BOOKS.
DR. ASA GRAY ON DARWINISM.*
PROFESSOR GRAY has, in the volume under notice, presented nu, with a compilation of extremely thoughtful and erudite essays,. collected from the scientific periodicals in which at various times. they originally appeared, as reviews of Mr. Darwin's book on the Origin of Species and of kindred works. The main object of the whole series is to vindicate the religious character of the evolu- tionist, of whose theory Professor Gray entertains a high opinion,. supporting it by several new and cogent arguments, based on his. own immediate observation and researches. Darwin himself, the priest and prophet of the new theory, thus expresses his convictions :—" To my mind, it accords better with what we know of the laws impressed on matter by the Creator, that the production and extinction of the past and present in- habitants of the world should have been due to secondary causes, than that each species has been independently created."' It is therefore evident that Professor Gray has not only reason, but authority on his side, when he affirms that the charge of atheism brought against the Evolutionists is a false conclusion, and that nothing hinders the most thorough-going of the school- from endorsing the noble dictum of Aristotle, philosopher and naturalist,—" the Divine it is which holds together all Nature."
Experience teaches us to argue from analogy, and to refer pro- ductions in the past to the same causes or sets of causes as those- we see operating in the present. It is nowhere within the know- ledge of living man that God acts, or has acted, on any principle of caprice, working, as Lord Bacon says, "by means of His own rules upon the creature, as fully and exactly as He could by miracle and new creation." The immediate source of the volition, inherent in matter is out of our ken, we see only the effects pro- duced by it, and to suppose that it ever acted in any other way than that in which it now acts is obviously to suppose that the- earlier ages of the world were not regulated by the laws which, obtain in our own, and that some radical and wholly unaccount- able change has taken place in Nature and her modes of pro- duction and transmutation since the commencement of our era. Moreover, the whole tide of investigation and speculation with regard to the various departments of natural science seta in the direction of evolution ; and again, arguing from analogy, we can- not be wrong in apprehending a probable synthesis and harmony of the circle of natural and physical sciences. The theory of derivative process in the origin of animal species chimes in wonderfully well with the result of M. Alphonse de Candolle's botanical investigations, an account of which was published, be- fore the appearance of Darwin's hypothesis, in the GeographicBotanigue Raisonnie. "Existing vegetation," says M. de Can- done, in the final chapter of this classical work, "must be re- garded a§ the continuation, through many geological and geographical changes, of the anterior vegetations of the world ; consequently, the present distribution of species is explicable only in the light of their geographical history." Certain species or- quasi-species may, in his opinion, have originated througfi diversification under geographical isolation, and yet others inde- pendently of such cause.
With regard to geology, Sir Charles Lyell has given us his con- viction that "the natural operations now going on account for all known geological changes connecting the past with the present by imperceptible gradations," and Professor Geikie has long since taught us that not only upon such an hypothesis can the exist-
• Darwinians : Essays ated Reviews pertaining te Darwinism. By Asa Gray, Pro- fessor of Natural History in Harvard University. New York : Appleton and 0o. ence, structure, and position of the sedimentary, organic, and igneous rocks of the earth be rightly explained and under- stood. Extending our inquiries into the domain of physics and chemistry, we find the scientific world, with but few in- dividual exceptions, quite content to accept the nebular hypo- thesis framed by Laplace, and to believe that the matter of the Solar system existed originally in the form of a vast diffused revolving mass, which, gradually cooling and contracting, threw off, in obedience to mechanical laws, successive rings, from which subsequently, by the same laws, were produced the several planets, satellites, and other bodies of the system. Such a theory is indeed justly regarded as the complement and corollary .of the Newtonian doctrine, which proves that certain forces acting upon matter in certain directions produce planetary orbits of the exact measure and form in which observation shows them to exist. The merest tyro in science regards light, heat, elec- tricity, magnetism, chemical affinity, and mechanical power as varieties or derivative and convertible forms of one force, instead of believing them independent species; and chemists have lately hinted their anticipation that some or all of the supposed elementary bodies will be found to be themselves compound and derivative, while here and there appears a man bold enough to record his conviction that all these substances will be at last reducible to one, precisely as Macke' believes that he can trace the genesis of man and of all species to a single simple element,—the proto- plasmic cytode.
