290 SCIENCE PROGRESS. 



the main responsible for the new varieties which arise from 

 time to time. This opinion Prichard considered to be 

 probably well grounded ; and the conclusion that size and 

 stature chiefly depend on the mother he also thought to be 

 well established. Hence we see that his judgment and 

 penetration were not always proof against popular convic- 

 tions insufficiently sustained by evidence. These strange 

 views about the relative importance of the two parents 

 seem to have disappeared, and only traces of them are to 

 be found in the popular beliefs of the day. 



The author dismisses the extreme cases of the supposed 

 effect of the mother's imagination upon the unborn child as 

 manifestly absurd ; but looks with some favour upon the 

 opinion, also held by Erasmus Darwin whom he quotes, 

 that the future offspring may be effected by the imagination 

 of the parent at the moment of conception. In proof of 

 the ancient origin of this belief he alludes to Jacob's ex- 

 periments upon the flocks of Laban. 



When, however, Prichard comes to reconsider all his 

 suggested causes of variation he is dissatisfied with them 

 and admits that " the circumstances — are of a more per- 

 manent nature," and that it is often " impossible to discover 

 any peculiar circumstance in the condition of the mother ". 

 This leads him to consider the similar instances among 

 domestic animals and among plants and at this point he 

 anticipates in a truly remarkable manner Darwin's general 

 conclusions as to the origin of our domestic breeds. 



" It is generally supposed," he says on page 557, "that 

 cultivation is the most productive cause of varieties in the 

 kind, both in the animal and vegetable kingdom. But it 

 may be questioned, does cultivation actually give rise to 

 entirely new varieties, or does it only foster and propagate 

 those which have sprung up naturally, or as it is termed 

 accidentally ? 



" In this latter way the influence of art is very impor- 

 tant in constituting breeds, as of cattle, dogs, horses. The 

 artificial process consists in a careful selection of those in- 

 dividual animals which happen to be possessed, in a greater 

 degree than the generality, of any particular characters 



