216 COMMON DISEASES. 



The other factor to be considered in explaining this varia- 

 tion is in the (hffering conditions of food and care under which 

 hogs are kept in different yards and different locaHties. Where 

 the feeding and care has been such as to secure the best physi- 

 cal strength and vitality, the hogs are naturally less susceptible. 

 the disease does not assume the most virulent type, and the per- 

 centage of mortality may not be so high as among hogs kept un- 

 der less favorable conditions. 



FIG. 77. HOG CHOLERA— SWINE PLAGUE. (M. H. R.) 



Subcutaneous haemorrhages of swine plague, resembling those of haem- 

 orrhagic septicaemia in cattle. Note the dark spots. 



Swill-barrel cholera. — The fact must not be lost sight of, in 

 this connection, that frequent outbreaks of swine disease appear 

 and alarm neighborhoods when the trouble is due to local causes. 

 They are usually diseases of the digestive apparatus and due to 

 errors in feeding. All the patients become diseased from the same 

 source and in the same way l)ut the disease does not sprcatl. 

 Several neighbors may make the same mistake at the same time 

 and get similarly bad results. These are the cases which are 

 called hog cholera and which yield to treatment. 



Early symptoms. — When these diseases appear the hair be- 

 comes harsh antl dry, the eyes may be watery, and locomotion 

 becomes weak and irregular , with imperfect control of the hind 

 legs. The skin around the flanks and fore legs may become pur- 

 ple ; the skin of the cars frequently becomes much inflamed, and 

 if the hog lives for several days, may assume a scabby appearance. 

 Sometimes the tips of the ears slough off. The sick hogs sepa- 

 rate themselves from the rest of the herd, are disposed to hide in 

 sheltered places, and seem but little inclined to move about. There 



