TUBERCULOSIS 269 



next, and then the disease spreads to the intestines, the 

 liver, the spleen, the lungs, the chest cavity, and may in 

 the final stages be found in most of the inner parts of the 

 body. 



PREVALENCE OF THE DISEASE. 



This disease is most prevalent among swine in those 

 sections of the country where cattle are most affected, 

 which usually is in the dairy sections and sections where 

 beef cattle are being fed for market. More hogs are being 

 condemned at the large packing centers for tuberculosis 

 than for all other diseases combined, including hog 

 cholera. Furthermore, while comparatively a few years 

 ago few animals were condemned, at the present time it 

 is thought that about 3 per cent are affected, and the 

 disease is gaining headway very rapidly. That is, a larger 

 percentage of hogs is being condemned every year. 



All hogs affected with tuberculosis are not necessarily 

 condemned. If the disease is present only in the first 

 stages J so that just a few organs of the body are affected, 

 these parts only are condemned ; while if the disease has 

 become general so that it is found in various parts of the 

 carcass, the entire hog is condemned. These condemned 

 carcasses are almost a complete loss. They are used for 

 the manufacture of cheap grease and fertilizer. The lard 

 is rendered from such a carcass in an enclosed receptacle 

 like a steam boiler called a tank, by means of live steam 

 under pressure. This boils out the lard which is then 

 pressed from the solid matter. The heat in such a process 

 is sufficiently great to destroy all disease germs. Thus 

 even if the lard, or the rest of the contents of the tank, 

 were used for other purposes than those mentioned it 

 would not be particularly dangerous. 



