediately begins to take place through the gelatine, the 
drops become elongated, advance towards one another, touch, 
and unite. If, on the contrary, the two neighbouring drops 
are both more concentrated or both less concentrated than 
the medium, they exhibit signs of repulsion as in Fig. 4. 

Diffusion not only sets up currents in the water and in 
the solutes, but it also determines movements in any particles 
that may be in suspension, such as blood corpuscles, particles 
of Indian ink, and the like. These particles are drawn along 
with the water stream which passes from the hypotonic centres 
or regions toward those which are hypertonic. 

These considerations suggest a vast field of inquiry in 
biology, pathology, and therapeutics. Inff animation, for 
example, is characterized by tumefaction, turgescence of the 
tissues, and redness. The essence of inflammation would ap- 
pear to be destructive dis-assimilation with intense catabolism. 
We have seen that a centre of catabolism is a hypertonic 
focus of diffusion. Hence the osmotic pressure in an in- 
flamed region is increased, turgescence is produced, and 



DIFFUSION AND OSMOSIS 



59 



the current of water carries with it the blood globules which 
produce the redness. 

The phenomenon of agglutination may also possibly be 
due to osmotic pressure, a positive centre of diffusion attract- 
ing and agglomerating the particles held in suspension. 

Tactism and Tropism. The phenomena of tactism and 
tropism may also be partly explained by the action of these 
diffusion currents of particles in suspension, these polar 







attractions and repulsions. 
In all experiments on this 
subject we should take 
into account the possible 
influence of osmotic pres- 
sure, since many of the 
causes of tactism or 
tropism also modify the 
osmotic pressure at the 
point of action, and it is 
possible that this modifi- 
cation is the true cause of 
the phenomenon. Osmo- 
tactism and osmotropism 
have not as yet been suffi- 
ciently studied. 

Thus it may be said 
that osmotic pressure 
dominates all the kinetic 
and dynamic phenomena 
of life, all those at least which are not purely mechanical, 
like the movements of respiration and circulation. The study 
of these vital phenomena is greatly facilitated by the concep- 
tion of the field of diffusion and poles of diffusion, and of 
the lines of force, which are the trajectories of the molecules 
of the solutes, and the particles and globules in suspension. 

The Morphogenic Effects of Diffusion. Many interesting 
experiments may be made showing variations of the lines 
of force in a field of diffusion, and how liquids subjected only 
to differences of osmotic pressure diffuse and mix with one 



FIG. 5. Liquid figures of diffusion. 

The six negative poles of diffusion are 
coloured with Indian ink. The positive 
pole in the centre is uncoloured and is 
formed by a drop of KNO 3 solution. 



6o 



THE MECHANISM OF LIFE 



another in definite patterns. When a liquid diffuses in 
another undisturbed by the influence of gravity, it produces 
figures of geometric regularity, and we may thus obtain figures 
and forms of infinite variety. The following is our method of 
procedure. A glass plate is placed absolutely horizontal and is 
covered with a thin layer of water or of saline solution. Then 
with a pipette we introduce into the solution, in a regular 
pattern, a number of drops of liquid coloured with Indian ink. 
A wonderful variety of patterns and figures may be obtained 

by employing solutions 
of different concentra- 
tion and varying the 
position of the drops. 

Instead of the water 
or salt solution, we 
may spread on the 
plate a 5 or 10 per 
cent, solution of gela- 
ti ne, containing various 
salts in solution. If 
now we sow on this 
gelatine drops of vari- 
ous solutions which 
give colorations with 
the salts in the gela- 
tine, we may obtain 
forms of perfect regu- 
larity, presenting most beautiful colours and contrasts. The 
drops, of course, must be placed in a symmetrical pattern. 
In this way we may obtain an endless number of ornamental 
figures. 

In order to cover a lantern slide 81 cm. x 10 cm., about 5 c.c. 
of gelatine is required. To this amount of gelatine we add a 
single drop of a saturated solution of salicylate of sodium, and 
spread the liquid gelatine evenly over the plate. When the 
gelatine has set, we put the plate over a diagram, a hexagon 
for instance, and place a drop of ferrous sulphate solution at 
each of the six angles. The drops immediately diffuse 




FlG. 6. Pattern produced in gelatine by the 
diffusion of drops of concentrated solutions of 
nitrate of silver and bromide of ammonium. 



DIFFUSION AND OSMOSIS 



through the gelatine, and the result after a time is the 
production of a beautiful purple rosette. The gelatine must 
be carefully covered to prevent its drying until the diffusion 
is complete. The preparation may then be dried and mounted 
as a lantern slide, and will give the most brilliant effect on 
projection. If the gelatine has been treated with a drop of 
potassium ferrocyanide solution instead of salicylate of sodium, 
a few drops of FeS0 4 will give a blue pattern. Or we may 
treat the gelatine 
with ferrocyanide 
of potassium and 
salicylate of sodium 
mixed, and thus 
obtain an inter- 
mediary colour on 
the addition of 
FeSO 4 . We may, 
indeed, vary indef- 
initely the nature 
and concentration 
of the solution, as 
well as the number 
and position of the 




FIG. 7. Pattern produced in gelatine by the diffusion 
of drops of silver nitrate and sodium carbonate. 



drops. The results 

have all the charm 

of the unexpected, which adds greatly to the interest of the 

experiment. 

These experiments are not merely a scientific toy. They 
show us the possibility, hitherto unsuspected, that a vast 
number of the forms and colours of nature may be the result 
of diffusion. Thus many of the phenomena of life, hitherto 
so mysterious, present themselves to us as merely the conse- 
quences of the diffusion of one liquid into another. One 
cannot help hoping that the study of diffusion will throw still 
further light on the subject. 

If a number of spheres, each capable of expansion and 
deformation, are produced simultaneously in a liquid, they will 
form polyhedra when they expand by growth. This is the 



62 



THE MECHANISM OF LIFE 



precise architecture of a vast number of living organisms and 
tissues, which are formed by the union of microscopic polyhedra 
or cells. A section of such a polyhedral structure would 
appear as a tissue of polygons. It is interesting to note that 
the simple process of diffusion will produce such structures 
under conditions closely allied to those which govern the 
development of the tissues of a living organism. 

We may obtain this cellular structure by a simple ex- 




FiG. 8. Pattern produced in gelatine by the diffusion of drops of a solution 
of nitrate of silver and of citrate of potassium. 



periment. On a glass plate we spread a 5 per cent, solution 
of pure gelatine, and when set sow on it a number of drops of 
a 5 to 10 per cent, solution of ferrocyanide of potassium. The 
drops must be placed at regular intervals of 5 mm. all over 
the plate. When these have been allowed to diffuse and the 
gelatine has dried, we obtain a preparation which exactly 
resembles the section of a vegetable cellular tissue (Fig. 9). 
The drops have by mutual pressure formed polygons, which 
appear in section as cells, with a membranous envelope, a 



DIFFUSION AND OSMOSIS 63 

nucleus, and a cytoplasm, which is in many cases entirely 
separated from the membrane. These cells when united 
form a veritable tissue, in all respects similar to the cellular 
structure of a living organism. 

In the preparation showing artificial cells the cellular 
structure is not directly visible until the gelatine has dried. 
One sees only a gelatinous mass analogous to the protoplasm 
of a living organism. This mass is nevertheless organized, or 




FlG. g. Tissue of artificial cells formed by the diffusion in gelatine 
of drops of potassium ferrocyanide. 

at least in process of organization, as we may see by the 
refraction when its image is projected on the screen. 

During the cell-formation, and as long as there is any 
difference of concentration in the gelatine, each cell is the 
arena of active molecular movement. There is a double 
current, as in the living cell, a stream of water from the 
periphery to the centre, and of the solute from the centre to 
the periphery. This molecular activity the life of the 
artificial cell may be prolonged by appropriate nourishment, 



64 THE MECHANISM OF LIFE 

i.e. by continually repairing the loss of concentration at the 
centre of the cell. 

The life of the artificial cell may also be prolonged by 
maintaining around it an appropriate medium. If we 
prematurely dry such a preparation of artificial cells, the 
molecular currents will cease, to recur again when we restore 
the necessary humidity to the preparation. This to my mind 
gives us a most vivid picture of the conditions of latent life in 
seeds and many rotifera. 

These artificial cells, like living organisms, have an 
evolutionary existence. The first stage corresponds to the 
process of organization, the gelatine representing the blas- 
tema, and the drop the nucleus. Thus the cell becomes 
organized, forming its own cytoplasm and its own enveloping 
membrane. 

The second stage in the life of this artificial cell is the 
period during which the metabolism of the cell is active 
and tends to equalize the concentration of the liquid in the 
cell and in the surrounding medium. 

The third stage is the period of decline. The double 
molecular current gradually slows down as the difference of 
concentration decreases between the cell contents and its 
entourage. When this equality of concentration has become 
complete the molecular currents cease, the cell has terminated 
its existence ; it is dead. The currents of substance and 
of energy have ceased to flow the form only remains. 

These artificial cells are sensible to most of the influences 
which affect living organisms. Like living cells they are 
influenced both in their organization and in their development 
by humidity, dryness, acidity, or alkalinity. They are also 
greatly affected by the addition of minute quantities of 
chemical substances either to the gelatinous blastema or to 
the drops which represent the primary nuclei. We may in 
this way obtain endless varieties, nuclei which are opaque or 
transparent, with or without a nucleolus, and cells containing 
homogeneous cytoplasm without a nucleus. We may also 
obtain cells with cytoplasm filling the whole of the cellular 
cavity or separated from the cell-membrane. We may obtain 



DIFFUSION AND OSMOSIS 65 

cells imitating all the natural tissues, cells without a mem- 
branous envelope, cells with thick walls adhering to one 
another, or cells with wide intracellular spaces. 

The forms of these artificial cells depend on the number 
and relative position of the drops which represent the nuclei, 
and on the molecular concentration or osmotic tension of the 
solution. The number of the cellular polyhedra is determined 
by the number of centres of diffusion. The magnitude of the 
dihedral angles, from which radiate three and occasionally four 




FlG. 10. Artificial liquid cells, formed by coloured drops of concentrated 
salt solution in a less concentrated salt solution. 



walls, depends on the position of the hypertonic poles of 
diffusion. The curvature of a surface is determined by the 
differences of concentration on either side. Between isotonic 
solutions the surface is plane, whilst it is curved between 
solutions of different osmotic pressures, the convexity being 
directed towards the hypertonic solution. 

The time required for these artificial cells to grow varies 
from two to twenty -four hours, according to the concentra- 
tion of the gelatine, the growth being most rapid in dilute 
solutions. 

Similar cells may be produced in water. If we pour a 
thin layer of water on a horizontal plate, and with a pipette 

5 



66 



THE MECHANISM OF LIFE 



sow in it a number of drops of salt water coloured with Indian 
ink, we may obtain artificial cells composed entirely of liquid, 

1 laving the same characters as those 
produced in a gelatinous solution. 

It is possible by liquid diffusion 
to produce not only ordinary cells 
but ciliated cells. If we spread a 
layer of salt water on a horizontal 
glass plate, and sow in it drops of 
Indian ink, artificial cells are pro- 
duced by diffusion. At the edge 
of the preparation there is often to 
be seen a sort of fringe, analogous 
to the cilia of living cells (Fig. 
11). 

These tissues of artificial cells 
demonstrate the fact that inorganic 
matter is able to organize itself into 
forms and structures analogous to 
those of living organisms under the 
action of the simple physical forces 
of osmotic pressure and diffusion. The structures thus pro- 
duced have functions which are also analogous to those of 
living beings, a double current of diffusion, an evolutionary 
existence, and a latent vitality when desiccated or congealed. 




FIG. ii. Liquid cells with a 
fringe of cilia, obtained by 
sowing coloured drops of con- 
centrated salt solution in a 
weaker salt solution. The 
contents of the cells have un- 
dergone segmentation. 



CHAPTER VI 
PERIODICITY 

Periodic Precipitation. A phenomenon is said to be periodic 
when it varies in time and space and is identically reproduced 
at equal intervals. We are surrounded on all sides by periodic 
phenomena ; summer and winter, day and night, sleep and 
waking, rhythm and rhyme, flux and reflux, the movements of 
respiration and the beating of the heart, all are periodic. 
Our first sorrows were appeased by the periodic rhythm of 
the cradle, and in our later years the periodic swing of the 
rocking-chair and the hammock still soothe the infirmities of 
old age. 

Sound is a periodic movement of the atmosphere which 
brings to us harmony and melody. Light consists of periodic 
undulations of the ether which convey to us the beauty of 
form and colour. Periodic ethereal waves waft to us the 
wireless message through terrestrial space and the radiant 
energy of the sun and stars. 

It is therefore not to be wondered at that the phenomena 
of diffusion are also periodic. According to Professor Quinke 
of Heidelberg, the first mention of the periodic formation of 
chemical precipitates must be attributed to Rungc in 1885. 
Since that time these precipitates have been studied by a 
number of authors, and particularly by R. Liesegang of 
Diisseldorf, who in 1907 published a work on the subject, 
entitled On Stratification by Diffusion. 

In 1901 I presented to the Congress of Ajaccio a number 
of preparations showing concentric rings, alternately trans- 
parent and opaque, obtained by diffusing a drop of potassium 
ferrocyanide solution in gelatine containing a trace of feme 



68 



THE MECHANISM OF LIFE 



sulphate. At the Congress of Rheims in 1907 I exhibited the 
result of some further experiments on the same subject. 

These periodic precipitates may be obtained from a great 
number of different chemical substances. The following is 
the best method of demonstrating the phenomenon. A glass 
lantern slide is carefully cleaned and placed absolutely level. 
We then take 5 c.c. of a 10 per cent, solution of gelatine and 
add to it one drop of a concentrated solution of sodium 
arsenate. This is poured over the glass plate whilst hot, and 
as soon as it is quite set, but before it can dry, we allow a 
drop of silver nitrate solution containing a trace of nitric 

acid to fall on it from 
a pipette. The drop 
slowly spreads in the 
gelatine, and we thus 
obtain magnificent 
rings of periodic pre- 
cipitates of arsenate of 
silver, with which any 
one may easily repeat 
'the experiments de- 
tailed in this chapter. 

Circular Waves of 
Precipitation. The 
wave-front of the peri- 
odic rings of precipi- 
tates is always perpendicular to the rays of diffusion. The 
distance between the rings depends on the concentration of 
the Diffusing solution. The greater the fall of concentration, 
the less is the interval between the rings. Each ring repre- 
sents an cquipotcntial line in the field of diffusion. These 
equipotential lines of diffusion give us the best and most 
concrete reproduction of the mode of propagation of periodic 
waves in space. They are, in fact, a visible diagram of 
the propagation of the waves of light and sound. Occasion- 
ally we may observe in the gelatine the simultaneous pro- 
pagation of undulations of different wave-length, just as we 
have them in the ether and the air. These diffusion wavelets 




FIG. 12 Lines of diffusion precipitate, showing 
the simultaneous propagation of undulations 
of different wave-length. 



PERIODICITY 



69 






give us a very beautiful representation of the simultaneous 
propagation of undulations of different wave-length in the 
same medium. 

Like waves of light and sound, these waves of diffusion are 
refracted when they pass from one medium into another of a 
different density, where they have a different velocity. When, 
for instance, a diffusion wave passes from a 5 per cent, solu- 
tion of gelatine into a 10 
per cent, solution, the 
wave-front is retarded, the 
retardation being propor- 
tional to the length of the 
path through the denser 
medium. Hence the wave- 
front is flattened, the cur- 
vature of the refracted 
wave being less than that 
of the original wave of 
diffusion. The contrary is 
the case when the wave- 
front passes into a medium 
where its velocity is 
greater. The middle of 
the wave-front now travels 
faster than the flanks, and 
the curvature is increased. 

These diffusion rings 
furnish us with most ex- 
cellent diagrams of refrac- 
tion at a " diopter," I.e. a 

spherical surface separating two media of different densities. 
Fig. 14 shows the refraction at a convergent diopter, i.e. a 
surface where the denser medium is convex. The diffusion 
waves in this case emanate from the principal focus of the 
diopter, and therefore become plane on passing through the 
convex surface of the denser gelatine. 

These periodic diffusion rings also illustrate the phenomena 
of colour diffraction. Diffusion waves of different wave- 




FIG. 13. Waves of diffusion refracted at 
a plane surface on passing from a less 
concentrated into a more concentrated 
solution. The refracted wave-front is 
flattened, the wave length being less in 
the denser medium. 



THE MECHANISM OF LIFE 



length are unequally refracted by a gelatine lens. Hence 
rings of different wave-length which, originating at the same 
spot, are at first concentric, are no longer parallel after passing 
through a gelatine lens. A convergent lens which will change 
the long spherical incident waves into shorter plane waves, 
will transform the short incident waves into concave waves 
whose curvature is opposite to that of the original waves, i.e. 
it will transform a divergent into a convergent beam. This 

is an illustration of what 
is called the aberration of 
refrangibility. 

In the same way we may 
demonstrate the course of 
diffusion waves through a 
gelatine prism, showing the 
refraction on their incidence 
and again on emergence. 
The prism is made of a 
stronger gelatine solution, 
which is more refractive than 
the gelatine around it. The 
waves of diffusion whilst 
traversing the prisrn are 
retarded, and this retarda- 
tion is greatest at the base 
where the passage is longer. 
Hence the wave-front is 

tilted towards the base of the prism, and this tilting is re- 
peated when the wave-front leaves the prism. 

If we examine diffusion waves of different wave-length on 
their emergence from the gelatine prism, we shall see that 
they cut one another. With a dense prism, the wave-front 
of the shorter waves is more tilted towards the base than the 
wave-front of the longer waves. For diffusion as for light 
the shorter waves are the most refracted. Both refraction 
and dispersion are due to the unequal resistances of the 
medium to undulatory movements of different periodicity. 
Diffraction. When light traverses a minute orifice, instead 




FIG. 14. Translormation ot a spherical 
wave-front into a plane wave-front by 
a convergent diopter. 



PERIODICITY 



of passing on in a straight lineynit spreads out like a fan, 
''forming a diverging cone of light; just as if the orifice were 
itself a luminous point. This is the phenomenon of diffraction 
which has hitherto been considered incompatible with the 
emission theory of light. Diffusion waves may also be made 
to pass through a narrow orifice, when they will behave 
exactly like the waves of light. The new waves radiate from 
the orifice like a fan, instead of giving a cone of waves 
bounded by lines passing through the circumference of the 
orifice and the original centre of radiation. Thus on passing 
through a small orifice 
diffusion waves exhibit 
the phenomenon of dif- 
fraction just as light 
waves do. 

Interference. The 
phenomenon of inter- 
ference may also be 
illustrated by waves of 
diffusion. If on a gelatine 
plate we produce two 
series of diffusion waves 
from two separate centres, 




FIG. 15. Diffraction oi diffusion waves on 
passing through a narrow aperture. 



we get at certain points 
an appearance corre- 
sponding to the inter- 
ference of two sets of light waves. This appearance is best 
shown by sowing on the gelatine film a straight row of 
drops equidistant from one another. It should be remarked 
that this phenomenon of the production of circles of pre- 
cipitate separated by transparent spaces, although periodic, 
is not of necessity vibratory or undulatory. It would thus 
appear that periodic phenomena may be propagated through 
space without vibratory or oscillatory motion. If we submit 
to a critical examination the various experiments which have 
established the undulatory theory of light, we find that they 
do indeed demonstrate the periodic nature of light, but in no 
wise prove that light is a vibratory movement of the ether. 



72 THE MECHANISM OF LIFE 

On the contrary, the hypothesis that light is propagated by 
vibratory movements is open to many objections. Even the 
Zeeman effect, although it may tend to establish the fact that 
light is produced by vibratory movement, by no means proves 
that it is propagated in the same manner. When the theory 
was accepted that the transmission of light was periodic it 
was supposed that this periodic transmission could only be 
vibratory or undulatory in character, since waves or vibrations 
were the only periodic phenomena known at that time. We 
now know that there are other means of periodic transmission 
which are apparently not undulatory. The periodic precipitates 
produced by diffusion show us the transmission of spherical 
waves through space, which follow the laws of light, although 

the periodic phenomenon is 
apparently emissive rather 
than vibratory. 

It will be remembered 
that Newton considered light 
to be produced by projectile- 
like particles emanating from 

FIG. i6.-Inu.ie, em : C of diffusion a centre, and proceeding in 
waves. straight lines in all directions. 

This emission theory of light 
was abandoned in favour of Huygens" undulatory theory. 

