575.2 393 



III 

 The Study of Variations : A Rejoinder 



PEOFESSOR HENSLOW has apparently completely misunder- 

 stood my paper in this Magazine for April. My object was, 

 leaving the whole question of facts and observations out of con- 

 sideration, merely to point out some reasons for the well-known 

 difference of opinion on this subject among present-day biologists. 



In referring to Professor Henslow's theory I endeavoured to 

 show that another explanation, quite as plausible and equally in 

 accordance with the facts adduced by himself, could be advanced. 

 Thus there would be two theories in the field, both explaining the 

 facts, and neither absolutely negatived or directly supported by 

 these facts. Consequently, to test the merits of the rival theories 

 a fresh series of data would be required. The ultimate decision 

 might be in favour of Professor Henslow and the Lamarckians, and 

 opposed to the Darwinians, or vice versd, or might show that both 

 theories were partially correct. I did not doubt the facts, or even 

 assert that the conclusions drawn were incorrect, but argued that 

 this possibility of double interpretation proved the conclusions to be 

 inadequately supported. Professor Henslow says he does "not quite 

 see, if the conclusions be correct, how the argument can be faulty." 

 This statement must surely be due to an oversight, for it is notorious 

 that right conclusions may accidentally be arrived at through 

 fallacious arguments. But I did not suggest that his conclusions 

 were either correct or incorrect ; my position is, that in either case 

 the facts on which they are founded would equally support other 

 conclusions. 



On page 313, paragraphs 1, 3, 4, 5 ; and again on page 314, 

 paragraph 1 ; and page 315, paragraphs 3 and 4, he makes a series 

 of statements in reference to the Neo-Lamarckian position, which 

 position he considers I have misunderstood. (1) ". . . The purport 

 of Neo-Lamarckism is precisely that embodied in the words of Darwin 

 quoted, or the discovery of ' the primary cause of modification.' " 

 (2) " Neo-Lamarckism is only concerned with tracing out the causes 

 which originate or bring about the variations themselves." (3) " 'No 

 selection except from general strength.' In this last [kind of varia- 

 tion] I seem to recognise my own position." 



I find it difficult to reconcile these three statements. The 

 meaning of the first position appears quite plain, ' the primary cause 



