32 INTERNAL SECRETIONS 



and shape of the skull in horned cattle are much less marked 

 after prepuberal castration, there being a great resemblance 

 in the size and shape of the skull in the castrated cow 

 and the ox. The ox and the castrated cow are very similar 

 also in the proportions of the body. Castration leads, according 

 to Tandler and Keller, to a convergence of both sexes. The 

 skeletons of the castrated cow and bull represent something 

 like an asexual type. 



These statements of Tandler and Keller are in accordance 

 with those made previously by Franz (1909) on the pelvis of 

 the sheep. Franz examined the pelves of new-born lambs and 

 of fully grown male and female sheep ; he found no striking 

 sexual differences in new-born lambs, whereas the pelvis in 

 fully grown sheep was very different in both sexes {Figs. 19-22). 

 These differences are due to variation in the size and shape of 

 the bones which compose it. But in male and female sheep 

 which were castrated soon after birth, Franz found the pelvis 

 two years after the operation, i.e., at a time when the growth of 

 the animal is completed, very similar in castrated animals of 

 both sexes (Figs. 23 and 24). The figures leave no doubt about 

 the tendency of the pelvis of the castrated male and female 

 to approach a common form or an asexual type. If a small 

 particle of the ovary remained in the body the pelvis developed 

 normally. 



There can be no doubt that in mammals there is no develop- 

 ment of characters characteristic of the other sex after 

 castration. On the contrary, what we see in mammals gives 

 us new and important evidence that castration, performed at 

 an age when sexual characters are not yet very marked, leads 

 the organism to a form common to both sexes. The obser- 

 vations of Franz on the pelvis, and of Tandler and Keller on the 

 skull, are very important in this connection. ^ It may be also 

 that the observations made on the mammary gland of the ox 

 where an increased growth was recorded, and those on the 

 mammary gland of the cow where an underdevelopment 

 occurs, can be taken as further evidence for the conclusion of 

 Tandler and Gross. But for the mammary gland the question 

 would appear to be not yet decided. (For the castrated deer 

 see Tandler and Gross, 1913, pp. 31-40). 



*New important data as to this were given by Zawadowsky (1922). 