It was said that the phenomena of interference and diffrac- 
tion could not be explained by the theory of emission, while 
the undulatory theory gave a simple explanation. The 
scientific mind was unable to conceive the idea of emission 
and periodicity as taking part in the same phenomenon. 
The savants and thinkers who have meditated on this question 
have always considered the theory of emission and that of 
periodicity as incompatible. Nevertheless, we are here in 
presence of a phenomenon in which emission and periodicity 
exist simultaneously. The molecules emanating from our 
drop are diffused in straight radiating lines, and yet produce 
periodic precipitates which are subject to interference and 
diffraction like the undulations of Huygens. 

The phenomena associated with the pressure of light, the 




PERIODICITY 73 

discovery of the cathode rays and the radiations of radium, 
together with the introduction of the electron theory of 
electricity, all seem to have brought again into greater 
prominence Newton's original conception of the emissionary 
nature of light. 

Some of the phenomena of radiation can be explained only 
by the emission theory, and others by the undulatory theory 
of light. All these difficulties would be solved if we admitted 
the hypothesis that radiating bodies project electrons, which 
produce in the ether periodic waves similar to those formed in 
our gelatine films by the molecules of diffusion. 

These diffusion films are of the greatest possible service in 
the practical teaching of optics. They place before the eye 
of the student a working model as it were of the undulations 
of light. When projected on the screen, they give excellent 
pictures of the phenomena of refraction, diffraction, and 
interference, and the simultaneous propagation of undulation 
of different wave-lengths, and they show in a visible manner 
the changes of wave-length in media of different densities. 

Diffusion waves differ greatly in length, varying from 
several millimetres to 2 p. Many are even shorter than this, 
too short to be separately distinguished even under the highest 
power of the microscope, when they give the effect of moire or 
mother-of-pearl. 

It is easy to construct a spectroscopic grating in this way 
with fine lines whose distance apart is of the order of a micron, 
separated by clear spaces. Every physical laboratory may 
thus produce its own spectroscopic gratings, rectilinear, circular, 
or of any desired form. 

The most beautiful colour effects may be produced with 
these diffusion gratings, as we have shown at the Congress of 
Rheims in 1907. We have a considerable collection of these 
diffusion gratings, some with very fine lines, giving a very 
extended spectrum, and others with coarser striations which 
give a large number of small spectra. 

This study of periodic precipitates is of the highest interest 
when we come to investigate the production of colour in 
natural objects, such as the wings of insects or the plumage of 



74 THE MECHANISM OF LIFE 

birds. Many tissues have this lined or striated structure and 
exhibit interference colours like those of the periodic precipi- 
tates, their structure showing alternate transparent and opaque 
lines, whose width is of the order of a micron. This is the 
structure of muscle, and to this striated surface is also attribut- 
able many of the most beautiful colours of nature, the gleam 
of tendon and aponeurosis, the fire of scarab and beetle, the 
colours of the peacock, and the iridescence of the mollusc and 




FlG. 17. Photomicrograph of striated structure or a periodic precipitate of 
carbonate and phosphate of lime (magnified 500 times). 

the pearl. The study of liquid diffusion has given us an idea 
of the physical mechanism by which these striated tissues are 
produced, a mechanism which up to the present time has not 
been even suspected. Our experiments show how readily such 
striped or ruled structures may be produced in a colloidal 
solution by the simple diffusion of salts such as are found in 
every living organism. 

To make a spectroscopic grating by diffusion we proceed 
as follows. We take 5 c.c. of a 10 per cent, solution of 
gelatine, and add to it one drop of a concentrated solution 



PERIODICITY 75 

of calcium nitrate. We spread the gelatine evenly over 
a plain glass lantern slide and allow it to set. After it is 
set, but before it dries, we place in the centre of the slide a 
drop of concentrated solution containing two parts of sodium 
carbonate (Na 2 CO 3 ) to one of dibasic sodium phosphate 
(Na 2 HPO 4 ). Tribasic sodium phosphate alone without the 
addition of the carbonate will also give good results. If the 
phosphate solution is placed on the gelatine in the form of a 
drop, we obtain circular periodic precipitates. If it is desired 
to make a rectilineal grating, we deposit the phosphate solution 
on the gelatine in a straight line by means of two parallel 
glass plates. In this way we may obtain lines of periodic 
precipitation to the number of 500 to 1000 per millimetre, 
forming gratings which produce most beautiful spectra. 

Pearls and mother-of-pearl both owe their iridescence to a 
similar ruled structure, which is developed in the living tissue 
of a mollusc. They are, in fact, periodic precipitates of phos- 
phate and carbonate of lime deposited in the colloidal organic 
substance of the mollusc. They have the same structure and 
the same chemical composition ; they have the same physical 
properties, the glow, the fire, and the brilliancy of our spectro- 
scopic gratings. In these experiments, indeed, we have realized 
the synthesis of the pearl, not only a chemical synthesis, but 
the synthesis of its structure and organism. 

We have been able to make these periodic precipitates by 
the reaction of a great number of chemical substances, giving 
a bewildering variety of form and structure. Some of these 
recall the form of various organisms, and especially of insects, 
as may be seen in Fig. 18. 

All the phenomena of life are periodic. The movement of 
heart and lungs, sleep and waking, all nervous phenomena, have 
a regular periodicity. It is possible that the study of these 
purely physical phenomena of periodic precipitation may give 
us the key to the causation of rhythm and periodicity in living 
beings. 

Besides this periodic precipitation there appear to be other 
chemical reactions which are periodic. Professor Bredig of 
Heidelberg has lately described a curious phenomenon, the 



7 6 



THE MECHANISM OF LIFE 



periodic catalysis of peroxide of hydrogen by mercury. He 
thus describes his experiment : " We place in a perfectly 
clean test tube a few cubic centimetres of perfectly pure 
mercury. Upon this we pour 10 c.c. of a 10 per cent, solution 
of hydrogen peroxide. The mercury speedily becomes covered 
with a thin, brilliant bronze-coloured pellicle which reflects 
light. Then little by little catalysis of the hydrogen peroxide 
begins, with liberation of oxygen. After some time, from five 
to twenty minutes, the liberation of gas at the surface of the 




FIG. 1 8. Articulate form produced by periodic precipitation. 

mercury ceases, the cloud formed by the gas bubbles disappears, 
and the bron/e mirror at the surface of the mercury lights up 
with the glint of silver. There is a pause of one or more 
seconds, and then the catalytic action begins afresh, commenc- 
ing at the edges of the mirror. The cloud is again formed 
and again disappears. This beautiful and surprising rhythmic 
phenomenon may continue at regular intervals for an hour or 
more." 

A slight alkalinity of the liquid is necessary to start the 
phenomenon. This explains the retardation at the beginning 



PERIODICITY 77 

of the experiment, since the rhythmic catalysis cannot begin 
until the hydrogen peroxide has dissolved a little of the glass 
so as to render it slightly alkaline. The catalytic process may, 
however, be set going at once by adding a trace of potassium 
acetate to the solution. 

We may even obtain a curve giving an automatic record of 
the periodicity of this catalytic action. For this purpose the 
oxygen given off is led to a manometer, which registers on a 
revolving drum the periodic variation in pressure. The curve 
thus obtained presents a remarkable resemblance to a tracing 
of the pulse. The frequency and character of the undulatory 
curve is modified by physical and chemical influences. Like 
circulation or respiration, periodic catalysis has its poisons, 
and exhibits signs of fatigue, and of paralysis by cold. 

The rhythmic catalysis of Bredig produces an electrical 
current of action between the mercury and the water just like 
that produced by the rhythmic contraction of the heart, and 
this current may be registered in a similar way by means of the 
Einthoven galvanometer. Thus the heart-beat may be but an 
instance of rhythmic catalysis, since both produce the same 
phenomena, movement, chemical action, and periodic currents. 
In the chapter on physiogenesis we shall return to the study 
of this question and consider another rhythmic phenomenon 
which is the result of osmotic growth. 



CHAPTER VII 

COHESION AND CRYSTALLIZATION 

CHEMICAL affinity is the force which holds together the 
different atoms in a molecule. Cohesion is the force which 
holds together molecules which are chemically similar. 
Although physical science distinguishes three states of matter, 
solid, liquid, and gaseous, yet here as elsewhere there are no 
sharp dividing lines, but rather an absolute continuity. We 
have in fact many intermediate states ; between liquids and 
gases there are the various conditions of vapour, and between 
liquids and solids we get viscous, gelatinous, and paste-like 
conditions. The only real difference between solids, liquids, and 
gases is the intensity of the force of cohesion, which is 
considerable in solids, feeble in liquids, and absent in gases. 

A living organism is the arena in which are brought into 
play the opposing forces of cohesion and disintegration. The 
study of cohesion is therefore a vital one for the biologist, and 
especially cohesion under the conditions which obtain in living 
beings, vi/. in liquids of heterogeneous constitution. The 
forces of cohesion brought into play under these conditions 
may be beautifully illustrated by a simple experiment. We 
take a plate of glass, well cleaned and absolutely horizontal. 
On it we pour a layer of salt water, and in the middle we 
carefully drop a spot of Indian ink. The drop at once begins 
to diffuse, and we obtain a circular figure, like the monopolar 
field of diffusion already described, the rays of diffusion radiating 
from the centre in all directions. 

If we keep the plate carefully protected from all disturbing 
influences, after some ten to twenty minutes we shall see the 

coloured particles returning on their path, and the centre of 

78 



COHESION AND CRYSTALLIZATION 



Each line of force 



the drop becoming more and more black, 
becomes segmented into granules, 
which gradually increase in si/e, and 
approach nearer to one another and 
to the centre of the drop, until it 
assumes the mulberry appearance shown 
in the photograph (Fig. 19). 

If we sow a number of drops of 
Indian ink in regular order on the 
surface of a salt solution, we obtain 
most beautiful patterns formed by the 
mutual repulsion of the drops. Figs. 
20, 21, and 22 represent the successive 
aspects of seven drops of Indian ink 
thus sown on a layer of salt solution, 
and kept undisturbed long enough to allow of their evolution. 




FIG. 19, Muriform cohesion 
figure formed by a drop 
of Indian ink in a solution 

of salt. 




FIG. 20. Seven similar drops of Indian ink diffusing in a salt solution. 
Two minutes after introducing the drops. 

Fig. 20 shows the aspect after two minutes, when the diffusion 
is almost complete. In Fig, 21, photographed after fifteen 



8o 



THE MECHANISM OF LIFE 



minutes, the colouring matter has almost entirely reunited to 
form separate granulations; whilst in Fig. 22, taken after 
thirty minutes, these granulations are rearranged to form an 
agglomeration around the centre of each drop. 

The following experiment, which is more difficult, will show 
the cohesive attraction of one drop for another. A plate of 
glass is adjusted absolutely horizontal, and covered as before 
with a layer of salt solution. On this we sow a number of 
drops of the same salt solution coloured with Indian ink. 




FlG. 21. The same drops 15 minutes later, showing the granulation 
appearance. 

The drops must be of exactly the same concentration as the 
salt medium, so as to avoid any difference of osmotic pressure 
between the drops and the medium, otherwise the drops would 
not remain intact but would diffuse into the solution. Since 
under these conditions the liquid of the medium around the 
drops is perfectly symmetrical and homogeneous, it cannot 
exercise any influence on the liquid of the drops. 

It is otherwise, however, with the colouring matter of the 



COHESION AND CRYSTALLIZATION 



81 



drops. The particles of Indian ink may be seen passing from 
one drop to another, the coloured circles become elongated 
towards one another, touch, and finally unite. If, as in Fig. 23, 




FlG. 22. The same drops after 30 minutes. The granulations have 
agglomerated at the centre of the drops. 

the drops are of different size, the larger one will have a 
preponderating attractive action and eat up the smaller drops. 
In the figure, six small drops are placed around a large one, 
and the smaller drops have begun to be 
deformed and to move towards the larger 
drop. This central drop is also deformed, 
and has assumed a more or less hexagonal 
form, under the influence of the attraction 
of the six smaller ones. It may be noticed 
that the least prominent angle of the hexa- 
gon is opposite the small drop which is FlG - 2 3- 
farthest away from it, whilst one of the 
smaller drops has already begun to be 
swallowed up by the large one. This 
cohesion phenomenon is very slow in its action, but after 
an hour or two the central drop will be found to have com- 
6 




-Attraction 
between coloured 
drops in an isotonic 
solution. 



82 THE MECHANISM OF LIFE 

pletely absorbed the six smaller ones, and only one large drop 
will remain. 

Incitbation. In the living organism we frequently find 
conditions similar to those realized in this experiment, viz. 
very slow movements of diffusion in liquids containing particles 
in suspension. In such cases the consequences must be the 
same, viz. granulation and segmentation. Consider for a 
moment the incubation of an egg. The heat of incubation 
determines a certain amount of evaporation through the 
shell, with a concentration of the liquid near the surface. As 
a consequence of this superficial concentration we get 
segmentation of the vitellus, with the production of a morula. 

Artificial Parthenogenesis. The experimental partheno- 
genesis of Loeb and Uelagc consists in plunging the egg into 
a liquid other than sea water, and returning it again to its 
original medium. This operation will necessarily determine 
slow movements of diffusion in the egg, which will give rise 
to segmentation. It may be objected that segmentation is 
also produced by a solution which is isotonic with sea water. 
Such a solution would not indeed produce an exchange of 
water with the egg, but it would set up an exchange of 
electrolytes, since there would be a difference of their osmotic 
pressure in the egg and in the new isotonic medium. The 
extremely slow movements of diffusion thus produced would 
be very favourable to the action of the cohesive force on 
the particles in suspension, and hence to the segmentation 
of the egg. 

Few physical phenomena give us a deeper insight into the 
phenomena of life than those which we here contemplate. 
There is still another experiment which is even more convinc- 
ing. On the surface of our horizontal salt solution we sow 
a number of drops of a more concentrated salt solution 
at equal distances around the circumference of a circle. 
Movements of diffusion arc thus set up in the interior of 
the circle, and after a time, when this diffusion has become 
so slow as to be almost imperceptible, a furrow begins to 
appear in the coloured mass. Then a second and third 
appear, and others crossing the former break up the mass 



COHESION AND CRYSTALLIZATION 83 

into segments. Finally the segmentation becomes complete, 
and the preparation presents a muriform appearance, looking 
in fact something like a mulberry (Fig. 24). If the prepara- 
tion is preserved for several hours longer, we may see the 
cells formed by segmentation unite around the circumference 
so as to form a hollow bag corresponding to a gastrula, as 
shown in Fig. 25. 

These preparations are extremely sensitive to external 




FIG. 24. A circle of eight drops 01 Indian ink 30 minutes after they have been 
sown in a salt solution. The drops have undergone diffusion and sub- 
sequent cohesion, resulting in a reticulate structure. 

influences, which renders the demonstration of cohesion 
phenomena difficult. I have nevertheless on several occasions 
been able to project the experiment on the screen during a 
lecture. The segmentation is influenced by very slight 
currents of diffusion, and I have many preparations showing 
the segmentation regularly distributed in various ways along 
radial diffusion lines. We may in this way produce many 
varieties of structure lamellar, vacuolate, or cellular, in fact 



84 



THE MECHANISM OF LIFE 



all the tissue structures which are met with in living organisms. 
All these structures are retractile, the retraction going on 
very slowly for a long time, as if the force of cohesion 
continued to act in the web of the structure even after its 
formation was complete. The phenomenon is a purely 
physical synthetic reproduction of the phenomenon of coagula- 
tion, the cohesion figure being in fact a retractile clot. 

Crystallization. When we evaporate a solution of a 
crystalloid it becomes more concentrated, slow movements of 




FlG. 25. The same preparation several hours later, showing a cellular 
gastrula-like structure. 

diffusion are set up, and at a given moment agglomeration 
occurs, the agglomerates taking the form of crystals. Thus 
crystallization may be regarded as a particular case of con- 
glomeration by cohesion, differing only in the regularity of 
the arrangement of the molecules, which gives the geometrical 
form of the crystal. Hence we can easily understand how 
the presence of a crystalline fragment may facilitate the 
process of crystalli/ation. Consider a liquid in which 
extremely slow movements of diffusion are taking place. 
If the liquid is perfectly homogeneous there will be no centre 
of attraction to which the molecules may become attached. 



COHESION AND CRYSTALLIZATION 



If, however, a crystal or other heterogeneous structure is present, 

it forms a centre of 

cohesion which will 

attach any molecules 

that are brought by 

diffusion into its 

sphere of attraction. 

We have succeeded 

in photographin 



the arrangement of 
the molecules of a 
liquid around a crys- 
tal in the act of 
formation (Fig. 26). 
For this purpose we 
add to the solution 
traces of some col- 
loidal substance, such 
as gelatine or gum, 
so as to delay the crystallization. 




FIG. 26. Field of crystallization of sodium 
chloride (magnified 60 diameters). 



It may thus be shown 
that the molecules of 
the surrounding liquid 
are already arranged 
in crystalline order 
for some distance from 
the crystal, forming 
a sort of field of 
crystallization. The 
arrangement of this 
regular field varies in 
( 1 i fferen t cases, and 
is more or less com- 
plicated according to 
circumstances. One 
of the most frequent 
forms is that shown 
in Fig. 27, which is 
the field around a crystal of sodium chloride. In the centre 




FIG. 27. Field of crystallization around a crystal 
of sodium chloride in process of formation. 



86 THE MECHANISM OF LIFE 

of the crystal is a square with well-marked outline. At each 
corner of this square there is a straight line at right angles to 
the diagonal, which will form the sides of the crystal in process 
of formation. From the middle of each side arise yet other 
perpendiculars, which in their turn bear other cross lines, each 
new line being set at right angles to its predecessor. A later 
stage of crystallization is shown in Fig. 27, where the two 
squares one inside the other at an angle of 45 are clearly 
indicated. 




FIG. 28. Three crystals of sodium chloride in process of formation, each in 
the centre of a field of crystallization. 

Every crystallizable substance gives a different characteristic 
field of crystallization. In 1903, at the Congress of Angers, 
I terminated my address by these words : " The field of 
crystallization may serve to determine the character of a 
substance in solution." I have subsequently received from 
Carbonell y Soles of Barcelona an interesting work on this 
subject, which he contributed to the International Congress 
of Medicine at Madrid in 1903, entitled Application de la 
crystalogenia experimental a la investigation toxicologica de 
cas alcalo'ides. 



COHESION AND CRYSTALLIZATION 



Six years ago I received from Australia an exceedingly 
beautiful photograph of a thin pellicle found in a rain gauge. 
My correspondent supposed that this strange figure might 
have been produced under the influence of an electric or 
magnetic field. I was able to assure him by return of 
post that the figure was the result of the crystallization of 
copper sulphate in a colloidal medium. In return I received 
a letter verifying this fact, and saying that there were copper 
works in the neigh- 
bourhood, and the 
air was filled with 
the dust of copper 
sulphate. 

Living beings 
are but solutions of 
colloids and crystal- 
loids, and their tis- 
sues are built up by 
the aggregation of 
these solutes. We 
have already seen 
how the forces of 
crystallization are 

modified in colloid FIG. 29. Crystallization of sodium chloride in a col- 
solutions. This loidal solution, giving a plant- like form. 

force of crystalliza- 
tion must play an important role in the metamorphoses of the 
living organism, and influence their morphology. It may 
therefore be of interest to investigate some of the numberless 
forms of crystallization in colloidal solutions. 

Figs. 9 and 30 represent the forms produced by chloride 
of sodium and chloride of ammonium respectively, in 
solutions of gelatine of different degrees of concentration. 
Their resemblance to vegetable growth is so remarkable that 
several observers on first seeing them have called them " Fern- 
crystals. 1 ' 

I should like here to recall to your notice the work of an 
English observer. Dr. E. Montgomery of St. Thomas's 




88 



THE MECHANISM OF LIFE 



Hospital, which was published as long ago as 1865. This 
work was recently brought to my notice by the kindness of 
Professor Baumlcr of Freiburg. He says : " Crystals are not 
strangers in the organic world. Many organic compounds are 
able to assume crystalline forms under certain conditions. 

Rainey has shown that many shells consist of globular crystals 

*' 




FIG. 30. Form produced by the crystallization of chloride of ammonium 
in a colloidal solution, 

i.e. of mineral substances made to crystallize by the influence 
of viscid material.''' In this connection I may also mention 
the interesting work of Otto Lehman n of Karlsruhe on liquid 
crystals. 

