2o8 



HARDWICKE'S SCIENCE-GOSSIP. 



Now it has been sometimes objected that to deny 

 the inheritance of acquired characters is equivalent to 

 denying the possibility of all modification in descent, 

 since every new modification must be "acquired" 

 by the species at some period of its existence. This 

 objection is, of course, based upon an initial mis- 

 conception of the recognised meaning of the word 

 " acquired " in this connection. 



By an *^ acquired" character is meant a character 

 ■which is not in any sense present in the fertilised 

 ovum from which the organism it belongs to was 

 developed, but is acquired by that organism at some 

 period ajter the first cell-division. 



An inherent or congenital character, on the other 

 hand, is a character which does exist potentially in the 

 fertilised ovum befo7-e the first cell-division. 



The question before us can then be expressed 

 concisely as follows : " Can an acquired character 

 become congenital ? " 



It is well-known that Erasmus Darwin * and, later, 

 Lamarck f conceived the idea that species are not im- 

 mutable, and that the individuals representing them 

 at the present day are descended from other simpler 

 forms ; that Lamarck explained this process of evolu- 

 tion chiefly by an innate tendency to development 

 along certain lines, partly by the growth of organs in 

 response to a desire on the part of the animal, and 

 partly by the transmission of the effects of increased 

 use and disuse, of habit, or of the direct effects of the 

 environment. It is clear that the last class of means 

 of transmutation indicated is the only attempt at a 

 scientific explanation of the phenomena in question ; 

 of the other explanations, the first is essentially un- 

 scientific, and the second is too preposterous to need 

 discussion. The last suggestion is. however, in quite 

 a different position. We know that as a matter of 

 fact increased use or disuse of a particular part has, 

 during a single lifetime, a considerable effect on that 

 part ; and we are familiar with changes produced in 

 an individual by the direct effect of the environment. 

 What more natural than to suppose that such con- 

 siderable changes are hereditary, and that in course of 

 time their accumulation will effect a modification of 

 specific rank ? So thought Lamarck, and he accord- 

 ingly formulated his "second law:" "Everything 

 that nature has made individuals acquire or lose by 

 the influence of circumstances under which their 

 race is placed for a long time, and consequently by 

 the influence of the predominant use of a particular 

 organ, or by that of a continual falling off in the use 

 of such a part, she preserves by the act of generation 

 to the new individuals which follow, provided that 

 the acquired modifications are common to the two 

 sexes, or to those individuals which have produced 

 the new one." J It is obvious that this "law" is 



* "Zoonomia." 



+ " Philosophic Zoologique." 



X " Deiixiciiic Lot. Tout ce que la nature a fait acquerir ou 

 perdre aux individus par I'influence des circonstances ou leur 

 race se trouve depuis longtemps exposde, et par consequent 



quite inadequate to account for all the phenomena of 

 organic evolution. It offers, for example, no explana- 

 tion of all the complex and wonderful phenomena of 

 adaptation. As we have seen, it only furnished a 

 small part of Lamarck's explanation. His philosophy 

 completely failed to convince the great mass of 

 thinking men of the truth of evolution. Goethe was 

 perhaps the most notable and enthusiastic of his few 

 partisans ; but later on, as Mr. Herbert Spencer tells 

 us,* there was a small band of evolutionists in Eng- 

 land who accepted Lamarck's second law as at least a 

 partial explanation of that transmutation of species 

 which they believe had taken place. For the rest they 

 were totally at a loss. Hardly a biologist or geologist 

 agreed with them. Sir Charles Lyell had argued 

 brilliantly against Lamarck : Mr. Huxley was a firm 

 anti-evolutionist. Then came the " Origin of 

 Species," with the luminous principle of natural 

 selection, which has effected so profound a change in 

 the attitude of the world to the doctrine of evolution, 

 and which is too familiar to need exposition here. 

 We may, however, point out the great and funda- 

 mental difference between the Lamarckian and Dar- 

 winian theories of evolution. Apart from the fact 

 that that part of Lamarck's explanation which is 

 alone worthy of serious consideration constitutes but 

 a small portion of his whole conception, we must 

 remember that even this is a mere ^/>;'/m speculation, 

 and is not supported by a single fact of observation or 

 experiment. Darwin's theory of natural selection, on 

 the other hand, rests secure on the threefold base of 

 the facts of variation, of heredity, and of the struggle 

 for existence. And the method by which these 

 " factors " must co-operate to secure the " survival of 

 the fittest " is obvious as soon as it is stated. In other 

 words natural selection is a vera causa, and its enemies 

 are obliged to confine themselves to the task of trying 

 to demonstrate that at most it can effect but little in 

 the direction of the transmutation of species.f And 

 in addition to this the results of artificial selection by 

 breeders can be pointed to for the demonstration of 

 what actually has been done by a selective process 

 continued for many generations. But we cannot 

 adduce similar considerations on behalf of the so-called 

 Lamarckian factor. It has never been proved to be 

 a vera causa, and for this reason — while the facts of 

 the modification of organs by use and disuse, or by 

 the direct action of the environment during an in- 

 dividual lifetime are perfectly well established, the 

 inheritance of the effects of such modifications are 

 not. 



It is true that the adherents of the theory in ques- 



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

 cellc d'un d^faut constant d'usage de tellepartie, eUe le con- 

 serve par la g<Sn6ration aux nouveaux individus qui en pro- 

 viennent, pourvu que les changements acquis soient communs 

 aux deux sexes ou a ceux qui ont produit ces nouveaux 

 individus." — "Philosophic Zoologique," tome i. p. 235, edition 

 Savy, 1873. 



* " Factors of Organic Evolution," pp. 2-3. 



t E.g., vide Dr. St. G. Mivart, "Nature," December 6tli, 

 1888. 



