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least constant that individuals of the same species, however different, produce together j "quelque different qu'ils soient, peuvent toujours produire ensemble." But Cuvier warns us not to conclude, when individuals of two different races produce an intermediate and fecund offspring, that they must be of the •ame species, and that they have not been originally distinct.—P. 13.

"' The number of varieties, or amount of variation,' says Cnvier, 'relates to geographical circumstances.' At the present day, many such varieties appear to have been confined around their primitive centre, cither by seas which they could neither traverse by swimming or by flight, or by temperatures which they wcro not able to support, or by mountains which they could not cross, etc."*

Daily observation, comparison, and reflection, on recent and extinct organisms, pursued from the date of these remarks (1798) to the close of his career (1832) failed to bring the requisite proof, or to impress the mind of Cuvier •with any amount of belief worth mentioning, as to the nature of the cause operative in the production of the species of which he was the first to demonstrate the succession.

Lamarck, without contributing additional results from observation and experience, affirms that the changes defined by Cuvier do not "stop at a certain point," but progress with the continued operation of the causes producing them. That, moreover, such-changes of form and structure induce corresponding changes in actions, and that a change of actions, growing to a habit, becomes another cause of altered structure; that the more frequent employment of certain parts or organs leads to a proportional increase of development of such parts; and that, as the increased exercise of one part is usually accompanied by a corresponding disuse of another part, this very disuse, by inducing a proportional degree of atrophy, becomes another element in the progressive mutation of organic forms.f

These principles seem entitled to be regarded as of the nature of those called "verse causa;" by Bacon, and they are agreeable with known powers and properties of animated beings; only observation has not disclosed more than a very limited ex

* " Les varies do chocune ont dft fitro d'autant plus fortes ct plus nombreuses, quo les circon(tanccs dcs licnx ou de sa nature lui ont permis do s'rtendre plus loin; c'cst cequi peut fnirecroire que les prniidcs di/Vtfrences quo so tronvent parmi les homines, les chicns, ct les autres etres rt-pnndue« partout le monde, ne sont que des eflets des cnuscs accidentelles, eu uu mot. des tarietei."— P. 14.

t Philosophic Zoologiquc, 8vo, 1809, torn. i. chaps, iii. vi. vii.

tent of their operation,—limited both as to the time in which that operation has been watched, and limited consequently as to the amount of the change produced.

When Cuvicr affirms that such capacity to vary proceeds only to a certain point, he may mean that it has not been watched and traced beyond such point. Cuvier admits the tendency to hereditary transmission of characters of variation. Neither he nor any other physiologist has demonstrated the organic condition or principle that should operate so as absolutely to prevent the progress of modification of form and structure correlatively with the operation of modifying influences, in successive generations. 'But those who hastily or prematurely assume an indefinite capacity to deviate from a specific form are as likely to obstruct as to promote the solution of the question.

The principles, based on rigorous and extensive observation, which have been established sinco the time of Cuvicr, and have tended to impress upon the minds of the most exact reasoners in biology the conviction of a constantly operating secondary creational law, are the following:—The law of irrelative or vegetative repetition, referred to at p. 437, of Mr. Darwin's work; the law of unity of plan or relations to an archetype; the analogies of transitory embryonal stages in a higher animal to the matured forms of lower animals: the phenomena of parthenogenesis; a certain parallelism in the laws governing the succession of forms throughout time and space; the progressive departure from type, or from the more generalized or more specialized structures, exemplified in the series of species from their first introduction to the existing forms.* In his last Sublished work f Professor Owen does not esitate to state " that perhaps the most important and significant result of pal;coiitological research has been the establishment of the axiom of the continuous operation of the ordained becoming of living things." The italics are the author's. As to his own opinions regarding the nature or mode of that "continuous creative operation," the Professor is silent. He gives a brief summary of the hypotheses of others, and as briefly touches upon the defects in their inductive bases.| Elsewhere he has restricted himself to testing the idea of progressive

* The most numerous illustrations of this principle are to be found in Owen's palceontological works and memoirs; but he refrains from announcing it ns a general law, probably regarding ths induction as being yet incomplete.

11'alseontolopy, or ft Systematic Summary of Extinct AnimuU, and their Geological delations, 8vo., I860, p. 3.; and President's Address to the British Association at Leeds, 1868, p. 3.

i Palaeontology, p. 404.

transmutation by such subjects of natural history as he might have specially in hand; as, e.g. the characters of the chimpanzee, gorilla, and some other animals.

