Dilation of the Heart. 323 



ness. The pulse is slow, weak, or indistinct, compressible, be- 

 coming accelerated, unequal, irregular, and intermittent when the 

 patient is excited. Palpitation is frequent, breathing is difficult 

 or easily embarrassed and there is a tendency to dropsy of the 

 limbs and dependent parts. These symptoms are usually associa- 

 ted with considerable prostration and depression. 



These are often complicated by symptoms of valvular disease 

 or dilatation. 



Atrophy progresses slowly and rarely causes death in the earlier 

 stages. In its advanced .stages when dropsy has supervened little 

 can be done even in its mitigation. In the earliest stages only 

 can good be done by employing measures calculated to remove 

 its causes and thus put a stop to its progress. 



DILATATION OF THE HEART. 



Result of obstruction to circulation. In right ventricle usually. In au- 

 ricle from narrow auriculo-ventricular opening. Pure dilatation from sud- 

 den extreme blood pressure as in inflammations of the lungs. In fat cattle 

 from fatty obstructions around the heart and great vessels. Weakness of 

 cardiac muscles in fatty degeneration, fevers, debility, etc. Symptoms, 

 dyspnoea under slight exertion, unsteady walk, cold, dropsical limbs, venous 

 pulse, pulse small, weak, irregular, intermittent, with palpitations. Treat- 

 ment, in early stages arrest the causes, arsenic, digitalis, fatten for butcher. 



Dilatation of the right cavities of the heart is one of the most 

 common heart diseases of the horse. It is an almost constant 

 condition in advanced broken wind, and is a frequent concomitant 

 of hypertrophy 'and an occasional one of atrophy of the heart. 

 Its usual direct cause is some obstacle to the free escape of blood 

 from the cavity affected. Thus in broken wind the difficulty of 

 the circulation through the lungs causes accumulation in the pul- 

 monary artery and right ventricle of the heart, the walls of which 

 are distended because of the unwonted internal pressure. When 

 the dilatation of this ventricle reaches a certain stage the auri- 

 culo-ventricular opening is equally widened, the valves become 

 insufficient to close it and the right auricle and venae cavse par- 



