British Quarterly Review, American Edition, Vol. LIV / July and October, 1871

by Various

It is all very well to explain the presence of muscular variations in man by the tendency to reversion to an earlier condition of existence, but it is of the utmost importance in the first place to be sure that our evidence justifies us in concluding that particular and exceptional muscles in man representing muscles highly developed in some of the lower animals owe their origin to descent. This is the very question upon which proof is wanting. The variations may be due to descent, but it by no means follows that they must be due to descent, and it is still more difficult to be certain that they are not due to the operation of some undiscovered factor.

For many years past, naturalists, in their desire to discover the relationship between the many divergent forms of living things, appear to have closed their eyes to the remarkable differences which establish distinct characteristics between very closely allied forms, and which tend to show that the latter are not so closely related as the hypothesis of Darwin concludes. What, for instance, is the explanation of the fact that in no two animals or men are the branches of the arteries or nerves given off from the larger trunks at precisely the same points or in precisely the same manner, and why are variations in the muscles to be detected in each individual subject?—we cannot call them accidental. Will descent account for the hundreds of variations we meet with, as well as for those particular kinds which have been minutely described by Mr. Wood and others, and of which the evolutionists have made so much? Here, as in many other instances, we find inferences based on a very one-sided, if not a very imperfect statement of the facts. In order to account for all the anatomical varieties, it will be necessary again to call in the help of that 'unknown law' which the advocates of natural selection invoke when they find themselves in a difficulty.

But we come now to consider whether Mr. Darwin is more correct in his assertion concerning the close correspondence in the chemical composition of the tissues and fluids of the different species, than he is upon the question of minute structure. How is it that we find specific characters in the blood, bile, milk, saliva, gastric juice, urine, and other fluids and secretions of nearly related animals? The blood of the Guinea pig differs in important characteristics from that of the rat, mouse, rabbit, and squirrel. The most important constituent of the blood undergoes crystallization, and the form of the blood crystal is very different in the several members of the rodent class. By some undiscovered law of correlation of growth, perhaps, may be explained the curious fact that the blood-corpuscles of the tailless Guinea pig crystallize very readily in beautiful tetrahedra, while those of another rodent in which the tail is remarkably developed take the form of six-sided plates, and in yet another which possesses only a faint apology for a caudal appendage, we find blood crystals taking the form of the most beautiful rhomboids.

The blood of one species will not efficiently nourish the tissues of another; and in cases in which life is temporarily supported by alien blood artificially introduced into the vessels, it is probable that the foreign fluid is gradually destroyed and eliminated, and at last, entirely replaced by blood which is slowly formed anew in the animal's own vessels. Not only does the blood of man differ from that of the lower animals, but the blood of every species of animal differs from that of every other species.

But if we submit any of the other fluids mentioned above to careful chemical and physical analysis, we shall find each endowed with special characteristic properties, and distinguished from the rest by well-marked and constant characters; and we have reason to believe that the more minutely such investigation is carried out, the larger will be the number of divergent characters and properties established.

Mr. Sorby has lately been examining, by the aid of the spectroscope, many of the colouring matters of the leaves and petals of flowers and plants, and has demonstrated the presence of a large number of new substances which can be most positively distinguished from one another by spectrum analysis. Substances belonging to different plants which appear to the eye of nearly the same tint, often exhibit very different characters when submitted to spectroscopic examination.[65] There seems to be, in fact, no limit to divergence in essential particulars in cases in which the correspondence is only to be found in most general and superficial characters. We will recur for a moment to the question of minute structure as illustrated by plants. If the reader will be at the trouble of placing under his microscope, one after another, the petals of any half-dozen flowers of a red or blue colour, he will soon be able to discover anatomical differences by which each of them could be recognised independently of its colour. Moreover, if he studies the subject with sufficient care, he will find that new structural peculiarities will be demonstrated, of the existence of which he had no idea when the investigation was commenced.

Series of facts like those adduced above not only seem to militate against the acceptance of the doctrine of natural selection in its present form, but they cannot be contemplated without exciting in the mind a desire to entertain the hypothesis of fixity of species, or some derivative hypothesis not opposed to that idea.

