Pathogenesis, Anatomical Changes. 1081 



flammatory condition in the tissue of the valves and in the 

 wall of the heart. The surface of the valves becomes rough 

 and masses of thrombi are deposited. These interfere mechan- 

 ically with the circulation and at the same time the circulatory 

 disturbances are much increased by the simultaneous myocar- 

 ditis. 



Anatomical Changes. In most cases the valves of the left 

 half heart are affected, less often those of the right half as well, 

 or even exclusively (Endocarditis valvularis) ; the pulmonary 

 valves are involved in exceptional cases only. In this respect 

 cattle make an exception in so far as in them disease of the 

 tricuspid_ valves is more frequent. An inflammation of the 

 endocardial lining of the muscular wall (Endocarditis 

 parietalis) is rare. 



Endocarditis occurs in two forms, one being designated 

 as verrucous (Endocarditis valvularis verrucosa), the other as 

 ulcerous (E.. valv. ulcerosa) ; either one of them may pass into 

 the other. In the verrucous variety nodules are found on those 

 surfaces of the valves which face the blood stream, or at their 

 margins; these are as large as poppy seeds or larger, they 

 may later become confluent, forming larger nodes, and on the 

 surfaces of the valves coagulated blood is deposited. It may 

 happen that the inflammation does not progress further, the 

 verrucous elevations gradually becoming smaller and leaving 

 only a thickening of the valves. But in other cases ulcers 

 with red, uneven borders develop, their bases covered with 

 a grayish-red or yellowish deposit, or the inflammatory process 

 is ulcerous from the beginning. Fibrin is deposited upon the 

 ulcerating surface of the valves in thick, uneven masses which 

 make the opening smaller. 



In consequence of the ulcerous destruction the valve be- 

 comes thinner, in some cases it is bulged out by the blood 

 pressure (Aneurysma valvulare acutum) and is eventually 

 ruptured (A. valv. acut. ruptum). If the destructive process 

 is rapid, irregular cleft-like openings form with swelled, gnawed 

 borders (Valvula fenestrata) without aneurysmal changes. 

 When the inflammation is continued to the endocardial lining 

 of the heart, a purulent inflammation may arise in the heart 

 muscle, giving rise to bulging and to rupture of the thinned 

 muscular wall (Aneurysma cordis acutum). _ Occasionally the 

 valve is even torn from the chordae tendineae or from its 

 attachment. 



Loose blood clots or loosened portions of the valvular tissue 

 lead to embolism in various organs, which may be followed by 

 purulent inflammation. 



Symptoms. The clinical picture of acute endocarditis is 

 characterized by its great variability. The varying nature of 

 the inflammatory process and of the infectious virus, the 



