218 COMMON DISEASES. 



they are usually more numerous near the blind pouch. These ul- 

 cers are irregular in outline, with yellowish or dark centers, and 

 frequently appear as being raised above the surface. Small ulcers 

 may also be seen in the back part of the mouth and in the throat. 



The spleen is frequently enlarged, and darker in color than 

 natural. Small bright red spots are found on the surface or 

 through the deeper structure of the kidneys. 



Swine plague post mortem. -In swine plague the lung le- 

 sions are most prominent. The skin may show the same purple 

 spots and areas as in hog cholera. The lungs show scattered and 

 sharply defined areas, which are dark red in color, and solid, like 

 liver. The lining membrane of the chest may be diseased ; but 

 it is not uniformly so, and when this occurs, it usually follows dis- 

 ease of the lung tissue. The bowels may show various stages and 

 conditions of congestion, hemorrhage and inflammation, but not 

 the typical "button-ulcers" of hog cholera. Hog cholera is essen- 

 tially an infectious disease of the bowels. 



The cause. — We must not forget that swine plague and hog 

 cholera are both infectious diseases, and that each has its prime 

 origin in a specific germ. Simple conditions of keep and feed 

 have much to do with making the animals more susceptible, but 

 mere matters of food and surroundings cannot serve as first cause 

 of either hog cholera or swine plague. The predisposing factors 

 in the causation of these diseases must be given due consideration, 

 but the most important thing to remember is that both are -due to 

 specific germs, that they never appear without infection, and that 

 they may be carried from one place to another. If the hog is fed 

 exclusively on corn diet, or from a swill barrel that has been used 

 for years and never scalded or allowed to dry in the sun ; if it is 

 kept shut up in dark, damp, and perhaps filthy pens, it will not be 

 able to resist any disease as would one kept under more favorable 

 conditions. 



It is evident to all who have given the subject careful atten- 

 tion that swine hygiene should receive far more attention in the 

 future than it has had in the past, and that here there is a large 

 field for scientific study. Good lungs and good digestion must 

 be regarded as the pig's chief protection against disease. Good 

 digestion aids in the destruction of bacteria in the food, while con- 

 gestion or catarrhal inllannnation of the mucous membrane of 

 stomach may result in a smaller percentage of acid in the gastric 



