MULTIPLE FACTORS 235 
times, ete. It would require a large number of off- 
spring to prove the multiple factor hypothesis if the 
reappearance of the grandparental types be de- 
manded for such a proof. 
Fic. 58.—Short-eared by lop-eared rabbit. F ,son of last; F2, daughter 
of F, by his sister. (After Castle.) 
Several excellent cases of multiple factors have been 
worked out with Indian corn. Height of plant 
(as a concomitant of its vigor), length of ear, and 
