282 CIllCULATOHY APPARATUS. 



formed substance. Tliis must uot be taken to mean that suppu- 

 ration never complicates the morbid anatomy of endocarditis. 

 Only, when pus is formed, it is ahvays confined to the loose 

 connective tissue between the lamella? of the valves, and to the 

 subendocardial connective tissue ; moreover it never collects in 

 any quantity, but always takes the form of minute abscesses, no 

 bigger than a pin's head, which cause pustular elevations of the 

 endocardium. 



The third factor which plays a more or less conspicuous ])'Avi 

 in every case of acute endocarditis, is the ])recipitation of fibrin 

 upon the roughened surface of the aft'ected valve. I lay stress 

 on the fact that fibrin alone is usually deposited ; the thrombus 

 rarely contains any red corpuscles. I cannot help thinking that 

 owing to the naked-eye resemblance of the fibrinous deposit to 

 the proper outgrowth from the tissue, their real distinctness is 

 often overlooked. The precipitated fibrin (fig. 87, d) fills up 

 all the little inequalities of the surface, and increases the total 

 bulk of the efflorescence to such a disproportionate extent, that 

 it strikes the observer much more forcibly than the morbid 

 change in the valve itself. To conclude ; the coagulation of the 

 fibrin is not, any more than in an aneurism, to be regarded as a 

 salutary phenomenon, as a first step towards recovery. The 

 fibrin readily becomes disintegrated. It does not therefore 

 operate as a check either to the progress of the ulceration, or to 

 the perforation of the valve, while it enhances the risk of meta- 

 static inflammations consequent on embolism of its detached 

 fragments* 



B. Valvular Aneurism, 



§ 251. The way in which the so-called valvular aneurism 

 originates, is worthy of particular notice. Under this name — 

 taken broadly — we understand any circumscribed bulging in the 

 continuity of a valve. Conditions of this sort are not as a rule 

 in any way Connected with endocarditis. They are Saccular or 

 pouch-like inflexions of a valve, in wdiosd formation both of its 

 lamellae (without any previous change in their structure) take 

 part. The pouch invariably opens on that side of the valve 

 which is exposed to most pressure when the valve is closed, 

 while the sac itself is on the opposite side. In the aortic valves, 

 we enter the aneurismal sacculus from the sinus of Valsalva ; in 



