On the Effects of Castration and Ovariotomy upon Sheep. 27 



(28) Mauersberg, 'Ophthalmoscope,' 1910, vol. 8. 



(29) 5, Maddox, ' Tests and Studies of the Ocular Muscles,' 1907, 2nd edition. 



(30) ' Eeports of His Majesty's Inspectors of Mines,' 1910, Cd. 5794, Cd. 5676, Cd. 5676, 



1 to 7. 



r(31) Debate on Coal Mines Bill, reported in 'The Times,' November 24, 1911, and in the 

 'Colliery Guardian,' December 1, 1911, p. 1075. 



On the Effects of Castration and Ovariotomy upon Sheep. 



By F. H. A. Marshall, Fellow of Christ's College, Cambridge, and University 

 Lecturer in Agricultural Physiology. 



.(Communicated by Prof. J. N. Langley, F.E.S. Eeceived December 20, 1911, — 

 Eead February 22, 1912.) 



It is well known that castration, when performed in early life and before 

 ■sexual maturity has been reached, has a marked effect not only in inhibiting 

 the development of the accessory male organs, but in changing the general 

 conformation of the body. Thus in castrated guinea-pigs, oxen, and capons, 

 as well as in eunuchs, the bones of the limbs tend to be abnormally long, 

 this result depending upon an arrest in the ossification of epiphyses. The 

 secondary male characters are also in many cases suppressed, so that there 

 ds an apparent approximation to the female type. Thus in red deer if the 

 -testes are removed in quite immature animals the antlers fail to make their 

 appearance, and in fallow deer castration at birth limits the horn formation 

 to the development of single dugs. Secondary sexual characters, however, 

 are not always correlated with the presence of the essential reproductive 

 ■organs, even in mammals. Thus the withers in the gelding resemble those 

 of the horse rather than those of the mare, in which the withers are lower. 

 Moreover, in certain varieties of cattle in Italy, the horns in the ox, if 

 castration has been carried out young, are far longer than those of either the 

 hull or the cow. 



Ovariotomy in the female is often said to lead to the assumption of male 

 ■characters, but there is little experimental evidence that this is actually the 

 case. In the human female complete removal of the ovaries, if carried out 

 in early life, besides preventing the onset of puberty and the occurrence 

 of menstruation, produces effects on the general form and appearance, 

 individuals so operated upon being said, in some cases, to show resemblances 



