Page images
PDF

mendous rate of increase in a few years from a single pair of birds producing two young ones each year, and this only four times in their life; in fifteen years such pair would have increased to nearly ten millions!" * The passenger-pigeon of the United States exemplifies such rate of increase, where congenial food abounds. But, as a general rule, the animal population of a country is stationary, being Kept down by a periodical deficiency of food, and other checks. Hence the struggle for existence j and the successful result of adapted organization and powers in a well-developed variety, which Mr. Darwin generalizes as " Natural Selection," and •which Mr. Wallace f illustrates as follows:—

"An antclopo with shorter or weaker legs must necessarily suffer more from the attacks of the feline carnivora; the passenger-pigeon with less powerful wings, would sooner or later bo affected in its powers of procuring a regular supply of food." j: . If, on the other hand, "any species should produce a variety having slightly increased powers of preserving existence, that variety must inevitably in time acquire a superiority in numbers." "During any change tending to render existence more difficult to a species, tasking its utmost powers to avoid complete extermination, those individuals forming the most feebly organized variety would suffer first; the same causes continuing the parent species would next suffer, would gradually diminish in numbers, and with a recurrence of similar unfavorable conditions, must soon become extinct. The superior variety would then alone remain, and on a return to favorable circumstances would rapidly increase in numbers and occupy the place of the extinct species and variety. The variety would now have replaced the species of which it would be a more perfectly developed and a more highly organized form." •;

Buffon regarded varieties as particular alterations of species, as supporting and illustrating a most important principle—the mutability of species themselves. The so-called varieties of a species, species of a genus, genera of a family, etc., were, with him, so many evidences of the progressive amount or degrees of change which had been superinduced by time and generations upon a primordial type of animal. Applying this principle to the two hundred mammalian species of which he had given a history in his great work, he believed himself able to reduce them to a very small number of primitive stocks or families. || Of these he enumerates fifteen: besides which, Buffon specifies certain isolated forma, which represent, as he

* Proceedings of the LimiJEan Society, 1858, p. 65.

f Proceedings of tho Linnoenn Society (dated from " Termite." February, 1858), vol. iii. p. 58.

i Wallace, loc. cit. p. 85.

$ Ib., p. 58.

I. Ubtoire Naturello, torn. xiv. p. 338.

forcibly and truly expresses it, both species and genus ; * such are the elephant, rhinoceros, hippopotamus, giraffe, camel, lion, bear, and mole, t Palaeontology has since revealed the evidences of the true nature and causes of the present seeming isolation of some of these iorms.

Such evidences have been mainly operative with the later adopters and diffusers of Buffon's principle in the reduction of the number of primitive sources of existing species, and the contraction of the sphere of direct creative acts. Thus Lamarck J reduces the primordial forms or prototypes of animals to two, viz. the worm (vers), and the monad (iiifiisoires); the principles which in the course of illimited time operated, on his hypothesis, to produce the present groups of animals led from the vibrio, through the annelids, cirripeds, and molluscs to fishes, and there met the other developmental route by way of rotifers, polypes, radiaries, insects, arachnidcs, and Crustacea. The class of fishes, deriving its several forms from combinations of transmuted squids and crabs, then proceeded through the well-defined vertebrate pattern up to man. With a philosophic consistency, wanting in his latest follower, Lamarck sums up: "Cette serie d'animaux commencant par deux branches ou so trouvent les plus imparfaits, les premiers de chacune do ces branches ne rc^oivent 1'existence que par generation directe ou spontan6e." §

Mr. Darwin, availing himself of the more exact ideas of the affinities and relationships of animal groups obtained by subsequent induction, says: "I believe that animals have descended from at most only four or five progenitors," [evidently meaning, or answering to, the type forms of the four or five "sub-kingdoms " in modern zoology], " and plants from an equal or lesser number."

But if the means which produce varieties have operated " through the enormous species of time, within which species are changed," || the minor modifications which produce, under our brief scope of observation, so-called varieties, might well amount to differences equivalent to those now separating sub-kingdoms; and, accordingly, "analogy," Mr. Darwin logically admits, "would lead us one step further, namely, to the belief that all animals and plants have descended from some one prototype;" ^ and summing up the conditions which all living things have

* " Quelqucs especcs Isoldes, qui, comme cello de 1'homme, fassent en meme temps espece «t genre."—Tom. cit. p. 335.

t Ib., p. 360.

11'hilosophie Zob'logique, vol. ii. p. 463.

$ Ib., p. 403.

|| Vestiges of Creation, p. 231.

