224 



tbe heart restored to perfect vigor and normal action. Organic changes 

 involving the heart or valves, however, usually grow worse and event- 

 ually prove fatal. Therefore it is necessary that we arrive at an appre- 

 ciation of the true nature and causes, so that we may be able to form a 

 true estimate of the possibilities for recovery or encouragement for 

 medical treatment. 



Disease of the heart may occur at any age, but it is witnessed most 

 frequently in young horses, which, when being trained for fast work, 

 are often subjected to excessive hardship and fatigue. Nervous or timid 

 animals also suffer from such diseases more frequently than those of a 

 sluggish disposition. Any cause which induces a violent or sudden 

 change in the circulation may result in injury to tbe heart. Symptoms 

 which may frequently denote disease of the heart are difiQcult breath- 

 ing or short-windedness, dropsies of the limbs, habitual coldness of the 

 extremities, giddiness or fainting attacks, inability to stand work al- 

 though tbe general appearance would indicate strength and ability, etc. 



INFLAMMATORY DISEASES OF THE HEART. 



This, will embrace myocarditis, endocarditis, and pericarditis. 



MVOCARDITIS — IXFLA.MMATION OF THE MUSCULAR STRUCTURE OF THE HEART. 



This is of rare occurrence without implication of the endocardium or 

 pericardium. That inflammation of the muscular wallsof tbe heart may 

 frequently exist to some slight degree, induced by excessive action, can 

 not be doubted. Post-mortem examinations occasionally reveal abscess 

 and degeneration within the walls of this organ, which were not sus- 

 pected during life. Myocarditis primarily involves the interstitial mus- 

 cular tissue and the blood vessels, and presents itself in a sub-acute or 

 chronic type, which often leads to induration or bypertropby, occasion- 

 ally to tbe formation of pus and abscess. It may also lead to a dilata- 

 tion of the heart and rupture. 



Causes. — Over-exertion or heart strain, influenza, rheumatism, pyae- 

 mia, extension of endocarditis or pericarditis, etc. Myocarditis usually 

 involves the endocardial membrane very early in the attack, and devel- 

 ops all the symptoms of endocarditis. Hence we will consider, as most 

 distinctive of inflammation of the heart, endocarditis. 



ENDOCARDITIS — INFLAMMATION OF THE LINING MEMBRANE OF THE HEART, U8UALLT 



INVOLVING THE MUSCULAR STRUCTURE. 



It is frequently found in general rheumatism, involving the serous 

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

 Endocarditis is a much more frequent disease among horses than we 

 are generally aware, and often gives rise to symptoms which, at first, 

 are obscure and unnoticed. I have witnessed two enzootics of influenza 

 in which 20 per cent, of the animals attacked developed symptoms of 



