ORGANS OF INTERNAL SECRETION 305 



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 dis- 

 cussed at some length by Cunningham, Morgan, 1 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 the complete 

 development of the antlers, these are shed prematurely and are 

 replaced in the next season by incomplete antlers with a tendency 

 towards peruke formation, and these, on being thrown off, are 

 not renewed. Partial castration in the immature stag is said 

 to result in a weaker horn formation ; but the effect is general, and 

 shows no restriction to the side on which the testis is wanting. 2 



The results of castration in the fallow deer have been in- 

 vestigated by Fowler, 3 who summarises his results under five 

 headings : (1) Complete castration at birth limits the horn 

 formation to the development of single dugs ; (2) Castra- 

 tion in mature life tends to produce asymmetry in the growth 

 of the horns ; (3) The antlers of castrated deer are often shed 

 prematurely if the operation is performed after they have lost 

 the velvet, but antlers which have grown after castration may 

 be retained for over two years ; (4) Incomplete castration 

 shortly after birth is followed by a weak development of the 

 antlers, which are otherwise normal ; (5) One-sided castration 

 may result in the abnormal or incomplete development of one 

 antler, the other antler being nearly normal. The last point 

 would seem to require confirmation. 



In the prong-buck (Antilocapm americana), which is the 



1 Morgan, Experimental Zoology, New York, 1907. 



2 These statements are based chiefly upon the results of Caton's experi- 

 ments with Wapiti and Canadian deer (Caton, Antelope and Deer of Atneiica, 

 2nd Edition, New York, 1881. See also Holdich, " Exhibition of Antlers of 

 Deer showing Arrest of Development due to Castration"), Proc. Zool. Soc,, 

 1905. Some further examples of sexual correlation are given in Chapter I. of 

 this work, and Morgan, loc cit. Dr. Seligmann informs me that stags which 

 fail to grow antlers (i.e. occasional " sports") have well-developed testicles. 



3 Fowler, " Notes on Some Specimens of Antlers of the Fallow Deer," &c., 

 Proc. Zool. Soc., 1894. 



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