Physiology, Physiological Chem- 

 istry and Experimental Pathology 

 of the Testis 



HOMER WHEELON 



ST. LOUIS 



I. Introduction 



Dual Function of Testis. Incorporated within the testis are many 

 cells in addition to those which are responsible for the production of 

 spermatozoa. Among those located in the interstices between the semi- 

 niferous tubules are certain glandular elements known as the interstitial 

 cells. These cells exercise an important influence upon the development, 

 architecture, metabolism and activities of the body. Berthold in 1849, 

 the pioneer in the study of internal secretions, pointed out that the testes 

 possessed a dual function viz., the production of spermatozoa and the 

 elaboration of an internal secretion. Inasmuch as the interstitial cells so 

 modify bodily structures that the purpose of the germplasm, namely, re- 

 production, is assured, these two functions serve a common purpose. 



II. The Evolution of Factors Characterizing Sex 



Relation of Reproduction to Sex. Sex and reproduction, although 

 intimately associated, are fundamentally unlike. Reproduction may be 

 defined as those processes by which life is continued from generation to 

 generation. The perpetuation of species by reproduction is accomplished 

 in two ways viz., by a sexual and by an asexual process. Asexual repro- 

 duction agamogenesis is common among the lower animals and may 

 take the form of binary fission, spore formation, gemmation or budding. 

 Sexual reproduction gamogenesis consists essentially of the union of 

 two cells and the following development of this zygotic element. 



With the development of many celled organisms Metazoa and Meta- 

 phylia the reproductive tissue or germplasm was early set apart from 

 the body tissues or somatoplasm. Associated with the division of the 

 plasms appeared reproductive tissues of two types that giving rise to 

 male and that giving rise to female elements. In such organisms, repro- 

 duction necessitates the expulsion and subsequent union of the cells pro- 



431 