In conclusion, we may recall the words of Schwann himself, 
the originator of the cell theory : " The formation of the 
elementary shapes of an organism is but a crystallization of 
substances capable of imbibition. The organism is but an 
aggregate of such imbibing crystals/ 1 



CHAPTER VTII 

KARYOKINESIS 

IN 1873, Hermann Fol, writing of the eggs of Geryonia, thus 
describes the phenomenon of karyokinesis : " On either side 
of the residue of the nucleus there appears a concentration of 
plasma, thus forming two perfectly regular star-like figures, 
whose rays are straight lines of granulations. There are other 
curved rays which pass from one star or centre of attraction 
to the other. The whole figure is extraordinarily distinct, 
recalling in a striking manner the arrangement of iron filings 
surrounding the poles of a magnet. Sachs" theory is that the 
division of the nucleus is caused by centres of attraction, and 
I agree with him, not on theoretical grounds, but because I 
have actually seen these centres of attraction." 

Since the discovery of Hermann Fol, a great number of 
explanations have been given, all of them theoretical, to 
account for the figures and phenomena of karyokinesis. 
Many of these so-called explanations arc mechanical, while 
others invoke the aid of magnetism or electricity to account 
for the resemblance of the figures of karyokinesis to the mag- 
netic or electric phantom or spectre. Among the authors who 
have dealt with this question we may mention Hartog of 
Cork, Gallardo of Buenos Ayres, and Rhumbler of Gottingen. 

In 1904 I presented to the Grenoble Congress, and in 
1906 to the Lyons Congress, a series of photographs and 
preparations of experimental karyokinesis. I showed how, in 
a solution analogous to that found in the natural cell, the 
simple processes of liquid diffusion, without the intervention of 
magnetism or electricity, may reproduce with perfect accuracy 
and in their normal sequence the whole of the movements and 



90 THE MECHANISM OF LIFE 

figures which characterize the phenomenon of karyokinesis. 
This experiment consists not merely in the production of a 
certain figure, such as is obtained in the magnetic spectre, hut 
in the reproduction of the movement itself, and of all the 
successive forms which are seen in the natural phenomenon. 
These are evolved before the eyes of the spectator in thefr 
regular order and sequence. 

I may here reproduce the text of my communication at 
Grenoble : " Until I introduced the conception of a field of 
diffusion, there was no proper means of studying the 
phenomena of diffusion, which obey the laws of a field of 
force as expounded by Faraday. Moreover, no one suspected 
the possibility of reproducing by liquid diffusion a spectre 
analogous to the electro-magnetic phantom. Guided by this 
theory of a diffusion field of force, I have been able to 
reproduce experimentally the figures of karyokinesis by simple 
diffusion. With regard to the achromatin spindle, Professor 
Hartog has shown that the two poles of the spindle are of the 
same sign, and not of opposite signs as was at first supposed. 
In the process of karyokinesis the two centrosomes, i.e. the 
two poles of the achromatin spindle, repel one another. They 
must therefore be poles of the same sign. An electric or 
magnetic spectre showing a spindle between two poles of the 
same sign is unknown ; such a thing would appear to be an 
absolute impossibility. What is impossible in electricity and 
magnetism, however, is quite possible in the artificial diffusion 
field ; we can here have a spindle between two poles which 
repel one another that is, between poles of the same sign. 
Fig. 31 is a photograph of such a spindle produced by 
diffusion. On either side are two poles of concentration, 
which represent the centrosomes, each pole being surrounded 
by a star-like radiation. These poles being alike, repel one 
another. In the preparation one may see the distance between 
the two poles slowly increase, the poles gradually separating 
from one another just as do the centrosomes of an ovum 
during karyokinesis. This preparation, then, which is pro- 
duced entirely by diffusion, presents a perfect resemblance to 
the achromatin spindle in k^irineyoksis. . , 



KARYOKINESIS 91 

u The spindle of which we give a photograph in Fig. 31 
was made by placing in salt water a drop of the same solution 
pigmented with blood or Indian ink, and placing on either 
side of this central drop a liypertonic drop of salt solution 
more lightly coloured. After diffusion had gone on for some 
minutes, we obtained the figure which we have photographed. 
I would draw your attention to the equatorial plane, which 
shows that the spindle is not formed by lines of force passing 
from one pole to the other, as would be the case between two 
poles of contrary sign, but by two forces acting in opposite 
directions. On either side the pigment of the central drop 




FlG. 31. Diffusion figure representing karyokinesis. Achromatin spindle 
between two similar poles of concentration. 

has been drawn towards the hypertonic centre nearest to it. 
In the median line, however, the pigment is attracted in 
opposite directions by equal forces, and therefore remains 
undisturbed, marking the position of the equatorial plane. 
This observation applies equally to the equatorial plane 
in natural karyokinesis, whose existence is thus readily ex- 
plained. 

"It is hardly necessary to insist on the fact that liquid 
preparations like these are of extreme delicacy and sensitive- 
ness, and require for their production, and still more for their 
photography, the greatest care and skill, which can only be 
acquired by long practice. 



THE MECHANISM OF LIFE 



"We are able to produce by diffusion not only the 
achromatin spindle, but also the segmentation of the 
chroniatin, and the division of the nucleus. If in the saline 
solution we place a coloured isotonic drop between two 
coloured hypertonic drops, all the figures and movements 
of karyokinesis appear successively in their due order. The 
central drop, representing the nucleus between the two lateral 

drops or centrosomes, first be- 
comes granular. Next we see 
what appears to be a rolled- 
up ribbon analogous to the 
chroniatin band, which soon 
breaks into fragments analo- 
gous to the chromosomes. 
These arrange themselves 
around, and are gradually 
attracted towards the cen- 
trosomes, where they accumu- 
late to form two pigmelited 
nuclear masses. A partition 
then makes its appearance in 
the median line, and this 
partition becomes continuous 
with the boundary of the 
spheres around the centro- 
somes. Finally we have two 
^Us in juxtaposition, each 
with its nucleus, its proto- 
plasnij and its enveloping 

membrane. I have been able 
to photograph these successive stages of the segmentation of 
the chroniatin just as I have those of the achromatin spindle" 
(Fig. 32). 

This memoir, written in 1904, clearly asserts the homo- 
polarity of the centrosomes, and shows that the nuclear 
division is the result of a bipolar action, two poles of the 
same sign exerting their influence on opposite sides of the 
nucleus. It also emphasizes the important fact that diffusion, 




FIG. 32. Four successive stages in 
the production of artificial karyo- 
kinesis by diffusion. 



KARYOKINESIS 93 

and as far as we know diffusion alone, is able to produce a 
spindle between homologous poles. 

A glance at the photograph is enough to show that the 
spindle is formed between poles of the same sign. The lines 
of diffusion radiate from one centre and converge towards 
the other centre in curves, giving the double convergence 
characteristic of a spindle. The central drop merely supplies 
the necessary material, and should have a concentration but 
slightly less than that of the plasma, so as not to set up its 
own lines of diffusion. The photograph shows clearly that the 
rays of the spindle traverse the equator without any break. 
It has been objected that these lines form not so much a 
spindle as two hemi-spindlcs, but it is clear that these two 
hemi-spindles arc continuous and form a single sheaf of rays 
uniting the two poles of concentration. This is a phenomenon 
entirely unknown in the magnetic or electric fields, where two 
poles of the same sign, one on either side of a pole of the 
contrary sign, give two separate spindles. In a magnetic field 
it is impossible to make the lines emanating from one pole 
converge, except to a pole of opposite sign. Hence if we 
admit the homopolarity of the centrosomes, we must also 
admit that diffusion is the vera causa of karyokinesis, since, as 
I showed at the Grenoble Congress in 1904, diffusion and 
diffusion alone is capable of producing a spindle between two 
poles of the same sign. 

Nuclear Division. In order to reproduce artificially the 
phenomena attending the division of the nucleus, we may 
proceed as follows. We cover a perfectly horizontal glass 
plate with a semi-saturated solution of potassium nitrate 
to represent the cytoplasm of the cell. The nucleus in 
the centre is reproduced by a drop of the same solution 
coloured by a trace of Indian ink, the solid particles of 
which will represent the chromatin granules of the nucleus. 
The addition of the Indian ink will have slightly lowered 
the concentration of the central drop, and this is in 
accordance with nature, since the osmotic pressure of the 
nucleus is somewhat less than that of the plasma. We 
next place on either side of the drop which represents the 



94 THE MECHANISM OF LIFE 

nucleus a coloured drop of solution more concentrated 
than the cytoplasm solution. The particles of Indian ink 
in the central drop arrange themselves in a long coloured 
ribbon, apparently rolled up in a coil, the edges of the 
ribbon having a beaded appearance. After a short time 
the ribbon loses its beaded appearance and becomes smooth, 
with a double outline, as is shown in A, Fig. 32. This coil 
or skein of ribbon subsequently divides, forming a nuclear 
spindle, while the chromatin substance collects together in 
the equatorial plane as in B, Fig. 32. 

A more advanced stage of the nuclear division is shown 
at C, Fig. 32, where the chromatin bands of artificial chromo- 
somes are grouped in two conical sheafs converging towards the 
two centrosomes. For some considerable time these conical 
bundles remain united by fine filaments, the last vestiges of 
the nuclear spindle. The final stage is that of two artificial 
cells in juxtaposition, whose nuclei are formed by the original 
centrosomes augmented by the chromatin bands or chromo- 
somes (Fig. 32, D). 

The resemblance of these successive phenomena to those 
of natural karyokinesis is of the closest. The experiment 
shows that diffusion is quite sufficient to produce organic 
karyokinesis, and that the only physical force required is that 
of osmotic pressure. If in the cytoplasm of a cell there are 
two points of molecular concentration greater than that of 
the general mass, the nucleus must necessarily divide with all 
the phenomena which accompany karyokinesis. In nature 
these two centres of positive concentration are introduced into 
the protoplasm of the cell by fecundation that is, by the 
entrance of the centrosomes of the sperm cell. In certain 
abnormal cases the concentration may be produced in the cell 
itself by the formation of two centres of catabolism or 
molecular disintegration, since, as we have seen, molecular 
disintegration raises the osmotic pressure. This phenomenon, 
namely the production of karyokinesis from centres of cata- 
bolism, may account for the abnormal karyokinesis of cancer 
cells and the like. The subject is one which would well repay 
further investigation. 



KARYOKINESIS 



95 



It has been found in our experiments that in order to obtain 
the regular division of the artificial nucleus represented by the 
intermediary drop, the latter must have an osmotic pressure 
slightly below that of the plasma. This leads to the supposi- 
tion that a similar condition must obtain in the natural cell. 
It may be noticed, moreover, that the grains of pigment follow 
the direction of the flow of water, being carried along by the 
stream. This would appear to show that the nucleus of a 
natural cell has also a molecular concentration less than that 
of the plasma a result either of dehydration of the plasma, 
or of some diminution in the molecular concentration of the 
nucleus. 

Other phenomena of karyokinesis may also be closely 




FlG. 33. Equatorial crown produced 
by diffusion. 

imitated by diffusion. For instance, in the diffusion prepara- 
tion we notice at each extremity of the equator a V-shaped 
figure with its apex towards the centre, corresponding exactly 
to what in natural karyokinesis is called the equatorial crown. 

We may also produce diffusion figures of abnormal karyo- 
kinesis. Fig. 34 represents such a form, a triaster produced 
by diffusion. 

Artificial karyokinesis may also be produced by hypotonic 
poles of concentration that is to say, when the central drop 
representing the ovum is positive and the lateral drops 
representing the centrosomes are negative with respect to the 
plasma. In this case, however, the resemblance to natural 
karyokinesis is less perfect. 



96 THE MECHANISM OF LIFE 

Without attaching to it an importance which is not 
warranted by experimental results, it is interesting to note 
that we have here two methods of fertilization, hypertonic and 




FIG. 34. A triaster produced by diffusion. 

hypotonie, i.e. by centrosomes of greater concentration and 
by centrosomes of less concentration than that of the plasma 
of the ovum, and that we have in nature two corresponding 
results, vix. two different sexes. It is possible that we have in 
these two methods of producing nuclear division the secret of 
the difference of sex. 



CHAPTER IX 

ENERGETICS 

MOVEMENT is everywhere ; there is no such thing as immobility ; 
the very idea of rest is itself an illusion. Immobility is only 
apparent and relative, and disappears under closer examination. 
All terrestrial objects are driven with prodigious velocity around 
the sun, and the dwellers on the earth's equator travel each 
day around the 40,000 kilometres of its circumference. All 
objects on the globe are in motion, the inanimate as well as the 
living. The waters rise in vapour from the sea, float over 
mountain and valley, and return down the rivers to the sea 
again. Still more marvellous is the current of water which flows 
eternally from dew and rain, through the sap of plants and 
the blood of animals to the mineral world again. The very 
mountains crumble and their substance is washed down into 
the plains ; the winds move the air and raise the waves of the 
sea, whilst the strong ocean currents are produced by variations 
of temperature in different parts. This agitation, this incessant 
and universal motion, has been a favourite subject of poetic 
contemplation. Heraclitus writes : " There is a perpetual flow, 
all is one universal current ; nothing remains as it was, change 
alone is eternal." Ovid writes in his Metamorphoses : " Believe 
me, nothing perishes in this vast universe, but all varies, and 
changes its figure. I think that nothing endures long under 
the same appearance. What was solid earth has become sea, 
and solid ground has issued from the bosom of the waters." 

The French poetess Mme. Ackermaim has expressed the 
same idea in beautiful verse : 

"Ainsi, jamais d'arret. L'immortelle matiere, 
Un seul instant encore n'a pu se reposer. 
La Nature ne fait, patiente ouvnere, 
Que defaire et recomposer. 



98 THE MECHANISM OF LIFE 

Tout se metamorphose entre ses mains actives; 
Partout le mouvemcnt incessant et divers, 
Dans le cercle eternel des formes fugitives, 
Agitant 1'immcnsc univers." 

It was only towards the middle of last century that mankind 
in the long search after unity in nature began to reali/e that all 
the movements of the universe are the manifestations of a single 
agent, which we call energy. In reality all the phenomena of 
nature may be conceived as diverse forms of motion, and the word 
" energy " is the common expression applied to all the various 
modes of motion in the universe. It was by the study of heat, 
and more especially of thermodynamics, that we obtained our 
conceptions of the science of energetics. 

It was in Munich in 1798 that the English engineer Count 
liumford first observed that in the operation of boring a cannon 
the copper was heated to such a degree that the shavings 
became red-hot. This suggested his famous experiment, in 
which a heavy iron pestle was turned by horse power in a 
metal mortar filled with water. The water boiled, and when 
more water was added this also became heated to ebullition, 
and so on indefinitely. liumford argued that the heat thus 
obtained in an indefinite quantity could not be a material 
substance; that motion was the only thing added to the 
water without limit, and that therefore heat must be 
motion. 

While RumfoixTs experiment showed the transformation of 
motion into heat, the steam engine was soon afterwards to 
demonstrate the opposite transformation, viz. that of heat 
into motion. 

The actual state of our knowledge with regard to the 
science of energy rests on two principles, that of Mayer and 
that of Carnot. 

The first principle was defined by J. R. Mayer, a medical 
practitioner of Heilbronn, whose work, Bemerkungen ueber 
die Kriifle der unbelebten Natiir, was published in 1842. " All 
physical phenomena," says Mayer, " whether vital or chemical, 
are forms of motion. All these forms of motion are susceptible 
of change into one another, and in all the transformations the 



ENERGETICS 99 

quantity of mechanical work represented by different modes of 
motion remains invariable." 

The energy of a given body is the amount of transferable 
motion stored up in that body, and is measured by its capacity 
of producing mechanical work. 

Ostwald thus defines energy: "Energy is work, all that 
can be obtained from work, and all that can be changed into 
work." Different forms of energy may be measured in different 
ways, but all forms of energy can be measured either in 
units of mechanical work or in units of heat, in kilogramme- 
metres or foot-pounds or in calories, according as the energy 
in question is transformed into mechanical work or into heat. 
The first principle of energetics, the conservation of energy, 
may be thus expressed: "Energy is eternal; none is ever 
created, and none is ever lost. The quantity of energy 
in the universe is invariable, and is conserved for ever in its 
integrity." 

The unit by which we measure quantities of heat is the 
calory, the amount of heat required to raise the temperature 
of one kilogramme of water one degree Centigrade. 

The practical unit of mechanical work is the kilogramme- 
metre, the work required to raise the weight of one kilogramme 
to the height of one metre. The theoretical unit of work is 
one erg, the work required to move a mass of one gramme 
through one centimetre against a force of one dyne. 

Joule of Manchester was the first to verify Mayer's law 
quantitatively. By an experiment analogous to that of 
Rumford, he transformed work into heat, arranging his 
apparatus so that he might measure the amount of heat 
produced and the work expended. On dividing the quantity 
of work that had disappeared by the quantity of heat which 
had been disengaged, he found that 424 kilogramme- 
metres of work had been expended for each calory of heat 
produced. 

Him of Colmar measured the ratio of work to heat in the 
steam engine. He found that for each calory of heat which 
had disappeared there were produced 425 kilogramme-metres 
of work. 



ioo THE MECHANISM OF LIFE 

This number 425 has therefore been accepted as representing 
in calories and kilogramme-metres the transformation of work 
into heat, and of heat into work. 

Further measurements on the transformations of other 
forms of energy, chemical energy and electrical energy, have 
shown that Joule's law of equivalents is general, and that 
the quantity of mechanical work represented by any form of 
energy remains undiminished after transformation, whatever 
the nature of that transformation. 

Energy presents itself to us under two forms, potential and 
actual. Potential energy is slumbering energy, energy localized 
or locked up in the body. In order to transform potential 
energy into actual energy, there is required the intervention 
of an additional awakening, stimulating, or exciting energy 
from without. This stimulating energy may be almost 
infinitesimal in amount and bears no quantitative relation to 
the amount of energy transformed. It is the small amount 
of work required to turn the key which liberates an indeter- 
minate quantity of potential energy. 

Actual energy, on the other hand, is energy in movement, 
awake and alert, ready to be transformed into any other form 
of energy without the intervention of any such external 
stimulating force. 

The passage of a given quantity of energy from the 
potential into the actual state is effected gradually, and during 
the time of transformation the sum of the actual and the 
potential energy remains constant. 

A weight suspended by a cord possesses a quantity of 
potential energy equal to the product of its weight into the 
height through which it can fall. This energy is locked up in 
a certain space, it cannot be transformed without the inter- 
vention of some external energy to cut the cord. During the 
falling of the weight, at the middle of its path, half of this 
slumbering energy has become kinetic, and is represented by 
the vis viva of the weight, while the other half is still 
potential and is equivalent to the work which the weight will 
accomplish during the second half of its fall. At any moment 
the sum of these two energies, the sleeping and the waking 



ENERGETICS 101 

energies, represents the total potential energy of the weight 
before it began to fkll. 

So with the powder in a gun. The potential energy of 
the powder cannot become actual without some stimulus, 
some exciting force from without to set it free. It is the 
external work of pressing the trigger that liberates the 
potential energy of the powder, transforming it into the actual 
energy of combustion, and the kinetic energy of the projectile. 

Since energy is work, and work is a function of motion, 
there is in reality no such thing as energy in repose. Matter 
according to our modern conception is a complex of molecules, 
atoms, and electrons ; we conceive the molecules of matter 
as always in movement, animated with cyclic or vibratory 
motion, these oscillatory or rotatory movements representing 
the potential energy of the body in question. Potential 
energy is thus the expression of molecular motion without 
translation of the molecules as a whole in space. 

When this potential energy is transformed into actual 
energy by the intervention of some external force, we get a 
current of energy, a transference of the molecules in space. 
Thus, when an external force has released the weight, the 
molecular orbits in the falling body change in form, and the 
potential energy of the molecular motion becomes the kinetic 
energy of the falling body. Similarly in the conduction of 
heat, the energy of the hot body is transferred to a colder 
body by transmission of the vibratory motion from molecule 
to molecule. So again with chemical energy, the molecular 
ju$tion of combustion may be transformed into the radiant 
energy of the ethereal waves. 

Actual energy may be regarded as a current of molecular 
motion. To make the matter clearer, let a mass of matter 
be represented by a regiment of soldiers. Then each soldier 
will represent an electron, a company will be an atom, and a 
battalion will be a molecule. As long as the soldiers mark 
time, turn, or otherwise exercise without advancing, we have 
simply an accumulation of potential energy. The word of 
command, " March," is the exciting force which suddenly 
transforms this potential into kinetic energy. The marching 



102 THE MECHANISM OF LIFE 

regiment is a representation of a body possessing kinetic 
energy. Potential energy is energy confined to a certain point 
in space, whereas actual energy is a current of energy, 
continually changing its place or form. Energy is like water- 
power potential in the lake, actual in the waterfall or 
river. 

