life of the earth have the inhabitants changed entirely; that is, five periods might be marked out, each of which contained no living species that had existed in the former one. The same families and genera were represented, for the most part, in successive periods, but with specific differences. These changes were not effected abruptly; probably at long intervals one species after another disappeared; but before, or simultaneously with such disappearance, a new one took its place in the economy of nature, until finally not one of the original ones was left. Such is the general rule; and yet as our knowledge of the subject at present stands, it is not invariably the case. Twice the thread of existence seems to have been abruptly broken; once at the junction of the secondary and tertiary periods, where a gap appears to be formed, only crossed by microscopic diatomaceæ, and one shell, and one coral, according to Hugh Miller; and again, between the palæozoic and the secondary division, where the chasm is only crossed, if at all, by two doubtful species of plant. It is not improbable, however, that future researches may discover links of much more close connection, even between these, than has hitherto been suspected. Professor Owen remarks, "that species, or forms so recognized by their distinctive characters and the power of propagating them, have ceased to exist, and have successively passed away, is a fact no longer questioned. That they have been exterminated by exceptional cataclysmal changes of the earth's surface has not been proved. But why do species perish? We see, or think we see, reasons why an individual life should be limited in time. Obvious changes of tissue take place, the natural tendency of which is the destruction of the vitality or activity of the organism. But no such changes as these can be observed in the individuals of a species. So far as we know, the last generation of a disappearing race is as hardy and vigorous as the first. Our author acknowledges that but little can be said demonstratively on this point. Man, during his reign, has had some influence on, and beyond this, some experience of, the disappearance of species. He has hunted down certain beasts of prey, and well nigh exterminated them, as well as others less noxious, as the dodo, and the dinornis. He has witnessed even recently the disappearance of many birds, amongst others the hook-billed parrot of New Zealand and the Great Auk of our own islands. "As a cause of extinction in times anterior to man, it is most reasonable to assign the chief weight to those gradual changes in the conditions affecting a due supply of sustenance to animals in a state of nature, which must have se companied the slow alternations of sea and land brought about in Paleontology, p. 399. the æons of geological time."* This can, however, only apply to terrestrial animals, except perhaps in certain cases where a deeper or a shallower sea may possibly be unfavourable to continued life. In the case of land animals, there are circumstances rendering them obnoxious to extirpating influences. Our author considers that in proportion to the bulk of a species will be the difficulty of the contest which it has to maintain against surrounding agencies. The larger the animal, the more likely it will be to suffer from seasons of scarcity or drought, or to be made a prey of from its conspicuous size, by predatory tribes. The larger species are also much less prolific than the smaller. "The actual presence, therefore, of small species of animals in countries where larger species of the same natural families formerly existed, is not the consequence of degeneration-of any gradual diminution of the size of such species-but is the result of circumstances, which may be illustrated by the fable of "The Oak and the Reed;" the smaller and feebler animals have bent and accommodated themselves to changes to which the larger species have succumbed."+ The causes operative in the extinction of species are thus summed up : "That their limitation in time, in some instances or in some measure, may be due to constitutional changes accumulating by slow degrees in the long course of generation, is possible. But all hitherto observed causes of extirpation point either to continuous slowly operating geological changes, or to no greater sudden cause than the, so to speak, spectral appearance of mankind on a limited tract of land not before inhabited. It is most probable, therefore, that the extinction of species, prior to man's presence or existence, has been due to ordinary causes-ordinary in the sense of agreement with the laws of organization and of the never-ending mutation of the geographical and climatal conditions on the earth's surface. species and individuals of species least adapted to bear such influences, and incapable of modifying their organization in agreement therewith, have perished. Extinction, therefore, on this hypothesis implies the want of self-adjusting power in the individuals of the species subject thereto."-p. 399. The It can scarcely be doubted that in this passage the expressions are so cautious as to verge upon obscurity; and that the account of the extinction of species may be interpreted as meaning almost anything or nothing, according to the phase of mind of the reader. 3. If little satisfactory can be ascertained concerning the extinction of species, still less is known on their origin. Species have been observed disappearing, and in some few instances perhaps the last *Palæontology, p. 398. Ibid p. 399. " individual has been seen alive; but no one has ever consciously seen the first; Professor Owen says, that " on the more mysterious subject of their coming into being no light has yet been thrown by experiment or observation." The learned writer is again somewhat obscure on this point. Utterly disavowing the hypothesis of development" as supported either by De Maillet, Lamarck, the author of the "Vestiges," or Messrs. Wallace and Darwin, and equally repudiating the "degeneration" theory of Buffon, he still seems to be a believer in "development" in some form; or to say the least, in the production of species by "secondary causes (p. 403); holding that biologists may entertain this idea, without committing themselves to any current theory on the mode of operation of such second cause. He holds that although the nature of the forces operating to produce a lichen or one of the algae may not be so well understood as those concerned in the formation of a crystal, yet, "that the species of the mineralogist and the botanist should be owing to influences so different as is implied by the operation of a second cause, and the direct interference of a first cause is not probable." He seems also, by a continuation of this passage, to express some confidence in the artificial production of protozoa by external influences; but "with regard to the species of higher organisms, distinguishable as plants and animals, their origin is as yet only matter of speculation." It would have been more satisfactory to the curious-and amongst these, in such matters as the present, we rank ourselves had the professor spoken out more decidedly his own views onl development. Acknowledging that there are principles based on rigorous