ACUTK KNI^OCARDITIS IN THK HORSE. I23 



of active microbic growth, or of degenerative changes, the vegetations 

 may break down suddenly, throwing into the blood-stream large 

 numbers of fragments, which produce multiple, simple, or specific 

 embolisms, and in some cases rapidly progressive septicaemia. 



In ulcerative endocarditis (which is still rarer than the preceding) 

 the serous membrane shows loss of substance ; true ulcers may 

 develop on the walls of the ventricles, or on the valves ; most fre- 

 quently on the mitral. Starting in the endocardium, and at first 

 limited in extent, these ulcers extend more or less rapidly in size and 

 depth, and may perforate and partially destroy the valves. When 

 affecting the parietal endocardium they sometimes extend beyond its 

 deep layer, erode the myocardium, and produce a kind of aneurism. 



Visceral complications due to emboli are frequent. The blood is 

 charged with micro-organisms, masses of cells, and broken-down 

 material from the ulceration, and is greatly changed in character. 

 Pyaemic or septicaemic lesions are not infrequent. 



In acute endocarditis affecting the valves diagnosis becomes possible 

 as soon as a murmur develops. When, however, localised in the 

 parietal endocardium or affecting the valves, but without causing 

 insufficiency, detection is impossible. It is perhaps well to repeat 

 that even when alarming general symptoms occur, suggesting acute 

 endocarditis, the existence of a murmur is of doubtful significance, and 

 may be due to old-standing heart disease, the accompanying disturb- 

 ance resulting from some other affection, such as pneumonia. In most 

 cases minute examination of the patient is necessary before giving an 

 opinion, and sometimes a few days must be allowed to elapse for the 

 condition to develop. 



The prognosis of acute endocarditis is very grave ; although in the 

 horse it may not prove fatal, it produces lesions which are not only 

 incurable, but which become more marked with lapse of time, and 

 often make rapid progress when animals are put to heavy work soon 

 after leaving hospital. 



Treatment is of little value. Bleeding, counter- irritation, and the 

 internal administration of digitalis, salicylate of soda, iodide of potas- 

 sium, alcohol, and diuretics have been recommended. 



When endocarditis appears during the course of another disease, a 

 general infection or a microbic disease of any kind, it forms a menacing 

 complication ; but treatment should still be principally directed against 

 the primary morbid condition, and not against the complication. 



The belief that acute endocarditis can be cut short by any system 



