RESULTS OF CASTRATION IN DUCKS. 49 



youthful condition. In addition castration may have specific 

 results, not associated with secondary sexual characters. Tandler 

 and Grosz have recently made an extensive study of eunuchs 

 which may be briefly and incompletely summarized as follows: 

 The individual tends to retain youthful characters. Thus the 

 larynx is like that of a boy; the voice high pitched and likely 

 to break similarly to that of a boy at puberty; beard, body, 

 axial and pubic hairs sparse or wanting. The epiphyses remain 

 open for a long time, consequently the eunuch is usually very 

 long limbed. Fat tends to develop in certain parts of the body. 

 The skin is usually soft, poor in pigment, and of a peculiar yel- 

 lowish color. Facial wrinkles of a peculiar type are also found. 

 The effects of castration of male deer and cattle have been noted. 

 Less is known of the doe, but horns sometimes develop, appar- 

 ently as the result of abnormal ovaries (Rorig). Similarly in 

 the Hardwick breed of sheep, which are horned in the male 

 only, the horns fail to develop after castration (Shattock and 

 Seligmann). In reindeer, however, where both sexes are horned, 

 castration does not affect the development or renewal of the 

 horns. Other vertebrates have been little studied. Nussbaum, 

 however, finds that the nuptial organs of the male frog do not 

 develop on castration. 



Experimental castration in insects has been studied by Oude- 

 mans, Kellogg, Regen, Meisenheimer and Kopec. The last two 

 have also transplanted the gonads from one sex to the other. 

 They agree that no modifications of the secondary sexual char- 

 acters occur. Wheeler, who has recently made an extensive 

 review of the subject, including its physiological side, reaches 

 the same conclusion. 



In some other arthropods, however, very different results have 

 been obtained. Giard, Smith and Potts have studied parasitic 

 castration in various Crustacea. Their results may be summar- 

 ized thus : The secondary sexual characters of the female remain 

 unaltered, but the male becomes more or less modified in the 

 direction of the female. In extreme cases, after recovery, ova 

 have been found in the testes, the individual having become 

 hermaphroditic. 



This brief review shows that castration varies in its influence 



