575.8 3 2 ^ 



VI. 



Lyell and Lamarckism. 



A Reply to Professor W. K. Brooks. 



PROFESSOR BROOKS, in Natural Science for February, p. 89, 

 has informed us that Romanes was mistaken in including him 

 among American Lamarckians, and has at the same time explained 

 why he considers Lamarckism untenable. His reasons do not 

 appear to me adequate, and although I can scarcely hope to induce 

 him to alter his intellectual position, I desire to ask the attention of 

 other biologists to the following criticism of his arguments. 



He believes, apparently, that his objections are essentially those 

 expressed by Lyell in his " Principles of Geology," published long 

 before Darwin's theory was made known. It is true that Lyell was 

 unconvinced by Lamarck, but convinced of the truth of evolution by 

 Darwin. Brooks maintains that Lyell's objections to Lamarck's 

 particular views still remain unanswered, and supposes, if I understand 

 him rightly, that his article merely recapitulates and expounds Lyell's 

 arguments. Careful consideration of the article leads me to conclude, 

 first, that Brooks's arguments are not those of Lyell, and, secondly, 

 that they are not sound. I will give my reasons for these conclusions 

 in their order. 



According to Professor Brooks, Lyell proved that the effects of 

 the environment were not inherently adaptive, and therefore, whether 

 inherited or not, could not be accepted as the cause of the evolution 

 of adaptations. After perusal of Lyell's reply to Lamarck's views in 

 the " Principles of Geology," I fail to find any indication of this 

 proposition. The general tenor of Lyell's argument, as I understand 

 it, is that the environmental forces may and do produce results some 

 of which are adaptive, and which do become hereditary, but that the 

 departure from the specific type so caused is definitely limited ; and 

 that the capacity for change within these limits is merely a fixed 

 property of the species, which, like other specific properties, is 

 immutable in its extent. The importance of the question is sufficient 

 justification for quoting in full Lyell's own summary of his arguments. 

 It is as follows : — 



1 . " There is a capacity in all species to accommodate themselves, 

 to a certain extent, to a change of external circumstances, this extent 

 varying greatly, according to the species. 



