DISEASES OF THE HEAET. 231 



creased as to induce increased growth in the muscular structure of 

 the heart, constituting hypertrophy of the walls of the ventricles, 

 more particularly of the left, with corresponding fullness of the left 

 auricle and pulmonary veins, thereby producing fullness of the cap 

 illaries in the lungs, pressure upon the air cells, difficult or asth- 

 matic breathing — greatly increased in attempts to work — until in a 

 few months many of these cases become entirely disabled for work. 

 Sometimes, too, dropsical effusions in the limbs or into the cavities of 

 the body result from the irregular and deficient circulation. De- 

 rangement of the urinary secretion, with passive congestion of the 

 kidneys, may also appear. 



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 sud- 

 den and marked rise in temperature. The pulse rapidly decreases 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. Wlien 

 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. \Vhen 

 the valves of the right side are affected we may find a regurgitant 

 pulsation in the jugular vein. Occasionally it happens that the heart 

 contracts more frequently than the pulse beats — that is, there may be 

 twice as many contractions of the heart in a minute as there are pulse 

 Avaves in the arteries. The pulse is always very fast. In some cases 

 we find marked lameness of the left shoulder, and when the animal 

 is turned short to the left side he may groan with pain, and the heart's 

 action become violently excited, although pressure against the chest 

 n-all will not produce pain unless roughly applied. The animal is 

 not disposed to eat or drink much; the surface of the body and legs 

 is cold — rarely excessively hot — and frequently the body of the ani- 

 mal is in a subdued tremor. In nearly all cases there is partial sup- 

 pression of the urinary secretion. The symptoms may continue 

 with very little modification for three or four days, sometimes seven 

 days, without any marked changes. If large fibrinous clots form 

 in the heart the change will be sudden and quickly prove fatal unless 

 they become loosened and are carried away in the circulation; then 

 apoplexy may result from the plugging of arteries too small to give 