All who have brought the transmutative speculations to the test of observed facts and ascertained powers in organic life, and have published the results, usually adverse to such speculations, are set down by Mr. Darwin as " curiously illustrating the blindness of preconceived opinion;" and whosoever may withhold assent to his own or other transmutationists* views, is described as "really believing that at innumerable periods of the earth's history certain elemental atoms suddenly flashed into living tissues." (P. 483.) Which, by the way, is but another notion of the mode of becoming of a species as little in harmony with observation as the hypothesis of natural selection by external influence, or of exceptional birth or development. Nay, Mr. D. goes so far as to affirm—

"All the most eminent paleontologists, namely, Cuvicr, Owen, Agixssin, Barrande, Falconer, E. Forbes, etc., and all our greatest geologists, as Lycll, Murchison, Sedgwick, etc., have unanimously, often vehemently, maintained the immutability of species."—P. 310.

But if by this is meant that they as unanimously reject the evidences of a constantly operative secondary cause or law in the production of the succession of specifically differing organisms, made known by Paleontology, it betrays not only the confusion of ideas as to the fact and the nature of the law, but an ignorance or indifference to the matured thoughts and expressions of some of those eminent authorities on this supreme question in Biology.

One of the disciples would seem to be as short-sighted as the master in regard to this distinction.

"It hag been urged," writes Dr. Hooker, "against the theory that existing species have arisen through tho variation of pre-existing ones and tho destruction of intermediate varieties, that it is a hasty inference from n few facts in the life of a few variable plants, and is therefore unworthy of confidence; but it appears to ma that the opposite theory, which demands an independent creative act for each species, is on equally hasty inference."—Hooker, p. xxv.

Here it is assumed, as by Mr. Darwin, that no other mode of operation of a secondary law in the foundation of a form with distinct specific characters, can have been adopted by the Author of all creative laws than the one which the transmutationists have imagined. Any physiologist who may find the Lamarckian, or the more diffused and attenuated Darwinian, exposition of the law inapplicable to a species, such as the gorilla, considered as a step in the trans

mutative production of man, is forthwith clamored against as one who swallows up every fact and every phenomenon regarding the origin and continuance of species "in the gigantic conception of a power intermittently exercised in the development, out of inorganic elements, of organisms the most bulky and complex, as well as the most minute and simple." Significantly characteristic of the partial view of organic phenenoma taken by the transmutationists, and of their inadequacy to grapple with the working out and discovery of a great natural law, is their incompetency to discern the indications of any other origin of one specific form out of another preceding it, save by their way of gradual change through a series of varieties assumed to nave become extinct.

But has the free-swimming medusa, which bursts its way out of the ovicapsule of a campanularia, been developed out of inorganic particles? Or have certain elemental atoms suddenly flashed up into acalephal form? Has the polype-parent of the acalcphe necessarily become extinct by virtue of such anomalous birth? May it not, and does it not proceed to propagate its own lower species in regard to form and organization, notwithstanding its occasional production of another very different and higher kind. Is the fact of one animal giving birth to another not merely specifically, but generically and ordinally, distinct, a solitary one? Has not Cuvier, in a score or more of instances, placed the parent in one class, and the fruitful offspring in another class, of animals? Are the entire series of parthenogenetie phenomena to be of no account in the consideration of the supreme problem of the introduction of fresh specific forms into this planet? Are the transmutationists to monopolize the privilege of conceiving the possibility of the occurrence of unknown phenomena, to be the exclusive propounders of beliefs and surmises, to cry down ever)' kindred barren speculation, and to allow no indulgence in any mere hypothesis save their own? Is it to be endured that every observer who points out a case to which transmutation, under whatever term disguised, is inapplicable, is to be set down by the refuted theorist as a believer in a mode of manufacturing a species which he never did believe in, and which may be inconceivable?

We would ask Mr. Darwin and Dr. Hooker

to give some thought to these queries, and

if they should see the smallest meaning in

them, to reconsider their future awards of

the alternative which they may be pleased

to grant to a fellow-laborer, hesitating to

accept the proposition, either that life com

i mcnced under other than actually operating

• laws, or that " all the beings that ever lived on this earth have descended," hy the way of "natural selection," from a hypothetical unique instance of a miraculously created primordial form.

