DISEASES OF HEART; BLOOD VESSELS, AND LYMPHATICS. 261 
whole region of the 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. 
Symptoms.—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 DEGENERATION 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 
