HEREDITY AND EVOLUTION 93 



the new individual which springs from it, by cell 

 division and the complex process of differentiation. 1 

 Much is implied in tracing to such a germ-cell 

 the beginning of a new individual, of whatever 

 species. In case of dependence on double parentage, 

 there is in the single life-movement a two-fold 

 agency, conveying a double impress, providing for 

 variation in the life of the offspring, impossible if 

 reproduction were restricted to development by 

 division of a single cell. 



When the question arises, How is transmission of 

 variations possible ? the perplexities are the greatest 

 which gather around any biological problem, for the 

 germinal force is restricted to a nucleus, whose move 

 ments are visible only by the aid of microscopic 

 power. , In view of the minuteness of this cell, the 

 fineness of nuclear fibres in which movement first 

 appears, and the vastness of the organism thence 

 developed, we cannot marvel when we find Weismann . 

 say, No one of the many attempts to solve the 

 problem . . . can be regarded as even the beginning 

 of a solution. 2 And all this complexity of conditions, 

 combinations, and movements, be it observed, is 

 concerned exclusively with the origin of organic 

 structure, before the large question of intelligence 

 has even come into view. When this exclusively 

 organic reference is considered, there is ground for 

 reasonable surprise when we mark the readiness with 

 which a histologist adds further complications of 

 mental life and action. Thus Weismann says, In 

 the higher organisms, the smallest structural details, 

 and the most minute peculiarities of bodily and mental 



1 Weismann s Heredity, vol. i. p. 167. 2 Ibid., vol. i. p. 167. 



