CHAPTER V 



THE OVARY AS AN ORGAN OF INTERNAL 

 SECRETION 



The synchronization found between development in the ovary 

 and activity in the accessory reproductive organs immedi- 

 ately suggests that one controls the other, and it has become 

 abundantly clear that the ovary is responsible for the growth 

 and cyclic changes of the uterus, vagina, and mammary 

 glands. Furthermore, the evidence shows that the nervous 

 system plays a very minor part in this correlation, which 

 is maintained by means of internal secretions. This view is 

 based primarily upon ovariectomy and transplantation experi- 

 ments, and in a lesser degree upon cases of abnormal sexuality. 

 Such evidence in itself is not quite complete, and the ultimate 

 proof (extraction of the active substances themselves from the 

 ovary) is only just being obtained after a long period of very 

 indifferent work. 



The effects of ovariectomy and ovarian transplantation, and 

 the earlier experiments on the use of ovarian preparations, 

 are discussed below. 



{a) EFFECTS OF OVARIECTOMY 



Gonadectomy in both mammals and birds leads to the 

 development of a type which is intermediate between the two 

 sexes, and which may conveniently be regarded as approxi- 

 mating to the neutral embryonic condition. In birds this 

 neutral type tends to resemble superficially the male (the 

 homozygous sex). 



In birds, ovariectomy still leaves intact the rudimentary right 

 gonad, which may subsequently develop into testis tissue. This 

 results in sex-reversal, which should not be confused with 



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