304 THE PHYSIOLOGY OF REPRODUCTION 



prostate glands. Similiarly it has been stated that Cowper's 

 glands are probably dependent upon testicular influence for 

 their growth and activity (p. 240). 



More remarkable is the close correlation that exists between 

 the testes and the secondary sexual characters of the male — that 

 is to say, those characters which are found only in the male sex, 

 but are not directly connected with the organs of generation. 



Thus, it is notorious that castration before puberty in man 

 prevents the growth of hair on the face, arrests the development 

 of the male chest and pelvis, and preserves the high-pitched 

 voice of boyhood by hindering the growth of the larynx, while 

 at the same time it exercises a marked influence over the mental 

 characteristics.-'^ It is equally well known that at the time of 

 puberty, when the testes begin to assume their functional 

 activity, there is a corresponding development of the secondary 

 sexual characters, both in Man and in a large number of animals. 

 This correlation appears to be still closer in those animals in 

 which the increased testicular activity that takes place in the 

 breeding season is associated with a periodic development of 

 other sexual characters. Thus, in the male elephant the glands 

 on the side of the face emit a musky secretion during rut.^ 



Darwin,^ in elaborating his theory of sexual selection, 

 collected together numerous examples of secondary sexual 

 differences occurring in animals of various kinds. More recently 

 Cunningham, in a work upon Sexual Dimorphism, has cited 

 a number of further cases,* in many of which the structural 



1 According to Hikmet and Regnault (" Les Eunnques de Constantinople," 

 Bull, et Mem. de la Soc. d' Anthropologie de Paris, vol. ii., 5th series, 1906), 

 the eunuchs of Constantinople have the following mental characteristics ; — ■ 

 They are avaricious, illogical, obstinate (i.e. cannot change their ideas), have 

 no judgment, accept information without proof; are not cruel, but fond 

 of children and animals ; are faithful in their affections, but have no courage ; 

 their mental activity is very slight, and they are extremely fanatical. Senility 

 is premature, but the teeth are kept solid and white. For skeletal differences 

 in eunuchs, see below. ^ Cf. page 305. 



' Darwin, The Descent of Man, Popular Edition, London. 



* Cunningham {J.T.),Se3malDimorphisminthe Animal Kingdom, London, 

 1900 ; " The Heredity of Secondary Sexual Characters in Relation to Hor- 

 nones,".4rcfe./. Entwick. Mech., vol. xxvi., 1908. See also Hegar, Korrelationem 

 der Keimdrilsen und Oeschlechtsbestimmung, 1893 ; and Selheim, " Zur Lehre 

 von den sekundaren Geschlechtscharakteren," Beitrdge zu Qeburtsh. u. Oyndk. , 

 vol. i., 1898. 



