THE THEORY OF MUTATIONS 93 



that question in a previous article, but there are 

 some other points to be dealt with, notably those 

 of Mutations. And in this present article I pro- 

 pose to deal with the views of the distinguished 

 Amsterdam botanist whose name is associated with 

 that theory. 



According to Darwin natural selection acted 

 upon spontaneous slight variations constantly 

 occurring in all species of plants and animals. 

 " Natural selection," he says, " acts only by the 

 preservation and accumulation of small inherited 

 modifications." This view as to the accumulation 

 of small modifications was acutely criticized on 

 its first appearance before the world by Mivart, 

 who stated that natural selection utterly fails to 

 account for the conservation and development 

 of the minute and rudimentary beginnings, the 

 slight and insignificant commencements of struc- 

 tures, however useful these structures may after- 

 wards become."* Moreover, he argued that 

 such small peculiarities might, before they had 

 sufficiently developed to be of real advantage to 

 their possessor, be an actual injury as affording 

 further and useless living material requiring 

 nourishment. And in this connexion he enters 

 into a long consideration of Darwin's theory as 

 exemplified in the neck of the giraffe, a discussion 

 which will be quite familiar to all students of the 

 evolutionary theory, f But further he argued (p. 109) 

 that " there are difficulties in the way or account- 

 ing for such origination by the sole action of 



* Genesis of Specif s, p. 26. 



t See p. 68 for an account of this matter. 



