34 



THE EGGS OF MAMMALS 



tainment of a certain degree of follicle maturity and full 

 ovum size is necessary before activation of the pituitary 

 hormones can be attained in developing animals. It is to 



H 

 O 



o 

 o 



p, 50 

 O 



10 



100 



500 



600 



2U0 300 4U0 



DIAMETER OF FOLLICLE 



Fig. 7. Showing the relation of ovum growth to folhcle growth. Data on the 

 mouse. (From Brambell, 1930, courtesy of The Macmillan Company.) 



be remembered, however, that the release of substances 

 from the normal gland in vivo and the injection of excised 



70- 



> 

 o 



o 



g 40- 

 H 



< 



50 



30 



20 



(b) 



/ •: 



. OBSERVATIONS 



X CALCULATED POINTS 



50 



100 



400 



450 



500 



Fig. 8. 



150 200 250 300 350 



DIAMETER OF FOLLICLE, n. 



Same as Fig. 7. Data on the rat. (From the Proceedings of the Royal 

 Society.) 



preparations are not comparable phenomena. Furthermore, 

 dwarf mice pituitaries can stimulate ovarian growth in im- 

 mature recipients (Smith and MacDowell, 1931) yet their 



