Diseases of the Heart. 203 



when matiire. NotTiing can be done to remedj unless the 

 disease is due to some remediable affection of the lungs. 



ENLAEGEMENT (HYPEBTKOPHY) OF THE HEABT. 



This is a simple increase of the muscular substance and 

 may be confined to one side of the heart or to one ventri- 

 cle. It is usually caused by some obstruction to the cir- 

 culation through the arteries, or in horses or dogs by ha- 

 bitual violent work. 



Symptoms. The heart's beats are more forcible and 

 prolonged and the interval of silence shortened ; the pulse 

 is fuU and roUiag ; the first sound is low, muffled and pro- 

 longed, the second sound imnaturaUy loud, and sometimes 

 repeated if one ventricle only is affected ; the heart sounds 

 may be heard over an unusually large area, the lungs be- 

 ing soimd, and the dtilhiess on percussion is equally ex- 

 tended. The pulse is usually regular and if excited to ir- 

 regularity or intermission soon returns to its normal stand- 

 ard if the patient is left at rest. 



Pure hypertrophy rarely implies imminent danger and 

 many hard-worked horses survive to an old age with 

 greatly enlarged hearts. But if associated with dilatation, 

 impaired strength, livid mucous membranes, blowing mur- 

 murs with the first heart sound, and paroxysms of diffi- 

 cult breathing it may prove fatal at any time. 



Treatment. If possible remove the obstacle to the cir- 

 culation. Then adopt a restricted, gently laxative diet, 

 perfect rest in fatteniug animals or only light work in 

 horses, and the daily use of digitalis or aconite, unless 

 there is extreme dilatation. Arsenic is also given with 

 benefit, but in advanced cases, or those due to irremedi- 

 able obstruction, no treatment is of any avail. 



WASTING (ATBOPHY) OP THE HEAET. 



This is much less frequent than hypertrophy. It may 

 be due to compression of the heart and its nutrient vessels 

 by effusion into the pericardium, or the formation of false 