We are aware that Professor Owen and others, who have more especially studied the recently discovered astounding phenomena of generation summed up under the terms parthenogenesis and alternation of generations, have pronounced against those phenomena having, as yet, helped us "to penetrate_ the mystery of the origin of different species of ammals,"andhaveaffirmed, at least so far as observation has yet extended, that "the cycle of changes is definitely closed;" that is, that when the ciliated " monad " has given birth to the " gregarina," and this to the "cercaria," and the "cercaria" to the "distoma,"—that the fertilized egg of the fluke-worm again excludes the progeny under the infusorial or monadic form, and the cycle again recommences.* But circumstances are conceivable,—changes of surrounding influences, the operation of some intermittent law at long intervals, like that of the calculating-machine quoted by the author of "Vestiges," — under which the monad might go on splitting up into monads, the gregarina might go on weeding gregarina?, the ccrcana cercaria?, etc., and thus four or five not merely different specific, but different generic, and ordinal forms, zoologically viewed, might all diverge from an antecedent quite distinct form. For how many years, and by how many generations, did the captive polype-progeny of the Medusa aurita go on breeding polypes of their species (Hydra tuba), without resolving themselves into any higher form, in Sir John Dalyell's aquarium! t The natural phenomena already possessed by science are far from being exhausted, on which hypotheses, other than transmutative, of the production of species by law might be based, and on a foundation at least as broad as that which Mr. Darwin has exposed in this essay.

We do not advocate any of these hypotheses in preference to the one of "natural selection," we merely affirm that this at present rests on as purely a conjectural basis. The exceptions to that and earlier forms of transmutationism which rise up in the mind of the working naturalist and original observer, are so many and so strong as to have left the promulgation and advocacy of the hypothesis, under any modification, at all times to individuals of more imaginative temperament; such as Demaillet in the last

* President's Address to the British Association at Leeds, p. 27.

f See tlio beautiful work entitled, - linre and Remarkable Animals of Scotland," •:;.>. vol. i. 1847, by Sir J. G. Dalyell.

century, Lamarck in the first half of the j present, Darwin in the second half. The great names to which the steady inductive advance of zoology has been due during those periods, have kept aloof from any hypothesis on the origin of species. One only, m connection with his palzcontological discoveries, with his development of the law of ir'relative repetition and of homologies, including the relation of the latter to an archetype, has pronounced in favor of the view of the origin of species by a continuously operative crcational law; but he, at tho same time, has set forth some of the strongest objections or exceptions to the hypothesis of the nature of that law as a progressively and gradually transmutational one.

Mr. Darwin rarely refers to the writings of his predecessors, from whom, rather than [ from the phenomena of the distribution of j the inhabitants of South America, he might j be supposed to have derived his ideas as to ; the origin of species. When he does allude 'to them, their expositions on the subject are j inadequately represented. Every one studying the pages of Lamarck's original chapters (iii. vi. vii., vol. i., and the supplemental chapter of "additions " to vol. 11. of the "Philosophic Zoologique"), will see how much weight he gives to inherent constitutional adaptability, to hereditary influences, and to the operation of long lapses of time on successive generations, in the course of transmuting a species. The common notion of Lamarck's philosophy, drawn from the tirades which a too figurative style of illustrating the reciprocal influence of innate tendencies and outward influences have drawn upon the blind philosopher, is incorrect and unjust. Darwin writes:—

"Naturalists continually refer to external conditions, such as climate, food, etc., as the <>nly possible cause of variation. In one very limited sense, as we shall hereafter sec, this may bo true; but it is preposterous to attribute to mere external conditions, the structure, for instance, of the woodpecker, with its feet, tail, beak, and tongue, so admirably adapted to catch insects under tho bnrk of trees. In the case of the misscltoe, which draws its nourishment from certain trees, which has seeds that must be transported by certain birds, and which has flowers with scparato sexes absolutely requiring the agency of certain insects to bring pollen from one flower to the other; it is equally preposterous to account for the structure of i ins parasite, with its relations to several distinct organic beings, by the effects of external conditions, or of habit, or of the violation of tho plant itself.

"Tho author of the ' Vestiges of Creation' would, I presume, say that, after a certain unknown number of generations, some bird had given birth to a woodpecker, and some plant to tho misscltoe, and that these had been produced perfect as we now see them; but this assumption seems to mo to be no explanation, for it leaves the case of the co-adaptations of organic beings to each other and to tlicir physical conditions of life untouched and unexplained."—P. 3.

