526 



THE GRAMMAR OF SCIENCE 



the sexes, and the purposes we conceive this distinction 

 serves in the economy of hving forms ; then we wish 

 to describe how the parent hands down his character- 



istics to the child, and how the new hfe itself takes its 

 origin and develops stage by stage. These topics are 

 dealt with in the Evolution of Sex, XheTTheory of Heredity, 

 and Embryology. 



The third and last great division of Biology is con- 



