290 OBITUARY X 



indifferent, but which are just as strongly heredi- 

 tary as the advantageous variations. The advan- 

 tageous structure is but one product of a modified 

 general constitution which may manifest itself by 

 several other products ; and the selective process 

 carries the general constitution along with the 

 advantageous special peculiarity. A given species 

 of plant may owe its existence to the selective 

 adaptation of its flowers to insect fertilisers ; but the 

 character of its leaves may be the result of varia- 

 tions of an indifferent character. It is the origin 

 of variations of this kind to which Darwin refers in 

 his frequent reference to what he calls " laws of 

 correlation of growth " or " correlated variation." 



These considerations lead us further to see the 

 inappropriateness of the objections raised to 

 Darwin's theory on the ground that natural 

 selection does not account for the first commence- 

 ments of useful organs. But it does not pretend 

 to do so. The source of such commencements is 

 necessarily to be sought in different variations, 

 which remain unaffected by selection until they 

 have taken such a form as to become utilisable in 

 the struggle for existence. 



It is not essential to Darwin's theory that 

 anything more should be assumed than the facts 

 of heredity, variation, and unlimited multiplication ; 

 and the validity of the deductive reasoning as to 

 the effect of the last (that is, of the struggle for 

 existence which it involves) upon the varieties 



