A. Dastre

“ When we ask the various philosophical schools what life is, some show us a chemical retort, and others show us a soul. Whether vitalists or of the mechanical school, these are the adversaries who since philosophy began have vainly contested the possession of the secret of life. We need not concern ourselves with this eternal quarrel. We need not ask Pythagoras, Plato, Aristotle, Hippocrates, Paracelsus, Van Helmont, and Stahl what idea they formed of the vital principle ”

“ Collective Life.—With the exception of the physiologist, no one, neither he who is ignorant nor he who is intellectual, nor even the doctor, troubles his head about the life or the death of the element, although this is the basis, the real foundation, of the activity manifested by the social body and by its different organs. The life of the individual, of the animal, depends on these elementary partial lives just as the existence of the State depends upon that of its citizens. To the physiologist, the organism is a federation of cellular elements unified by close association. ”

“ I am not expressing a chimerical hope when I predict that science will conquer disease. Medicine has at last issued from the contemplative attitude of so many centuries; it has engaged in the struggle, and signs of victory are already appearing. Disease is no longer the mysterious power which it was impossible to escape. Pasteur gave to it a body. The microbe can be caught. In the words of Schopenhauer, an alteration of the atmosphere so slight that it is impossible to detect it by chemical analysis may bring on cholera, yellow fever, the black plague, diseases which carry off thousands of men ”

“ If our intellect requires images or symbols to embrace the facts and to grasp their relation, it may introduce them here. It will materialize energy, it will make of it a kind of imaginary being, and confer upon it an objective reality. And for the mind, as long as it does not become the dupe of the phantom which it itself has created, this is an eminently comprehensive artifice which enables us to grasp readily the relations between phenomena and their bond of affiliation. ”

“ Man’s unhappy plight is the constant theme of philosophies and religions. Without referring to its moral basis, it has a physical basis due to four causes—the physical imperfection or disharmony of nature, disease, old age, and death—or rather of three, for what we call old age is perhaps a simple disease. These are the great sorrows of man, the sources of all his woes. Disease attacks him, old age awaits him, and death must tear him from all the ties which he has formed. ”

“ Difficulty of Interpretation.—In this as in all other examples we must know the nature of the beings that we see lasting on and braving the centuries. Is it the individual? Is it the species? Is it a living being, properly so called, having its unity and its individuality, or is it a series of generations succeeding one another in time and extending in space? In a word, the question is one of knowing if we have to do with a real tree or with a genealogical tree. We are just as uncertain when we deal with animals. ”

“ The most striking thing in living matter is its growth. An animal, a vegetable, is something which is first more or less minute, and which grows. Its characteristic is to expand—from the spore, the seed, the slip, the egg—it grows.
Whether we are dealing with a cellular element, a plastid, or a complex being, their condition is the same in this respect. No doubt when the animal or plant has reached a certain stage of development its growth is stopped, and for a more or less lengthy period it remains in the adult stage, in what seems to be equilibrium. ”

“ When it is a question of cold-blooded vertebrates, which live in water and in most cases have an internal temperature which is not distinguishable from that of the environment, we see less clearly the thermal rôle of food. It seems then that the production of heat is an episodic phenomenon, not existing for itself.
However that may be, food is in the second place a source of thermal energy for the organism. Can it be said, inversely, that every substance which we introduce into the economy, and which is there broken up and gives off heat, is a food? ”

“ Man knows that death, this dreamless sleep that knows no waking, will be followed by the dissolution of his body. And what a dissolution will there be for the body, the object of his continual care! Remember the description of Cuvier—the flesh that passes from green to blue and from blue to black, the part which flows away in putrid venom, the other part which evaporates in foul emanations, and finally, the few ashes that remain, the tiny pinch of minerals, saline or earthy, which are all that is left of that once animated masterpiece. ”

“ Is it true that no being can escape the cruel fate of old age and death, to which we and all the representatives of the higher animality are exposed? Or, on the other hand, are any beings immortal? Biology answers that, in fact, some beings are immortal. There are beings to whose life no law assigns a limit, and they are the simplest, the least differentiated and the least perfect. Death thus appears to be a singular privilege attached to organic superiority, the ransom paid for a masterly complexity. ”

“ We know perfectly well that brute matter is inert, that all the manifestations of activity of which it is the theatre are provoked. Inertia is for it the equivalent of irritability in living matter. But while it is not necessary to introduce this idea into the physical sciences, where it has reigned since the days of Galileo, it was, on the contrary, necessary to affirm it in biology, precisely because it was in biology that the opposing doctrine of vital spontaneity ruled supreme. ”