Although of late much attention has been given to variation, the inheritance of variability, and progressive hereditary changes in the structure of the body, the advocates of evolution have only advanced statements of the most general kind. They have not entered into details; they have not suggested at what particular period in the life of the individual the change in structure occurs. They are silent as to the precise nature of the change, and the several steps by which it is brought about; and they say nothing concerning the characters and properties of the matter, which is the actual seat of the change. It is not sufficient to show us the bone or muscle, the structure of which is modified, and to assure us that the modification in question is due to the law of variability; for the hypothesis deals with the change itself, and we should be informed concerning the phenomenon which are antecedent to the change, and the exact circumstances which determine any particular modification advanced in illustration of the working of the supposed law. Further, it should be definitely determined what degree of change suffices to affect the fully-formed bone and muscle, and whether structural changes occurring at or after the period of full development of the body are inherited or not. The reader is probably aware that Mr. Darwin has invented an hypothesis specially to meet this part of the question—the hypothesis of Pangenesis. But he has recently remarked that it has not yet received its 'death-blow'—an observation which excites a doubt whether its author is not ready to abandon it. This hypothesis was only advanced tentatively from the first. It is incompatible with a number of facts, and appears more and more improbable as the phenomena it comprises are carefully investigated. Many observers well qualified to form a correct judgment felt almost certain from the very first that Pangenesis could not be maintained.

Seeing that, at every period of life, matter exists in every part of the body in at least two very different states, in each of which different classes of phenomena occur, Mr. Darwin should have informed us in what particular matter of the body in his opinion the metabolic property probably resided, and he should have explained at what period of life the change which was to result in the production of a new variety or species occurred. He does not, of course, suppose that fully-formed bone, or muscle, or nerve, changes its characters; nor would he maintain that in old age, or indeed long after adult life had been attained, any great alteration of structural form was possible. If, then, it is only in the plastic state during the early period of development that the changes surmised to take place can occur, the author of the hypothesis should either have given more information upon the details, or he should at the least have shown that microscopical observation had yielded no facts adverse to his doctrine; and something surely should have been suggested concerning the nature and origin of the inherent metabolic property, or tendency, or capacity, which is assumed by the terms of the hypothesis.

It should, however, be stated here that many evolutionists repudiate entirely the idea of any peculiar property under any circumstances influencing matter in the living state which does not influence it in the non-living condition, for the acceptance of the idea of such property would involve an answer to the inquiry as to the nature and origin of the property assumed, and it would have to be shown when and under what circumstances it was acquired by the matter. The evolutionist believes only in the properties which belong to matter as matter, and which are coexistent with the matter itself. The admission of an inherent property peculiar to the living state of matter, almost amounts to the admission of a vital power; but such an hypothesis, it need scarcely be said, would be incompatible with the doctrine of evolution. But physical evolutionists who persist in attributing all the phenomena of living beings to physical agencies only, ignore the most important changes occurring in every form of living matter. Again and again, they repeat the statement that the changes in living matter are molecular; but this is merely a word which is perfectly meaningless as applied to the changes in question, since the 'molecule' is undefined, has not been described, and is quite unknown. The very same authorities acknowledge that conclusions not based upon evidence cannot advance science, or be looked upon as scientific, and yet, with an inconsistency that is extraordinary, they state with confidence that they understand the nature of these changes. But they have not been able to learn anything of them whatever by experiment, nor can they discover any means of imitating them in matter in the laboratory. The changes in question are quite peculiar to living matter; they occur in all living matter, but in living matter only. These changes differ entirely from any other changes of which we have any cognizance. Nothing surely can be more illogical or unscientific than to assert that actions about which we know nothing are of the same kind or nature as actions which are understood, and can be brought about whenever we will. Yet physicists, chemists, and indeed most scientific men, have fully committed themselves to the dogmatic creed that the phenomena of living matter are, like all the other phenomena of nature, due to antecedent physical change. There are no physical phenomena to which they can point, that in the remotest degree resemble the actions peculiar to living matter.