466 HOMEE WHEELON 



proteins whfch contain toxic bodies. More recently, the beneficial results 

 following the administration of testicular preparations have been con- 

 sidered due to the presence of nucleoalbum rich in phosphorus, resembling 

 lecithin or glycerophcsphates (Sajous). Microscopic studies have defi- 

 nitely shown the presence of fatty particles in the interstitial cells and 

 lymphatics of the testis, the fat content varying with the sexual cycles. 

 Certain investigators, especially Duesberg, contend that these microscopi- 

 cal bodies represent the internal secretion of the testes. However, it is not 

 justifiable at the present time to accept such observations as proving the 

 presence of an internal secretion. 



The pharmacodynamics of the testis remains indeterminate. Tes- 

 ticular extracts are complex in nature, and it is at present impossible to 

 obtain pure extracts of the interstitial cells alone. Up to the present time 

 an active principle has not been obtained from the testes which will insure 

 the same reactions as the presence of the testes themselves. However, the 

 results of testicular activity are not pronounced at any one moment ; their 

 influence is exerted continuously. Furthermore, the testes are not essential 

 to the life of the individual ; their purpose is solely to further the develop- 

 ment and maintenance of the sex signs in tissues present. Disturbances 

 of other endocrin glands (Bell) are known to exert marked influences over 

 the metabolism and perhaps, in the absence of the testes, are responsible in 

 great part for the results following removal of the gonadal influence. 

 However, such glands are common to both sexes, while a specific inter- 

 stitial gland is normally confined to one sex. 



V. Alterations in Sex and Their Relation to the Testes 



1. Assumption of Male Characteristics by the Female. Darwin re- 

 cords the case of a duck which in her old age assumed the perfect winter 

 Miid summer plumage of the drake. Bandoin describes a case -of "sex inver- 

 sion" in a bird as the result of diseased ovaries. Castration of the female 

 duck causes it to gradually lose the female characters and assume those 

 of the male. 4 According to Brant, hens invariably acquire cock's plumage 

 after the loss or degeneration of the internal genitals, most commonly 

 because of degeneration of the oviducts. L. Loeb describes the case of a 

 male guinea pig which possessed certain female secondary sexual char- 

 acters. The testes were small and had not descended. They were made 

 up of interstitial cells and typical tubules which lacked spermatogonia. 

 The interstitial cells were abnormal, containing vacuoles and eosinophilic 

 bodies. The mammary glands were female in character. Old female 

 deer, which have become sterile, incline to antler formation, as do also 



* For bibliography pertaining to male sex characters in female birds, the reader 

 is referred to the work of Larcher. 



