142 A NEW THEORY OF EVOLUTION. 



in the germ-cell, and the embryo develops 

 into a foetus that in due time evolves an adult 

 of the type that produced the germ -cell. 

 This outcome, except for accident, is invari- 

 able, and we conclude that before there can 

 be any specific variation in a type there 

 must be some change within the germ-cell 

 of that type. But how can external influ- 

 ences affect the germ-plasm ? A seed may, 

 as we have seen, be stunted by climatic or 

 other unfavourable influences ; but if it do 

 grow, it invariably produces an organism of 

 its parental type. 



