354 THE PHYSIOLOGY OF REPRODUCTION 



breeding season, largo follicles weie found in the grafts, while at a 

 later period corpora lutea were present, showing that ovulation had 

 occurred in the transplanted ovaries. In one case, a homoplastip 

 graft was found to be normal after fourteen months, while a normal 

 heteroplastic graft was composed entirely of healthy ovarian tissue 

 (with follicles and ova) after six months. In these experiments the 

 ovaries were grafted into the substance of the kidneys. 



Honioplastic transplantation was 

 found to lie more easily accom- 

 plished than heteroplastic trans- 

 plantation. This result could hardly 

 be ascribed to increased difficulties 

 in the performance of the latter 

 operation, since the technique was 

 identical in each case. Further- 

 more, our successes in heteroplastic 

 transplantation were usually obtained 

 in experiments in which two rats 

 from the same litter were known to 

 have been employed, so that the 

 ovaries were grafted into whole 

 sisters, but we were not sure of the 

 relationship in every case. 



These experiments clearly indicate 

 that the nature of the ovarian influ- 

 ence is chemical rather than nervous, 

 since the successfully grafted ovaries, 

 while still maintaining their func- 

 tions, had lost their normal nervous 

 connections. It is probable, there- 

 fore, that the uterus depends for its 

 proper nutrition upon substances 

 secreted by the ovaries. 



Further evidence in support of 

 the view that the ovary produces an 

 internal secretion is provided by the results of ovarian medication 

 or the administration of preparations of ovarian substance for 

 medicinal purposes. It is somewhat difficult, however, to know 

 precisely what value to assign to this practice about which medical 

 authorities still apj>ear to differ. Brown-Sequard T seems to have been 

 the first to employ ovarian extracts medicinally. He supposed them 

 to produce similar effects to those br. night about by testieular extracts, 



1 HP > \vn-Sequard, "Des Etfets produits cluv I'Hoiniue par des Injections, 

 ' /,'. ,/, / Soe. /- IMd., 1889. 



FIG. 95. Transverse section 

 through uterus of rat after 

 ovariotomy, showing degen- 

 erative changes. 



(Of. Figs. 94 and 96. From 

 Marshall and Jolly.) 



