So 



BASIS OF INVESTIGATION. 



constitution would be born when he was thirty-five, the child with 

 the best brain when he was sixty, and the best all-around child when 

 he was between forty-five and fifty. 



Cup*. 2.0 



y 



FIG. 3. DIAGRAM OF THE DEVELOPMENT OF THE BRAIN AND BODY. 



FORMULA FOR HEREDITY. 



To express the matter mathematically let : 



T=age of ancestor at time of reproduction. 



t=average age of reproduction of the race. 



^r^age at which ancestor reaches average development with K 

 activity. 



K=grade of mental activity of ancestor. 



k=average mental activity of the race. 



k x =:grade of mental activity required to maintain ancestor in 

 uniform condition. 



m change arising from K-k activity in a unit of time. 



M=average race inheritance. 



Q=inheritance of any individual. 



Then :- 



CT-t 1 ) mCT-t 1 ) mCT-t 1 ) mlT-t 1 ) 



2 4 8 16 



will express the inheritance of an individual as received from a sin- 



