Page:The Times, Origin of Species.djvu/2

 hood. No competent thinker of the present day dreams of explaining these indubitable facts by the  notion of the existence of unknown and undiscoverable adaptations to  purpose. And we would remind those who, ignorant of the facts, must be moved by authority, that no one has asserted the incompetence of the  doctrine of final causes, in its application to physiology and anatomy,  more strongly than our own eminent anatomist, Professor Owen, who,  speaking of such cases, says (On the Nature of Limbs, pp. 39, 40),—"I  think it will be obvious that the principle of final adaptations fails  to satisfy all the conditions of the problem." But, if the doctrine of final causes will not help us to comprehend the anomalies of living structure, the principle of adaptation must surely  lead us to understand why certain living beings are found in certain  regions of the world and not in others. The palm, as we know, will not grow in our climate, nor the oak in Greenland. The white bear cannot live where the tiger thrives, nor vice versa, and the more the  natural habits of animal and vegetable species are examined, the more  do they seem, on the whole, limited to particular provinces. But when we look into the facts established by the study of the geographical  distribution of animals and plants it seems utterly hopeless to attempt  to understand the strange and apparently capricious relations which  they exhibit. One would be inclined to suppose a priori that every country must be naturally peopled by those animals that are fittest to  live and thrive in it. And yet how, on this hypothesis, are we to account for the absence of cattle in the Pampas of South America, when  those parts of the New World were discovered? It is not that they were unfit for cattle, for millions of cattle now run wild there; and the  like holds good of Australia and New Zealand. It is a curious circumstance, in fact, that the animals and plants of the Northern  Hemisphere are not only as well adapted to live in the Southern  Hemisphere as its own autochthones, but are in many cases absolutely  better adapted, and so overrun and extirpate the aborigines. Clearly, therefore, the species which naturally inhabit a country are not  necessarily the best adapted to its climate and other conditions. The inhabitants of islands are often distinct from any other known species  of animal or plants (witness our recent examples from the work of Sir  Emerson Tennent, on Ceylon), and yet they have almost always a sort of  general family resemblance to the animals and plants of the nearest  mainland. On the other hand, there is hardly a species of fish, shell, or crab common to the opposite sides of the narrow isthmus of Panama. Wherever we look, then, living nature offers us riddles of difficult solution, if we suppose that what we see is all that can be known of it. But our knowledge of life is not confined to the existing world. Whatever their minor differences, geologists are agreed as to the vast thickness of the accumulated strata which compose the visible part of  our earth, and the inconceivable immensity of the time of whose lapse  they are the imperfect, but the only accessible witnesses. Now, throughout the greater part of this long series of stratified rocks are  scattered, sometimes very abundantly, multitudes of organic remains,  the fossilized exuviae of animals and plants which lived and died while  the mud of which the rocks are formed was yet soft ooze, and could  receive and bury them. It would be a great error to suppose that these organic remains were fragmentary relics. Our museums exhibit fossil shells of immeasurable antiquity, as perfect as the day they were  formed, whole skeletons without a limb disturbed—nay, the changed  flesh, the developing embryos, and even the very footsteps of primeval  organisms. Thus the naturalist finds in the bowels of the earth species as well defined as, and in some groups of animals more numerous  than, those that breathe the upper air. But, singularly enough, the majority of these entombed species are wholly distinct from those that  now live. Nor is this unlikeness without its rule and order. As a broad fact, the further we go back in time the less the buried species  are like existing forms; and the further apart the sets of extinct  creatures are the less they are like one another. In other words, there has been a regular succession of living beings, each younger set  being in a very broad and general sense somewhat more like those which  now live. It was once supposed that this succession had been the result of vast successive catastrophes, destructions, and re-creations en masse; but  catastrophes are now almost eliminated from geological, or at least  palaeontological speculation; and it is admitted on all hands that the  seeming breaks in the chain of being are not absolute, but only relative  to our imperfect knowledge; that species have replaced species, not in  assemblages, but one by one; and that, if it were possible to have all  the phenomena of the past presented to us, the convenient epochs and  formations of the geologist, though having a certain distinctness, would  fade into one another with limits as undefinable as those of the  distinct and yet separable colours of the solar spectrum. Such is a brief summary of the main truths which have been established concerning species. Are these truths ultimate and irresolvable facts, or are their complexities and perplexities the mere expressions of a  higher law? A large number of persons practically assume the former position to be correct. They believe that the writer of the Pentateuch was empowered and commissioned to teach us scientific as well as other truth, that  the account we find there of the creation of living things is simply  and literally correct, and that anything which seems to contradict it  is, by the nature of the case, false. All the phenomena which have been detailed are, on this view, the immediate product of a creative  fiat and consequently are out of the domain of science altogether. Whether this view prove ultimately to be true or false, it is, at any rate, not at present supported by what is commonly regarded as logical  proof, even if it be capable of discussion by reason; and hence we  consider ourselves at liberty to pass it by, and to turn to those views  which profess to rest on a scientific basis only, and therefore admit of  being argued to their consequences. And we do this with the less hesitation as it so happens that those persons who are practically  conversant with the facts of the case (plainly a considerable advantage)  have always thought fit to range themselves under the latter category. The majority of these competent persons have up to the present time maintained two positions,—the first, that every species is, within  certain defined or definable limits, fixed and incapable of  modification; the second, that every species was originally produced by  a distinct creative act. The second position is obviously incapable of proof or disproof, the direct operations of the Creator not being  subjects of science; and it must therefore be regarded as a corollary  from the first, the truth or falsehood of which is a matter of evidence. Most persons imagine that the arguments in favour of it are overwhelming; but to some few minds, and these, it must be confessed,  intellects of no small power and grasp of knowledge, they have not  brought conviction. Among these minds, that of the famous naturalist Lamarck, who possessed a greater acquaintance with the lower forms of  life than any man of his day, Cuvier not excepted, and was a good  botanist to boot, occupies a prominent place. Two facts appear to have strongly affected the course of thought of this remarkable man—the one, that finer or stronger links of affinity  connect all living beings with one another, and that thus the highest  creature grades by multitudinous steps into the lowest; the other, that  an organ may be developed in particular directions by exerting itself  in particular ways, and that modifications once induced may be  transmitted and become hereditary. Putting these facts together, Lamarck endeavoured to account for the first by the operation of the  second. Place an animal in new circumstances, says he, and its needs will be altered; the new needs will create new desires, and the attempt  to gratify such desires will result in an appropriate modification of  the organs exerted. Make a man a blacksmith, and his brachial muscles will develop in accordance with the demands made upon them, and in like  manner, says Lamarck, "the efforts of some short-necked bird to catch  fish without wetting himself have, with time and perseverance, given  rise to all our herons and long-necked waders." The Lamarckian hypothesis has long since been justly condemned, and it is the established practice for every tyro to raise his heel against  the carcass of the dead lion. But it is rarely either wise or instructive to treat even the errors of a really great man with mere  ridicule, and in the present case the logical form of the doctrine  stands on a very different footing from its substance. If species have really arisen by the operation of natural conditions, we ought to be able to find those conditions now at work; we ought to be  able to discover in nature some power adequate to