ORGANS OF INTERNAL SECRETION 351 



disappears, while characteristic cells known as " summer cells " 

 become developed. Bulloch and Sequeira ^ state that in cases 

 of children with carcinomata of the supra-renals, this is asso- 

 ciated with premature development of the genital organs and 

 the accessory generative glands. 



General Conclusions regarding the Internal Secretions 

 OF THE Ovary and the Testis 



It will be convenient at this point to summarise the con- 

 clusions which have been tentatively arrived at concerning the 

 nature and purpose of the internal secretions of the ovary and 

 the testis. 



The mammalian ovary, in addition to its oogenetic function, 

 is an organ elaborating a chemical substance or substances 

 which react on the general metabohsm and control the nutrition 

 of the uterus. The secretion is probably produced by the cells 

 of the foUicular epithehum, or by the interstitial cells of the 

 stroma, or, perhaps, by both combined.^ It is formed in greater 

 or less quantity at all times, but is produced in increased 

 abundance at certain recurrent periods, when it brings about 

 those conditions of growth and hypersemia which characterise 

 the prooestrous processes. It is at these periods also, in typical 

 cases, that the foUicles become mature. After ovulation, which 

 occurs during oestrus, the secretory cells of the ovary show still 

 greater activity, and become converted by a process of simple 

 hypertrophy into the luteal cells of the corpus luteum. If the 

 ovum is fertihsed, these cells continue to increase in size until 

 nearly mid-pregnancy (or, in some animals, a somewhat earher 

 period), when they exhibit signs of degeneration. If pregnancy 



' Bulloch and Sequeira, "On the Relation of the Supra-renal Capsules 

 to the Sexual Organs," Trans. Path. Soc, vol. Ivi., 1905. 



2 Limon (loc. cit.) suggested, as a result of his experiments in grafting, 

 that the ovarian secretion is elaborated by the interstitial cells. It should 

 here be remembered that the follicular epithelial and interstitial cells are 

 almost certainly identical by origin, and so probably similar potentially 

 (p. 124), and that both of these cellular elements have been described as 

 taking part in the formation of the corpus luteum (p. 148) ; and also, that 

 those interstitial cells which do not form part of the corpus luteum have 

 been stated to undergo an independent hypertrophy during pregnancy 

 (p. 345). 



