position and decomposition, which in fact constitutes its true universal nature. I do not see that this leaves anything to be desired, unless it be a more direct and explicit indication of the two correlative conditions of a determinate organism and a suitable medium. This criticism however applies rather to the formula than to the conception; and the conditions are implied in the conception, -the conditions of an organism to sustain the renovation, and a medium to minister to the absorption and exhalation; yet it might have been better to express them. With this modification, the definition is unexceptionable, -enunciating the one phenomenon which is common to all living beings, and excluding all inert bodies. Here we have, in my view, the first elementary basis of true biological philosophy.

:

It is true, this definition neglects the eminent distinction between the organic and the animal life, and relates solely to the vegetative life; and it appears to violate the general principle of definitions,-that they should exhibit a phenomenon in the case in which it is most, and not in that in which it is least developed. But the proposed definition is shown, by these very objections, to rest upon a due estimate of the whole biological hierarchy for the animal life is simply a complementary advancement upon the organic or fundamental life, adapted to procure materials for it by reaction upon the external world, and to prepare or facilitate its acts by sensations, locomotion, etc., and to preserve it from unfavourable influences. The higher animals, and Man especially, are the only ones in which this relation is totally subverted,the vegetative life being destined to support the animal, which is erected into the chief end and preponderant character of organic existence. But in Man himself, this admir. able inversion of the usual order becomes comprehensible only by the aid of a remarkable development of intelligence and sociality, which tends more and more to transform the species artificially into a single individual, immense and eternal, endowed with a constantly progressive action upon external nature. This is the only just view to take of this subordination of the vegetative to the animal life, as the ideal type towards which civilized humanity incessantly

VEGETATIVE AND ANIMAL LIFE.

9

tends, though it can never be fully realized. We shall hereafter show how this conception is related to the new fundamental science which I propose to constitute: but in pure biology, the view is unscientific, and can only lead us astray. It is not with the essential properties of humanity that biology is concerned; but with the individual in his relation to other organic beings; and it must therefore rigorously maintain the conception of animal life being subordinated to the vegetative, as a general law of the organic realm, and the only apparent exception to which forms the special object of a wholly different fundamental science. It should be added that, even where the animal life is the most developed, the organic life, besides being the basis and the end, remains common to all the tissues, while, at the same time, it alone proceeds in a necessarily continuous manner, the animal life, on the contrary, being intermittent. These are the grounds on which M. de Blainville's definition of life must be confirmed, while, nevertheless, we may regard the consideration of animality, and even of humanity, as the most important object of biology. This analysis of the phenomenon of life will help us to a clear definition of the science which relates to it. We have seen that the idea of life supposes the mutual relation of two indispensable elements, an organism, and a suitable medium or environment. It is from the reciprocal action of these two elements that all the vital phenomena proceed;-not only the animal, but also the organic. It immediately follows that the great problem of positive biology consists in establishing, in the most general and simple manner, a scientific harmony between these two inseparable powers of the vital conflict, and the act which constitutes that conflict: in a word, in connecting, in both a general and special manner, the double idea of organ and medium with that of function. The idea of function is, in fact, as double as the other; and, if we were treating of the natural history of vital beings, we must expressly consider it so: for, by the law of the equivalence of action and reaction, the organism must act on the medium as much as the medium on the organism. In treating of the human being, and especially in the social state, it would

Definition of
Biology.

1

be necessary to use the term function in this larger sense: but at present there will be little inconvenience in adopting it in its ordinary sense, signifying organic acts, independently of their exterior consequences.

