656 SPORADIC DISEASES. 



larity of the pii]se, and a tendency to cedema of the extremities, 

 with difficulty or inability on the part of the animal to perform 

 ordinary labour. 



I have repeatedly watched the progress of this disease, and 

 have found that when the animal is near death there has been 

 capriciousness of the appetite, extreme muscular debility, a pecu- 

 liar rusty-red appearance of the visible mucous membranes, and 

 a want of correspondence between the pulse and the contraction 

 of the heart. The cardiac sounds have been often loud, amount- 

 ing to palpitation, but the impulse has been feeble, and the pulse 

 weak and irregular, arising from the fact that the feeble cardiac 

 impulse is not transmitted. 



In hypertrophy of the heart, more particularly that of the 

 left ventricle, when the walls are increased in thickness, and 

 the cardiac contractions proportionately strong, the blood is 

 propelled into the arteries with increased force, and the pulse 

 is strong and hard, so long as the circulation is unimpeded 

 by aortic obstruction ; but when the heart is atrophied, or its 

 walls attenuated, and its cavities enlarged, the pulse will be of 

 the opposite character — soft, weak, and irregular. If the liyper- 

 trophied heart's action be intermitting, the strong pulse will be 

 intermitting also ; but in atrophy the pulse will be intermitting 

 and irregular, even providing that the beatings of the heart be 

 regular in their succession. 



The post mortem examinations reveal the heart apparently 

 enlarged, but the enlargement is due to dilatation of its cavities 

 and attenuation of its walls. The muscular structure of the 

 wdiole organ presents a pale or fawn-coloured appearance, is soft to 

 the touch ; and when examined microscopically, the most notice- 

 able change is the absence of the transverse strise of the muscular 

 fibres, with here and there true fatty degeneration. In the dog, 

 atrophy of the muscular fibres is generally due to fatty infil- 

 tration, which, pressing upon the muscular fibres, cause their 

 removal by absorption. But in the horse the change is more 

 commonly found in the sarcous elements themselves, by which 

 they first lose their truly muscular characteristics and their 

 power of contractility, and finally become converted into a fatty 

 material. 



I cannot recommend any treatment calculated to arrest the 

 progress of this change in the horse, but would suggest that 

 the chlorate of potash (which has the po^Yer of arresting some 