The true reason, no doubt, why the doctrine of evolution, as ap- plied to animal existences, has failed to become popular, is that it involves the origin of the human race, and affects, as some suppose, the dignity of man's position as the creature distinctively soul- endowed. The scientific difficulty of this knotty point,—which is the logical outcome and conclusion of the theory of development,—lies in the explanation of Mr. Darwin's term, "differentiation." Mr. Darwin says :—" In each member of the vertebrate series, the nerve-cells of the brain are the direct off-shoots of those pos- sessed by the common progenitor of the whole group. It thus becomes intelligible that the brain and mental faculties should be capable, under similar conditions, of nearly the same course of development, and consequently of performing nearly the same functions." Now the brain-cells of man, as he is at present constituted, have no known analogy or representa- tive among the lower animals. In order to fill up the gap existing between the highest extant group of the simile and man, Ilmckel has found it necessary to invent an intermediate extinct species, to which he gives the name of "speechless ape- men," assigning to them the glacial, post-glacial, and historic periods, summed up in the Anthropolithic Age. The fact is, that there exists a notable hiatus in the ascending scale, for which 'hitherto evolutionists have failed to account satisfactorily. It is easy to silence, or at least to puzzle, lay objectors by the use of long scientific terms and phrases, but among physiologists much doubt and uncertainty exists with regard to the application of the word "differentiation," in the sense in which evolutionists are at present fond of employing it. Cells may or may not be admitted to be spontaneously generated, but it can at least be shown that each kind of cell, once in existence, has its own special endowments, and its own special method of develop- ment. One kind of cell has never been known to develop into or to perform the functions of another kind. Nerve-cells can- not, by means of any conceivable process, become cells of another sort of tissue, even in the same structure ; nor will the cells com- posing the olfactory nerve exchange office with those which con- stitute the optic, the auditive, or any other of its coadjutors, begotten of the same substance and on the same territory. With this truth present to the mind, it is difficult to understand how the brain-cells of the ape can ever have so altered in character and in destiny as to have "differentiated" themselves into human brain- cells. Mr. Herbert Spencer might, perhaps, wish to dispose of this difficulty, as he seeks to do with its analogue, upon the very thres- hold of the evolution theory, by assuming that the distance appar- ently separating inorganic from organic substances may be bridged over by an hypothesis relegating the dissimilarity of mode and function to, a mere difference of molecular adjustment and arrangement. But if philosophy can theoretically solve the pro- blem of life with so much ease, how comes it that chemistry
remains still practically unable to demonstrate this assumed con- vertibility of matter. Despite all the confidence hypothetically entertained on the subject of the identity of inorganic and organic compounds, no scientific man has yet been able to construct a single particle of organisable protein, much less a vitally endowed c,e11. It will be evident on a little reflection that the most
important inference deducible from the theory of develop- ment, as expounded by the materialistic school, is one which refers all modes of being, organic and inorganic, to the operation of mere mechanical power. But if this be a true conclusion, it is hard to comprehend how that power—unconscious and character- less—should be capable of giving rise to various forms, seeing that the effects of mere mechanism uninfluenced by volition cannot be other than unique. How comes it that chemical in- gredients controlled by one and the same force, and unsolicited by any extraneous or inherent will, should assume so many kaleidoscopic forms as those which go to make up the actual Kosmos ? Is there no hand to move the instrument, no power to shake the many-coloured molecules into the varied patterns they are seen to assume? The Theist, or even the Pantheist, has at least an intelligible reply to offer, but what is the position of the Materialist, who denies the existence of any other force than that of a blind and invariable mechanism, operating upon matter alike in all modes of being, uninfluenced by external intel- lect and without internal consciousness, a force which be can physically dissipate, a matter which he can chemically dissolve and evaporate ? Until some answer is given to this ques- tion, we cannot accept the idea presented to us under the term differentiation as a definite and comprehensible one ; nor can we hold that the atheistic school has advanced one step towards the elucidation of the difficulty it has so boldly set itself to explain, since Professor Huxley wrote these words :—" The question of questions for mankind, the problem which underlies all others, and is more deeply interesting than any other, is the ascertainment of the place which man occupies in nature, and of his relations to the universe of things. Whence our race has come, what are the limits of our power over nature and of nature's power over us, to what goal we are tending, are the pro- blems which present themselves anew and with undiminished interest to every man born into the world."
It is not, then, against the facts involved in Mr. Darwin's theory that we contend, but against the interpretation given to those facts by the materialistic school. The hypothesis of evolution is favoured by discovery, by inductive reason, and by analogy ; the puzzle lies only in the method assigned to it by modern science. We think with Professor Gray, that the belief in a gradual evolution extending upward from the lowest forms is in the main scientifically sound, and experimentally probable, but that, in accepting the issues of such a doctrine, we must care- fully guard ourselves against the common error of insufficient thought, which leads certain evolutionists to ignore the prime and moving principle of the theory to which they give their adhesion, viz., that secret of the potency of matter which alone explains Pro- fessor Tyndall's "mystery of causation."
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