THE TESTICLE AND THE OVARY 363 



Heape * has suggested that heat may be due to a " generative 

 ferment " which he supposes to be periodically present in the blood. 

 At the same time he is of opinion that a hypothetical substance 

 called " gonadin," which is secreted by the generative glands, is also 

 an essential factor. The precise relation in which gonadin and the 

 generative ferment were supposed to stand to one another is not 

 very clear. 



Assuming that heat and menstruation are brought about, either 

 directly or indirectly, through a stimulus depending upon the 

 secretory activity of the ovary, it is still an open question as to 

 what part of the organ is concerned in the process. Fraenkel 2 has 

 supposed that the secretion in question is supplied by the corpus 

 luteum. This conclusion is based upon nine cases in which the 

 corpus luteum was destroyed by the cautery, and in eight of which 

 the next menstrual period was missed. In the remaining case it is 

 supposed that the secretion responsible for producing menstruation 

 had already been formed in sufficient quantity and passed into the 

 circulation at the time of the cauterisation. Fraenkel's theory, 

 however, is disproved by the fact that ovulation in most Mammals 

 does not occur until oastrus, or, at any rate, until the end of the 

 prooestrum (see p. 131), and consequently corpora lutea are not 

 present in the ovaries (for the corpora lutea dating from one oastrus 

 do not always persist until the next oestrus, which may be many 

 months afterwards). Heape's observations 3 on the absence of 

 corpora lutea in menstruating monkeys may be again cited in this 

 connection. Moreover, Kies* 4 has reported a case of a woman with 

 whom menstruation occurred normally after an operation in which 

 an oozing corpus luteum, which was a source of haemorrhage in the 

 peritoneal cavity, had been peeled 1 out. It should be mentioned that 

 Fraenkel's views on menstruation are part of a general theory which 

 is discussed more fully below (p. 368). 



Seeing that the corpus luteum is not responsible for inducing 

 menstruation, it becomes necessary to conclude that either the 

 follicular epithelial cells or the interstitial cells of the ovarian stroma 

 (or both of these) are concerned in bringing about the process 

 (see p. 119). 



Some experiments by Mr. Runciman and the author 5 on bitches 



1 Heape, "Ovulation and Degeneration of Ova in the Rabbit," Proc. Roy. 

 >S'oc., B., vol. Ixxvi., 1905. 



2 Fraenkel, " Die Function des Corpus Luteum," Arch. f. Gynak., vol. Ixviii., 

 1903. 



3 Heape, "The Menstruation and Ovulation of Macacus rhesus" Phil. Trans., 

 B., clxxxviii., 1897. 



4 Ries, "A Contribution to the Function of the Corpus Luteum," Amer. 

 Jour. Obstet., vol. xlix., 1904. 



5 Marshall and Runciman, "On the Ovarian Factor concerned in the 

 Recurrence of the CEstrous Cycle," Jour, of P/iysioL, vol. xlix., 1914. 