If Op. cit., p. 484.

in common, this writer infers from that analog)', that probably all the organic beings which have ever lived on this earth, have descended from some one primordial form, into which life was first breathed." *

By the latter scriptural phrase, it may he inferred that Mr. Darwin formally recognizes, in the so-limited beginning, a direct creative act, something like that supernatural or miraculous one which, in the preceding page, he defines, as " certain elemental atoms which have been commanded suddenly to flash into living tissues." He has, doubtless, framed in his imagination some idea of the common organic prototype; but he refrains from submitting it to criticism. He leaves us to imagine our globe void, hut so advanced as to be under the conditions which render life possible; and he then restricts the Divine power of breathing life into organic form to its minimum of direct operation. All subsequent organisms henceforward result from properties imparted to the organic elements at the moment of their creation, prc-adapting them to the infinity of complications and their morphological results, which now try to the utmost the naturalist's faculties to comprehend and classify. And we admit with Buckland, that such an aboriginal constitution, "far from superseding an intelligent agent, would only exalt our conceptions of the consummate skill and power, that could comprehend such an infinity of future uses, under future systems, in the original groundwork of his creation."

We would accordingly assure Professor Owen that he "may conceive the existence of such ministers, personified as nature without derogation of the Divine power;" and that he, with other inductive naturalists, may confidently advance in the investigation of those " natural laws or secondary causes, to which the orderly succession and progression of organic phenomena have been committed.'^ We have no sympathy whatever with biblical objectors to creation by law, or with the sacerdotal revilers of those who would explain such law. Literal scripturalism in the time of Lactantius, opposed and reviled the demonstrations of the shape of the earth; in the time of Galileo it reviled and persecuted the demonstrations of the movements of the earth ; in the time of Dean Cockburn of York, it anathematized the demonstrations of the antiquity of the earth; and the eminent geologist who then personified the alleged anti-scriptural heresy, has been hardly less emphatic than his theological assailant, in his denunciations of some of the upholders of the "becoming and succession of species by natural law," or by

[merged small][ocr errors]

"a continuously- operating creative force." What we have here to do, is to express our views of the hypothesis as to the nature and mode of operation of the creative law, which has been promulgated by Messrs. Wallace and Darwm.

The author of the volume " On the Origin of Species," starts from a single supernaturally created form. He does not define it; it may have been beyond his power of conception. It is, however, eminently plastic, is modified by the influence of external circumstances, and propagates such modifica- | tions by generation. Where such modified descendants find favorable conditions of existence, there they thrive j where otherwise they perish. In the first state of things, the result is so analogous to that which man brings about, in establishing a breed of domestic animals from a selected stock, that it suggested the phrase of "Natural Selection ;" and we are appealed to, or at least "the young and rising naturalists with plastic minds," are adjured to believe that the reciprocal influences so defined have operated through divergence of character and extinction, on the descendants of a common parent, so as to produce all the organic beings that live, or have ever lived on our planet.

Now we may suppose that the primeval prototype began by producing in the legal generative way, creatures like itself, or so slightly affected by external influences, as at first to be scarcely distinguishable from their parent. When as the progeny multiplied and diverged, they came more and more under the influence of "Natural Selection," so, through countless ages of this law's operation, they finally rose to man. But, we may ask, could any of the prototype's descendants utterly escape the surrounding influences? To us such immunity, in the illimitable period during which the hypothesis of natural selection requires it to have operated, is inconceivable. No living being, therefore, can now manifest the mysterious primeval form to which Darwin restricts the direct creative act; and we may presume that this inevitable consequence of his hypothesis, became to him an insuperable bar to the definition of that form.

But do the facts of actual organic nature square with the Darwinian hypothesis? Are all the recognized organic forms of the present date so differentiated, so complex, so superior to conceivable primordial simplicity of form and structure, as to testify to the effects of natural selection continuously operating through untold time? Unquestionably not. The most numerous living beings now on the globe are precisely those which offer such a simplicity of form and * On the Nature of Limbs, p. 482.

structure, as best agrees, and we take leave | All these would be interpreted as the to affirm can only agree, with that ideal | earliest evidences of the modifying and speprototype from which, by any hypothesis , cies-changing influences, according1 to the

of natural law, the series of vegetable and animal life might have diverged.

If by the patient and honest study and comparison of plants and animals, under their manifold diversities of matured form, and under every step of development by which such form is attained, any idea may be gained of a hypothetical primitive organism,—if its nature is not to be left wholly to the unregulated fancies of dreamy speculation—we should say that the form and condition of life which are common, at one period of existence, to every known kind and grade of organism, would be the only conceivable form and condition of the one primordial being from which " Natural Selection " infers that all the organisms which have ever lived on this earth have descended.

