March 6, 1890] 



NATURE 



415 



. . . These modifications of structure, which are all strictly 

 inherited, characterize several improved breeds, so that they 

 ■cannot have been derived from any single domestic or wild stock. 

 With respect to cattle. Prof. Tanner has remarked that the lungs 

 and liver in the improved breeds ' are found to be considerably 

 reduced in size when compared with those possessed by animals 

 having perfect liberty.' . . . The cause of the reduced lungs in 

 highly- hred animals which take little exercise is obvious" (pp. 

 299-300). And on pp. 301, 302, and 303, he gives facts showing 

 the effects of use and disuse in changing, among domestic animals, 

 the characters of the ears, the lengths of the intestines, and, in 

 various ways, the natures of the instincts. 



Clearly the first thing to be done by those who deny the 

 inheritance of acquired characters is to show that the evidence 

 Mr. Darwin has furnished by these numerous instances is all 

 worthless. Herbert Spencer. 



Let me remind the readers of Nature that the discussion 

 which has been going on in these columns, between the Duke of 

 Argyll and Mr. Thiselton Dyer, arose out of a reference in Mr. 

 Wallace's book on " Darwinism" to the dislocation of the eyes 

 of flat-fishes. Two views have been expressed as to the origin 

 of this arrangement — the one endeavouring to explain it as a 

 «ase in which a "sport" or congenital variation, had been 

 selected and intensified ; the other attributing it to the direct 

 action of the muscles of ancestral flat-fishes which had pulled 

 the eye out of its normal position, the dislocation thus estab- 

 lished being transmitted to offspring, and its amount increased 

 by like action in each succeeding generation. In common 

 with Mr. Wallace and other naturalists, I spoke of this latter 

 hypothesis as one of transmission of an "acquired character." 

 The term " acquired character " was clearly enough defined by 

 this example ; it has been used in England for some years, and 

 its equivalent in German (ef~cVorbene E'genschaften) has been 

 defined and used for the purpose of indicating the changes in 

 a parent referred to by Lamarck in the following words 

 ("Philosophic Zoologique," tome i. p. 235, edition Savy, 



''* Premiere Loi. — Dans tout animal qui n'a point depasse le 

 terme de ses developpements, I'emploi plus frequent et soutenu 

 d'un organe quelconque, fortifie peu a peu cet organe, le 

 developpe, I'agrandit, et lui donne une puissance proportionnee 

 a la duree de cet emploi ; tandis que le defaut consant d'usage 

 <le tel organe, I'affaiblit insensiblement, le deteriore, diminue 

 progressivement ses facultes, et finit par le faire disparaitre. 



*^ Deuxicnie Loi.— TonK ce que la nature a fait acqiiirir o\x 

 perdre aux individus par I'influence des circonstances ou leur 

 race se trouve depuis longtemps exposee, et par consequent par 

 I'influence de I'emploi predominant de tel organe, ou par celle 

 d'un defaut constant d'usage de telle partie, elle le conserve par 

 la generation aux nouveaux individus qui en proviennent, 

 pourvu que les changements acquis soient communs aux deux 

 sexes ou a ceux qui ont produit ces nouveaux individus." 



The meaning of the term "acquired characters" is accord- 

 ingly perfectly familiar to all those who have any qualification 

 for discussing the subject at all. It is used by Lamarck, and has 

 been used since as Lamarck used it. Naturalists are at present 

 interested in the attempt to decide whether Lamarck was justi- 

 fied in his statement that acquired changes are transmitted from 

 the parents so changed to their offspring. Many of us hold that 

 he was not ; since, however plausible his laws above quoted may 

 appear, it has not been possible to bring forward a single case 

 in which the acquisition of a character as described by Lamarck 

 and its subsequent transmission to offspring have been con- 

 clusively observed. We consider that, until such cases can be 

 produced, it is not legitimate to assume the truth of Lamarck's 

 second law. We admit, of course, the operation of the environ- 

 ment and of use and disuse as productive of " acquired charac- 

 ters " ; but we do not find any evidence that these particular 

 characters so acquired are transmitted to offspring. Ace )rdingly 

 it has been held by several naturalists recently (whom I will call 

 the anti-Lamarckians, and among whom I include myself) that it 

 is nece-sary to eliminate from Mr. Darwin's teachings that small 

 amount of doctrine which is based on the admission of the 

 validity of Lamarck's second law. As everyone knows, Mr. 

