ELEMENTS OF ORIGINALITY 185 



laws concerning the distance between the bodies. It 

 has been found (by McClendon) that fertiHzation 

 increases the electrical conductivity of the egg. Why 

 in fertilization the spermatozoon of one form will not 

 activate the ovum of some other form, perhaps not 

 even of some closely related fo^-m, is readily under- 

 standable on this view of the gametes. It may be 

 recalled that in Loeb's experiments on artificial par- 

 thenogenesis it was found that the presence of certain 

 ions permitted and of other ions inhibited the activa- 

 tion of the egg. 



XXIII. My theory of heredity. {See pages 231- 

 233.) 



This theory for the first time gives a basic con- 

 ception of heredity, and transfers, or reduces, the 

 problem of heredity from morphology (chromo- 

 somes) to atomic physics. 



XXIV. The statement of the cause of the differ- 

 ence in length between man's infancy and the infancy 

 of the apes. 



"Infancy" here means: the period from birth to 

 physiological (sexual) maturity. This maturity waits 

 on and accompanies a specific chemical condition in 

 an organism. The phenomenon of man's long in- 

 fancy, as compared with the ape's short infancy, 

 represents a retardation of the rate of progression of the 

 chemical reactions, between birth and maturity, which 



