232 



of tliese materials may "be carried from tlie 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 usu- 

 ally consist of thickening or induration of the inflamed structures. 

 But while the eifects 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 usuall}^ remain, obstructing the free passage of the 

 blood through the openings of the heart, thereby inducing secondary 

 changes which take place slowly at first, but ultimately seriously 

 impair the animal's usefulness. AVhat was but a slight obstruction 

 to the circulation during the first few weeks after the subsidence of 

 the cardiac inflammatory attack becomes in process of time so much 

 increased 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 i^ulmonary veins, thereby producing fullness of the capillaries 

 in the lungs, pressure uj)on the air cells, difficult or asthmatic breath- 

 ing — greatly increased in attemjits to work — until in a few months 

 many of these cases become entirely disabled for work. Sometimes, 

 too, droi)sieal effusions in the limbs or into the cavities of the body 

 result from the irregular and deficient circulation. Derangement 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 are left 

 with some permanent thickening of the valves, which constitutes the 

 beginning of A^alvular disease. 



Symptoms. — As already stated, myocarditis is seldom recognized 

 until pericarditis or endocarditis supervenes. Staggering gait with 

 j)ainful movement of the fore-limbs, a constant irregularity of the 

 heart's action, but equality of strength regardless of the rapidity of 

 the heart-beats, constitutute perhaps the most prominent sj^mptoms 

 which characterize myocarditis. When the disease is associated with 

 rheumatism, influenza, or other zymotic diseases, these symx^tomsmay 

 not be sufficiently well defined to attract the attention they deserve, 

 and medical treatment prescribed for the mitigation of such disease 

 often serves to aggravate the cardiac affection. In chronic myocar- 

 ditis we generally find a persistent i^alpitation with irregularity of 

 beat, which, upon exercise, becomes greatly intensified. Change in 



