v GENERATIVE SYSTEM OF THE FEMALE 205 



became gravid only five months after the operation. Grigorieff 

 also obtained a similar result. 



In a third series of experiments Foa attempted the grafting 

 of the embryo ovaries in male guinea-pigs under various conditions, 

 in adult males and immature males, castrated or not at the 

 time of grafting. In these cases also the ovaries attached them- 

 selves, and developed up to a certain point, but later on slowly 

 and progressively underwent atrophy. Thus the male organism 

 for some reason unknown does not constitute a medium adapted 

 to conserve for any length of time the function of the grafted 

 ovary, although striking root and a certain degree of development, 

 up to the formation of Graafian follicles, are possible. 



The most recent transplantations of the ovaries were attempted 

 with success by Halban (1899-1902) both in the guinea-pig and 

 the female baboon (Cynocephalus). He called attention more 

 particularly to the fact that the arrest of development of the 

 genital apparatus, specially of the uterus, which is the unfailing 

 consequence of bilateral ovariotomy, does not ensue after trans- 

 plantation of the two ovaries. This result excludes the hypothesis 

 of possible nervous influences promoted by the ovary on the other 

 organs, and is in favour of the doctrine of internal secretion. 



We have already examined the causal relation existing between 

 maturation and bursting of the Graafian follicle, and the periodic 

 phenomena which occur in the uterus (v. page 179 et seq^. Now 

 Born originated the hypothesis that this functional connection 

 between the ovary and the uterus is effected by a product of the 

 internal secretion of the corpus luteum, which is developed at the 

 point of rupture of the follicle. This hypothesis was confirmed 

 by the researches carried out under the direction of Frankel and 

 Cohn (1901). They noticed that spaying performed on rabbits 

 from six to twenty-four hours after fertilisation invariably prevents 

 the attachment to the uterus and the development of the fecundated 

 ovum, and the same effect is produced, when instead of extirpating 

 the ovaries, all the corpora lutea existing in them are cauterised 

 with a red-hot needle. Frankel observed also that the cauterisa- 

 tion of the corpora lutea prevented the progressive development 

 of the ovum which had already struck root in the uterus and 

 begun to develop. These facts demonstrate that both the plant- 

 ing in the uterus of the fertilised ovum and its development there 

 are dependent on an internal secretion of the lutein cells. As 

 these are formed after the bursting of the follicle, even when 

 fertilisation and pregnancy do not take place, it is logical to 

 consider that menstruation in women, or the corresponding active 

 state of the uterine mucosa which accompanies the period of 

 " heat " in animals, depends also on the internal secretion of the 

 corpora lutea. 



Lastly, Frankel gave prominence to the fact that destruction 



