gland, and not to metabolic changes set up by a nervous reflex arising 

 from the function of sperm ejaculation. 



Corresponding results have been obtained in the female by extirpa- 

 tion of the ovaries, double obphorectomy before puberty not only pre- 

 venting the onset of puberty and the occurrence of menstruation, but 

 modifying the future growth of the whole body in the direction of the 

 male character. It has been shown recently by Marshall and Jolly, in a 

 paper read before the Royal Society, that the changes in the uterus which 

 determine menstruation are due, not to ovulation, but to an internal 

 secretion arising from the ovary. These observers suggest that the inter- 

 stitial cells of the ovary may be the seats of manufacture of this internal 

 secretion or hormone ; and it is interesting to note that, in a research 

 recently carried out by Miss Lane-Claypon, definite evidence is brought 

 forward of the origin of the interstitial cells of the testis from the germinal 

 epithelium and of the complete equipotentiality of those cells with those 

 which are forming the ova and Graafian follicles. Many observations 

 have been made on the effect of administering by the mouth preparations 

 ot ovaries, especially in cases where the morbid symptoms were presum- 

 ably due to abolition of the ovarian functions, either by disease or in 

 consequence of the operative removal of these organs. Although in many 

 cases favourable results are said to have been attained results which 

 would appear to prove the resistance of the ovarian hormone to diges - 

 tion in the alimentary canal it is difficult in this, as in most clinical 

 evidence, to judge how far the results were due to the treatment or to 

 the expectation of the medical man or patient. More definite evidence 

 of a direct influence of the ovary on the growth of the uterine mucous 

 membrane has been furnished by the experiments of Fraenckel, as well as 

 by those of Marshall and Jolly. At the suggestion of Born, Fraenckel 

 removed the ovaries of rabbits from one to six days after copulation, in 

 order to decide whether the ovary exercised any influence on the growth 

 of the mucous membrane of the uterus and its preparation for the fixation 

 of the ovum. In every case on subsequently killing the animal it was 

 found that the extirpation of the ovaries had prevented the fixation oi the 

 ova. On the other hand, if the ovaries were removed on or after the 

 fourteenth day of pregnancy, which in the rabbit lasts about 30 days, the 

 animals went on to full time and healthy foetuses were produced. The 

 fact that the corpus luteum of pregnancy grows enormously during the 

 first third of pregnancy and then diminishes in size, suggests that this 

 hypertrophy and growth of cells are for the express purpose of influencing 

 the mucous membrane; and Fraenckel states that destruction of the 

 corpora lutea by means of the galvano-cautery is as efficacious as total 

 removal of the ovaries in determining the end of pregnancy. The cells 

 which form the corpora lutea are derived, not from connective tissue cells 

 but from the interstitial cells lying immediately outside the Graafian 

 follicles. Their origin is, therefore, identical with that of the interstitial 

 cells of the ovary viz., from the primitive germinal epithelium. 



These experiments of Fraenckel have been confirmed by Marshall 



