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creases its breadth toward the right side. Ilypertrophy with dilatation 

 may affect the chambers of the heart conjointly or separately. This 

 form is by far the most frequent variety of cardiac enlargement. When 

 the entire heart is affected it assumes a globular appearance, the aj^ex 

 being almost obliterated, and situated transversely in the chest. The 

 bulk may become three or four times greater than the average size of 

 heart. 



Symptoms. — In hypertrophy of the heart, in addition to the usual 

 symptoms manifested in organic diseases of the heart, there is a power- 

 ful and heaving impulse at each beat, which may be felt on the left 

 side, often also on the right. These jjulsations are regular, and when 

 full and strong at the jaw there is a tendency to active congestion of 

 the capillary vessels, which frequently gives rise to local inflammation, 

 active haemorrhage, etc. If the pulse is small and feeble at the jaw we 

 may conclude that there is some obstacle to the escape of the blood from 

 the left ventricle into the aorta, which has given rise to the hypertro- 

 phy. In case of hypertrophy with dilatation, the impulse is not only 

 powerful and heaving, but it is diffused over the whole region of the 

 heart, and the normal sounds of the heart are greatly increased in in- 

 tensity. Percussion reveals an enlarged area of dullness, while the im- 

 pulse 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 j)ossibly live a number of years and be 

 capable of ordinary work; it depends largely upon concomitant disease. 

 As a rule, an animal affected with hypertrophy of the heart will soon 

 be incapacitated for work, and become useless and incurable. 



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

 be done. The iodide of i^otassa, in cases of valvular thickening, 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. Hydrocyanic 

 acid, in 30 drop doses twice a day, may relieve abnormal muscular ir- 

 ritability. General tonics, freedom from excitement or fatigue, avoid- 

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



DILATATION OF THE HEART. 



This is an enlargement of the cavities of the heart, and may be con- 

 fined to one or extend to all. Two forms of dilatation may be men- 

 tioned — 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 anaemia predisposes to it by producing relaxation of 

 muscular fiber. Changes in the muscular tissue of the heart-walls, 

 serous infiltration from pericarditis, myocarditis, fatty degeneration 



