THE TESTICLE AND THE OVARY 321 



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. Cunningham, in a work upon " Sexual 

 Dimorphism," has cited a number of further cases,^ in many of which 

 the structural peculiarities in question are shown to be closely 

 correlated with the essential organs of reproduction. 



The effects of castration in the stag, for example, are discussed 

 at some length by Cunningham, Morgan,* and other writers. If the 

 testes are removed in quite immature animals the antlers never 

 develop, even the knobs failing to make an appearance. If castration 

 is performed in stags whose antlers have just commenced to develop, 

 these remain covered by skin, forming the so-called peruke antlers, 

 which are not shed or renewed. If the operation is carried out after 



' According to Hikmet and Eegnault (" Les Eunuques de Constantinople," 

 Bidl. 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, p. 323. See also Kammerer, "TJrsprung der Geschlechtsunterschiede," 

 F'ortachr. natwrwiss: Forschung von AbderhaZden, 1912 ; and Hirschfeld, Sexiiale- 

 Pathologie, Bonn, 1917. 



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



^ Cunnini^ham (J. T.), Sexual Dimorphism in the Animal Kingdom, London, 

 1900 ; "The Heredity of Secondary Sexual Characters in Relation to Hormones," 

 Arch.f. EnttJlnck.-Mech., vol. xxvi., 1908 ; Hormones and Heredity, London, 1921. 

 See also Hegar, Korrelationem der Keimdrusen und Oeschlechtsbestimmung, 1893 ; 

 and Sellhein:^, " Zur Lehre von den sekundaren Geschlechtscharakteren," Beitrdge. 

 zu Oehwtsh. u. Oyndh, vol. i., 1898. 



* Morgan, Experimental Zoology, New York, 1907. 



