GREAT STEPS IN EVOLUTION 91 



we call them female and male organisms 

 respectively; we are at the foundation of 

 the differences between the two sexes. 



Again we would state our thesis that all 

 through the animal series, from active Infu- 

 sorians and passive Gregarines, to feverish 

 Birds and sluggish Reptiles, we read alterna- 

 tives or antitheses between activity and pas- 

 sivity, between liberal expenditure of energy 

 and a more conservative habit of storing. 

 This primarily depends on the ratio between 

 disruptive (katabolic) processes and con- 

 structive (anabolic) processes, and we regard 

 the sexes as expressions of the same contrast 

 within a given species. And do not kindred yet 

 contrasted forms, like goat and sheep, wasp 

 and bee, butterfly and moth, seem, as it were, 

 but the extreme expression of the same indi- 

 vidual and sex contrasts carried farther, upon 

 the plane of species, of genus, of order, or of 

 class? 



According to this view the deep constitu- 

 tional difference between the male and the 

 female organism, which makes of the one a 

 sperm-producer and of the other an egg-pro- 

 ducer, is due to an initial difference in the 

 balance of chemical changes. The female 

 seems to be relatively the more construc- 

 tive, whence her greater capacity for organic 



