TUBERCULOSIS 2!)1 



glands. The bacilli are almost entirely of bovine origin, 

 the hog coming in contact with them in the manure, or in 

 skim milk and whey. Due to the fact that hogs are not 

 kept for long periods of time, there is little opportunity for 

 the disease to make such progress as to permit the animal 

 to eliminate the bacilli: hence there is probably little, if 

 any, direct infection from one hog to another. 



The disease can be detected in the living animal most 

 easily by the intradennal tuberculin test, which avoids the 

 factor that makes the thermal tuberculin test unsatisfactory 

 namely, the rapid and wide variation in temperature of 

 the hog. 



Avian tuberculosis. It is eertain that tuberculosis has 

 made rapid progress in barnyard fowl in this country in 



Fig. 51. Avian Tuberculosis 



A section through the breast of a healthy bird and a section through that of a 



bird that died from tuberculosis. On account of the extreme emaciation the 



disease is frequently called "going light" 



recent years, due undoubtedly to the commerce in breeding 

 birds. In many sections of the country it is becoming of 

 great economic importance, in some instances causing the 

 death of 50 per cent, of the flock in a y ear. 



The disease is characterized by the extreme emaciation 

 of the bird in the last stages, and by paleness of the comb 

 and wattles. Lameness is also an indication, since the 

 joints are often affected. These manifestations of the dis- 