Any mechanism capable of causing one form of energy to 
pass into another is a transformer of energy. A steam engine 
is a transformer of energy, changing caloric energy into 
mechanical work. An electrical machine is a transformer 
of energy, converting mechanical motion into a current of 
electricity, whilst an electro-motor changes the movement of 
electrons into mechanical movement. Every living being, and 
even man himself, is but a transformer of energy, changing 
the energy derived from the earth and air and sun into 
mechanical motion, nervous energy, and heat. 

The first law of energetics, that of the conservation of 
energy, is analogous to Lavoisier's principle in chemistry, the 
conservation of matter. The sign of equality which unites 
the terms of a chemical equation expresses the fact that after 
every chemical reaction the same total mass of matter is 
present as before the transformation. This is also true of 
energy ; after every transformation we find exactly the same 
total quantity of energy as before it. This, however, tells us 
nothing as to the conditions of the transformation, or the 
causes, i.e. the anterior phenomena, which determined such 
transformation. 

The second principle of energetics, that of Carnot, 
enunciated in 1824, deals with the conditions under which a 
transformation of energy is possible. A mass of water at 
a certain height represents a quantity of potential energy 
equal to the product of its weight by its height ; but this 
energy cannot produce mechanical work unless the water is 
allowed to fall. Consider two lakes at the same altitude and 
of the same capacity, one of which is entirely landlocked, 
while the other has an open channel leading to the sea. Each 
lake represents the same quantity of potential energy, but the 
energy of the landlocked lake is useless, it cannot be trans- 



ENERGETICS 103 

formed ; whereas the other lake whose water can run into the 
sea realizes the conditions necessary for utilization, viz. the 
transforniability of its energy. The same may be said of all 
forms of energy ; a heat engine can only act as a transformer, 
change heat into work, if there is a difference of temperature 
between its source and its sink ; an electric motor can only 
work if there is a fall of potential between the entrance and 
the exit of the electric current. 

Energy presents itself to us as the product of two factors, 
weight and height in the waterfall, quantity and temperature 
in the heat engine, current intensity and potential in the 
electric motor. 

In considering these two factors we may note that one 
factor is always a quantity (Q) and the other an intensity 
(I). This latter expresses some sort of difference of position 
or condition, the height of the weight, a difference of tempera- 
ture in the heat engine, of pressure in the gas engine, or of 
electric potential in the dynamo or electric furnace. There can 
be no current of energy without this difference of potential, 
and therefore no transformation from one form of energy to 
another. 

The second law of thermodynamics, Carnot's law, may 
therefore be enunciated thus : " Energy cannot be transformed 
without a fall of potential. 11 

We may also derive this principle from a consideration of 
the formula of efficiency, the ratio of the work done by the 
transformer to the work done on the transformer. 

r, a , . energy transformed 

Efficiency = - ----- - - . 

total energy absorbed 

The total energy is the product QI, i.e. the product of the 
total quantity by the total intensity at our disposal. The 
transformed energy is Q(I I'), the product of the total 
quantity by the difference of intensity at the inlet and at the 
outlet of the machine. The formula for efficiency thus becomes 

Vlf ~ J = """ . If I represents a temperature, then in order 
that the efficiency may be positive I' must be less than I, 



104 THE MECHANISM OF LIFE 

there must be a fall of temperature in the machine. If I 
were greater than I, i.e. if the temperature at the outlet were 
greater than that at the inlet, the efficiency would be a 
negative one, and the transformer would have to borrow heat 
from some external source. 

Entropy. In every transformation of energy a certain 
portion of the energy is transformed into heat : a lamp gives 
out useless heat as well as light, a machine gives out useless 
heat as well as mechanical work. This loss of useful energy 
as heat occurs in every transference or transformation of 
energy ; it is only in the case of heat passing from a hotter to 
a colder body that there is no such transformation. When 
equality of temperature is established there has been no loss 
of energy, but the whole of the energy has become unutilizable, 
i.e. untransformable. In the formula of efficiency the fall of 
intensity I I' is now zero, and therefore the efficiency of the 

machine I = I is also zero. 

Since in all its transformations a certain fraction of the 
energy is changed into heat, there is a tendency in nature for 
all differences of temperature to become equalized. Hence 
the quantity of utilixable energy in the universe tends to 
diminish. Clausius called this unutilizable energy enmeshed 
in the substance of a body its entropy, and showed that in 
every transformation the amount of this unutilizable energy 
tended to increase. " The entropy of a system always tends 
towards a maximum value." 

If this gradual incessant increase of entropy is universal in 
nature, and if there is no compensatory mechanism, the 
universe must be tending towards a definite end, when the 
whole of its energy shall have been transformed into unutiliz- 
able heat with a uniform temperature. There is, however, 
reason to suppose that some such compensatory mechanism 
does in fact exist. Behind us stretches an infinite past, and 
in the future we believe that the phenomena of nature will be 
unrolled in a cycle which has no end. But the arguments 
derived from a study of entropy apply only to the facts and 
phenomena actually under our notice, the supposed impossi- 



ENERGETICS 105 

bility, without borrowing energy from without, of re-establish- 
ing the differences of temperature by drawing heat from a 
colder in order to concentrate it in a hotter body, and may 
not be absolutely identical with those obtaining in other ages. 
Our ignorance of such a phenomenon and our powcrlessness 
to produce it in no way argue that it is impossible. It may 
exist for aught we know in some other region of space, or in 
another time than ours. We may perhaps some day obtain 
artificially the conditions which would render possible such 
a phenomenon, since it may be possible to produce in the 
experimental laboratory conditions which are not spontane- 
ously reali/ed in nature under present, conditions. The future 
may perchance reveal to us absolutely new phenomena which 
have not hitherto been reali/ed. In his work on the evolution 
of matter and of energy Gustave le Bon gives expression to 
some interesting and original ideas on this subject. 

The laws of Mayer and Carnot alone are not sufficient to 
explain the phenomena of life, without some consideration of 
the laws of stimulus. Mayer's principle asserts the conserva- 
tion of energy, and Carnot^s the conditions necessary for its 
transformation, but these alone cannot account for the trans- 
formation of potential into actual energy. A weight suspended 
by a cord does not fall merely because there is room for its 
descent. We need the intervention of some outside force to 
cut the cord. In every transformation of energy this external 
force is required to cut the cord, or pull the trigger, some 
external force of excitation or liberation, an energy which may 
be infinitesimal in amount, and which bears no proportion 
to the quantity of potential energy it sets free. This inter- 
vention of an excitatory, stimulating, or liberating energy 
is universal. Every phenomenon of nature is but a trans- 
formation or a transference of energy, determined by the 
intervention of a minimal quantity of energy from without. 
This liberation of large quantities of potential energy by an 
exceedingly small external stimulus has not hitherto received the 
consideration it demands. Certain phenomena, such as those 
of chemical catalysis or the action of soluble ferments, excite 
our astonishment because such extremely small quantities of 



106 THE MECHANISM OF LIFE 

certain substances will determine the chemical transformations 
of large quantities of matter, there being no proportion 
between the amount of the catalytic substance and of the 
matter transformed. These phenomena are, however, only 
particular cases of the general law of energetics that trans- 
formation requires a stimulus. The cataly/er, or ferment, 
does not contribute matter to the reaction, but only the 
minimal energy necessary to liberate the chemical potential 
energy stored in the fermenting substance. 

We must therefore add a third to the two laws of ener- 
getics, Mayer's law of conservation, and Carnot's law of fall of 
potential. This third law is the law of stimulus, the necessity 
of the intervention of an external excitatory force capable of 
setting in motion the current of energy required for a trans- 
formation. This stimulus is the primary phenomenon, the 
determinant cause of such transformation. 

Three conditions, then, are required for a transformation or 
displacement of energy : 

1. The cause, the intervention of a stimulus which starts 
the transformation or displacement. 

2. The possibility, the necessary fall of potential. 

*3. The condition, the conservation of the energy con- 
cerned, since being indestructible its total quantity cannot 
alter. 

Every living being is a transformer of energy. The lower 
animals and man himself receive from food and air the potential 
energy which becomes actual under the process of oxydation. 
This chemical combustion is the source of all vital energy ; the 
ancients aptly compared life to a flame, and Lavoisier has 
shown that life, like the flame, is maintained by a process of 
oxydation. The energy derived from food and air is restored 
by the organism to the external world in the form of heat and 
mechanical motion. The celebrated experiments of Atwater 
show that there is an absolute equality between the energy 
obtained from the oxydation of the various aliments and the 
sum of the calorific and mechanical energy liberated by a living 
being. 

Man obtains his supply of energy either directly from the 



ENERGETICS 107 

vegetable world, or indirectly from vegetables which have 
passed through the flesh of animals. Vegetables in their turn 
obtain their substance from the mineral world and their 
energy from the sun. The salts, the water, and the carbonic 
acid absorbed by plants possess no store of potential energy. 
Whence then can they obtain the potential energy which they 
transmit to animals and man, if not from the sun? The 
energy of the solar radiations is absorbed by the chlorophyll of 
the leaves, and stored up in the organic carbohydrates formed 
by the synthesis of water and carbon. Chlorophyll has the 
peculiar property of reducing carbonic acid, and uniting the 
carbon with water in different proportions to form sugar and 
starch, whilst fats and vegetable albumens are also formed 
by an analogous reaction. All these complex bodies are 
stores of energy ; the vital processes of oxydation do but 
liberate in the human body the energy which the chlorophyll 
of plants has absorbed from the solar rays. 

We must look, then, to the sun as the direct source of all 
the energy which animates the surface of the earth. The sun 
looses the winds, and raises the waters of the sea to the 
mountain-tops, to form the rivers and torrents which return 
again to the sea ; the sun warms our hearths, drives our ships, 
and works our steam engines. There is no sign of life or 
movement on our planet which does not come directly or 
indirectly from the solar rays. 

It may be asked by what path does the chemical energy 
of the living organism pass into the mechanical energy of 
motion. It would appear that the intermediary step cannot 
be heat, as in the steam engine, since the necessary temperature 
would be quite incompatible with life. 

The formula for the efficiency of a thermic transformer is 

rn rjy 

r _ j ,, the ratio of the difference of the absolute temperatures 

at the source and at the sink, to the absolute temperature at 
the source. Calori metric measurements have shown that the 
efficiency of the human machine is about one-fifth, i.e. it can 
transform 20 per cent, of the energy absorbed. The ordinary 
temperature of muscle* is 38 C., or 311 absolute. We have 



io8 THE MECHANISM OF LIFE 

T ^1 1 
therefore - ? A1 =-20, or T = 388-75 absolute, i.e. 115'75 C. 

Thus, in order to obtain an efficiency of per cent, with 
an ordinary thermic transformer, having a temperature of 38 
at the sink, we should need a temperature of over 115 C. 
at the source. Such a temperature would be quite incompat- 
ible with the integrity of living tissues, and we may therefore 
conclude that the human organism is not a heat engine. 

We are indeed completely ignorant of the mode of trans- 
formation of chemical into kinetic energy in the living 
organism ; we know only that muscular contraction is accom- 
panied by a change of form ; at the moment of transformation 
the combustion of the muscle is increased, and during con- 
traction the stretched muscular fibre tends to acquire a 
spherical shape. It is this shortening of the muscular fibre 
which produces the mechanical movement. The step which 
we do not as yet fully understand is the physical phenomenon 
which intervenes between the disengagement of chemical 
energy and the occurrence of muscular contraction. Professor 
(TArsonval supposes that this missing step is a variation in 
the surface tension of the liquid in the muscular fibre. The 
surface tension of a liquid is due to the unbalanced forces of 
cohesion acting on the surface layer of molecules. Under 
the attraction of cohesion the molecules within the liquid are 
in a state of equilibrium, being equally attracted in all direc- 
tions, but those at the surface of the liquid are drawn towards 
the centre. The resultant of these attractive forces is a 
pressure normal to the surface, which is mechanically equiva- 
lent to an elastic tension tending to diminish the surface. 
In consequence of this surface tension the liquid has a tendency 
to assume the form in which its surface area is a minimum, 
i.e. the spherical form. If such a sphere is stretched into a 
cylinder or fibre by mechanical tension, it will shorten itself 
when released ; and if by any means we increase the surface 
tension of such a liquid fibre it will tend to assume a spherical 
form and contract just as a muscular fibre does. The surface 
tension of a liquid varies with its chemical composition ; the 
slightest chemical modification of a liquid alters the force of 



ENERGETICS 109 

this tension. We may therefore explain the mechanism of 
muscular contraction by supposing that a nervous impulse 
alters in some way the rate of combustion in a muscular fibre, 
that this alteration produces a momentary change in the 
chemical composition of the muscular cell, and that this 
change of chemical composition increases the surface tension 
of the cell sufficiently to provoke its contraction into a more 
spherical form. 

Ostwald has introduced a very useful conception for the 
study of this question of surface energy. A liquid surface 
contains a quantity of energy equal to its surface tension 
multiplied by its area, hence any variation either of area or of 
tension corresponds to a variation of its energy. This novel 
conception constitutes a valuable addition to the experimental 
study of the physiology of muscular action, since it gives us 
some idea of the mechanism by which chemical energy may be 
transformed into muscular contraction. 

Whatever the mechanism of transformation in the animal 
machine, we have to consider the same quantities as in other 
motor machines. These are : (1) the efficiency ; (2) the 
potential energy ; (tf) the power ; (4) the energy given up 
to the medium under the form of heat ; (5) the temperature. 

Muscles, then, are merely transformers which change 
chemical energy into mechanical work, the diminution of 
stored-up energy in a muscle being expressed by the sensation 
of fatigue. A muscle may be studied in four different phases : 
(1) in repose ; () in a state of tension ; (3) when doing positive 
work ; (4) when work is being done on it. 

When a muscle is in a state of tension, as when a weight 
is sustained by the outstretched arm, the muscle is producing 
no external work. The entire work done is converted into 
heat; just as it is in a dynamo or steam engine which is 
prevented from turning by a brake. Muscular contraction 
produces fatigue even when it does no external work. It is 
impossible for the muscle to support even the weight of the 
outstretched arm itself for any considerable time. 

A muscle is doing positive work when it is raising a weight 
or moving a body from one point to another. 



no THE MECHANISM OF LIFE 

The fourth state of muscular contraction is when th( 
muscle is doing negative work, i.e. when work is being done 
on it, as for instance when we go downstairs, or when a 
descending weight forces down the opposing arm which 
attempts to support it. In this case the muscles receive & 
portion of the energy lost by the descending weight, and thi? 
energy shows itself in the muscle in the form of heat. Trm 
increase of heat in a muscle doing negative work has been 
clearly demonstrated by the calorimetric experiments of Him 
and the thennometric experiments of Beclard. Hirifs ob- 
servations on muscular calorimetry show a production of heat 
corresponding to 150 calories per hour when in repose, 
248 calories per hour during positive work, and 287 during 
negative work. BeclaixTs thennometric measurements alsc 
show that the temperature of a muscle rises each time that it 
contracts, and that the rise of temperature is greatest when 
the muscle is doing negative work, least during positive work, 
and intermediate when in a state of tension. 

It is of the greatest importance in medical practice to 
distinguish between these different forms of muscular activity. 
There is a vast physiological difference between muscular 
contraction with the production of positive work, and muscular 
contraction without the production of work, or with negative 
work. To climb a flight of stairs is to contract the muscles 
with the production of work equal to the weight of the body 
multiplied by the height of the stairs. To descend the stairs 
is to contract the same muscles, but with the production oi 
negative work, and consequently a maximum of heat. To 
walk on level ground is to contract the muscles with the 
production of little or no external work ; as in a machine 
turning without friction in a vacuum. 

We have seen that a fall of potential and a current of energy 
are the necessary conditions for the production of any natural 
phenomenon. Hence we may assume that the phenomenon 
of sensation is also accompanied by a fall of potential and a 
current of energy. When we touch a hot body, there is a flow 
of energy from the hot body to the hand. When we touch a 
cold body, there is a current of energy in the opposite direction. 



ENERGETICS 1 1 r 

from the hand to the body. It was formerly held, and is still 
held by some physiologists, that the chief characteristic of life 
is the disproportion between an excitation and the response 
which it invokes from the organism. Such a doctrine can only 
be held by one who believes, at least implicitly, that the 
phenomena of life are supernatural, or at all events different 
in their nature from all other phenomena ; for the dispropor- 
tion between an excitation and the response it evokes is by 
no means confined to living things. This disproportion is 
universal in nature, and quite in conformity with the physical 
laws which govern the transformation of energy. The energy 
of living things is potential energy a fact which has been too 
little recognized. In the case of reflex actions it is self-evident, 
because the response is immediate, and always the same for the 
same stimulus. As in all other transformations, the stimulus 
consists in the intervention of a minimal quantity of external 
energy. 

Long before the discovery of the laws of energy, Lamarck 
had recogni/ed and formulated this fact. He writes : " What 
would vegetable life be without excitations from without, 
what would be the life even of the lower animals without this 
cause?" In another passage, seeking for a power capable of 
exciting the action of the organism, he says : " The lower 
animal forms, without nervous system, live only by the aid of 
excitations which they receive from without. In the lowest 
forms of life this exciting force is borrowed directly from the 
environment, while in the higher forms the external exciting 
force is transferred to the interior of the living being and 
placed at the disposal of the individual." 

This remark, that the movements of living things are not 
communicated but excited, that the external excitation only 
sets free latent or potential energy in the organism, shows 
that Lamarck had penetrated more deeply than many of the 
modern physiologists into the secrets of biological energy. 
We seek in vain in the text- books of physiology for any 
conception of potential energy in living beings, or the notion 
of an exciting force as the cause of sensation. All action of a 
living organism is reflex action. Every action has a cause, and 



H2 THE MECHANISM OF LIFE 

the cause of an organic action is an exciting energy from 
without, either immediate, or stored up in the nervous system 
from an external impression made at some previous epoch. 
Actions which are not evidently reHex are merely delayed 
reflexes; we have acquired the power of inhibiting, delaying, 
or modifying the response to an external stimulus, so that the 
same excitation may determine responses of very different 
kinds according to the mood produced by previous impressions. 
When carefully investigated, no action of ours is automatic ; 
every movement is determined by impressions derived from 
without. An action without a motive, that is without an 
external determining cause, would be an action without reason. 
In conclusion, we may formulate this general principle : 
The energy of a living being is potential energy ; sensations 
represent the intervention of an external exciting energy which 
provokes the response, i.e. the transformation of the potential 
energy already stored in the organism into the actual energy 
of motion and vital activity. 



CHAPTER X 
SYNTHETIC BIOLOGY 

THE course of development of every branch of natural science 
has been the same. It begins by the observation and classifi- 
cation of the objects and phenomena of nature. The next 
step is to decompose the more complex phenomena in order 
to determine the physical mechanism underlying them the 
science has become analytical. Finally, when the mechanism 
of a phenomenon is understood, it becomes possible to repro- 
duce it, to repeat it by directing the physical forces which are 
its cause the science has now become synthetical. 

Modern biology admits that the phenomena of life are 
physico-chemical in their nature. Although we have not as 
yet been able to define the exact nature of the physical and 
chemical processes which underlie all vital phenomena, yet 
every further discovery confirms our belief that the physical 
laws of life are identical with those of the mineral world, and 
modern research tends more and more to prove that life is 
produced by the same forces and is subject to the same laws 
that regulate inanimate matter. 

The evolution of biology has been the same as that of the 
other sciences ; it has been successively descriptive, analytical, 
and synthetic. Just as synthetic chemistry began with the 
artificial formation of the simplest organic products, so bio- 
logical synthesis must content itself at first with the fabrication 
of forms resembling those of the lowest organisms. Like other 
sciences, synthetic biology must proceed from the simpler to 
the more complex, beginning with the reproduction of the 
more elementary vital phenomena. Later on we may hope to 
8 



114 THE MECHANISM OF LIFE 

unite and associate these, and to observe their development 
under various external influences. 

The synthesis of life, should it ever occur, will not be the 
sensational discovery which we usually associate with the idea. 
If we accept the theory of evolution, then the first dawn of the 
synthesis of life must consist in the production of forms inter- 
mediate between the inorganic and the organic world forms 
which possess only some of the rudimentary attributes of life, 
to which other attributes will be slowly added in the course of 
development by the evolutionary action of the environment. 