Biology, then, may be regarded as having for its object the connecting, in each determinate case, the anatomical and the physiological point of view; or, in other words, the statical and dynamical. This perpetual relation constitutes its true philosophical character. Placed in a given system of exterior circumstances, a definite organism must always act in a necessarily determinate manner; and, inversely, the same action could not be precisely produced by really distinct organisms. We may then conclude interchangeably, the act from the subject, or the agent from the act. The surrounding system being always supposed to be known, according to the other fundamental sciences, the double biological problem may be laid down thus, in the most mathematical form, and in general terms: Given, the organ or organic modification, to find the function or the act; and reciprocally. This definition seems to me to fulfil the chief philosophical conditions of the science; and especially it provides for that rational prevision, which, as has been so often said, is the end of all true science; an end which abides through all the degrees of imperfection which, in any science, at present prevents its attainment. It is eminently important to keep this end in view in a science so intricate as this, in which the multitude of details tempts to a fatal dispersion of efforts upon desultory researches. No one disputes that the most perfect portions of the science are those in which prevision has been best realized; and this is a sufficient justification of the proposal of this aim, whether or not it shall ever be fully attained. My definition excludes the old division between anatomy and physiology, because I believe that division to have marked a very early stage of the science, and to be no longer sustainable. It was by the simple and easy considerations of anatomy that the old metaphysical view was discredited, and positivity first introduced into biology: but that service once accomplished, no reason remains for the separation; and the division, in fact, is growing fainter every day.

DEFINITION OF BIOLOGY.

11

Not only does my definition abstain from separating anatomy from physiology; it joins to it another essential part, the nature of which is little known. If the idea of life is really inseparable from that of organization, neither can be severed, as we have seen, from that of a medium or environment, in a determinate relation with them. Hence arises a third elementary aspect; viz., the general theory of organic media, and of their action upon the organism, abstractedly regarded. This is what the German philosophers of our day confusedly asserted in their notion of an intermediate realm,-of air and water,-uniting the inorganic and organic worlds: and this is what M. de Blainville had in view in what he called the study of exterior modifiers, general and special. Unhappily, this portion which, after anatomy proper, is the most indispensable preliminary of biology, is still so obscure and imperfect that few physiologists even suspect its exis

tence.

The definition that I have proposed aids us in describing not only the object or nature of the science, but its subject, or domain: for, according to this formula, it is not in a single organism, but in all known, and even possible organisms, that biology must endeavour to establish a constant and necessary harmony between the anatomical point of view and the physiological. This unity of subject is one of the chief philosophical beauties of biology; and, in order to maintain it, we must here avow that in the midst of an almost infinite diversity, the study of Man must always prevail, and rule all the rest, whether as starting-point or aim. Our hope, in studying other organisms, is to arrive at a more exact knowledge of Man: and again, the idea of Man is the only possible standard to which we can refer other organic systems. In this sense, and in this only, can the point of view of the antiquated philosophy be sustained by the deeper philosophy which is taking its place. Such is, then, the necessary consolidation of all the parts of biological science, notwithstanding the imposing vastness of its rational domain.

As for the means of investigation in this science, the first observation that occurs is that it affords a striking confirmation of the

Means of investigation.

philosophical law before laid down, of the inevitable increase of our scientific resources in proportion to the complication of the phenomena in question. If biological phenomena are incomparably more complex than those of any preceding science, the study of them admits of the most extensive assemblage of intellectual means (many of them new) and developes human faculties hitherto inactive, or known only in a rudimentary state. The logical resources which are thus obtained will be exhibited hereafter. At present, we must notice the means of direct exploration and analysis of phenomena in this science.

Artificial apparatus.

First, Observation acquires a new extenOBSERVATION. sion. Chemistry admitted the use of all the five senses; but biology is, in this respect, an advance upon chemistry. We can here employ an artificial apparatus to perfect the natural sensations, and especially in the case of sight. Much needing precaution in the use, and very subject to abuse, as is this resource, it will always be eagerly employed. In a statical view, such an apparatus helps us to a much better estimate of a structure whose least perceptible details may acquire a primary importance, in various relations: and, even in the dynamical view, though much less favourable, we are sometimes enabled by these artificial means to observe directly the elementary play of the smallest organic parts, which are the ordinary basis of the principal vital phenomena. Till recently, these aids were limited to the sense of sight, which here, as everywhere else, is the chief agent of scientific observation. But some instruments have been devised in our day to assist the hearing; and, though invented for pathological investigations, they are equally fit for the study of the healthy organism. Though rough at present, and not to be compared to microscopic apparatus, these instruments indicate the improvements that may be made hereafter in artificial hearing. Moreover, they suggest, by analogy, that the other senses, not excepting even touch, may admit of such assistance, hinted to the restless sagacity of explorers by a better theory of the corresponding sensations.

Next, the biologist has an advantage over the chemist in being able to employ the whole of chemical procedures, as