SYMPTOMS 



253 



virus found by us in the outbreaks we have studied." They 

 believe, however, tliat such a disease " would be possessed of 

 a low degree of contagiousness." 



Til c period of incubation varies from 7 to 14 days. Berry 

 states that it varies from one to three weeks and perhaps 

 longer. 



§ 183. Symptoms. The symptoms of hog cholera are 

 by no means constant. The best informed writers on the sub- 

 ject agree that hog cholera can not, with certain exceptions, 

 be positively diagnosed from the symptoms. Animals suffering 

 from various intestinal troubles frequently exhibit symptoms 

 which very closely resemble those of this disease. 



There are two recognizable forms, namely, the acute, and 

 the chronic or mild form. In the acute disease, the animals 

 die very suddenly after a few hours' or at most a few days' 

 sickness. In the other form, the disease runs a longer course. 

 There is usually a rise of temperature of from i to 3° F. 



The sick animals act dumpish and spiritless and lie quietly 

 in a corner or huddle together, usually concealing the head in 

 the litter. They refuse to move when disturbed and are more 

 or less oblivious to their suffering. The appetite varies. In 

 acute cases the animals may eat quite heartily up to within a 

 few hours before death. In more chronic forms they eat fairly 

 well until the end. There may or may not be diarrhea. Fre- 

 quently the bowels are costive. It is quite common in these 

 cases to have an active diarrhea during the last few days. The 

 color of the discharge depends largely on the food. Vomiting 

 rarely occurs. The changes in the respiration and the pulse 

 are difficult to determine. There is rarely any cough. Usually 

 there is considerable reddening of the skin on the nose, ears, 

 abdomen and on the inside of the thighs and public region. 

 Occasionally this reddening is very marked. The redness is 

 diffuse and becomes more intense as death approaches. In 

 some cases there is a discharge from the eyes. In the chronic 

 form the animal becomes emaciated. These symptoms vary 

 to such an extent that it is sometimes necessary to make a 