Long ago, the penetrating genius of Lamarck seized on the 
idea that a knowledge of life could only be obtained by the 
comparison of organic with inorganic phenomena. He writes : 
" If we would acquire a real knowledge of what constitutes life, 
of what it consists, what are the causes and the laws which 
give rise to this wonderful phenomenon of nature, and how 
life can be the source of the multitude of forms presented to 
us by living organisms, we must before all consider with great 
attention the differences which exist between inorganic and 
living bodies ; and for this purpose we must compare side by 
side the essential characters of these two classes of bodies." 

Synthetic biology includes morphogeny, physiogeny, and 
synthetic organic chemistry, which is also a branch of synthetic 
biology, since it deals with the composition of the constituents 
of living organisms. Synthetic organic chemistry is already a 
well-organized science, important by reason of the triumphs 
which it has already gained. The other two branches of 
biological synthesis, morphogeny, the synthesis of living forms 
and structures, and physiogeny, the synthesis of functions, can 
hardly as yet be said to exist as sciences. They are, however, 
no less legitimate and no less important than the sister science 
of synthetic chemistry. 

Although morphogeny and physiogeny do not exist as 
well-organized and recognized sciences, there are already a 
number of works on the subject by enthusiastic pioneers 
independent seekers, who have not feared to abandon the 
'paths of official science to wander in new and hitherto 
unexplored domains. 



SYNTHETIC BIOLOGY 115 

The first experiment in physiogeny was the discovery of 
osmosis by the Abbe Nollet in 1748. He filled a pig's bladder 
with alcohol, and plunged it into water. He noticed that the 
bladder gradually increased in volume and became distended, 
the water penetrating into the interior of the bladder more 
quickly than the alcohol could escape. This was the first 
recorded experiment in the physics of nutrition and growth. 

In 1866, Moritz Traube of Breslau discovered the osmotic 
properties of certain chemical precipitates. As I pointed out 
in the Revue Scientifique of March 1906, Traube made the 
first artificial cell, and studied the osmotic properties of 
membranes and their mode of production. This remarkable 
research should have been the starting - point of synthetic 
biology. The only result, however, was to give rise to 
numberless objections, and it soon fell into complete oblivion. 
" There are," says Traube, " a number of persons quite blind 
to all progress, who in the presence of a new discovery think 
only of the objections which may be brought against it." 
The works of Traube have been collected and published by 
his son (Gemmmelte Abhandlungen von Moritz Traube^ 
1899). 

In 1867 there appeared in England a paper by Dr. E. 
Montgomery, of St. Thomas's Hospital, On the Formation of 
so-called Cells in Animal Bodies. This paper, published by 
Churchill & Sons, is a most interesting contribution and 
one of great originality. The author says : " There can be no 
compromise between the tenets of the cell theory and the 
conclusions arrived at in this paper ; the distinction is thorough. 
Either the units of which an organism is composed owe their 
origin to some kind or other of procreation, a mysterious act 
of that mysterious entity life, by which, in addition to their 
material properties, they become endowed with those peculiar 
metaphysical powers constituting vitality. Or, on the other 
hand, the organic units, like the crystalline units of inorganic 
bodies, form the organism by dint of similar inherent qualities, 
form in fact a living being possessed of all its inherent 
properties, as soon as certain chemical compounds are placed 
under certain physical conditions. If the former opinion be 



Ii6 THE MECHANISM OF LIFE 

true, then we must clearly understand that there exists 
naturally a break in the sequence of evolution, a chasm 
between the organic and the inorganic world never to be 
bridged over. If, on the contrary, the latter view be correct, 
then it strongly argues for a continuity of development, a 
gradual chemical elaboration, which culminates in those high 
compounds which, under surrounding influences, manifest those 
complex changes called vital. 

"Surely it is not a matter of indifference or of mere words, 
if the extreme aim of physiology avowedly be the detection ot 
the different functions dependent on the vital exertions of a 
variety of ultimate organisms, and the discovery of the 
specific stimulants which naturally incite these functions into 
play. Or, on the other hand, if it be understood to consist 
rather in the careful investigation of the succession of chemical 
differentiations and their accompanying physical changes, 
which give rise to the formation of a variety of tissues that 
are found to possess certain specific properties, to display 
certain definite actions due to a further flow of chemical and 
physical modifications. 1 ' 

In 1871 there appeared a memoir by the Dutch savant 
Harting entitled Recherche de Morphologic synthetique sur 
la production artificielk de quelqucs formations calcaires 
organiques. This memoir, says Professor R. Dubois, had 
cost Harting more than thirty years of work. " Synthetic 
morphology is yet only in its infancy, let us hope that in a 
time equal to that which has already expired since the first 
artificial production of urea, it will have made a progress 
equal to that of its older sister, synthetic chemistry." 

In the Comptes Rendues of 1882 is the following note 
by D. Monnier and Karl Vogt : 

" 1. Figured forms presenting all the characteristics of 
organic growth, cells, porous canals, tubes with partition walls, 
and heterogeneous granules, may be produced artificially in 
appropriate liquids by the mutual action of two salts which 
form one or more insoluble salts by double decomposition. 
One of the component salts should be in solution, while the 
other salt must be introduced in the solid form. 



SYNTHETIC BIOLOGY 117 

44 52. Such forms of organic elements, cells, tubes, etc., may 
be produced either in an organic liquid or a semi-organic 
liquid such as sucrate of lime, or in an absolutely inorganic 
liquid such as silicate of soda. Thus there can no longer be 
any question of distinctive forms as characterizing organic 
bodies in contradistinction to inorganic bodies. 

"3. The figured elements of these pseudo-organic forms 
depend on the nature, the viscosity, and the concentration of 
the liquids in which they are produced. Certain viscous 
liquids such as solutions of gum arabic or chloride of zinc do 
not produce these forms. 

" 4. The form of these artificial pseudo-organic products is 
constant, as constant as that of the crystalline forms of 
mineral salts. This form is so characteristic that it may 
often serve for the recognition of a minimal proportion of a 
substance in a mixture. The observation of these forms is 
a means of analysis as sensitive as that of the spectrum. 
We may, for example, differentiate in this way the alkaline 
bicarbonates from the sesqui-carbonates or the carbonates. 

44 5. The form of these artificial pseudo-organic elements 
depends principally on the nature of the acid radical of the 
solid salt. Thus the sulphates and the phosphates generally 
produce tubes, while the carbonates form cells. 

44 6. As a rule these pseudo-organic forms are engendered 
only by substances which are found in the living organism. 
Thus sucrate of calcium will engender organic forms, whereas 
sucrate of strontium or barium does not do so. There are, 
however, some exceptions to this rule, such as the sulphates 
of copper, cadmium, zinc, and nickel. 

u 7. These artificial pseudo-organic elements are surrounded 
by veritable membranes, dializing membranes which allow 
only liquids to pass through them. These artificial cells have 
heterogeneous cell-contents, and produce in their interior 
granulations which are disposed in a regular order. Thus 
they are both in constitution and in form absolutely similar 
to the cellular elements which constitute living organisms. 

44 8. It is probable that the inorganic elements which are 
present in the natural protoplasm may play an important part 



Ii8 THE MECHANISM OF LIFE 

in determining the form which is assumed by the figured 
elements of the organism." 

In 1902, Professor Quinke of Heidelberg, who has conse- 
crated his life with such distinction to the physics of liquids, 
writes thus of the organogenic power of liquids in a paper 
published in the Annalen der Physlk under the title 
" Unsichtbare Fliissigkeitschichtcn " : " In 1837, Gustav Rose 
obtained organic forms by precipitation from inorganic 
solutions. By precipitating chloride of calcium with the 
carbonates of ammonium and other alkaline carbonates, he 
obtained small spheres which grew and were transformed 
into calcic rhombohedra. He also obtained a flocculent 
precipitate which later became granular and showed under 
the microscope forms like the starfish, and discs with 
undulated borders. At Freiberg, in certain stalactites, 
Rose also discovered forms consisting of six pyramidal cells 
around a spherical nucleus. 

"In 1889, Link obtained spherical granulations by the 
precipitation of calcic or plumbic solutions by potash, soda, or 
carbonic acid. These spherical granulations united after a 
time to form crystals. Sulphate of iron, ammoniated sulphate 
of zinc, sulphate of copper precipitated by sulphuretted 
hydrogen, and saline solutions precipitated by ferrocyanide 
of potash, all give granular precipitates or discs, of which the 
granular origin is quite perceptible. 

"Runge in 1855 was the first to describe the formation of 
periodic chemical precipitates. He used blotting paper as 
the medium in which various chemical substances met by 
diffusion. In this way he studied the mutual reactions of 
solutions of ferrocyanide of potash, chloride of iron, and 
the sulphates of copper, iron, manganese, and zinc. The 
coloured precipitates appeared at different positions in the 
paper, and disappeared periodically at greater or longer 
intervals. The designs formed by these coloured precipitates 
change with the concentration of the saline solutions, or on 
the addition of oxalic acid, salts of potash or ammonia, and 
other substances. These designs are shown in a number of 
beautiful illustrations which accompany the work. In this 



SYNTHETIC BIOLOGY 119 

case the capillarity of the paper necessarily exerts a certain 
influence on the formation of the figures, but in addition to 
this, Runge admits the intervention of another force hitherto 
unknown, which he calls ' Bildungstrieb, 1 the formative 
impulse, which he considers to be the elementary vital force 
in the formation of plants and animals. 

" In 1867, R. Bottger obtained arborescent forms and 
ramifications of metallic vegetation by sowing fragments the 
size of a pea of crystals of the iron chlorides, chloride of 
cobalt, sulphate of manganese, nitrate and chloride of copper, 
etc., in an aqueous solution of silicate of sodium of specific 
gravity 1'18. These forms are due, as I shall show later 
on, to the surface tension of the oily precipitate ; Bottger gives 
no explanation of the phenomenon. 

u To this force, vi/. that of surface tension, is also due the 
cellular forms obtained by Traube in 1866. These were 
obtained from gelatine and tannin, from acetate of copper or 
lead, and from nitrate of mercury in an aqueous solution of 
ferrocyanide of potassium. These cells and precipitated 
membranes have also been studied by Reinke, F. Cohn, H. de 
Vries, and myself, who all observed the regression of these 
membranes, which although colloidal at the beginning of the 
reaction speedily become friable. This entirely refutes the 
opinion of Traube as to the constitution of the precipitated 
membranes. He supposed them to consist of masses of solid 
substance, with smaller orifices which do not permit the 
passage of the membranogenous substance, whilst the larger 
orifices through which it can pass are soon closed by the 
precipitate, the membrane itself thus growing by a process 
of intussusception. 

" Later on Traube himself considered the precipitated 
membrane to be a thin, solid gelatinous layer in which the water 
was mechanically entangled. 

"Tamman has also made a number of experiments with 
solutions of the chlorides and sulphates of the heavy metals, 
and solutions of phosphates, silicates, ferrocyanides, and other 
salts. He found that most of these membranes were permeable 
to the membranogenous solution. According to Tamman, all 



120 THE MECHANISM OF LIFE 

precipitated membranes are hy drat eel substances, and some of 
them, like the ferrocyanide of copper and the tannate of 
gelatine are, when first formed, entirely comparable to liquid 
membranes in all their properties. 

" Graham had already obtained colourless jellies by the 
interaction of concentrated solutions of ferrocyanide of potas- 
sium and sulphate of copper. Blitschli also has recently 
described the microscopic appearance of precipitated mem- 
branes produced by ferrocyanide of potassium and acetate or 
chloride of iron. 

"Like Linke and Gustav Rose, Famintzin has obtained 
spheroidal precipitates by the reciprocal action of concentrated 
solutions of chloride of calcium and carbonate of potassium. 
These grow rapidly and suddenly, with concentric layers 
showing a spherical or flattened nucleus. He also obtained 
forms resembling sphero-crystals and starch grains. 

" Hartirig, Vogelsang, Hansen, Blitschli, and others have 
studied the structures which are formed by the reciprocal 
action of chloride of calcium and the alkaline carbonates. 
Vogelsang has found small calcareous bodies in the amorphous 
and globular precipitate formed by chloride of calcium and 
carbonate of ammonium. He describes spheres attached to one 
another, vesicles, and muriform structures. The number of 
these spheroids is increased by the addition of gelatine. 
Hansen has also studied Hal-ting's method for the formation 
of sphero-crystals by the action of the alkaline carbonates 
and phosphates on the salts of calcium in presence of albumen 
and gelatine. He considers that the latter retard the crystal- 
lization and assist the formation of the sphero-crystals. 

" I shall show later on that gelatine and albumen essentially 
modify the precipitate and do not merely act as catalytic 
substances. The researches of Famitzin, repeated and extended 
by Biitschli, show that sphero-crystals are produced by the 
reaction of chloride of calcium on carbonate of potassium 
without the presence of gelatine or albumen. Biitschli studied 
the spheroids of carbonate of lime by means of polarized light, 
and found that the layers were alternately positively and 
negatively polarized," 



SYNTHETIC BIOLOGY 121 

Such is the history of morphogenesis as described in 1902 
by the authority most qualified for the task, Professor Quinke 
of Heidelberg. 

In 1904, Professor Moritz Benedikt of Vienna treated the 
whole question in his book, Crystallization and Morphogenesis -, 
of which a French translation appeared in the Maloine Library. 
This book is full of original and suggestive ideas ; it describes 
the work of Harting, and more especially that of Van Sehroen, 
who considers that crystals like living beings begin as a cell 
and grow by a process of intussusception. Professor Benedikt 
has made a complete resume of the question in an article, " The 
Origins of the Forms of Life," which appeared in the Revue 
Scientlfique in 1905. 

In 1904, Professor Dubois of Lyons presented a report to 
the Society of Biology on his interesting experiments on 
mineral cytogenesis. The same year he gave a discourse at the 
university of Lyons on "The Creation of Living Beings," 
which has been published by A. Storck of Lyons. 

One of the most active of the modern morphogenists is 
Professor Herrera of Mexico, whose work is illustrated in the 
Atlas de Plasmogenie by Dr. Jules Felix of Brussels, one of the 
most enthusiastic disciples of the new science. There is a 
resume of Herrera's work in the Memoirs of the Societe 
Alzate, Mexico. 

A bibliography of the works which have appeared on this 
subject may be found in the book of Professor Rhumbler of 
Gottingen, Aus dent Liickengebiete zwischen Organischer und 
Anorganisclier Materie, 1906. 

In 1907, Dr. Luiz Razetti of Carracas published a magnifi- 
cent study of the subject under the title Qne es la vlda. 

In 1907, Dr. Martin Kuckuck of St. Petersburg repeated 
and extended the experiments of R. Dubois, and published his 
results under the title Archigonia, Generatio Spontanea, 
Leipzig, Ambrosius Barth. 

Butler Burke of Cambridge has also made a series of 
experiments with radium and barium salts analogous to those 
of Dubois. 

In 1909, Albert and Alexandre Mary of Beauvais published 



122 THE MECHANISM OF LIFE 

an interesting study of this question under the title Etudes 
experimentales sur la generation primitive^ published by Jules 
Rousset. 

I should mention also among the works of synthetic biology 
the publications of Professor Otto Lehmann of Karlsruhe, and 
in particular Fliissige Krystalle und die Theonen des Lebens, 
Leipzig, Ambrosius Barth. 

Professor Ulenhuth of Berlin has published his study 
on the osmotic growth of iron in alkaline hypochlorites under 
the title Untersuchungen ueber Antiformin, Berlin, Julius 
Springer. 

Professor Gariel has made a series of researches on osmotic 
growth which are published in Abraham's Recue'd (Feocperi- 
ences de physique. 

A. Lecha Marzo of Valladolid published his researches on 
the growth of aniline colours in the Gaceta Medica Catalana, 
1909, under the title Otra nueva flora artificiale. 

Dr. Maurice d'Halluin of Lille has also published a volume 
on osmotic growths under the title, Stephane Leduc a-t-il crce 
la vie? 

The subjects of the numerous memoirs that I have myself 
published during the last ten years upon the question are 
treated anew in the pages of this volume, and a resume of my 
researches on osmotic growth has already appeared in the 
Documents du Pr ogres, Sept. 1909. 

We have thus shown that synthetic morphogenesis has 
already attracted the attention of a certain number of ardent 
investigators. Morphogeny has now its methods and its 
results, and physiogeny is also developing side by side with it, 
since function is but the result of form. The field of research 
is opened, and workers alone are needed in order to reap an 
abundant harvest 



CHAPTER XI 

OSMOTIC GROWTHA STUDY IN MORPHOGENESIS 

THE phenomenon of osmotic growth has doubtless presented 
itself to the eyes of every chemist ; but to discover a pheno- 
menon it is not enough merely to have it under our eyes. 
Before Newton many a mathematician had seen a spectrum, 
if only in the rainbow ; many an observer before Franklin 
had watched the lightning. To discover a phenomenon 
is to understand it, to give it its due interpretation, and to 
comprehend the importance of the role which it plays in the 
scheme of nature. 

Osmotic Membranes. Certain substances in concentrated 
solution have the property of forming osmotic membranes 
when they come in contact with other chemical solutions. 
When a soluble substance in concentrated solution is immersed 
in a liquid which forms with it a colloidal precipitate, its 
surface becomes encased in a thin layer of precipitate which 
gradually forms an osmotic membrane round it. 

An osmotic membrane is not a semi-permeable membrane, 
as sometimes described, i.e. a membrane permeable to water 
but impermeable to the solute. It is a membrane which 
opposes different resistances to the passage of water and of 
the various substances in solution, being very permeable to 
water, but much less so to the different solutes. 

A soluble substance thus surrounded by an osmotic 
membrane represents what Traube has called an artificial 
cell. In such a cell the dissolved substances have a very 
high osmotic pressure, an expansive force like that of 
steam in a boiler ; the molecules of the solute exerting pressure 

on the walls of the extensible cell, and distending it like the 

123 



124 THE MECHANISM OF LIFE 

gas in a balloon. This pressure increases the volume of the 
cell, and in consequence water rushes in through the permeable 
membrane ai;d still further distends the cell. Most beautiful 
osmotic cells may be produced by dropping a fragment of 
fused calcium chloride into a saturated solution of potassium 
carbonate or tribasic potassium phosphate, the calcium 
chloride becoming surrounded by an osmotic membrane of 
calcium carbonate or calcium phosphate. This mineral 
membrane is beautifully transparent and perfectly extensible. 
It is astonishing to contemplate the contrast between the 
hard crystalline forms of ordinary chalk and these soft tran- 
sparent elastic membranes which have the same chemical 
constitution. These osmotic cells of carbonate of lime or 
phosphate of lime consist of a transparent membrane enclosing 
liquid contents and a solid nucleus of chloride of calcium. 
Their form is that of an ovoid or flattened sphere, and they 
may attain a diameter of seven centimetres or more. 

More frequently the osmotic growth consists of a number 
of cells instead of one large cell. The first cell gives birth to 
a second cell or vesicle, and this to a third, and so on, so that 
we finally obtain an association of microscopic cellular cavities, 
separated by osmotic walls a structure completely analogous 
to that which we meet with in a living organism. 

We may easily picture to ourselves the mechanism by 
which an osmotic cell gives birth to such a colony of 
microscopic vesicles. The membranogenous substance, the 
chloride of calcium, diffuses uniformly on all sides from the 
solid nucleus, and forms an osmotic membrane where it comes 
into contact with the solution. This spherical membrane is 
extended by osmotic pressure, and grows gradually larger. 
Since the area of the surface of a sphere increases as the square 
of its radius, when the cell has grown to twice its original 
diameter, each square centimetre of the membrane will receive 
by diffusion but a quarter as much of the membranogenous 
substance. Hence, after a time, the membrane will not be 
sufficiently nourished by the membranogenous substance, 
it will break down, and an aperture will occur through which 
the interior liquid oozes out, forming in its turn a new 



OSMOTIC GROWTH 



125 



membranous covering for itself. This is the explanation of 
the fact that all living organisms are formed by colonies of 
microscopical elements, although we must not forget that 
Nature often produces similar 
results in different ways. 

Osmotic growths may be 
obtained from a great number 
of chemical substances. The 
most easily grown are the 
soluble salts of calcium in 
solutions of alkaline phos- 
phates and carbonates, to 
which we have already al- 
luded. We may also reverse 
the phenomenon by growing 
phosphates and carbonates 
in solutions of calcium salts, 
but in this case the osmotic 
growths are not so beautiful. 

