CLASSIFICATION OF DISEASES. 65 



Give the causation. 



This disease was first described l)y Bennet, and then by Vir- 

 chow, in 1845; it occurs in the horse, dog, ox, pig, and cat. 



The real cause and nature of the disease are not very well un- 

 derstood, although it is probably of specific origin. 



What is the morbid anatomy ? 



There is an increase in the number of white corpuscles, aver- 

 aging about one white to fifty, twenty, or fifteen of the red blood- 

 cells, whereas, normally, the proportion is about one to three hun- 

 dred and fifty or five hundred. 



The blood is very pale and watery, and hardly stains the hands. 

 It coagulates very slowly, having three layers — the huffy coat, then 

 the pus-Ul'e layer, and the crassementum — whereas, normally, the 

 blood, after coagulating, is all one color; when three layers are 

 present, it is said to be pathognomonic of this affection. 



If the heart be examined, it will be found filled with clots which 

 are soft and greasy-like. The spleen is enlarged, weighing as much 

 as ten to fourteen pounds, whereas, normally, it weighs from one 

 and one-half to one and three-quarter pounds. Peyer's patches, 

 the lymphatics, or the marrow of the bone may be involved in this 

 disease. If one of these enlarged glands be cut through, the sec- 

 tion is soft and smooth, and the cut surface presents a dirty white 

 color, which, if scraped with a knife, a pus-like fluid is obtained, 

 found to contain mostly leucocytes when looked at under the mi- 

 croscope. 



What are the symptoms? 



Early, the symptoms resemble those of simple anasmia. The 

 symptoms usually show themselves slowly, and the first thing no- 

 ticed is the loss of strength and energ)^; the horse seems to become 

 lazy, while formerly it was high-lifed and vigorous, it now becomes 

 fatigued on the least exertion, puffs, and breaks out in a sweat. 

 There is thirst, capricious appetite, feeble and accelerated pulse, 

 the temperature varies from 101° to 104° F.; constipation early, 

 followed by diarrhoea. 



As the disease progresses, the animal gets weaker and weaker, 

 knuckles over, has signs of vertigo, roaring due to the enlarged 

 glands, in which case the horse stands with the legs separated and 

 head extended in order to get air. 



Death is due to asthenia and is preceded by delirium and coma. 



