120 DARWINISM AND HUMAN LIFE 



Of these {d) must inevitably be eliminated while 

 (a) are selected. The predominant survival of 

 (a) entails the survival of the adaptive variations 

 which are inherited. The contributory acquisi- 

 tions + M are not inherited ; but they are none 

 the less factors in determining the survival of the 

 coincident variations." Lamarckians believe that 

 useful modifications are in some degree sometimes 

 transmitted. On the view just sketched the modi- 

 fications are the screens or nurses of coincident 

 variations in the same direction. 



We can imagine conditions where swarthiness 

 was a character of life-saving value, where the 

 possessors of inborn variations in the direction of 

 swarthiness were favoured, where those who varied 

 in the direction of increased blondeness were 

 handicapped. It is readily intelligible that those 

 who could acquire swarthiness as an individual 

 somatic modification would also be favoured, and 

 that the acquired swarthiness might act as a Hfe- 

 saving screen until constitutional and heritable 

 swarthiness had time to establish itself. 



Furthermore, although modifications may not 

 be entailed, they may have occasionally important 

 indirect influences on the offspring. A starved 

 mother may have a weakly child. 



Modification-species. — In the case of animals 

 and plants which we do not know except in 

 particular surroundings, it is quite possible that 

 characters which we credit to inherited nature 

 may be impressed on every successive generation 

 by nurture. Especially among the more vegeta- 

 tive forms of hfe we find indications, which experi- 

 ment will some day test, that there are what may 

 be called " modification-species," which differ from 



