XXL— MITRAL INSUFFICIENCY IN THE HORSE. 



At the present time we have in stable No. 4 a horse with mitral 

 insufficiency of considerable standing, in which the clinical signs are 

 so well marked as to leave no doubt regarding the prognosis. Although 

 the horse is incurable, we have permission to detain it for some days. 

 I have particularly drawn 3'our attention to it, and profiting by the 

 opportunity offered, I intend this morning to speak of chronic mitral 

 endocarditis, and to relate an interesting case. 



The principal symptoms shown by our patient ma}' be summarised 

 as follows : — A loud systolic murmur perceptible over an extensive area 

 on both sides of the chest, of greatest intensity towards the middle 

 portion of the heart, and very clearly audible on applying the ear over 

 the caput muscles ; a feeble, irregular, intermittent pulse, cardiac 

 intermittency alternating with two or three rapid irregular heart- 

 beats ; finally, loss of breath and dyspnoea after a few moments' exercise. 

 With these facts before us diagnosis is easy. We have to deal with 

 a case of old-standing mitral insufficiency in which the period of 

 compensation is past, and which is complicated by changes in the 

 muscular tissue of the heart. 



In the horse, chronic mitral endocarditis is less frequent than aortic 

 insufficiency. Its aetiology is that of all \ah'ular changes. With rare 

 exceptions it results from acute endocarditis complicating certain 

 infectious diseases. In solipeds these are generally represented by 

 strangles, one of the various forms of pneumonia, or b}- the typhoid 

 form of influenza, which almost always gives rise to acute endocarditis 

 and to vah'ular changes. 



Inflammation of the mitral vahe produces changes which finally 

 render it insufficient ; the flaps become irregularly thickened, contracts 

 draw apart, and cease to entirely close the opening. The chronically 

 inflamed mitral valves show less varied and less deep anatomical 

 changes than the aortic valves; it is exceptional to see centres of 



