tr' 



42 ARE THE EFFECTS OF USE INHERITED ? 



a general " plasticity " , of type, the " indefinite 

 variability " thus caused being apparently irrelevant 

 to the change, if any, in the individual. 1 A vast 

 number of variations of structure have certainly 

 arisen independently of similar parental modifi- 

 cation as the preliminary. Whatever first caused 

 these " spontaneous " congenital variations affected 

 the reproductive elements quite differently from 

 the individual. " When a new peculiarity first 

 appears we can never predict whether it will be 

 inherited." Many varieties of plants only keep 

 true from shoots, and not from seed, which is by 

 no means acted on in the same way as the 

 individual plant. Seeing that such plants have 



1 See Origin of Species, pp. 5-8. "Changed conditions induce 

 an almost indefinite amount of fluctuating variability, by which the 

 i whole organization is rendered in some degree plastic " (Descent of 

 Man, p. 30). It also appears that " the nature of the conditions h 

 of subordinate importance in comparison with the nature of the or- 

 ganism in determining each particular form of variation ; perhaps 

 of not more importance than the nature of the spark, by which a 

 mass of combustible matter is ignited, has in determining the nature 

 of the flames " (Origin of Species, p. 8). 



