124 INTERNAL SECRETIONS OF THE OVARY 



puberty. It has been very clearly demonstrated that injections 

 of oestrin will cause the immature animal to show abruptly all the 

 extra-ovarian symptoms of oestrus (19, 652). To some extent 

 one is justified in calling this a condition of 'precocious puberty.' 

 On account of this reaction of the immature animal, it has been 

 supposed by many authors that cestrin is responsible for the 

 initial pre-pubertal development of the accessory organs. The 

 induction of precocious cestrus is, however, no real simulation of 

 the slow and steady growth which takes place in the pre-pubertal 

 organs, and these experiments only show that the first oestrus is 

 produced, like the subsequent ones, by the action of cestrin. 



It is possible, nevertheless, that oestrin is the factor concerned 

 in the development of the accessory organs, and that it is present 

 before puberty in amounts sufficient to produce uterine and 

 vaginal growth, but insufficient to cause oestrous symptoms. 

 This view is supported by Laqueur and co-workers (350) who 

 found that uterine growth may be caused by much smaller 

 amounts than are required to produce oestrus. Thus, -000007 

 mgm. per day for five days, or about -i m.u. in all, caused 

 growth of the immature rat uterus. Zondek and Aschheim (652) 

 found that treatment with their water-soluble oestrin for 14 days 

 increased the weight of the immature genitalia of mice from 

 15-27 mgms. to 75-92 mgms.; hence they conclude that oestrin 

 is the initial growth stimulus. Other evidence is lacking, and 

 Eels (202) was unable to find oestrin in the ovary ofthe new-born 

 child, in which the uterus is already undergoing development. 



There is, moreover, some reason to suppose that a separate 

 ovarian factor (presumably hormonic) is required for the initial 

 development and subsequent maintenance of the accessory 

 organs. Marshall (444) states: '. . . The conclusion to be drawn 

 ... is that the ovarian hormone which produces oestrus or heat 

 is different from that which is responsible for maintaining the 

 normal uterine nutrition.' Schroder (549) reached a similar 

 conclusion. 



There is no doubt that in many animals all the extra-ovarian 

 histological and physiological symptoms of oestrus can be 

 produced in the ovariectomized animal b}^ injection of oestrin, 

 but Asdell and Marshall (45) found that in anoestrous dogs 

 injection brought about the changes characteristic of prooestrus, 