The various silicates play 
an important part in the con- 
stitution of shells and of the 
skeletons of marine animals. 
Most of the metallic salts, and 
more especially the soluble 
salts of calcium, give rise to 
the phenomenon of osmotic 
growth when sown in solutions 
of the alkaline silicates. In this way, by using different 
silicates and varying the proportions and the concentra- 
tions, we may obtain an immense variety of osmotic 
growths. 

A good solution to commence with is the following: 

Silicate of potash, sp. gr. 1-3 (33 Keaume) . . 60 gr. 
Saturated solution of sodium carbonate . . .60 gr. 
Saturated solution of dibasic sodium phosphate . 30 gr. 
Distilled water . . . make up to 1 litre. 




FIG. 35. FIG. 36. 

Osmotic growths ot ferrocyanide ol 

copper. 



126 THE MECHANISM OF LIFE 

A fragment of fused calcium chloride dropped into this 
solution will produce a rapid growth of slender osmotic forms 
which may attain a height of 20 or BO centimetres. 

Small pellets may also be made of one part of sugar and 
two of copper sulphate and sown in the following solution, 
which must be kept warm until the growth is complete : 

Ten per cent, solution of gelatine . . . 10 to 20 c.c. 

Saturated solution of potassium ferrocyanide . 5 to 10 c.c. 

Saturated solution of sodium chloride . . 5 to 10 c.c. 

Warm water (32 to 40 C.) . . . 100 c.c, 




FIG. 37. Osmotic vermiform growth. 

(a] The sickle-shaped growth. 

(b] The growth broken by the upward pressure of the solution. 

(c] The wound having cicalri/cd, the stem continues to grow downwards. 

In this solution we can obtain osmotic growths which 
may attain to a height of 40 centimetres or more, vegetable 
forms, roots, arborescent twigs, loaves, and terminal organs. 
These growths are stable as soon as the gelatine* has cooled and 
set, and may be carried about without fear of injury (Fig. 35). 

Precipitated osmotic membranes are very widely distributed 
in nature. Professor Ulenhuth has seen iron growths in 
alkaline sodium hypochlorite (Javelle water), and Lecha- 
Marzo has demonstrated the osmotic growth of the various 



OSMOTIC GROWTH 127 

stains used for microscopy, in the liquids used for fixing pre- 
parations. 

We now know that the physical force which builds up these 
growths is that of osmotic pressure, since the slightest considera- 
tion will show the inadequacy of the usual explanation that the 
growth is due to mere differences of density, or to amorphous 
precipitation around bubbles of gas. These may indeed affect 
the phenomenon, but can in no way be regarded as its cause. 

One of our experiments throws considerable light on this 
question. In a glass vessel we placed a concentrated solution 
of carbonate of potassium, to which had been added 4 per 
cent, of a saturated solution of tribasic potassium phosphate. 
Into this solution we dropped a fragment of fused calcium 
chloride, and obtained a vermiform growth some 6 milli- 
metres in diameter. This growth was curved, at first growing 
upwards, then for a short distance horizontally, and finally 
downwards. The upward pressure of the solution, which was 
heavier than the growth, ultimately broke it at the top of the 
curve, as shown at &, Fig. 37. The liquid contents of the 
growth began to ooze out through the wound, but this after 
a time became cicatrized, and the stem continued to grow 
obstinately downwards once more, in opposition to the hydro- 
static pressure. In consequence of this pressure the growth 
is sinuous, tacking as it were from side to side like a boat 
against the wind. We give three successive photographs of 
this growth, which attained a length of over 10 inches. We 
have frequently obtained these vermiform growths forming 
a series of such loops, growing upwards and falling again 
many times in succession. 

Osmotic Growths in Air. Certain of these artificial cells 
may be made to grow out of the solution into the air. For 
this purpose we place a fragment of CaCl 2 in a shallow flat- 
bottomed glass dish, just covering the fragment with liquid. 
The best solution is as follows : 

Potassium carbonate, saturated solution . . 76 parts. 
Sodium sulphate, saturated solution . . . 
Tribasic potassium phosphate, saturated solution . 4 



128 THE MECHANISM OF LIFE 

The calcium chloride surrounds itself with an osmotic 
membrane ; water penetrates into the interior of the cell thus 
formed, and a beautiful transparent spherical cell is the result, 
the summit of which soon emerges from the shallow liquid. 
The cell continues to increase by absorption of the liquid at 
its base, and may grow up out of the liquid into the air for 
as much as one or two centimetres. 

This is a most impressive spectacle, an osmotic production, 
half aquatic and half aerial, absorbing water and salts by its 
base, and losing water and volatile products by evaporation 
from its summit, while at the same time it absorbs and 
dissolves the gases of the atmosphere. 

The aerial portion of an osmotic growth will sometimes 
become specialized in form. The summit of the growth 
develops a sort of crown or cup surrounded by a circular wall. 
This cup contains liquid, and continues to grow up into the 
air like the stem of a plant, carrying with it the liquid which 
has been absorbed by the base of the growth. 

The preceding experiments give us an explanation of the 
curious phenomena exhibited by so-called creeping salts. A 
saline solution left at the bottom of a vessel will sometimes be 
found after some months to have crept up to the top of the 
vessel. Cellular partitions formed in this way will be found 
extending from the bottom to the top of the vessel, and not 
only so, but the whole of the remaining liquid will be im- 
prisoned in the upper cells. 

Assimilation and Excretion. Like a living being, an 
osmotic growth absorbs nutriment from the medium in which 
it grows, and this nutriment it assimilates and organizes. If 
we compare the weight of an osmotic growth with that of the 
mineral fragment which produced it, we shall find that the 
mineral seed has increased many hundred times in weight. 
Similarly, if we weigh the liquid before and after the experi- 
ment, we shall find that it has lost an equivalent weight. 
The absorbed substance of an osmotic production must also 
undergo chemical transformation before it can be assimilated 
that is, before it can form part of the growth. Calcium 
chloride, for example, growing in a solution of potassium car- 




FIG. 38. Osmotic growth produced by sowing a mixture of CaCl 2 and MnCl 2 
in a solution of alkaline carbonate, phosphate, and silicate. The stem and 
terminal organs are of different colours. (One-third of the natural size.) 

9 



130 



THE MECHANISM OF LIFE 



bonate, is transformed into calcium carbonate. CaCl 2 + K 2 CO :i 
Thus an osmotic rowth can make a 




FlG. 39. An osmotic growth photographed by transverse light to show the 
construction of the terminal organs. 

choice between the substances offered to it. rejecting the 
potassium of the nutrient liquid, and absorbing water and the 
radical C0 a , while at the same time it eliminates and excretes 



OSMOTIC GROWTH 




FlG. 40. Osmotic growth in a solution of 
KNO-j, showing spine-like organs. 



chlorine, which may be found in the nutrient liquid after the 
reaction. 

Of all the ordinary physi- 
cal forces, osmotic pressure 1 
and osmosis alone appear 
to possess this remarkable 
power of organization and 
morphogenesis. It is a 
matter of surprise that this 
peculiar faculty has hitherto 
remained almost unsus- 
pected. 

Oxmotic Growths. If we 
sow fragments of calcium 
chloride in solutions of the 
alkaline carbonates, phos- 
phates, or silicates, we obtain 
a wonderful variety of fili- 
form and linear growths which may attain to a height of 
30 or 40 centimetres Some are so flexible that the sterns 

bend, falling in curves 
around the centre of growth, 
like leaves of grass. If we 
dilute this same liquid, as it 
becomes less concentrated 
the growths are more curved, 
ramified, dendritic, like 
those of trees or corals. 

In the culture of osmotic 
growths we may also by 
appropriate means produce 
terminal organs resembling 
flowers and seed-capsules. 
To do this we wait till 
the growth is considerably 
advanced, and then add a 

large quantity of liquid to the nutrient solution so as to 
diminish the concentration a hundredfold or more. Spherical 




FIG. 41. Terminal organs like catkins, 
developing in a solution of ammonium 
chloride. 



132 



THE MECHANISM OF LIFE 



terminal organs will then grow out from the ends of the 
stems, which may during their further growth become conical 
or pirifonu in shape. 

By superposing layers of liquid of different concentration 
and decreasing density, one may obtain knots and swellings 
in the osmotic growths marking the sin-faces of separation 
of the liquid. When a young growth in the vigour of its 
youth reaches the surface of the water, it spreads out 
horizontally over the surface of the liquid in thin leaves or 
foliaceous expansions of different forms. 




FIG. 42. An osmotic madrepore 

The preponderating influence in morphogenesis is osmotic 
pressure, the osmotic forms varying with its intensity, dis- 
tribution, and mode of application. Whatever the chemical 
composition of the liquid, similar osmotic forces, modified in 
the same manner, give rise to forms which have a family 
resemblance. The chemical nature of the liquid, however, is 
not entirely without influence on the form. Thus the presence 
of a nitrate in the mother liquor tends to produce points or 
thorns. Ammonium chloride in a potassium ferrocyanide 
solution produces growths shaped like catkins, and the alkaline 
chlorides tend to produce vermiform growths. 



OSMOTIC GROWTH 133 

Coralline growths may also be obtained by using appro- 
priate chemical solutions. For this purpose the solution 
of silicate, carbonate, and dibasic phosphate should be diluted 
to half strength, with the addition of 2 to 4 per cent, of a 
concentrated solution of sodium sulphate or potassium nitrate. 

Coral-like forms may also be grown from a semi-saturated 
solution of silicate, carbonate, and dibasic phosphate, to which 




FIG. 43. An osmotic mushroom form. 

has been added 4 per cent, of a concentrated solution of 
sodium sulphate or potassium nitrate. In this we may obtain 
beautiful growths like madrepores or corals, formed by a 
central nucleus from which radiate large leaves like the petals 
of a flower. The presence of nitrate of potassium produces 
pointed leaves with thorn-like processes recalling the forms 
of the aloe and the agave. 

Most remarkable fungus-like forms may be obtained by 
commencing the growth in a concentrated solution, and then 



134 THE MECHANISM OF LIFE 

carefully pouring a layer of distilled water over the surface of 




FIG. 44. Osmotic fungi. 



the liquid. The resemblance is so perfect that some of our 
productions have been taken for fungi even by experts. The 




FIG, 45. A shell-like calcareous osmotic growth. 



OSMOTIC GROWTH 



135 



stem of these osmotic fungi is formed of bundles of fine hollow 




FIG. 46. Osmotic growths in the form of shells. 

fibres, while the upper surface of the cap is sometimes smooth, 
and sometimes covered with small scales. The lower surface 




Fin. 



. 47. Capsnlar osmotic growth. The capsule has been broken to show 
the interior structure. 

of the cap shows traces of radiating lamellae, which are 
sometimes intersected by concentric layers parallel to the outer 



136 



THE MECHANISM OF LIFE 



surface of the cap. In this case the lower surface of the cap 
shows a number of orifices or canals similar to those seen in 
many varieties of fungus. 

Shell-like osmotic productions may be grown by sowing the 



S 
*'' 




FlG. 48. An osmotic growth in which the terminal organs are differently 
coloured from the stems, showing that the chemical evolution is different. 

mineral in a very shallow layer of concentrated solution, a 
centimetre or less in depth, and pouring over this a less con- 
centrated layer of solution. By varying the solution or concen- 
tration we may thus grow an infinite variety of shell forms. 



OSMOTIC GROWTH 



137 



Capsules or closed shells may be produced in the same way 
by superimposing a layer of somewhat greater concentration. 
These capsules consist of two valves joined together at their 
circumference. The lower valve is thick and strong, while the 
upper valve may be transparent, translucent, or opaque, but is 
always thinner and more fragile than the lower one. 

Ferrous sulphate sown in a silicate solution gives rise to 
growths which are green 
in colour, climbing, or 
herbaceous, twining in 
spirals round the larger 
and more solid calcareous 
growths. 

With salts of man- 
ganese, the chloride, 
citrate or sulphate, the 
stages of evolution of the 
growth are distinguished 
not only by diversities of 
form, but also by modifi- 
cations of colour. We 
may thus obtain terminal 
organs black or golden 
yellow in colour on a white 
stalk. In a similar way 
we may obtain fungi with 
a white stalk and a yellow 
cap, of which the lower 
surface is black. 




FlG. 49. Osmotic capsular growth with 

figured belt. 



Very beautiful growths may be obtained by sowing calcium 
chloride in a solution of potassium carbonate, with the addition 
of per cent, of a saturated solution of tribasic potassium 
phosphate. This will give capsules with figured belts, vertical 
lines at regular intervals, or transverse stripes composed of 
projecting dots such as may be seen in many sea-urchins. 
These capsules are closed at the summit by a cap, forming an 
operculum, so that they sometimes appear as if formed of two 
valves. Now and again we may see the upper valve raised by 



138 



THE MECHANISM OF LIFE 



the internal osmotic pressure, showing the gelatinous contents 
through the opening. 




FIG. 50. Amoeboid osmotic growth, floating free in the mother liquor. 

The calcareous capsules grown in a saturated solution of 
potassium carbonate or phosphate often take a regular ovoid 

form. If these arc 
allowed to thicken, 
they may be taken out 
of the water without 
breaking, and then 
present the aspect of 
veritable ooliths. 

Osmotic produc- 
tions may be divided 
into two groups. 
Some like the silicate 
growths are fixed. 
Like vegetables, they 
develop, become or- 
gan i/ed, grow, decline, 
die, and are disin- 

Fin. 51. Transparent osmotic cell, in which may tcgl'ated at the spot 
be seen the white calcareous nucleus. The where they are SOWll. 
summit of the cell bears osmotic prolongations. Others especiallv 

those which are grown 

in alkaline carbonates and phosphates, have two periods of 
evolution, the first a fixed period, and the second a wandering 




OSMOTIC GROWTH 



139 



one. During the first period their specific gravity is greater 
than that of the surrounding medium, and they rest immobile 




Flc;. 52. Amctboid osmotic growth with long crystalline cilia swimming 
about in the mother liquor. 

at the bottom of the vessel in which they are sown. As they 
grow, they absorb water and their specific gravity diminishes. 




FlG. 53. Osmotic growth swimming in mother liquor. The fin-like pro- 
longation grew out between two liquid layers of different concentrations. 

Little by little they rise up in the liquid, and finally acquire 
a considerable amount of mobility, being readily displaced by 
every current. Hence it is very difficult to photograph these 



140 



THE MECHANISM OF LIFE 



mobile osmotic growths, which swim about in the mother liquor 
and are often provided with prolongations in the forms of cilia, 
and sometimes with fins, which undulate as they move. Some 
of these ciliary hairs are evidently osmotic in their origin, 
being localized as a tuft at the summit of the growth. Others 

are apparently crys- 
talline in structure, and 
are spread over the 
whole surface of the 
swimming vesicle. An 
osmotic growth in- 
creases by the absorp- 
tion of water from a 
concentrated solution. 
When the solution is 
originally saturated it 
thus becomes super- 
saturated, and deposits 
these long ciliary crys- 
tals on the surface of 
the growth. 

When a capsule 
splits in two under the 
influence of the internal 
osmotic pressure, it may 
happen that the oper- 

v , . 4 , . culum or upper valve 

riG. 54. Capsular osmotic growth, the two . 

valves separated showing the colloidal con- floats away ill the 
tents. liquid. We thus obtain 

a free swimming organ- 
ism, a transparent bell-like form with an undulating fringe, 
like a Medusa. 

Frequently a single seed or stock will give rise to a whole 
series of osmotic growths. A vesicle is first produced, and 
then a contraction appears around the vesicle, and this con- 
traction increases till a portion of the vesicle is cut off* and 
swims away free like an amoeba. The same phenomenon may 
be observed with vermiform growths, a single seed often giving 




OSMOTIC GROWTH 



141 



rise in this way to a whole series of amoebifortn or vermiform 
productions. 

It must be remembered that in an osmotic growth the 
active growing portion is the gelatinous contents in the interior, 
the external visible growth being only a skeleton or shell. We 
may sometimes succeed in hooking up one of these long 
vermiform growths, breaking the calcareous sheath, and draw- 
ing out a long undulating translucid gelatinous cylinder. The 
outline of this cylinder is so well defined as to make us doubt 
whether the fine colloidal 
membrane which separates it 
clearly from the liquid can 
have been formed so rapidly, 
or if it may not perhaps exist 
already formed in the interior 
of its calcareous sheath. 

When a large capsular 
shell such as we have described 
bursts, it expels a part or the 
whole of its contents as a 
gelatinous mass which retains 
the form of the cavity. Simi- 
arly, if we suddenly dilute 
the mother liquor around an 
osmotic cell, it bursts by a 
process of dehiscence, and pro- 
jects into the liquid a part of 
its contents, which may thus 
become an independent vesicle, 
cell may produce a whole series of independent vesicles. 

It is even possible to rejuvenate an osmotic growth that 
has become degenerate through age. An osmotic production 
grows old and dies when it has expended the osmotic force 
contained in the interior of its capsule. A calcium osmotic 
growth which has thus become exhausted may be rejuvenated 
by transferring it to a concentrated solution of calcium chloride. 
It will absorb this, and thus be enabled to renew its evolution 
and growth when put back again into the original mother liquor. 




FIG. 55. Microphotograph showing 
the structure of various osmotic stems. 
(Magnified 25 diameters.) 

(a) Sodium sulphite. 

(b] Potassium bichromate. 

(c) Sodium sulphide. 

(d] Sodium bisulphite. 

In this way a single osmotic 



T42 



THE MECHANISM OF LIFE 



The structure of osmotic growths is no less varied than their 
form. Their stems are formed of cells or vesicles juxtaposed, 
showing cavities separated by osmotic walls. Sometimes the 
component vesicles have kept their original form, so that the 

I 







FIG. 56. Microphotograph showing the structure of osmotic stems. 
(Magnified 40 diameters.) 

stem has the appearance of a row of beads. Or the cells may 
be more or less flattened, the divisions being widely separated. 
Or again, by the absorption of the divisions, a tube may be 
formed, a veritable vessel or canal in which liquids can circulate. 



OSMOTIC GROWTH 



143 



The foliaceous expansions, or osmotic leaves, also present 
great varieties both of appearance and of structure. The 
veins may be longitudinal, fan-shaped, or penniform. We 
have occasionally met with leaves having a lined or ruled 
surface, giving most beautiful diffraction colours. The usual 
structure, however, is vesicular or cellular, as in Fig. 58. In 




FIG. 57. Photograph of an osmotic leaf 
showing the veins. 



photographs we often get the appearance of lacunae, but all 
these lacunae are closed cavities, the appearance being due to 
the transparency of the cell walls. 

In conclusion we may say that osmotic growths are formed 
of an ensemble of closed cavities of various forms, containing 
liquids and separated by osmotic membranes, constituting 
veritable tissues. This structure offers the closest resem- 



144 



THE MECHANISM OF LIFE 



blance to that of living organisms. Is it possible to doubt 
that the simple conditions which produce an osmotic growth 
have frequently been realized during the past ages of the 
earth ? What part has osmotic growth played in the 
evolution of living forms, and what traces of its action may 
we hope to find to-day ? Osmotic growth gives us fibrous 
silicates, phosphatic nodules, corals, and madrepores ; it also 
gives us formations which remind one of the "atolls,"" 
calcareous growths rising like a crown out of the water. 




FIG. 58. Photomicrograph of an osmotic leaf 
showing the cellular structure. 

The geologist may well consider what role osmotic growth 
may have played in the formation of the various rocks, 
siliceous, calcareous, barytic, magnesian, the fibrous and 
nodular rocks and atolls. The palaeontologist relies on the 
different forms found in his rocks to classify his specimens ; 
from the existence of a shell, he concludes the presence of life. 
Since, however, forms which are apparently organic may be 
merely the product of osmotic growth, it is evident that he 
must reconsider his conclusions. The same may be said of 
the various forms of coral or of fungoid growths. In the 



OSMOTIC GROWTH 



T45 




FlG. 59. Osmotic growth with nucleated terminal organs. 
(One-third of the natural size.) 



10 



146 



THE MECHANISM OF LIFE 



presence of a calcified or silicated fungus we can no longer 
argue with certainty as to the existence of life, without taking 
into consideration the possibility that the specimen in question 
may be an osmotic production. 

Whatever our opinion as to its signification, osmotic 




FIG. 60. A group of osmotic plants. 

growth demands the attention of every mind devoted to the 
study of nature. It is a marvellous spectacle to see a formless 
fragment of calcium salt grow into a shell, a madrepore, or a 
fungus, and this as the result of a simple physical force. 
Why should the study of osmotic growth attract less attention 
than the formation of crystals, on which so much time and 
labour has been bestowed in the past? 



