INTERNAL SECRETIONS 



89 



and it is noteworthy that this happens at whatever stage of 

 growth the operation is performed, the horns ceasing to grow 

 forthwith. It is clear, therefore, that the testicular stimulus 

 is essential, not only for the initiation of horn growth, but also 

 for its continuance and completion. In other horned breeds 

 of sheep (e.g. Dorset Horns, Scottish Blackfaced or Lonks) the 

 wethers have horns which are finer and less massive than those 

 of the rams and so approximate towards the horns of the female 

 (or more probably what is really the neutral) type. With deer 



Fig. 58. — Herdwick wetlier cas- 

 trated when four months old. 

 The horns are the same length 

 as they were at the time of 

 castration, (From Marshall and 

 Hammond, Jour, of Phijsiol.) 



Fig. 59. — Herdwick ram lamb 

 from which one testis was re- 

 moved four months after birth. 

 The horns continued to grow 

 and were symmetrical. (From 

 Marshall and Hammond, Jour, 

 of Physiol.) 



early castration prevents the development of the antlers. If 

 the operation is performed late, only " clump " or " peruke " 

 antlers, which are quite short, appear, and these persist instead of 

 falling off after the breeding season, as normal antlers do. If 

 castration is done when the antlejs have grown, these fall off 

 and are replaced next season by peruke antlers. The horn 

 sheath, however, is not shed. Speaking generally, with all 

 ungulate mammals that are sexually differentiated in respect 

 of horn growth, castration leads to a condition resembling that 

 existing in the female, which in these animals approaches more 

 closely to the neutral type than does the entire male. In the 

 eland, which like many horned sheep, is horned in both sexes, 



