DISEASES OF HORSES 365 



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 sus- 

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

 it generally 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 formation of fibrinous clots occurs in the cavity affected, some 

 of these materials may be carried from the cavity of the heart by the 

 blood current into remote organs, constituting emboli that are liable 

 to suddenly plug vessels and thereby interrupt important functions. 

 In the great majority of either acute or subacute grades of endocar- 

 ditis, whatever the exciting cause, the most alarming symptoms dis- 

 appear in a week or ten days, often leaving, however, such changes 

 in the interior lining or valvular structures as to cause impairment 

 in the circulation for a much longer period of time. These changes 

 usually consist of thickening 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 in- 

 convenience, or even wholly disappear, yet after the valvular struc- 

 tures 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 tlie heart, thereby inducing secondary 

 changes, which take place slowly at first, but ultimately seriously im- 

 pair the animal's usefulness. 



Endocardial inflammation is seldom fatal in its early stages, but 

 in many cases the recovery is incomplete, for a large proportion is 

 left with some permanent thickening of the valves, which constitutes 

 the beginning of valvular disease. 



Symptoms. Endocarditis may be ushered in by a chill, with 

 sudden and marked rise in temperature. The pulse rapidly de- 

 creases in strength or may become irregular, while the heart beats 

 more or less tumultuously. In the early stages soft-blowing sounds 

 may be heard by placing the ear over the heart on the left side, which 

 correspond in number and rhythm to the heart's action. Excessive 

 pain, though not so great as in acute pleuritis, is manifested when the 

 animal is compelled to trot; very often difficulty in breathing, or 

 shortness of breath, on the slightest exertion develops early in the 

 attack. When the valves are involved in the inflammatory process 

 the visible mucous membranes become either very pale or very dark 

 colored, and fainting may occur when the head is suddenly elevated. 

 When the valves of the right side are affected we may find a regur- 

 gitant pulsation in the jugular vein. 



In fatal cases of endocarditis death often occurs about the 

 fourth day, from the formation of heart clot or too great embarrass^ 

 ment of the circulation. Endocarditis may be suspected in all cases 

 where plain symptoms of cardiac affection are manifested in ani- 

 mals affected with influenza, rheumatism, or any disease in which 

 the blood may convey septic matter. 