CHAPTER XII 

THE PHENOMENA OF LIFE AND OSMOTIC PRO- 
DUCTIONSA STUDY IN PHYSIOGENESIS 

IT is impossible to define life, not only because it is complex, 
but because it varies in different living beings. The 
phenomena which constitute the life of o, man are far other 
than those which make up the life of a polyp or a plant; 
and in the more simple forms life is so greatly reduced 
that it is often a matter of difficulty to decide whether a 
given form belongs to the animal, vegetable, or mineral 
kingdom. Considering the impossibility of defining the exact 
line of demarcation between animate and inanimate matter, it 
is astonishing to find so much stress laid on the supposed 
fundamental difference between vital and non-vital phenomena. 
There is in fact no sharp division, no precise limit where 
inanimate nature ends and life begins ; the transition is 
gradual and insensible, for just as a living organism is made 
of the same substances as the mineral world, so life is a 
composite of the same physical and chemical phenomena 
that we find in the rest of nature. All the supposed 
attributes of life are found also outside living organisms. 
Life is constituted by the association of physico-chemical 
phenomena, their harmonious grouping and succession. 
Harmony is a condition of life. 

We are quite unable to separate living beings from the 
other productions of nature by their composition, since they 
are formed of the same mineral elements. All the aliments of 
plants-r-water, carbon, nitrogen, phosphorus, sulphur before 
their absorption and assimilation belonged to the mineral 

kingdom. The carbon and the water are transformed into 

147 



148 THE MECHANISM OF LIFE 

sugar and fat, the nitrogen and the sulphur into albumen, 
and the compounds so formed are then said to belong to the 
organic world. These organic bodies are returned once again 
to the mineral world by the action of animals and microbes, 
which transform the carbon into carbonates, and the nitrogen, 
sulphur, and phosphorus into nitrates, sulphates, and phosphates. 
Hence life is but a phase in the animation of mineral matter ; 
all matter may be said to have within itself the essence of life, 
potential in the mineral, actual in the animal and the vegetable. 
The flux and reflux of matter is alternate and incessant, from 
the mineral world to the living, and back again from the 
living to the mineral world. 

At the same time there is a continuous flux of energy. 
Organic matter contains potential energy, the energy of 
chemical combination ; and during its passage through the 
living being it is gradually stripped of this energy and returned 
to the mineral world. The first step in synthetic biology is 
the addition of potential energy to matter, the reduction of 
an oxide, the separation of a salt into its radicals, the pro- 
duction of some endothermic chemical combination. The 
energy stored up by such processes can be again liberated as 
heat, that fire which the ancients with wonderful prescience 
long ago recognized as the symbol of life. 

Attempts have been made to differentiate a living being by 
the nature of its chemical combinations, the so-called organic 
compounds. It was supposed that life alone could reali/e 
these and cause the production of the various substances which 
form the structure of living beings. Of late years, however, 
a large number of these organic substances have been artificially 
produced in the laboratory, and the synthetic problems which 
remain are of the same order as those which have been already 
solved. 

As one learns to know the mineral kingdom and the living 
world more intimately the differences between them disappear. 
Thus a living being was supposed to be characterized by its 
sensibility, i.e. its faculty of reaction against external im- 
pressions. But this reaction is a general phenomenon of 
nature ; there is no action without reaction. Neither can the 



THE PHENOMENA OF LIFE 149 

reaction to internal impressions, immediate or deferred, be 
considered as the characteristic of life, since osmotic growths 
exhibit a most exquisite sensibility in this direction. Since, 
then, the faculty of reaction is a general property of matter, 
the characteristics of life in the lower organisms are only three 
in number, vi/. nutrition, growth, and reproduction by fission 
or budding. But crystals are also nourished and grow in the 
water of crystallization. They have moreover a specific form, 
and every biologist who wishes to establish a parallel between 
the phenomena of the living and the mineral world is wont to 
compare living beings with crystals. Crystals, it is said, affect 
regular geometric forms, salient angles, and rectilinear edges, 
while living beings have rounded forms without any geometric 
regularity. Another supposed distinction is that living beings 
are nourished by intussusception, whereas crystals increase by 
apposition. Again, living beings are said to assimilate and 
transform the aliment they absorb, whereas crystals do not 
transform the matter which is added externally to their 
structure. Another supposed difference is that living things 
eliminate and discharge their products of combustion, while 
the evolution of a crystal is accompanied by no such elimina- 
tion. Finally, the phenomenon of reproduction is said to be 
the exclusive characteristic of a living being ; but crystals may 
also be reproduced and multiplied by the introduction of 
fragments of crystalline matter into a supersaturated solution. 

The resemblance between an osmotic growth and a living 
organism is much closer than that between a living being and 
a crystal, there being not only an analogy of form, but also of 
structure and of function. In order to find the physical 
parallel to life, we must turn to osmosis and osmotic growth 
rather than to crystals and crystallization. 

The first and most striking analogy between living beings 
and osmotic growths is that of form. The morphogenic 
power of osmosis gives rise to an infinite variety of forms. 
An osmotic growth, even at the first 'sight, suggests the idea 
of a living thing. One need only glance at the photographs 
of osmotic productions to recognize the forms of madrepore, 
fungus, alga, and shell. It is wonderful that a force capable 



ISO THE MECHANISM OF LIFE 

of such marvellous results should have hitherto been almost 
entirely neglected. 

A second analogy between vital and osmotic growths 
is to be found in their structure, both being formed by groups 
of cells or vesicles separated by osmotic membranes. An 
osmotic stem, formed by a row of cellular cavities separated 
by osmotic membranes, has a great structural resemblance 
to the knotted stems of bamboos, reeds, and the like. The 
foliaceous expansions of osmotic growths are formed by colonies 
of cells or vesicles disposed in regular lines, which may 
present various patterns of innervation, parallel, palmate, 
or pennate. Many of the lamellar osmotic growths are 
striped in parallel lines alternately opaque and transparent. 
The terminal organs have also their enveloping membranes, 
their pulp and nucleus, just like vegetable forms. 

The analogies of function are no less remarkable than 
those of form and structure. Nutrition is perhaps the most 
elementary and essential vital phenomenon, since without 
nutrition life cannot exist. Nutrition consists in the absorp- 
tion of alimentary substances from the surrounding medium, 
the chemical transformation of such substances, their fixation 
by intussusception in every part of the organism, and the 
ejection of the products of combustion into the surrounding 
medium. Osmotic growths absorb material from the medium 
in which they grow, submit it to chemical metamorphosis, 
and eject the waste products of the reaction into the sur- 
rounding medium. An osmotic growth moreover exercises 
choice in the selection of the substances which are offered for 
its consumption, absorbing some greedily and entirely rejecting 
others. Thus osmotic growths present all the phenomena of 
nutrition, the fundamental characteristic of life. 

In the living organism nutrition results in growth, 
development, and evolution. Growth and development also 
follow the absorption and fixation of aliment by an osmotic 
production. An osmotic production grows, its form develops 
and becomes more complicated, and its weight increases. An 
osmotic growth may weigh many hundred times as much as 
the mineral sown in the solution, the mother liquor losing a 



THE PHENOMENA OF LIFE 151 

corresponding weight. Thus growth, which has hitherto been 
considered an essential phenomenon of life, is also a phenomenon 
common to all osmotic productions. 

Osmotic growths like living things may be said to have an 
evolutionary existence, the analogy holding good down to the 
smallest detail. In their early youth, at the beginning of 
life, the phenomena of exchange, of growth, and of organiza- 
tion are very intense. As they grow older, these exchanges 
gradually slow down, and growth is arrested. With age the 
exchanges still continue, but more slowly, and these then 
gradually fail and are finally completely arrested. The 
osmotic growth is dead, and little by little it decays, losing its 
structure and its form. 

The membranes of an osmotic growth thicken with age, 
and thus oppose to the osmotic exchanges a steadily increasing 
resistance. Young osmotic cells appear swollen and turgescent, 
whereas old ones become flaccid, relaxed, and wrinkled. Ana- 
logous phenomena are met with in living organisms, the 
calcareous infiltration of the vessels representing the thicken- 
ing and hardening of the osmotic membranes. The plumpness 
of a child and the turgescence of young cells are but the 
expression of high osmotic tension, while relaxation and 
flaccidity of the tissues in old age betrays the fall of osmotic 
pressure in the intracellular tissues. 

Circulation of the nutrient fluid may also be observed in 
an osmotic growth as in a living organism. If we take a 
calcareous growth with long ramified stems and dilute the 
mother liquor considerably, we may see currents of liquid 
issuing from the summit of the growth currents which are 
made visible by the cloudy precipitates which they cause. 
The same current is also rendered visible in the stems them- 
selves by the motion of the granulations and gas bubbles in 
the interior of the osmotic cells. It is plain that some 
such circulation must exist, for how could a membrane be 
formed 30 centimetres from the seed if the membranogenous 
substance did not circulate through the stem ? A moment's 
consideration will show that the propulsion is due to osmotic 
pressure and not to mere differences of density, for the liquid 



152 THE MECHANISM OF LIFE 

which rises in the stem is a concentrated solution of calcium 
salt much denser than the mother liquor, and the current of 
liquid after rising in the si em may be seen to fall back again 
through the liquid. 

Organization has long been considered as one of the 
principal characteristics of life, I.e. the arrangement of matter 
so as to produce an animated and evolutionary form accom- 




FIG. 61. A group of osmotic orms. 

panied by transformation of energy. But osmotic growths are 
also organizations endowed with the same faculties, and the 
physical mechanism which is at the basis of their formation 
is the same as that which determines the organization of living 
matter. 

The phenomena of osmotic growth show how ordinary 
mineral matter, carbonates, phosphates, silicates, nitrates, and 
chlorides, may imitate the forms of animated nature without 



THE PHENOMENA OF LIFE 153 

the intervention of any living organism. Ordinary physical 
forces are quite sufficient to produce forms like those of living 
beings, closed cavities containing liquids separated by osmotic 
membranes, with tissues similar to those of the vital organs in 
form, colour, evolution, and function. 

It is only necessary to glance at the photographs of these 
osmotic growths to appreciate the wonderful variety of form. 
The variety of function is not less evident, and in many 
instances, especially with manganese salts, the difference of 
function of various regions is marked by differences of 
colour. When a large osmotic cell projects beyond the mother 
liquor and grows up into the air, it is evident that the function 
of liquid absorption must be locali/ed in the submerged part. 
In other cases we have a local evolution of gas, which may 
be demonstrated by growing a fragment of calcium chloride in a 
mother liquor composed of the following saturated solutions : 

Potassium carbonate . .76 parts. 
Potassium sulphate . 16 

Tri basic potassium phosphate . 4(> 

During the whole period of growth there is an abundant 
liberation of bubbles of gas, which is acurately limited to a 
belt around the base of the growth, and sometimes also to a 
cap at the summit. 

Since morphological differentiations of different parts is 
but the result of differences of evolution, i.e. of functional 
differences of the various parts, we may consider that osmotic 
growths possess the faculty of organization I ; ke living beings. 

An osmotic growth may be wounded, and a wound delays 
its growth and development like a disease or an accident in 
a living being. A wound in an osmotic production may also 
become cicatrized and covered with a membrane, when the 
growth will recommence exactly as in a living being. 

An osmotic growth is a transformer of energy. It 
increases in bulk, pushing aside the mother liquor, and thus 
doing external work. An osmotic growth has a temperature 
above its medium, since the chemical reaction of which it is 
the seat is accompanied by the production of heat. We know 



154 THE MECHANISM OF LIFE 

but little of the transformation of energy which takes place in 
an osmotic production, but we may say with certainty that it 
is capable of transforming both chemical energy and osmotic 
energy into heat and mechanical motion. 

An osmotic production is the arena of complicated chemical 
phenomena which produce a veritable metabolism. It has 
long been known that diffusion and osmosis may determine 
various chemical transformations. H. St. Clair Deville has 
demonstrated that certain unstable salts are partially 
decomposed by diffusion. Thus during the diffusion of alum, 
the sulphate of potash is separated from the sulphate of 
aluminium. Similarly, when the chloride or acetate of 
aluminium is caused to diffuse, the acids become separated 
from the aluminia. This decomposition is the result of the 
different resistance which the medium offers to the diffusion 
of different ions. This difference of resistance may even cause 
a difference of potential between two media, similar to the 
differences of potential in living organisms. Frequently also 
a difference of hydration in the chemical substances on 
either side of an osmotic membrane will determine a chemical 
reaction, which like all other chemical reactions is accompanied 
by a corresponding transformation of energy. The study of 
these chemical metamorphoses and the transformations of 
energy in osmotic growths has opened up a new subject for 
experimental investigation in the field of organic chemistry. 

Coagulation. There is a most remarkable analogy between 
the phenomena of coagulation as seen in living beings and the 
phenomena which occur when the liquid in the interior of an 
osmotic growth comes into contact with the mother liquor. 
When the sap of a plant or the blood of an animal escapes 
into the air or water of the surrounding medium, it coagulates, 
i.e. it changes from a liquid to a gelatinous consistency. In 
the same way, when the liquid in the interior of an osmotic 
growth leaks out into the mother liquor it forms a gelatinous 
precipitate. This gelatinous precipitation is a physico- 
chemical phenomenon of the same nature as coagulation. It is 
by the study of coagulation in liquids less complex than blood 
that we may hope to elucidate the mechanism of the process, 



THE PHENOMENA OF LIFE 155 

which is simply a physico-chemical phenomenon exactly 
analogous to gelatinous precipitation. Calcium phosphate 
is always prone to coagulate ; it has been called the gelatinous 
phosphate of lime, and we have already seen how readily 
tribasic calcium phosphate takes the form of beautiful trans- 
parent colloidal membranes which are gelatinous in texture. 

We may obtain colloidal precipitates exactly analogous to 
coagulated albumin by mixing a weak solution of chloride of 
calcium with potassium carbonate or tribasic phosphate. Like 
albumin this precipitate forms flakes, and is deposited slowly 
as a gelatinous colloidal mass. Like albumin also this calcic 
solution is coagulated by heat ; a solution of a calcic salt of a 
volatile acid on heating forms a precipitate which has all the 
appearance of albumin coagulated by heat. 

Finally, Arthus and Pages have shown that blood does not 
coagulate when deprived of its calcium salts by the addition of 
alkaline oxalates, fluorides, or citrates, and that the blood thus 
treated recovers its coagulability on the addition of a soluble 
salt of calcium. The coagulation of milk is also a calcium 
salt precipitation. Coagulation therefore would seem to be 
merely the colloidal precipitation of a salt of calcium. 

Diffusion and osmosis are the elementary phenomena of life. 
All vital phenomena result from the contact of two colloidal 
solutions, or of two liquids separated by an osmotic membrane. 
Hence the study of the physics of diffusion and osmosis is the 
very basis of synthetic biology. 

A living being exhibits two sorts of movements, those 
which are the result of stimulus from without, and those 
which are determined by an excitation arising from within. 
In the higher animals the stimulus or exciting energy coming 
from the entourage may be infinitely small when compared 
with the amount of energy transformed. Moreover, the 
response to an identical excitation may so vary as to give to 
these different responses an appearance of spontaneity. There 
is in reality no spontaneity, since the difference in response is 
governed by previous external impressions which have left 
their record on the machinery. There is in fact no such 
thing as a spontaneous action, since every action of a living 



i$6 THE MECHANISM OF LIFE 

being has as its ultimate cause a stimulus or excitation coming 
from without. 

The movements of the second category are also conditioned 
by an excitation, but the stimulus comes from within the 
organism. These movements consist principally of changes of 
nutrition, or movements of the circulation and respiration ; 
they are rhythmic in character and are probably produced by 
the same chemico-physical causes which determine rhythmic 
movements outside the living body. 

Just in the same wry osmotic growths present two sorts of 
movements, external movements and those which are connected 
with their nutrition. A free osmotic growth swimming in the 
mother liquor will alter its position and form under the influence 
of the slightest exterior excitation or vibration. It responds 
to every variation of temperature, or to a slight difference 
of concentration produced by adding a single drop of water, 
and reacts to every exterior influence by displacement or 
deformation. 

An osmotic growth also shows indications of movements 
which are connected with its nutrition, and these movements 
are rhythmic, like those of respiration or circulation in a living 
organism. The growth of an osmotic production shows itself 
not as a continuous process but periodically. The water 
traverses the membrane, raises the pressure, and distends the 
cell ; at first the cell wall resists by reason of its elasticity, it 
then suddenly relaxes, yielding to the osmotic pressure and 
bulging out at a thinner spot on the surface ; the internal 
pressure falls suddenly, and there is a pause in the growth. 

This rhythmic growth may be best observed by sowing 
in a solution of a tribasic alkaline phosphate, pellets composed 
of powdered calcium chloride moistened with glycerine, to 
which has been added 1 per cent, of monobasic calcium 
phosphate. The experiment is so arranged as to bend or 
incline the growing stems which shoot out from these 
grains. This may be done by carefully pouring above the 
mother liquor a layer of water, or a less concentrated solution. 
As the internal osmotic pressure rises, the drooping extremity 
of the twig will become turgescent and gradually lift itself 



THE PHENOMENA OF LIFE 157 

up, and then suddenly fall again for several millimetres. We 
have frequently watched this rhythmic movement for an hour 
or more a slow gradual elevation of the extremity of the 
twig and a rapid fall recurring every four seconds or so. 

It may be objected that the substance of an osmotic 
growth is continually undergoing change, whereas a living 
organism transforms into its own substance the extraneous 
matter which it borrows from its environment. The distinction, 
however, is only an apparent one. The substance of a living 
being is also continually undergoing chemical change ; it does 
not remain the same for a single instant. We see an evidence 
of this change in the evolution of age ; the substance of the 
adult is not that of the infant. In some living organisms 
such as insects, especially the ephemeridae who have but a 
brief existence, this change of substance is even more rapid 
than that in an osmotic growth. 

It has been objected that osmotic productions cannot be 
compared with living organisms since they contain no 
albuminoid matter. This is to consider life as a substance, 
and to confound the synthesis of life with that of albumin. 
If albumin is ever produced by synthesis in the laboratory it 
will probably be dead albumin. All living organisms contain 
albumin; this is probably due to the fact that albuminoid 
matter is particularly adapted for the formation of osmotic 
membranes. Our osmotic productions are composed of the 
same elements as those which constitute living beings ; an 
osmotic growth obtained by sowing calcium nitrate in a solution 
of potassium carbonate with sodium phosphate and sulphate 
contains all the principal elements of a living organism, viz. 
carbon, oxygen, hydrogen, nitrogen, sulphur, and phosphorus. 

The whole of the vegetable world is produced by the osmotic 
growth of mineral substances, if we except the small amount of 
organic matter contained in the seeds. 

The most important problem of synthetic biology is not so 
much the synthesis of the albuminoids as the reduction of 
carbonic acid. In nature this reduction is accomplished by the 
radiant energy of the sun, by the agency of the catalytic 
action of chlorophyll. 



158 THE MECHANISM OF LIFE 

The physico-chemical study of osmotic growth is as yet 
hardly begun ; we have but indicated the method, the way is 
open, and the problems awaiting solution are legion. Only work 
and ever more work and workers are required. Experiments 
should be made with substances which are chemically unstable 
like the albuminoids, substances which readily combine and 
dissociate again, alternately absorbing and giving up the 
potential energy which is the essence of life. Experiments 
should also be made with substances which readily unite or 
decompose under the influence of water, since hydration and 
hydrolysis appear to be the dominant mechanism in all vital 
reaction, as they undoubtedly are in osmotic growth, which 
consists of an increase of hydration on one side of an osmotic 
membrane and a diminution on the other side. 

Life is not a substance but a mechanical phenomenon ; it 
is a dynamic and kinetic transference of energy determined by 
physico-chemical reactions; and the whole trend of modern 
research leads to the belief that these reactions are of the 
same nature as those met with in the organic world. It is 
the grouping of physical reactions and their mode of associa- 
tion and succession, their harmony in fact, which constitutes 
life. The problem we have to solve in the synthesis of life 
is the proper attuning and harmonizing of these physical 
phenomena, as they exist in living beings, and there should 
be no absolute impossibility in our some day realizing this 
harmony in whole or in part. 

