118 Marshall and Jolly 



to the normal condition. It is hardly possible, however, that anything more 

 than a slight uterine atrophy could have occurred in so short a period as two 

 months, but our previous observations have shown that the degenerative 

 process may be far advanced after six months' castration. The white rat 

 into which the ovary was grafted did not belong to the same litter as the 

 castrated piebald rat, and so far as known was not a relative of it.^ 



In another experiment the ovaries were removed from a monkey and 

 grafted on to the peritoneum of another monkey (heteroplastic transplanta- 

 tion). At the same time the ovaries of the latter were removed from the 

 normal position and also grafted on to the peritoneum (homoplastic trans- 

 plantation). About two months later the monkey with the grafted ovaries 

 was killed, when it was found that the heteroplastic ovaries had been 

 absorbed, while the homoplastic ovaries were still in position but had 

 undergone a certain amount of fibrous degeneration. 



Conclusions. 



As a result of these experiments, taken in conjunction with those 

 described in our former paper, the following conclusions may be 

 drawn : — 



(1) Greater success attends transplantation of the ovaries into the kidney 

 than on to the peritoneum, probably on account of the greater vascularity 

 of the kidney. 



(2) Homoplastic transplantation of ovaries is very considerably easier 

 to perform successfully than heteroplastic transplantation. This fact can 

 scarcely be ascribed to differences in the technique of the two operations, 

 since this was identical in each experiment, the two animals being operated 

 upon simultaneously in the case of the heteroplastic transplantations. 



(3) Heteroplastic transplantation of ovaries is apparently easier to per- 

 form successfully when the two animals employed in the experiment are 

 near relatives of each other. In our experiments there were few exceptions 

 to this rule. 



(4) The presence of an animal's own ovaries does not seem to exert any 

 inhibitory influence on the successful attachment and growth of additional 

 ovaries obtained from another individual. 



(5) The presence of a successfully grafted ovary in an abnormal position 

 in the body, whether obtained from the same or from another individual, 

 is sufficient to arrest the degenerative changes which habitually take 

 place in the uterus after the complete extirpation of the ovaries, as other 

 experiments have shown. It may be concluded, therefore, that the 

 ovarian influence on the uterus is chemical rather than nervous in 

 nature. 



1 It is possible that the two rats employed in this experiment might have been sisters 

 belonging to different litters, since they were obtained from the same breeder. 



