122 CLINICAL VETKRINARY MEDICINE AND SURGERY. 



At one time new growths on the endocardium were always regarded 

 as fibrinous. They are really formed of embryonic cells and leucocytes, 

 held together by a small quantity of structureless exudate. Beneath 

 and around them the endocardium appears infiltrated with similar 

 cells, the number of which diminishes in proportion to the distance 

 from the vegetation. The persistence of the endothelium over the 

 surface of certain deposits indicates that the process develops partly 

 in the deep layer of the serous membrane ; as a rule, however, the 

 superficial layer is first loosened, and afterwards destroyed. There is 

 little or no discharge from the point ; acute endocarditis is pro- 

 liferative, not exudative. When the chordae tendineae are invaded, or 

 that portion of the endocardium into which they are inserted is 

 affected, they may snap or become detached from their insertion — 

 an accident sometimes followed by mitral insufficiency. When the 

 inflammation extends from the deep layer of the endocardium to the 

 heart muscle itself, it always remains limited to a very thin stratum. 

 It is possible, however, as I before stated, for both the muscle and 

 serous membrane to be simultaneously affected, and during infectious 

 diseases this occurs more frequently than might be imagined from the 

 few cases published. 



Vegetative, or verrucous, endocarditis is characterised by the 

 abundance and size of the granulations developed on the endo- 

 cardium. The proliferation of cells and exudation of leucocytes 

 rapidly produce luxuriant vegetations, varying greatly in size and 

 shape. In this case, also, the valves show the maximum of develop- 

 ment. Sometimes the growths resemble branching stalactites, covered 

 with conical prolongations, the long axes of which correspond in 

 direction with that of the blood-stream ; those fixed to the mitral 

 valve pointing towards the base of the ventricle ; those on the semi- 

 lunar valves towards the aorta. These large new growths are com- 

 posed of cells, etc., similar in nature to those forming the limited 

 vegetations of simple endocarditis. They usually show a superficial 

 fibrinous, and a deep organised layer, the latter continuous with the 

 endocardium ; some, however, are organised nearly throughout ; others 

 are almost exclusively fibrinous. Such large new growths are rare in 

 the horse, but are commoner in the dog. Not only do they diminish 

 the size of the orifices around which they are situated, and thus 

 produce functional disturbance, but they threaten embolism of in- 

 ternal organs. Incessantly agitated by the blood-stream, the fibrinous 

 •coagula covering these vegetations may become detached and carried 

 to a distance, produce infarcts in the viscera and in various tissues, thus 

 .giving rise to symptoms of very varying gravity. Under the influence 