Albert Gaudry says : " I cannot conceive why in determin- 
ing the connecting links of the animal world the fact that an 
organic body is formed of such and such elements should be of 
greater importance than the manner in which these elements 
are grouped. Descartes regarded extension as the essential 
property of an organized being ; he supposed it to be inert of 
itself, and that it had the Deity for its motive force. To-day 
the hypothesis of Descartes has given way to that of Leibnitz, 
who regards force as the essential property of the living being, 
the visible and tangible matter being only of secondary 
importance. If we regard the living being as a force, this 
orce is able to aggregate matter under such and such a form, 



THE PHENOMENA OF LIFE 159 

with such or such a structure, and such or such a chemical 
essence. It does not seem that the classification depending on 
differences of substance are any more important than those 
which depend on differences of form." 

The biological interest of osmotic productions is quite 
independent of the chemical nature of the substances which 
enter into their growth. All substances which produce 
osmotic membranes by the contact of their solutions exhibit 
phenomena analogous to those of nutrition. Osmotic morpho- 
genesis is a physical phenomenon resulting from the contact of 
the most diverse substances. It has given us our first glimpse 
of the manner in which a living being may be supposed to 
have been formed according to the ordinary physical laws of 
nature. We cannot at present produce osmotic growths with 
all the combinations found in living beings, but that is only 
because chemistry still lags far behind physics in the synthesis 
of organic forms. 

We are often told " not to force the analogy. " But error 
is equally produced by the exaggeration of unimportant 
differences. We have already seen that nutrition, absorption, 
transformation, and excitation are not the characteristics of 
living organisms alone ; nor is reaction to external impressions 
the appanage only of animate beings. To insist on the resem- 
blance between an osmotic production and a living being is not 
to force an analogy but to demonstrate a fact. 

Let us briefly recapitulate. An osmotic growth has an 
evolutionary existence ; it is nourished by osmosis and intus- 
susception ; it exercises a selective choice on the substances 
offered to it; it changes the chemical constitution of its 
nutriment before assimilating it. Like a living thing it ejects 
into its environment the waste products of its function. 
Moreover, it grows and develops structures like those of living 
organisms, and it is sensitive to many exterior changes, which 
influence its form and development. But these very pheno- 
mena nutrition, assimilation, sensibility, growth, and 
organization are generally asserted to be the sole character- 
istics of life. 



CHAPTER XIII 
EVOLUTION AND SPONTANEOUS GENERATION 

BY many biologists, even at the present day, the origin and 
evolution of living beings is considered to be outside the 
domain of natural phenomena, and hence beyond the reach of 
experimental research. The change in our views on this 
subject is due to a Frenchman, Jean Lamarck, who was the 
true originator of the scientific doctrine of evolution. At a 
time when the miraculous origin of every living being was 
regarded as an unchangeable verity, and was defended like a 
sacred dogma, Lamarck boldly formulated his theory of 
evolution, with all its attendant consequences, from spontaneous 
generation to the genealogy of man. 

In his Philosophic Zooloffique, which appeared in 1809, 
Lamarck put forth his claim to regard all the phenomena of 
life, of living beings, and of man himself as pertaining to the 
domain of natural phenomena. According to him, all bodies 
which are met with in nature, organic and inorganic alike, are 
subject to the same laws. Life is a physical phenomenon, and 
all the processes of life are due to mechanical causes, either 
physical or chemical. He writes : " A leur source le physique 
et le moral ne sont sans doute qu\me seule et mem* chose. II 
faut rechercher dans la consideration de Torganisation les 
causes memes de la vie." 

In the intellectual evolution of the human mind perhaps 
no advance has been more important than that of Lamarck 
the conquest of the domain of life by human intelligence. In 
conformity with the true scientific method, he founds his 
doctrine on the facts and phenomena of nature. " I confine 

myself," he says, " within the bounds of a simple contemplation 

1 60 



EVOLUTION 161 

of nature. 11 It was this observation of the gradual perfecting 
of living organisms from the simplest to the most com- 
plicated that inspired Lamarck with the idea of evolution 
and transformation. " How," he says, " can we help searching 
for the cause of such wonderful results? Are we not com- 
pelled to admit that nature has produced successively bodies 
endowed with life, proceeding from the simplest to the most 
complex ? " 

The various products of nature have been divided into 
classes, genera, and species, simply to facilitate their study. 
Modern research tends to show that there is no definite line of 
demarcation even between the animal, vegetable, and mineral 
kingdoms. All our classification is artificial, and the passage 
from one division to another is gradual and insensible. 
Lamarck expresses this idea very clearly : " We must remember 
that classes, orders, and families, and all such nomenclature, are 
methods of our own invention. In nature there are no such 
things as classes or orders or families, but only individuals. 
As we become better acquainted with the productions of 
nature, and as the number of specimens in our collections in- 
creases, we see the intervals between the classes gradually fill 
up, and the lines of separation become effaced. 11 

Lamarck also raises his voice against the supposed 
immutability of species. " Species have only a relative 
constancy, depending on the circumstances of the individuals. 
The individuals of a given species perpetuate themselves with- 
out variation only so long as there is no variation in the 
circumstances which influence their existence. Numberless 
facts prove that when an individual of a given species changes 
its locality, it is subjected to a number of influences which 
little by little alter, not only the consistency and proportions 
of its parts, but also its form, its faculty, and even its organiza- 
tion ; so that in time every part will participate in the 
mutations which it has undergone. 11 

Lamarck also clearly affirms the fact of spontaneous 

generation. " I hope to prove,"he says, " that nature possesses 

means and faculties for the production of all the forms which 

we so much admire. Rudimentary animals and plants have 

ii 



1 62 THE MECHANISM OF LIFE 

been formed, and are still being formed to-day, by spontaneous 
generation." 

Lamarck himself gives a resume of his doctrine in the 
following six propositions : 

1. " All the organized bodies of our globe are veritable 
productions of Nature, which she has successively formed 
during the lapse of ages. 

3. " Nature began, and still recommences day by day, with 
the production of the simplest organic forms. These so-called 
spontaneous generations are her direct work, the first sketches 
as it were of organization. 

3. "The first sketches of an animal or a vegetable 
growth being begun under favourable conditions, the faculties 
of commencing life and of organic movement thus estab- 
lished have gradually developed little by little the various 
parts and organs, which in process of time have become 
diversified. 

4. " The faculty of growth is inherent in every part of an 
organized body ; it is the primary effect of life. This faculty 
of growth has given rise to the various modes of multiplication 
and regeneration of the individual, and by its means any 
progress which may have been acquired in the composition and 
forms of the organism has been preserved. 

5. " All living things which exist at the present day have 
been successively formed by this means, aided by a long lapse 
of time, by favourable conditions, and by the changes on the 
surface of the globe in a word, by the power which new situa- 
tions and new habits have of modifying the organs of a body 
which is endowed with life. 

6. "Since all living things have undergone more or less 
change in their organization, the species which have been thus 
insensibly and successively produced can have but a relative 
constancy, and can be of no very great antiquity." 

The admirable work of Lamarck was absolutely neglected 
in France, where it was treated as unworthy even of consider- 
ation. This neglect profoundly afflicted Lamarck, who 
gradually sank a victim to the opposition of his contem- 
poraries. He left, however, one disciple, Etienne Jeoffroy St. 



EVOLUTION 



163 



Hilaire, but he too was soon reduced to silence under the 
weight of authority of his adversaries. 

Before the doctrine of evolution could live and take its 
proper place, it had to be reborn in England the country of 
liberty. This resuscitation was due to Darwin, who added to 




FIG. 62. Osmotic vegetation. 

it his illuminating doctrine of natural selection. But apart 
from this and a perfecting of its various details, Lamarck had 
already formulated the doctrine of evolution with perfect 
precision. Lamarck's work was still-born, whereas that of 
Darwin lived and grew to its full development. This was due, 
not to any imperfection or insufficiency in Lamarck's work, but 



64 THE MECHANISM OF LIFE 

the milieu into which it was born. It was the environment 
hat stifled the offspring of Lamarck. 

In 1868, Ernest Haeckel speaks of the genius of Lamarck 
a these words : " The chief of the natural philosophers of 
France is Jean Lamarck, who takes his place beside Goethe 
nd Darwin in the history of evolution. To him belongs the 
nperishable glory of being the first to formulate the theory 
f descent, and of founding the philosophy of nature on the 
slid basis of. biology," and adds, " There is no country in 
lurope where Darwin's doctrine has had so little influence as in 
'ranee " Haeckel has but done tardy justice in his discovery 
f and testimony to the genius of Lamarck. 

The spirit of opposition does not seem to have much 
banged in France since Lamarck's time. In 1907 the 
Lcademie des Sciences de Paris excluded from its Comptes 
benches the report of my researches on diffusion and osmosis, 
ecause it raised the question of spontaneous generation. 

The majority of scientists seem to consider that the question 
f spontaneous generation was definitely settled once for all 
hen Pasteur's experiments showed that a sterili/ed liquid, 
ept in a closed tube, remained sterile. 

Without the idea of spontaneous generation and a physical 
tieory of life, the doctrine of evolution is a mutilated 
ypothesis without unity or cohesion. On this point Lamarck 
Deaks most clearly : " Although it is customary when one 
jeaks of the members of the animal or vegetable kingdom to 
ill them products of nature, it appears that no definite con- 
option is attached to the expression. Our preconceived 
otions hinder us from recognising the fact that Nature herself 
ossesses all the faculties and all the means of producing living 
eings in any variety. She is able to vary, very slowly but 
ithout cessation, all the different races and all the different 
>rms of life, and to maintain the general order which we see 

1 all her works." 

The doctrine of Lamarck is frequently misinterpreted, 
^e often hear it expressed as " Function makes the organ/' or 
yen " Function creates the organ." This is equivalent to 
tying, "Life makes the living being," which is incomprehensible, 



EVOLUTION 165 

making of function a sort of immaterial and independent entity 
which constructs a material organ in order to lodge within it. 
No such idea is to be found in all the works of Lamarck. 
He formulates his law in the following terms : " In every 
animal which is still undergoing development, the frequent 
and sustained use of any one organ increases its size and power, 
whereas the constant neglect of the use of such organ weakens 
and deteriorates it, so that it finally disappears." 

In his expression of this law Lamarck insists on the fact 
that organization precedes function. He affirms only that 
function, i.e. action and reaction, modifies the organ ; or, in 
other words, that organisms are modelled by the action of 
exterior forces acting upon them. It is in this sense only 
that function may be said to make an organ, but this 
mode of expression should be avoided, as it is apt to be 
misunderstood. 

Astronomy teaches us that our globe was detached from 
the sun in an incandescent state, and geology asserts that this 
earth has passed through a period of long ages when its 
temperature was incompatible with the existence of life. It 
was only with the cooling of the earth crust that it was 
possible for living beings to make their appearance. Hence 
they must of necessity have been produced spontaneously 
from terrestrial material under the influences of chemical and 
physical forces. This opinion imposes itself on all who reflect 
and judge freely. In the same way the doctrine of evolution 
necessitates as a corollary the doctrine of spontaneous genera- 
tion. The doctrine of evolution should reconstitute every link 
in the chain of beings from the simplest to the most compli- 
cated ; it cannot afford to leave out the most important of all, 
viz. the missing link between the inorganic and the organic 
kingdoms. If there is a chain, it must be continuous in all its 
parts, there can be no solution of continuity. 

Evolutionists like Lamarck and Haeckel admit spontaneous 
generation, not as the most probable, but as the only possible 
explanation of the phenomenon of life. 

Lamarck shows us the apparition of living things at a 
certain epoch of the earth's evolution, and the gradual develop- 



166 



THE MECHANISM OF LIFE 



ment of more complicated forms as the conditions changed on 
the surface of the globe. Darwin shows how heredity and 
natural selection tend to accentuate the variations which are 
favourable to existence. Haeckel demonstrates the parallelism 
between ontogenesis and philogenesis between the successive 
forms in the evolution of the embryo and the successive forms 
of the individual in the evolution of a race. These are great 
and admirable conquests of the human intelligence, they have 




FIG. 63. Marine forms of osmotic growth. 

demonstrated the first appearance and the progressive evolution 
of living beings ; it now only remains for us to explain them. 

The doctrine of evolution, while enforcing the fact of 
spontaneous generation and progressive evolution, gives us no 
hint as to the physical mechanism of such generation. It does 
not tell us by what forces, or according to what laws, the simpler 
forms of life have been produced, or in what manner differences 
of environment have acted in order to modify them. The 
doctrine asserts the simultaneous variations in organic forms 
and in the physical influences which produce them, but says 



EVOLUTION 167 

nothing as to their mode of action. The Darwinian theory 
shows how acquired variations are transmitted and accentuated 
by natural selection, but it says nothing as to how these varia- 
tions may be acquired. In the same way we are in entire 
ignorance as to the physical mechanism of on togenetic develop- 
ment, the evolution of the embryo. 

The morphogenic action of diffusion produces osmotic 
growths of extreme variety. Most of these forms recall those 
of living things shells, fungi, corals, and algae. The analogy 
of function is quite as close as the resemblance of form. The 
study of osmosis, however, is as yet in its infancy, and osmotic 
productions vary with the physical conditions of chemical 
constitution, temperature, concentration, and the like. The 
study of the organizing action of osmosis on organic material 
has as yet been hardly attempted. 

Osmosis produces growths of great complexity, milch more 
complicated indeed than the more simple forms of living 
organisms. This marvellous complexity of an osmotic growth 
may be compared with another fact, the ontogenetic develop- 
ment of the ovum, a single cell which under favourable 
conditions of environment may evolve into a most complicated 
organism. These considerations lead to the belief that the 
beginning of life has not been the production of a simple 
primitive form from which all others are descended, but that 
a number of such primitive forms may have been produced, 
forms which by a rapid physical development attained a high 
degree of complexity. Osmotic morphogenesis shows us that 
the ordinary physical forces have in fact a power of organiza- 
tion infinitely greater than has been hitherto supposed by the 
boldest imagination. 

When we consider the ignorance in which we still remain 
as to the phenomena which pass before our very eyes, how can 
we expect to understand those which occurred in past ages, 
when the physical and chemical conditions were so immensely 
different from those which obtain in our own time ? What do 
we know even now of the physical and chemical phenomena 
which take place in the unfathomed depths of the ocean, 
where for aught we know even at the present time the same 



1 68 THE MECHANISM OF LIFE 

process may be going on the genesis of life, and the emergence 
of living beings out of the inanimate mineral world ? " Even 
now," says Albert Gaudry, "polyps and oceanic animalculae 
are building up vast coral reefs and rocks. The oxygen and 
hydrogen which existed once was water, the oxygen and nitrogen 
which once made air, the carbon, the phosphorus, the silica and 
the lime which once were solid rock, now form the substance 
of living beings. The silica is deposited in the skeleton of a 
sponge or a radiolaria, the shell of a foraminifera or the 
carapace of a crustacean, or unites with phosphorus to form 
the bones of a vertebrate. A very tumult of life has succeeded 
to the primitive silence of inert matter. Life has invaded the 
earth, and we see on all sides the inanimate mineral kingdom 
being changed into a living world. 1 " 

The admission that life may have appeared on the earth 
under the influence of natural forces and according to physical 
laws arid conditions different from those of the present era 
throws a vivid light on the study of biogenesis, spontaneous 
generation, and evolution. The means of research are now 
indicated, and we have only to study the documents already in 
our possession in order to know the conditions which obtained 
when life first appeared on the globe. We must endeavour to 
reproduce these conditions and to study their effects. 

Since all living beings are formed of the same elements as 
those of the mineral world, the term "organic" 11 as applied to 
combinations can only be used in order to emphasize the 
complexity of their constitution. It was formerly believed 
that these organic combinations were the result of life, and 
could not be reproduced except by living organisms. To-day 
many of these organic substances are produced in the 
laboratory from inorganic materials. In the past history of 
the globe it is easy to imagine conditions which would 
facilitate the synthesis of organic substances without the 
interposition of life. At the temperature of the electric 
furnace, which was that of the earth at an early period of 
its evolution, chemical combinations are possible quite other 
than those obtaining under the present conditions of tempera- 
ture and pressure. At the higher temperature of the early 



EVOLUTION 169 

geological era, silicides, carbides, phosphides, and nitrides 
were formed in stable combinations instead of the oxides, 
silicates, carbonates, phosphates, and nitrates of the present 
time. These combinations existed on the earth at a time 
when the conditions of temperature precluded the existence 
of water in a liquid state. As the temperature cooled, and 
the water vapour became condensed, it entered into chemical 
combination with the various rocks, producing organic com- 
pounds like acetylene, which results from the action of water 
on calcium carbide. H. Le'nicque has developed a theory as 
to the formation of various rocks under these conditions, 
which he communicated in 1903 to the French Society of 
Civil Engineers. 

The chemical evolution of the globe has undergone great 
changes as the temperature gradually fell and the constitution 
of its crust altered. As long as the temperature was higher 
than that at which water can exist, all chemical reactions 
must have taken place between anhydric substances, elements 
and salts in a state of fusion. These conditions are very 
different from those of the present-day chemistry, which is the 
chemistry of aqueous solutions. We may hope to be able to 
reproduce the earlier conditions by the experimental study of 
anhydric substances in a state of fusion. 

At a later period, that of the primary and secondary rocks, 
there was a uniform and constant temperature of about 40 C. 
The atmosphere was charged with water vapour, and all the 
conditions were present for the production of storms and 
tempests. The atmosphere during long ages must have been 
the seat of formidable and incessant electric discharges ; these 
discharges are the most powerful of all physical agents of 
chemical synthesis, and will cause nitrogen to combine directly 
to form various compounds nitrates, cyanides, and ammonia. 
Carbonic acid would also be present in abundance and would 
enter into combination with these nitrogenous compounds. 
In this way we may imagine that compounds were formed 
which by some process of physical synthesis subsequently gave 
rise to vast quantities of albuminoid matter. At that time 
the seas and oceans contained all those substances which have 



\70 THE MECHANISM OF LIFE 

since been fixed by the metamorphism of the primitive rocks, 
or deposited in the sedimentary strata. Most of the elements 
in our minerals were formerly in a state of solution in 
these primeval seas, which contained carbonates, silicates, and 
soluble phosphates in great abundance. As the crust gradually 
cooled, the terrestrial atmosphere of necessity altered in com- 
position, and the slow evolution of the atmosphere no doubt 
also exercised an influence on the development of living 
beings. 

Palaeontology teaches us that the earliest living organism 
appeared in the sea. The most ancient of living things, those 
of the primary ages, which were of greater duration than all 
other ages put together, were all aquatic. We find moreover 
that every living organism consists of liquids, solutions of 
crystalloids and colloids separated by osmotic membranes ; 
and it is significant that the ocean, that vast laboratory of 
life, is also a solution of crystalloids and colloids. It is 
evident, then, that we must look to the study of solutions if 
we would hope to discover the nature and origin of life. 

Life is an ensemble of functions and of energy-transforma- 
tions, an ensemble which is conditioned by the form, the 
structure, and the composition of the living being. Life, 
therefore, may be said to be conditioned by form, i.e. the 
external, internal, and molecular forms of the living being. 

All living things consist of closed cavities, which are 
limited by osmotic membranes, and filled with solutions of 
crystalloids and colloids. The study of synthetic biology is 
therefore the study of the physical forces and conditions which 
can produce cavities surrounded by osmotic membranes, which 
can associate and group such cavities, and differentiate and 
specialize their functions. Such forces are precisely those 
which produce osmotic growths, having the forms and 
exhibiting many of the functions of living beings. Of all 
the theories as to the origin of life, that which attributes it 
to osmosis and looks on the earliest living beings as products 
of osmotic growths is the most probable and the most 
satisfying to the reason. 

We have already seen that the seas of the primary and 



EVOLUTION 



171 



secondary ages presented in a high degree the particular 
conditions favourable for the production of osmotic growths. 
During these long ages an exuberant growth of osmotic 
vegetation must have been produced in these primeval seas. 
All the substances which were capable of producing osmotic 
membranes by mutual contact sprang into growth, the 
soluble salts of calcium, carbonates, phosphates, silicates, 
albuminoid matter, became organized as osmotic productions, 




FlG. 64. Osmotic shells and corals. 



were born, developed, evolved, dissociated, and died. 
Millions of ephemeral forms must have succeeded one another 
in the natural evolution of that age, when the living world 
was represented by matter thus organi/ed by osmosis. 

The experimental study of osmotic morphogeny adds its 
weight of evidence in the same direction. When we see under 
our own eyes the cells of calcium become organized, develop 
and grow in close imitation of the forms of life, we cannot 
doubt that such a transformation has often occurred in the 
past history of our planet, and the conviction becomes irresistible