DISEASES OF HORSES 371 



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 

 dullness, 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 

 concomitant disease. As a rule, an animal affected with hyper- 

 trophy of the heart will soon be incapacitated for work, and it 

 becomes useless and incurable. 



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

 it should be done. The iodide of potassa, in cases of valvular thick- 

 ening, 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 

 dilatation 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 

 frequent cause. General anemia predisposes to it by producing re- 

 laxation of muscular fiber. Changes in the muscular tissue of the 

 heart walls, fatty degeneration 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. General tonics, rich food, and rest 

 are the treatment. 



FATTY DEGENERATION OF THE HEART. 



Fatty degeneration may involve the whole organ, or may be 

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

 situated at the exterior, and gives it a m6ttled appearance. When 

 generally involved it is flabby, and in extreme cases collapses when 

 emptied or cut. Upon dissection the interior of the ventricles is 

 observed to be covered with buff-colored spots of a singular zigzag 

 form. This appearance may be noticed beneath the pericardium, 

 and pervading the whole thickness of the ventricular walls, and in 

 extreme cases those of the fleshy columns in the interior of the 

 heart. These spots are found to be degenerated muscular fibers and 

 colonies of oil globules. Fatty degeneration is often associated with 

 other morbid conditions of the heart, such as obesity, dilatation, 

 rupture, aneurism, etc. It may be connected with fatty diseases of 



