OVARY AS ORGAN OF INTERNAL SECRETION 8i 



such criteria must be the simulation in the ovariectomized 

 animal of ovarian influence, i.e. the induction of development or 

 change in the accessor}^ organs after removal of the ovaries. 



The prevention of ovariectomy effects by means of extracts 

 was attempted in 1900 by Jentzer and Beuttner (315) and in 

 1907 by Bucura (108), but no very definite results were 

 obtained. 



Since then a vast amount of work has been carried out with 

 ovarian extracts, interest largely centring on the production of 

 the changes characteristic of oestrus, and more recently on the 

 substitution of luteal activity. These experiments, dealt with 

 in Chapters VI and X, have completed the chain of evidence that 

 the ovary carries out its control of the accessory organs by 

 means of internal secretions. 



{e) THE INTERNAL SECRETION COMPLEX OF THE OVARY 



The work discussed in the preceding chapters shows that the 

 ovary performs three general functions by means of endocrine 

 activity: 



(a) Control of early development of the accessory organs and 



secondary sexual characters. 

 {h) Control of the cyclic changes characteristic of oestrus in 



the accessory organs. 

 (c) Control of the changes occurring during pregnancy. 



The question now arises as to w^hether one internal secretion can 

 perform all of such varied functions. Marshall originally 

 postulated that three ovarian hormones exist, one connected 

 with each of the above functions. Marshall also supposed 

 that the Graafian follicle probably produced the hormone 

 associated with oestrus, and the corpus luteum the one 

 associated with the changes of the luteal phase of the cycle 

 (pregnancy and pseudo-pregnancy). This conception has been 

 accepted in essence by many authorities, including Loeb (400), 

 Corner (125), Evans (425), and Courrier (137), the last of whom 

 says: ' Nous pouvons affirmer que I'ovaire secrete au moins 

 deux hormones, I'hormone folliculaire et Thormone luteinique.' 

 Recently, however, a tendency has arisen to regard the 



P.S.O. F 



