230 BUREAU OF ANIMAL INDUSTRY. 



EXDOCARDiriS, OR INFLAMMATION OF THE LINIXG MEMBRANE OF THE HEART, USUALLY 

 INVOLVING THE MUSCULAR STRUCTURE. 



Endocarditis frequenth' occurs as a complication of rheumatism, 

 some of the specific or zymotic fevers, septic poisoning, etc. This is 

 a more frequent disease among- horses than is generally known, and 

 often gives rise to symptoms which, at first, are obscure and unnoticed. 



In influenza we mav find the heart becoming involved in the disease, 

 in consequence of the morbid material conve3^ed through the heart in 

 the blood stream. In view of the fact that many affections, in even 

 remote portions of the body, may be traced directly to a primarj'' 

 endocardial disease, we shall feel justified in inviting special attention 

 to this disease. 



Endocarditis maj' be acute, subacute, or chronic. In acute iutlam- 

 mation we find a thickening and a roughened appearance of the endo- 

 cardium throughout the cavities of the heart. This condition may be 

 followed b}"" a coagulation of fibrin upon the inliamed surface, which 

 adheres to it, and by attrition soon becomes worked up into shreddy- 

 like granular elevations; this may lead to a formation of fibrinous 

 clots in the heart and sudden death early in the disease, the second or 

 third da}'. 



Subacute endocarditis, which is the most common form, may not 

 become appreciable for several days after its commencement. It is 

 characterized by being confined to one or more anatomical divisions 

 of the heart, and all the successive morbid changes follow each other 

 in a comparatively slow process. Often we would not be led to suspect 

 heart affection were it not for the distress in breathing, which it gen- 

 eralh' occasions when the animal is exercised, especially if the valves 

 are much involved. When coagula or vegetations form upon the 

 inflamed membrane, either in minute shreds or patches, or when forma- 

 tion of fibrinous clots occurs in the cavity affected, some of these mate- 

 rials ma\' be carried from the cavit}' of the heart by the blood current 

 into remote organs, constituting emboli that are lia])le to suddenly" plug 

 vessels and thereb}^ interrupt important functions. In the great major- 

 ity of either acute or subacute grades of endocarditis, whatever the 

 exciting cause, the most alarming s\'mptoms disappear in a week or ten 

 days, often leaving, however, such changes in the interior lining or 

 va'vular structures as to cause impairment in the circulation for a umch 

 longer period of time. These changes usually consist of thickening or 

 induration of the inflamed structures. But while the effects of the 

 inflammation in the membrane lining the walls of the ventricles may 

 subside to such a degree as to cause little or no inconvenience, or even 

 wholly disappear, yet after the valvular structures have been involved, 

 causing them to be thicker, less flexible than normal, they usually 

 remain, obstructing the free passage of the blood through the openings 

 of the heart, thereby inducing secondary changes which take place 