The last cited ingenious writer came to the task of attempting to unravel the " mystery of mysteries," when a grand series of embryological researches had brought to light the extreme phases of form that the higher animals passed through in the course of foetal development, and the striking analogies which transitory embryonal phases of a tiigher species presented to series of lower species in their permanent or completely de. veloped state. He also instances the abrupt departure from the specific type manifested by a malformed or monstrous offspring, and called to mind the cases in which such malformations had lived and propagated the deviating structure. The author of "Vestiges," therefore, speculates—and we think not more rashly or unlawfully than his critic has done—on other possibilities, other conditions of change, than the Lamarckian ones; as, for example, on the influence of premature birth and of prolonged fetation in establishing the beginning of a specific form different from that of the parent. And docs not the known history of certain varieties, such as that of M. Graux's cachemir-wooled sheep, which began suddenly by malformation, show the feasibility of this view ? * "The whole train of animated beings," •writes the author of " Vestiges of Creation," "are the results first, of an inherent impulse in the forms of life to advance, in definite times, through grades of organization terminating in the highest dicotyledons and mammals j second, of external physical circumstances, operating re-actively upon the central impulse to produce the requisite pe(juliarities of exterior organization, — the adaptation of the natural theologian." But he, likewise, requires the same additional element which Mr. Darwin so freely invokes. "The gestation of a single organism is the work of but a few days, weeks, or months; but the gestation (so to speak) of a whole creation is a matter involving enormous spaces of time." ..." Though distinctions admitted as specific are not now, to ordinary observation, superable, time may have a power over these." ..." Geology shows successions of forms and grants enormous spaces of time within which we may believe them to have changed from each other by the means which we see producing varieties. Brief spaces of time admittedly sufficing to produce these so-called varieties, is it unreasonable to suppose that large spaces of time

* Reports of the Juries Exhibition of tho Works of All Nations, 8vo., 1862, p. 70.

would effect mutations somewhat more decided, but of the same character ?" *

Unquestionably not, replies Mr. Darwin:—

"To give an imaginary example from changes in progress on an island: let the organization of n canine animal which preyed chicBy on rabbits, but sometimes on hares, become slightly plastic; let these same changes cause tho number of rabbits very slowly to decrease, and the number of hares to increase; the effect of this would bo that the fox or dog would be driven to try to catch more hares; his organization, however, being slightly plastic, those individuals with the lightest forms, longest limbs, and best eyesight, let the difference bo ever so small, would be slightly favored, and would tend to live longer, and to survivo during that timo of the year when food was scarcest; they would also rear more young, which would tend to inherit those slight peculiarities. The less fleet ones would be rigidly destroyed. I can see no more reason to doubt that these causes in a thousand generations would produce a marked effect, and adapt tho form of the fox or dog to tho catching of bares instead of rabbits, than that greyhounds can bo improved by selection and careful breeding." t

Of course, prosaic minds are apt to bore one by asking for our proofs, and one feels almost provoked, when seduced to the brink of such a draught of forbidden knowledge as the transmutationists offer, to have the Circean cup dashed away by the dry remark of a president of the British Association •—

"Observation of animals in n state of nature is required to show their degree of plasticity, or tho extent to which varieties do arise: whereby grounds may be had for judging of the probability of tho clastic ligaments and joint-structures of a feline foot, for example, being superinduced upon tin- moro simple structure of the toe with the non-retractile claw, according to tho principle of a succession of varieties in time."}

This very writer has, however, himself suggested an operative cause in the development of organized beings of a different and opposite character to that conceived by "Vestiges," to produce the teleological adaptations. Professor Owen has pointed out the numerous instances in the animal kingdom of a principle of structure prevalent throughout the vegetable kingdom, exemplified by the multiplication of organs in one animal performing the same function, and not related to each other by combination of powers for the performance of a higher function. The invertebrate animals, according to the professor, afford the most numerous and striking illustrations of the principles

* Vestiges of Creation, 8vo., 1846, p. 231.

t " On the Tendency of Species to form Varieties," etc., in "Proceedings of the Linntean Society," 1858, p. 48.

} Address, p. 44.

•which he has generalized as the "Law of Irrelative Repetition."

