58 The Acquirement of Secondary Sexual Characters. [Dec. 14, 



ductless glands, and the metabolic results arising from their function 

 must, as in analogous cases elsewhere, be attributed to the elaboration 

 of an internal secretion and its absorption into the general circulation. 



What particular cell elements are concerned in the production of 

 such a secretion cannot as yet be stated. Various possibilities arise 

 which demand the test of further experiment. 



The function of spermatogenesis, although not itself the whole or 

 sufficient cause, may be the initial factor of a dual or even a more 

 complex process. 



It is quite within the bounds of possibility that certain of the 

 epithelial cells within the tubuli may produce a pro-secretin such as is 

 produced within the intestinal epithelium ; that the chemical changes 

 accompanying spermatogenesis in other of the cells of the tubule may 

 lead to the conversion of this pro-secretin into a secretin, much as the 

 acid chyme does in the case of the pro-secretin present in the intestinal 

 cells ; and that the secretin so formed may, without being shed into 

 the lumen of the tubule, be transferred to the lymph spaces, and thus 

 eventually reach the general circulation, and incite those metabolic 

 changes in distant parts of the body which disclose themselves as 

 secondary sexual characters. The intimate connection that arises in 

 the process of spermatogenesis between the spermatoblasts and the 

 " sustentacular " cells is a phenomenon not yet explained : this 

 phenomenon possibly coincides with the interaction suggested. 



In regard to the interstitial cells of the stroma, they have characters 

 so unmistakeably glandular that some secreting function, probably a 

 sexual one, must be assigned to them, and they may, of course, take a 

 part in the elaboration of such a secretion as that suggested. 



But the great variation in the proportion of such cells present 

 in different forms of mammals makes it difficult to formulate any 

 hypothesis to test by way of experiment, and we are not as yet in a 

 position to make any statement in regard to them. 



We have to acknowledge our indebtedness to Mr. George Jonas, of 

 Duxforcl, for much technical information ; to Mr. Marcus Van Raalte 

 for generous help in defraying portion of the expense incurred by the 

 work; and to Mr. C. S. Wallace, Mr. H. J. Marriage, and Dr. H. C. 

 Jonas, for assistance in various ways and on various occasions. 



Preparations illustrating the various observations referred to are 

 now in the museum of the Eoyal College of Surgeons, London. 