Now the form in question is the nucleated cell, having the powers of receiving nutritive matter from without, of assimilating such nutriment, and of propagating its kind by spontaneous fission. These powers are called " vital," because as long as they are continued the organism is said to live. The most numerous and most widely diffused of living beings present this primitive grade of structure and vital force, which grade is inferior to that of the truly definable " plant" or "animal," but is a grade represented and passed through by the germ of ever)-, even the highest, class of animals, in the course of embryonic development. The next stages of differentiated or advanced organization are defined as follows in Professor Owen's last publication :—

"When tho organism is rooted, has neither mouth nor stomach, exhales oxygen, and has tissues composed of 'cellulose' or of binary or ternary compounds, it is called a 'plant.' When tho organism can move, when it receives the nutritive matter by a mouth, inhales oxygen, and exhales carbonic acid, mid develops tissues, tlio proximate principles of which are quaternary compounds of carbon, hydrogen, oxygen, and nitrogen, it is called on 'animal.' But tho two divisions of organisms called 'plants' and • animals' arc specialized members of tho great natural groups of living things; and there are numerous organisms, mostly of minute size .and retaining the form of nucleated cells, which manifest the common organic characters, but without tho distinctive supcradditions of true plants or animal- Such organisms are called 'protozoa,' and include the sponges or .\i:i"i-/>tii':'it, the Foraminifcra or Bhizopods, the i'fiii/1-i/sti'inn . the Diatomacece, Desmidice, Greyarince, and most of the so-called Polyyastria of

[ocr errors]

infusorial animalcules of older

[ocr errors]

hypothesis of Lamarck. They arc the organisms respecting which the first living phvsiologists hesitate to apply the Harveian axiom omne victim ab ovo, believing the possibility of their spontaneous origin to be by no means experimentally disproved. The prevalence of the essential first step in the production of all higher organisms, viz. through the combined matter of the " germcell " and " sperm-cell," has no doubt strongly inclined physiologists to believe impregna- j tion to be an absolute condition of the beginning of all existing organisms. But, as the president of the British Association stated, in his " Address " at Leeds :—

"' In regard to lower living things, analogy is but hazardous ground for conclusions. Tho single-celled organisms, such as many of the socalled animalcules of infusions, which arc at a stage of organization too low for a definite transfer to cither the vegetable or animal kingdoms, offer a field of observation and experiment which may yet issue in giving us a clearer insight into tlic development of the organic living cell.'— 'Whether an independent free-moving and assimilating organism, of a grade of structure similar to, and scarcely higher than, the "germcell," may not arise by a collocation of particles, through tho operation of a force analogous to that which originally formed tho germ-cell in tho ovarian stromn, is a. question which cannot bo answered until every possible rare and pains have been applied to its solution.'"—P. 28.

Professor 1 'one-hot believes that he is authorized by the results of his experiments to answer that question in the affirmative. It is one of supreme importance, and which has, hitherto, never received such an amount of painstaking experimental research as it merits; and the best observations, the most carefully conducted and ingeniously devised arrangements for insuring success, are undoubtedly those of the patiently observant professor of Zoology in the " Ecole de Medecine," and "Ecole superieure des Sciences," at Rouen.* This, at least, may be affirmed, that the inductive groundwork of his opponents is by no means such as can justify any dogmatic negation of Heterogeny as applicable to the simplest Protozoa.

On the basis, therefore, of analogical probability, it may be inferred:—that the prim-r ordial as well as all other forms of organic beings, originate, and have ever originated, from the operation of secondary' and continuously operating creative laws: and that the various grades of organisms now in being,

« Pouchot, " He'teVofjenie, ou TraM de la Ge"ne'lation spoutnne'e, base sur des nouvelles Experiences," Svo., 1869.

from the microscopic monad upwards, indicate the various periods in time at which the first step of the series they respectively terminate began. The monad that by "natural selection" has ultimately become man, dates from the furthest point in the remote past, upon which our feigners of developmental hypotheses can draw with unlimited credit: the monad which by its superficial vibratile cilia darted across the field of the microscope we wero looking through this morning, is the result of the collocation of particles which, without "sudden flash," took place under the operation of the heterogeneous organizing force of yesterday.

