3911.] 



Castration and Ovariotomy upon Sheep. 



31 



Herdwiek rams depend for its initiation upon a stimulus set up by the 

 testes, but that this stimulus is necessary for the continuance of horn growth, 

 which stops as soon as the testes are removed. 



Six Herdwiek ewe lambs were also obtained in August, 1910, and three of 

 these were operated upon when about three months old, the remainder being 

 kept as controls. At that time none of these six ewes had any perceptible 

 trace of horns or scurs. The operations and subsequent history of the ewes, 

 were as follows : — 



(1) The ovaries, Fallopian tubes, and uterus were completely removed. 

 About seven months after the operation, when the ewe was 10 months old, 

 it was noticed that small scurs were beginning to grow from the frontal 

 bones. These continued to enlarge, but only very slightly. When the ewe 

 was about 17 months old it died from hoven. The skull and skeleton were- 

 kept and preparations made. The scurs may now be seen on the skull 

 as small projections about £ inch long. The epiphyses of some of the bones, 

 (particularly those of the metacarpal and metatarsal bones) appear to be 

 slightly longer than those from the skeleton of a normal Herdwiek ewe 

 of the same age, and this result may possibly have been due to the extirpation 

 of the ovaries. 



(2) The ovaries and Fallopian tubes (but not the uterus) were removed. 

 The ewe is still alive. There are at present only doubtful traces of scurs,. 

 and these, such as they are, have made no progress in development in the 

 last seven months, but seem rather to have become reduced so as now to be- 

 scarcely perceptible. 



(3) The ovaries, Fallopian tubes, and upper parts of the uterine cornua 

 were removed. The ewe is still alive, but, as in the preceding experiment, 

 there are now only doubtful indications of scur growth, the skull being 

 merely somewhat bumpy in the position where the horns or scurs should 

 grow. 



In each of the three animals the removed generative organs were quite 

 infantile. They have been preserved. 



It is clear, therefore, that the removal of the ovaries in young Herdwiek 

 lambs before puberty does not lead to an acquirement of horns, which in 

 this breed are male characters. It must be mentioned, however, that in 

 neither of the three normal ewes could any trace of scurs be detected. One* 

 of these was killed at about the same time as the death of the spayed ewe 

 (No. 1) and the skeleton of this animal was preserved. The skull is quite 

 smooth in the position corresponding to that of the scurs in the spayed ewe.* 



* The other two normal ewes unfortunately died earlier, and their skulls were not 

 kept, but no scurs had been detected in these shortly before their death. 