and extensive observation of facts, which have tended to impress on the minds of the closest reasoners in biology the conviction of a "continuously operative secondary creational law," he offers no suggestion whatever as to the mode of operation of such a law, and leaves the reader in doubt as to what is meant by it-whether it is to be understood as a "creation," or only as a "development." The principles above referred to are enume rated as "the law of irrelative or vegetative repetition; the law of unity of plan or relations to an archetype; the phenomena of parthenogenesis; and the progressive departure from general type as exemplified in the series of species from their first introduction to the present time." Yet the law suggested as that in continuous operation is most vaguely suggested as the "ordained becoming of living things." Commenting upon the theory of "Natural * Palæontology, p. 398. † Loc. Cit. P. 407. * Selection" as propounded by Mr. Darwin, our author thus sums up his views on "Development :" "Observation of animals in a state of nature, however, is still required to show their degree of plasticity, or the extent to which varieties do occur; whereby grounds may be had for judging of the probability of the elastic ligaments and joint-structures of a feline foot, for example, being superinduced upon the more simple structure of the toe, with the non-retractile claw, according to the prin ciple of a succession of varieties in time. "Farther discoveries of fossil remains are also needed to make known the antetypes, in which varieties, analogous to the observed See the Eclectic for March, for an account of this theory. Our notice of Mr. Darwin's work in the March number was chiefly concerned with its scientific aspect. As a supplement to this, and bearing upon its logical merits, and its moral tendencies, we subjoin the following brief extracts from the Daily Express, of March 28th :-They form part of an acute analysis of the book by Archbishop Whateley. "I must, in the first place, observe that Darwin's theory is not inductive-not based on a series of acknowledged facts pointing to a general conclusion-not a proposition evolved out of the facts, logically, and of course including them. To use an old figure, I look on the theory as a vast pyramid resting on its apex, and that apex a mathematical point. "Let no one say that it is held together by a cumulative argument. Each series of facts is laced together by a series of assumptions, and repetitions of the one false principle. You cannot make a good rope out of a string of air bubbles. . . . "The pretended physical philosophy of modern days strips man of all his moral attributes, or holds them of no account in the estimate of his origin and place in the created world. A cold atheistical materialism is the tendency of the so-called material philosophy of the present day. Not that I believe that Darwin is an atheist; though I cannot but regard his materialism as atheistical. I think it untrue, because opposed to the obvious course of nature, and the very opposite of inductive truth. And I think it intensely mischievous." After entering somewhat minutely into the scientific objections, the writer concludes with these words : "I need hardly go any further with these objections. But I cannot conclude without expressing my detestation of the theory, because of its unflinching materialism; because it has deserted the inductive track, the only track that leads to physical truth;-because it utterly repudiates final causes, and thereby indicates a demoralized understanding on the part of its advocates. In some rare instances it shows a wonderful credulity. Darwin seems to believe that a white bear, by being confined to the slops floating in the Polar basin, might be turned into a whale; that a Lemur might easily be turned into a bat; that a three-toed tapir might be the great grandfather of a horse! or the progeny of a horse may (in America) have gone back to the tapir. "But any startling and (supposed) novel paradox, maintained very boldly, and with something of imposing plausibility, produces, in some minds, a kind of pleasing excitement, which predisposes them in its favour; and if they are unused to careful reflection, and averse to the labour of accurate investigation, they will be likely to conclude that what is (apparently) original must be a production of original genius, and that anything very much opposed to prevailing notions must be a grand discovery,-in short, that whatever comes from the bottom of a well' must be the truth' supposed to be hidden there." ones in existing species, might have occurred, seriatim, so as to give rise ultimately to such extreme forms as the giraffe. "This application of paleontology has always been felt by myself to be so important, that I have never omitted a proper opportunity for impressing the results of observations showing the 'more generalized structures' of extinct, as compared with the more specialized forms' of recent animals. 6 “But observation of the effects of any of the above hypothetical transmuting influences in changing any known species into another has not yet been recorded. And past experience of the chance aims of human fancy, unchecked and unguided by observed facts, shows how widely they have ever glanced away from the gold centre of truth."* The generalization of structure here referred to in opposition to specialization, bears directly upon the views of the author as to the "advance and progress in the main" of organisms; but we pass over this part of the subject, in order to come to a point of immediate practical interest-one connected with the history of man and the period or date of his introduction upon earth. Amidst all the mutations of geological opinion, it has generally, perhaps universally, been held, that all the known geological periods or epochs, even to the post-pleiocene or pleistocene, were completed before man appeared. It has certainly never been suspected (until recently) that man had seen what is called the Driftperiod. It has been a received article of belief in science and in history, that the earth was prepared, in great measure as we now see it, before any human inhabitants took possession of it. Recent discoveries, however, have tended to unsettle, in some measure, this belief; and to indicate (should their authenticity be demonstrated) that the duration of man's sojourn on this planet dates from a somewhat more remote epoch than we have been accustomed to consider. What are these discoveries? and what is their significance ? Certain flint weapons-so appearing-have been from time to time discovered in stratified gravel, by independent investigators, both in France and England. In the valley of the Somme, near Abbeville and Amiens, great numbers of these flints, now technically known as "celts," have been discovered by M. Boucher de Perthes, from 1847 up to the present time. Similar bodies have been discovered by Mr. Prestwich, Mr. Flower, and many others, in England, 17 and 20 feet below the surface, in undisturbed ground. So far all scems innocent enough; but what are these celts," and what are the strata in which they are found? In these beds of gravel, from which the flints were taken, there are 66 * P. 406. |