 Darwin's own theory of the natural selection of congenital varia- 

 tions in the struggle for existence is entirely distinct from 

 Lamarck's theory, and the latter was only admitted by Darwin 

 as being possibly or probably true in regard to some cases, and of 

 minor importance. Although Darwin expressly states that he 



was more inclined to attach importance to Lamarck's theory in 

 the later editions of the " Origin of Species," the anti-Lamarckians 

 are convinced that it is conducive to the progress of knowledge 

 to reject that theory altogether until (if ever) it is placed on a 

 solid basis of observed fact ; and in the meantime to try if it is 

 possible to explain the cases which seem most favourable to 

 Lamarck's view by the application of Darwin's own theory. 



It is essential for those who are not thoroughly familiar with 

 Darwin's writings to note that this does not involve a rejection 

 of the conclusion that the action of external conditions upon a 

 parent may be such as to modify the offspring. That is an 

 important part of Mr. Darwin's own theory, and, as I recently 

 pointed out in Nature, it is to such action of the environment 

 upon the parent that Mr. Darwin attributed the origin of those 

 congenital variations upon which natural selection acts. This 

 disturbance of the parental body (I cojipared it to the shaking 

 up of a kaleidoscope), and with it of the germs which it carries, 

 resulting in "sporting "or "variation" in the offspring, is, it 

 should hardly be needful to state, a totally different thing to the 

 definite acquirement of a structural character by a parent as the 

 result of the action upon it of the environment, and the trans- 

 mission to offspring of that particular acquired structural character. 

 I am not concerned to inquire here whether, or how far. Prof. 

 Weismann's theory of the continuity of the germ-plasm admits of 

 the action of external forces on a parental body in such a way as to 

 disturb the germ-plasm and induce variation. Prof. Weismann 

 can very well defend his own views. All that I am concerned 

 with — and that quite independently of the conclusions of Prof. 

 Weismann — is whether it is or is not reasonable, useful, or indeed 

 legitimate, to assume the truth of Lamarck's second law, in the 

 absence of any direct proof that any such transmission as it 

 postulates takes place. Those who think Lamarck's second law 

 to be true have been urged to state (i) cases in which the trans 

 mission of acquired characters is directly demonstrated, or (2) 

 cases in which it seems impossible to explain a given structure 

 except on the assumption of the truth of that law. If they fail to 

 do this, they are asked to admit that Lamarck's second law is 

 unproven and unnecessary. 



The response which has been made to this attempt to arrive at 

 facts is beside the mark. Mr. Cope writes to Natitre merely 

 assercing, " If whatever is acquired by one generation were not 

 transmitted to the next, no progress in the evolution of a character 

 could possibly occur," — an opinion peculiar to himself, and cer- 

 tainly one which cannot be taken in place of fact. The Duke of 

 Argyll then "interpolates" (to use his own word) a general 

 statement of his beliefs, and in the last of his letters a statement 

 of " what his position is." We really are not concerned in this 

 matter with beliefs or positions. We want well-ascertained facts 

 and straightforward reasoning from facts. The Duke of Argyll 

 has not assisted us. When on a recent occasion he was asked to 

 cite an instance of what he called "a prophetic germ" in the 

 adult structure of a plant or animal having, in his opinion, such 

 claims to this title as he had ascribed to the electric organ of 

 skates, the Duke was unable to reply. He wrote as a substitute 

 something about embryological phenomena, which had nothing 

 to do with the case. He has not yet ventured to stake his ofi- 

 asserted right to offer an opinion upon zoological topics, on the 

 reception which his attempt to deal with the details of a par- 

 ticular case of organic structure would obtain : in this, I think, he 

 is wise. 



The Duke similarly tries to evade the appeal to facts when he 

 is pressed by Mr. Dyer to state cases of the transmission of 

 acquired characters. In doing so, however, he has, it must be 

 admitted, revealed an astonishing levity. He answers (par. 9 

 of his letter) that in all domesticated animals, and especially in 

 dogs, we have constant proof that many acquired characters may 

 become congenital. This is mere assertion ; we require details. 

 It is maintained, on the contrary, by anti-Lamarckians that the 

 whole history of artificial selection, and of our domesticated 

 animals, furnishes a mass of evidence against the theory of the 

 transmission of acquired characters, since if such cases occurred 

 they would be on record, and moreover would have been utilized 

 by breeders. 



The subsequent proceeding of the Duke is almost incredible. 

 In the following paragraphs of his letter he gives up his con- 

 tention that acquired characters are transmitted, coupling his 

 retreat with unwarrantable charges against those who have 

 lately raised the question as to whether this is the case or 

 not. He correctly states what is meant by the term "acquired 

 characters," and declares that this meaning has been expressly 

 invented for the purposes of the present discussion by "for- 