"We perceive," says lie, •' in tlio fact of the endoskelcton consisting of n succession of segments similarly composed—in the very power of enunciating special, general, and serial liomologies—an illustration of that law of vegetative or irrelative repetition, which U so much more conspicuously manifested by the segments of the cxoskclcton of the invcrtebrata: as, for example, in the rings of the centipede and worm, anil in the more multiplied parts of the skeleton of the Echinodcrms. The repetition of similar segments in the spinal column, and of similar elements in a vertebral segment, is analogous to the repetition of similar crystals, as the result of the polarizing force in tho growth of an inorganic body. Not only docs tho principle of regetative repetition prevail more and more as we descend in the scale of animal life, but the forms of the repeated parts of the skeleton approach more and ronrc to geometrical figures; as we see, for example, in the external skeleton! of the echini and star-fishes; nay, the calcifying salt assumes the same crystalline figures which characterize it, when deposited and subject to the general polarizing force on t of the organized body. Here, therefore, we have direct proof of tho concurrence of such general all-pervading polarizing force, with the adaptive or special organizing force, in the development of an animal body."

In addition, therefore, to the organizing principle, however explained, producing the special "adaptations," and admitted as the "second" power in the production of species by " Vestiges," Professor Owen states—

"There appears also to be in counter-operation during the building up of such bodies, a general polarizing force, to the operation of which the similarity of forms, the repetition of parts, the signs of the unity of organization may be mainly ascribed; the platonic ttia or specific organizing principle would seem," he adds, "to be in antagonism with the general polarizing force, and to subdua and mould it in subserviency to the exigencies of the resulting specific form." *

An index of the degree in which the polaric or irrelative repetitive force has operated is given by that character of the animal's organization which is expressed by the term of " a more generalized structure. V. Baer pointed out that the structure was "more generalized," in the ratio of the proximity of the individual to the starting point of its existence. In proportion as the individual is subject to the action and re-action of surrounding influences, in other words, as it advances in life, does it acquire a more specialized structure—more decided specific and individual characters, t Owen has shown

* Archetype of the Vertebrate Skeleton, 8vo, 1840. p. 171.

t "The extent to which the resemblance, expressed by the term ' Unity of Organization,' may

that the more generalized structure is in a very significant degree, a characteristic of many extinct as compared with recent animals; and it may be readily conceived that specialization of structure would be the result of the progressive modification of any organ applied to a special purpose in the animal economy.

We have cited these attempts to elucidate the nature of the organizing forces, to show the prevalent condition of the most advanced physiological minds in regard to the cause of the successive introduction of distinct species of plants and animals. Demaillet invoked the operation of the external influences or conditions of life, with consentaneous volitional efforts, in order to raise species in the scale, as the fish, e. g., into the bird.* Buflbn called in the same agency to lower the specicr, l:y way of degeneration, as the bear, e. g., into the seal, and this into the whale.f Lamarck added to these outward influences the effects of increased or decreased use or action of parts. The Author of "Vestiges," availing himself of the ingenious illustration of a pre-ordained exception, occurring at remote intervals, to the ordinary course, derived by Babbage from the working of his calculating engine, threw out the suggestion of a like rare exception in the character of the offspring of a known species, and he cites the results of embryological studies, to show how such "monster," either by excess or defect, by arrest or prolongation of development, might be no monster in fact, but one of the preordained exceptions in the long series of natural operations, giving rise to the introduction of a new species. Owen applies the more recent discoveries of Parthenogenesis to the same mysterious problem. A polype, e. g., breaks up into a pile of medusa'; "the indirect or direct action of the conditions of life" might tend to harden the integument and change the medusa into a star-fish. But he resists the seduction of possibilities, and governed by the extent of actual observation, says :—" The first acquaintance with these marvels excited the hope that we were about to penetrate the mystery of the origin of species; but as far as observation has yet extended, the cycle of changes is definitely closed." J

Mr. Wallace calls attention to the " tre

be traced between the higher and lower organized animals, bears an inverse ratio to their approximation to maturity." (Oxen, Ltcturts on Inxtrtein-ala, p. 645.)

* Tcliiamed, on Entr«tiens d'un Philosophe Indien arec un Missionaire Francois, Amsterdam, 8vo, 1748.

t Histoire Naturelle, elc., 4to, torn. xtv. 1766.

j Address to the British Association at Leeds, 1868, p. 27.

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