DISEASES OF HEART, BLOOD VESSELS, AND LYMPHATICS.. 261 



whole region of thfe heart, and the normal sounds of the heart are 

 greatly increased in intensity. Percussion reveals an enlarged area 

 of dullness, while the impulse is usually much stronger than normal. 



Dropsy of the pericardium will give the same wide space of dull- 

 ness, but the impulse and sound are lessened. An animal with a 

 moderate degree of enlargement may possibly live a number of years 

 and be capable of ordinary work; it depends largely upon con- 

 comitant disease. As a rule, an animal affected with hypertrophy 

 of the heart will soon be incapacitated for work, and becomes useless 

 and incurable. 



Treatment. — ^If the cause can be discovered and is removable, it 

 should be done. The iodid of potassium, in cases of valvular thicken- 

 ing, may be of some benefit if continued for a sufficient length of 

 time; it may be given in 2-dram doses, twice a day, for a month or 

 more. The tincture of digitalis may be given, in cases where the 

 pulse is weak, in doses of 2 teaspoonfuls three times daily. This 

 remedy should not be continued if the pulse becomes irregular. 

 General tonics, freedom from excitement or fatigue, avoidance of 

 bulky food, good ventilation, etc., are indicated. 



DILATATION OF THE HEART. 



This is an enlargement, or stretching, of the cavities of the heart, 

 and may be confined to one or extend to all. Two forms of dilata- 

 tion may be mentioned— simple dilatation, where there is normal 

 thickness of the walls, and passive, or attenuated, dilatation, where 

 the walls are simply distended or stretched out without any addition 

 of substance. 



Causes. — Any cause producing constant and excessive exertion of 

 the heart may lead to dilatation. Valvular disease is the most fre- 

 quent cause. General anemia predisposes to it by producing relaxa- 

 tion of muscular fiber. Changes in the muscular tissue of the heart 

 walls, serous infiltration from pericarditis, myocarditis, fatty degen- 

 eration and infiltration, and atrophy of the muscular fibers may all 

 lead to dilatation. 



Symftoms. — The movements of the heart are feeble and pro- 

 longed, a disposition to staggering or vertigo, dropsy of the limbs, 

 very pale or very dark-colored membranes, and difficult breathing 

 on the slightest excitement. 



Treatment. — General tonics, rich feed, and rest. 



FATTY DEGENEHATION OF THE HEART. 



Fatty degeneration may involve the whole organ, or may be lim- 

 ited to its walls, or even to circumscribed patches. The latter is 

 situated at the exterior, and gives it a mottled appearance. When 



