CIRCULATORY AND LYMPHATIC SYSTEMS 283 



corrugated appearance. Fatty degeneration and fatty infiltration of the 

 walls of the heart are now and again also met with, the two latter 

 generally in complication with a somewhat similar condition of the 

 liver. But the most of these lesions are only made manifest at the 

 post-mortem examination. The most common form, however, of 

 heart disease in the horse and dog is that termed hypertrophy. 



436. Hypertrophy, or enlargement, of the heart may be con- 

 sidered as follows : 



(1) Hypertrophy without dilatation, when the walls of the 



heart are thickened, but the capacity of the cavities 

 remain unchanged. 



(2) Hypertrophy with dilatation, when the cavities are en- 



larged as well as the walls being thickened, and when 

 the heart is enlarged throughout, with the walls very 

 thin, flabby, and pale, and the cavities dilated. 



437. Atrophy, or attenuation, of the heart is an affection 

 where not only is the organ itself much smaller than normal, but 

 the walls and cavities are also diminished. 



438. When a horse is noticed, while pulling a load up a hill, to 

 stop every few steps almost breathless, to have dilated nostrils and 

 staring eyes, and the heart beating with a thumping sound loud 

 enough to be heard, or fluttering with an irregular sound while the 

 pulse is scarcely perceptible, and there is a waving flow in the jugular 

 vein up the neck, it may be then set down that some heart complica- 

 tion is present. A slight canter will produce similar symptoms with 

 an affected horse. Owing to the thick walls of the sides and front of 

 the chest of all the domestic animals — with the exceptions of the dog 

 and cat — the sounds of the heart are very difficult to define, thus 

 making it almost impossible to distinguish one disease from another 

 by sounding. The best mode of detecting the sounds of the heart of 

 the horse is to lift the near fore-leg, pull it well forward, and apply 

 the ear to the side behind the elbow. Treatment for a diseased heart 

 is of little avail ; but the horse may live a long time, and do a lot of 

 farm work, so long as it is slow and easy. As the legs are inclined 