Accordingly we find that every grade of structure, from the lowest to the highest, from the most simple to the most complex, is now in being,—a result which it is impossible to reconcile with the Darwinian hypothesis of the one and once only created primordial form, the parent of all subsequent living things. The changes which our planet has undergone in the course of geological time have been accompanied by the loss of many minor links which connected together the existing evidences of gradational structure; but the general laws regulating the progress and diversity of organic forms, having been the same throughout all time, so it happens, according to the testimony of the most experienced palaeontologists, that—

"Every known fossil belongs to somo one or other of the existing classes, and that the organic remains of the most ancient fossiliferous strata do not indicate or suggest that any earlier and different group of beings remains to bo discovered, or has been irretrievably lost in the universal metamorphism of the. oldest rocks."*

That forms, recognized as species by their distinctive characters and the power of propagating them, have ceased to exist, and have successively passed away, is a fact now unquestioned; that they have "been exterminated by exceptional cataclysmal changes of the earth's surface, as was surmised at the first acceptance of the fact of extinction, has not been proved; that their limitation in time may, in some instances, or in some degree, be due to constitutional changes, accumulating by slow degrees in the long course of generations, is possible: but all the traceable and observed causes of extirpation point either to continuous slowly operating geological changes, or to no greater sudden cause than the apparition of mankind on a limited tract of land not before inhabited. It is now, therefore, generally inferred that the extinction of species, prior to man's existence, has been due to ordinary causes—ordinary in the sense of agreement with the great laws of never-ending mutation of geographical and * Owen's Palaeontology, p. 18.

THIRD SERIES. LIVING AGE. 505

climatal conditions on the earth's surface. The individuals of species least adapted to bear such influences and incapable of modifying their organization in harmony therewith, have perished. Extinction, therefore, on this hypothesis, is due to the want of selfadjusting, self-modifying power in the individuals of the species.

In the joint paper on the tendency of varieties to form species by natural means of selection,* one of the authors writes:—

"Any minute variation in structure, habits, or instincts, adapting the individual better to the new conditions, would tell upon its vigor and health. In the strugglo it would hnve a bettor chance of surviving, and those of its offspring which inherited the variation would also havo a, better chance. Let this work go on for a thousand generations, and who will pretend to affirm," asks Mr. Darwin," that a new species might not be tho result?"

Thereupon is adduced the imaginary example of dogs and rabbits on an island, which we have already cited.

Now this, we take leave to say, is no very profound or recondite surmise ; it is just one' of those obvious possibilities that might float through the imagination of any speculative naturalist; only, the sober searcher after truth would prefer a blameless silence to sending the proposition forth as explanatory of the origin of species, without its inductive foundation.

In the degeneration-theory of Bufibn, man is one of the primitive types,—the created apes and monkeys are derivatives. He might have illustrated it as follows :—

To give an imaginary example from changes in progress on an island: let the organization of a wild man feeding chiefly on fruits become slightly plastic; let corresponding changes cause the sources of food on the ground very slowly to decrease, and those on the trees to increase ; the effect of this would be that the man would try to climb more for food. Suppose also that a tiger or like destructive carnivore should swim over and settle in the island, which happened to be destitute of flints for weapons. The human organization being slightly plastic, those individuals with the longest and strongest arms, and with the most prehensile use of the great toe, let the difference be ever so small, would be slightly favored, would survive during that time of the year when food was scarcest on the ground, but ripe and ready on certain trees; they would also rear more young which would tend to inherit these slight peculiarities. The best climbers would escape the tigers, the worst would bo rigidly destroyed.

* By Darwin and Wallace. " Proceedings of the Linnamn Society/' August, 1858, p. 45.

Buffon would have seen no more reason to doubt that these causes, in a thousand generations, would produce a marked effect, and adapt the form of the wild man to obtain fruits rather than grains, than Darwin now believes that man can be improved by selection and careful interbreeding into a higher, more heroic, more angelic form! The advocate of Buffon's hypothesis might point out that it is on islands, as Borneo and Sumatra, for example, where the orang-utan— the obvious result of such " degradation by natural selection" — is exclusively found. And is it not there also, and in some other islands of the Malayan Archipelago, where the next step in the scale of " degeneration" is exhibited in the still longer-armed Ungkas and other tail-less Hylobates? And though we call them "tail-less" yet they have the "os coccygisj" and this being a terminal appendage of stunted vertebrae, offers the very condition for the manifestation of an occasional developmental variety. If cats, after accidental mutilation or malformation, can propagate a tail-less breed, why may not apes produce a tailed variety, and by natural selection in a long course of ages, degenerate into endless incipient species of "baboons and monkeys ?*'

But Mr. Darwin, it may be said, repudiates the coarse transmutational conditions and operations of Buffon and Lamarck; or, if there be any parallel between his and Buffon's illustration of the changing of species, at all events such parallels must run in opposite directions.

