MITRAL INSUFFICIENCY IN THE HORSE. 1 39. 



Corrigan's pulse, — and the signs of dyspnoea produced by a few minutes' 

 exercise, led me to diagnose old-standing mitral endocarditis with 

 insufficiency. On the other hand, the diastolic murmur, the ver}' 

 marked venous pulse, and the cedema indicated dilatation of the right 

 heart, with reflux and stasis of blood in the vessels of the systemic 

 circulation. 



I kept this case for a time to afford you an opportunity of following 

 the course of the disease. At the end of a week the hind limbs 

 became swollen. The lower surface of the abdomen and of the chest 

 showed extensive cedema. 



The animal was slaughtered. The principal lesions found on post- 

 mortein examination were as follows : — The abdominal cavities con- 

 tained some quarts of a yellowish limpid serosity without fibrinous 

 flocculi. The veins of the systemic circulation were dilated. Over 

 almost its entire surface, but especially along the course of its vessels, 

 the large colon showed abundant subserous oedema. The liver was 

 very large ; on incision the condition known as "cardiac liver" was 

 seen to be well developed. The other abdominal viscera, especially 

 the kidneys and spleen, were engorged with blood. 



The pleural cavities contained 4 to 5 quarts of serous fluid, resem- 

 bling that in the peritoneum. The lung was blackish, heavy, and 

 congested ; its tissue was in some places oedematous, in others dense 

 and sclerosed. The heart was enormous ; the right heart especially 

 had become enlarged ; its cavities were greatly dilated, the auricle 

 being almost four times its normal capacity. The left auricle was also 

 much dilated, and the walls of the corresponding ventricle (which were 

 slightly hypertrophied) showed areas of sclerosis. The flaps of the 

 mitral valve, more particularly the principal, were thickened, shortened, 

 puckered, and at certain points of ahiiost cartilaginous consistence. 



The course of the morbid condition produced by mitral lesions is 

 fatally progressive. Whether or not insufficiency be complicated 

 by contraction, the circulation gradually becomes impeded, and the 

 resulting symptoms more marked ; the general condition steadily 

 increases in gravity, until at last death terminates the case. 



Chronic mitral endocarditis being in the long run fatal, how does 

 death occur ? 



Mitral lesions usually kill slowly. Among the organs (which are 

 all gravely affected) two, the heart and lung, still actively continue 

 their functions. Though first affected, overloaded in the beginning, 

 and in the last stages burdened with the ever-increasing arterial 

 tension, the heart continues to struggle against the growing vascular 



