ORIGIN OF SPECIES 231 



life-germ of heredity is very great per unit of mass 

 of the matter which contains it."" 



In heredity numerous specific and pronounced 

 paternal traits are transmitted to the offspring 

 through the medium of a single cell, so small that one 

 drop may contain millions of them. That the human 

 child inherits psychic qualities and traits from the two 

 parents, is a widely held view. Thus, Eugen Fischer, 

 director of the Kaiser Wilhelm Institute for Anthro- 

 pology, recently stated that "the question as to the 

 hereditary transmission of mental endowments must 

 be answered absolutely in the affirmative." It is plain 

 that morphology, physiology, and chemistry cannot 

 throw much light upon the problem of how ultimately 

 this is possible. 



My theory of heredity is an integral part of my 

 theory of life; it results directly from the basic con- 

 ception of life and the life-process which the theory 

 gives. 



The germ-cells themselves, the activation of the 

 egg in fertilization, and the entire series of changes 

 initiated by the entrance of the spermatozoon into 

 the egg or (in artificial parthenogenesis) by certain 

 physicochemical means — all must be conceived in 

 the terms of the theory. 



According to the theory, the sex-cells (like all other 



" The Origin and Evolution of Life, 12. 