“ All food is nothing but this matter and this energy. All its characteristics, our views as to its rôle, its evolution, all the rules of alimentation are simple consequences of this principle, interpreted by the light of energetics.
And first of all, let us ask what forms of energy are afforded by food? It is easy to see that there are two—food is essentially a source of chemical energy; and secondarily and accessorily, it is a source of heat. [Pg 124] Chemical energy is the only energy, according to the second law of energetics, which may be transformed into vital energy. ”

“ Besides the fact that the old age to which they seemed to succumb is really a disease, a generalized sclerosis, autopsy always reveals some lesion more or less directly responsible for the fatal issue.
Man, like all the higher animals, is therefore subject to the law of lethality. But while animals have no idea of death and are not tormented by the sentiment of their inevitable end, man knows and understands this destiny. He has with the animals the instinct of self-preservation, the instinct of life, and at the same time the knowledge and the fear of death. ”

“ It dominates physics under the name of the theory of kinetic energy. The minds of men in our own time are so strongly impregnated with this idea that most scientists of ordinary culture get no glimpse of the world of phenomena but by means of this conception. And yet it is only an hypothesis. But it is so simple, so intuitive, and appears to be so thoroughly verified by experiment, that we have ceased to recognize its arbitrary and unnecessarily contingent character. Many physicists from this standpoint consider the kinetic theory as an imperishable monument. ”

“ If we go to the bottom of things, and fix our attention on the real living unities, on the cells of which the organism is composed, we shall find around them the juices, rich in water, which are their real environment. If these juices are diluted or concentrated the least in the world, life stops. The cell, the whole animal, falls into a state of latent life, or dies. “All living beings are aquatic,” said Claude Bernard. “Beings that live in the air are in reality wandering aquariums,” said another physiologist. “No moisture, no life,” wrote Preyer. ”

“ It is not necessary to repeat that the geometrical mould in which Descartes cast his philosophy has long since been broken. The celebrated philosopher, in defining matter by one attribute—extension, does not enable us to grasp its activity, an activity revealed by all natural facts; and in defining the soul by thought alone, prevents us from seeking in it the principle of this material activity. This purely passive matter, consisting of extension alone, this bare matter was to Leibniz a pure concept. ”

“ Hence we have a result which can be immediately applied in the theory of food—namely, that heat is in the dynamical order an excretum of the animal life rejected by the living being, just as in the substantial order, urea, carbonic acid and water, are the materials used up and again rejected by it. We therefore must not think of the transformation in the animal organism of heat into vital energy, as certain physiologists always do. ”

“ Phenomena for purposes of analysis were classed in separate and distinct compartments: weight, heat, electricity, magnetism, light. Each phenomenon was studied without reference to that it succeeded or that which should follow. Nothing could be more artificial than such a method as this. In fact, there is a sequence in everything, everything is connected up, everything precedes and succeeds in nature—in nature there are only series. The isolated fact without antecedent or consequent is a myth. Each phenomenal manifestation is in solidarity with another. ”

“ EARLY THEORIES. Animism—Vitalism—The Physico-Chemical Theory—Their Survival and Transformations.
The fundamental theories of science are but the expression of its most general results. What, then, is the most general result of the development of physiology or biology—that is to say, of that department of science which has life as its object? What glimpse do we get of the fruit of all our efforts? The answer is evidently the response to that essential question—What is Life?
There are beings which we call living beings; there are bodies which have never been alive—inanimate bodies ”

“ The study of the extrinsic or physico-chemical conditions necessary to vital manifestations teaches us our first truth—namely, that they are not infinitely varied as might be supposed. They present, on the contrary, a remarkable uniformity in their essential qualities. The fundamental conditions are the same for the animal or vegetable cells of every species. They are four in number:—moisture, the air, or rather oxygen, heat, and a certain chemical constitution of the medium, and the last condition, the enunciation of which seems vague, becomes more precise if we look at it a little closer. ”

“ We take into account, a priori, the conditions that must be fulfilled by the monocellular being in order to escape the inevitability of evolution, of the succession of ages, of old age, and of death. It must be able indefinitely to maintain itself in a normal régime, without changing, without increasing, maintaining its constant morphological and chemical composition, in an environment vast enough for it to be unaltered by the borrowings or the spendings resulting from its nutrition—i.e., it must remain constant in the presence of the constant being. ”

“ The Idea of Energy Derived from the Kinetic Theory.—The notion of energy is not less clear than the notion of matter, it is only more novel to our minds. We are led to it by the mechanical conception which now dominates the whole of physics, the kinetic conception, according to which in the sensible universe there are no phenomena but those of motion. Heat, sound, light, with all their manifestations so complex and so varied, may, according to this theory, be explained by motion. ”