590 DR MARSHALL AND MR W. A. JOLLY 



in order to prevent them from breeding. We understand from Principal M'Call, of 

 Glasgow, that normal heat does not occur in dogs on whom this operation has been 

 performed. 



Ovariotomy is also sometimes performed on mares, and usually with the object of 

 repressing those vicious symptoms which so often occur during the oestrous periods 

 and render the animals at such times almost or quite unworkable. Details of fifty 

 consecutive cases of ovariotomy in troublesome mares are given in two papers by 

 Hobday (1902, 1906), who shows that the operation is frequently followed by perfectly 

 successful results. From these papers it does not appear certain that oestrus is 

 completely prevented after the removal of the ovaries, but the violent symptoms which 

 rendered the mares useless for work were in nearly every instance suppressed. In one 

 «ase ovariotomy was undertaken to prevent oestrus, and the result was regarded as 

 having been " satisfactory." Other mares are described as having been operated on 

 because they were " always in oestrum," and so, presumably, unworkable, and in these 

 cases also the result of the ovariotomy is said to have been satisfactory. 



The statements of certain writers regarding the condition of the uterus subsequent to 

 double ovariotomy are in opposition to the views of those who hold that heat and menstrua- 

 tion may occur after the performance of that operation. Thus Knauer (1900) says 

 that removal of the ovaries in rabbits brings about a premature menopause, the uterus 

 undergoing atrophy. Similar statements have been made by Sokoloff (1896), Hofmeier, 

 Benkiser (1891), and Buys and Vandervelte (1894). Hofmeier and Benkiser, how- 

 ever, ascribe the degenerative changes in the generative organs after ovariotomy to an 

 insufficiency in the blood supply consequent upon the operation of removal, while Buys 

 and Vandervelte are disposed to regard these changes as being the indirect result of an 

 assumed severance of nerves passing to the uterus and vagina. Limon (1904), on the 

 other hand, states that he found no sign of atrophy in the generative organs after the 

 transplantation of the ovaries to an abnormal position, and, therefore, that the respective 

 explanations offered by Hofmeier and Benkiser and by Buys and Vandervelte are 

 inadequate. But Limon does not appear to have made more than a superficial 

 examination of the organs to which he refers ; he mentions also that the experiments of 

 Knauer, Bjbbert, and Rubinstein point to the same conclusion as his own, and support 

 the view that the proper nutrition of the uterus is dependent upon the existence of an 

 internal ovarian secretion. 



Our own observations on this matter are such as seem to us definitely to exclude 

 the possibility of the recurrence of normal heat after the ovaries have been removed for 

 a period longer than a few months. 



The blood supply of the uterus is derived largely from the uterine artery which is 

 given off in the pelvis, and is in no way interfered with by the operation of ovariotomy. 

 The ovarian artery in the experiments described below was necessarily severed at a 

 point a little short of its entrance to the ovaries, and in all our experiments the blood 

 supply of the uterus may be said to have been unimpaired. 