Mr. Darwin starts from a single created prototype, from which it is difficult to conceive he can mean any other course of organic progress than an ascensive one. But of this, in the absence of a definition of the starting point, we cannot be perfectly sure. "Natural selection" may operate in both directions. The following, for example, would have been cordially welcomed by Buffon as a testimony in favor of his "d6g6neration" hypothesis:—

"In North America the black bear was seen by Ilcarno swimming for Iiours with widely open mouth, thus catching, liko n whale, insects in the water. Even in so extreme a cuso as this, if the supply of insects were constant, and if better adapted competitors did not already exist in the country, lean see no difficulty in n raco of bears being rendered, by natural selection, more nnd more aquatic in their structure and habits, with larger nnd larger mouths, till n creature was produced as monstrous as a whale." •

If the ursine species had not been restricted to northern latitudes, we might have surmised this to have been one of the facts connected with " the distribution of the inhabitants of South America," which seemed to * Darwin, p. 184. (1st edition.)

VIr. Darwin, when naturalist on board H.M.S. Beagle, " to throw some light on the origin of species." * But the close resemblance of the style, and of the tone and frame of mind which could see no difficulty in the adequacy of the above-cited circumstances of "external conditions, of habit, of volition," tochange a bear into a whale, to those exemplified in Jie " Philosophic Zoologique," point strongly to the writings of Lamarck as the true sugjester of Mr. Darwin's views of animated lature. We look, however, in vain for any instance of hypothetical transmutation in Lamarck so gross as the one above cited; we must descend to older illustrators of the favorite idea, to find an equivalent case of the bear in pursuit of water-insects, and we find one in the following :—

"Car il pent arriver, comme nous scavons qu'en effet il arrive assez souvent, quo Irs poissons niles ct volans chnssant ou etant chasses dans la inn, cmportes du dcsir do la proie on dc la crainto do hi mort, on bicn pousscs pcntfitro it quelqnes pas dn rivage par dcs vagues qu'cxcitoit uno teinpete, soicnt tombed dans dcs roseaux ou dans dcs herbages, d'ou ensuite il ne lenr fut pas possible de rcprendro vers la mcr 1'essor qui les en avoit tire's, ct qn'en cet <?tat ils ayent contract^ uno plus grando facultc de voler. Alors leurs nagcoircs n'etant plus balances dcs caux de la mer, so fcndirent ct sc dejetterent par la Eifcheresse. Tandisqu'ils trouvcrentdans les roseanx ct les herbages dans lesqucls ils c'toient tombcs, quelqnes nlimens pour so soutenir, les luyaux de leurs nagcoircs, separe's les uns des autres, se prolongcrent et so revetirent de barbcs; ou, pour parlcr plus juste, les membranes qui auparavant les nvoient tenus colle'a les uns mix autres se mc'tamorphoserent. La barbc formeo de ces pellicules dcjctecs s'allongea clle-meme; la pcau de ccs nnimanx sc rcvetit insensiblcmcnt d'un duvet do la mOmo coulcur dont cllc e*toit peintc, ct co duvet grnndit. Les petits ailerons qu'ils nvoient sous lo venire, ct qui comme leurs nageoircs, Icur nvoient nklc* a se promcncr dans la mcr, devinrent dcs piecls, ct Icur scrvircnt & marcher sur la tcrrc. II so lit encore d'autres petits changemens dans leur figure. Lo bee ct lo col dcs uns s'allongcrcnt: ccux dcs nutres co raconrcirent: il en fut do memo du rcstc da corps. Cepcndant l.i conformite do la premiere figure eubsiste dans lo total; ct cllo esc ct sera toujours nise'o ii reconnoitre.

"Examincz en cffct toutcs les especcs do poulos, grosses ct pctitcs, memo cellcs des Indes, cellos qui eont liuppc'cs, ou relics qui no lo sont pas; ccllcs dont les plumes sont il rebours telles qu'on en voit Ji Damietto, c'est-ii-dire, dont le plumage cst couche do la queue it la tcte; vous trouvercz dans la mcr dcs cspeces toutcs semblablcs, c"cailleuscs ou sans dcaillcs. Toutcs les cspeces de perroquets dont les plumages sont si divers, leg oiscaux les plus rarcs ct les plus singuliercment marquetcs sont conformcs ;• des poissons points, comrao eux, de noir, de brim, dc gris, do jiumo,

* Darwin, p. 1. (1st edition.)

« PreviousContinue »