The Mechanism of Life

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

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

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

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.

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.

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 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 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. 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.

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.

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.