DISEASES OF SWINE 487. 



can not be differentiated from it. Interference with both respira- 

 tory and digestive functions may be seen when the disease is widely 

 generalized, and the systematic alterations will be shown by pro- 

 gressive emaciation and weakness. Localization of the disease in 

 bones or joints may produce lameness and other visible indications, 

 but these are comparatively very rare. 



In the majority of cases no intimation of the presence of the 

 disease will be given until the animal is slaughtered, and the dis- 

 covery of a number of tuberculous hogs in a drove of apparently 

 prime, well-finished animals is often the cause of great surprise 

 and disappointment to their owner, and in such cases the lesions 

 may be sufficient to prove the disease generalized and the tubercle 

 bacilli to be so widely distributed as to render the meat unfit for 

 food purposes. (B. A. I. Cir. 144.) 



The Tuberculin Test. In those cases where the disease is not 

 characterized by prominent symptoms, but where the animals are 

 suspected of having the disease, the tuberculin test is recommended. 

 This makes it possible to slaughter the reacting animals in the early 

 stages of the disease and thus obtain some remuneration for the car- 

 casses and at the same time get rid of the infection. This is especially 

 important in holding over brood sows, as our experiments have indi- 

 cated that the milk of these sows may contain tubercle bacilli and 

 thus infect the young pigs. 



In reviewing the questions of detection and eradication of tuber- 

 culosis in hogs it is noticeable at once that there are but few recorded 

 instances in which any reliable tuberculin tests have been made. 

 This may be due to the fact that the temperature of a hog is subject 

 to rapid changes under conditions which would not cause noticeable 

 variations with cattle. These alterations of temperature in individual 

 hogs are so great within short spaces of time, and from such appar- 

 ently insignificant causes, that it seems at first thought that no 

 change caused by the injection of tuberculin could ever be sufficient 

 to permit one to reach any definite conclusion as to the presence or 

 absence of tuberculosis. 



In the experiments of Schroeder and Mohler, of the Bureau 

 of Animal Industry, recorded in Bulletin 88, it was found desir- 

 able to keep the hogs as quiet as possible during the test, it having 

 been shown that excitement affects the temperatures of hogs very 

 quickly. Each hog was therefore placed in a rectangular crate 

 about twelve hours before the first temperature was taken, and 

 remained in this confinement continuously until the tuberculin 

 test was completed. The crates, while large enough to permit the 

 hogs to get up and down easily, were still close enough to prevent 

 their turning around or moving backward and forward to such 

 an extent as to interfere with the insertion of the thermometers. 

 Crates that are made 4 feet long, 1 foot 2 inches wide, and 2 feet 

 high, inside measurement, have proven entirely satisfactory in re- 

 straining hogs weighing from 50 to 150 pounds. Unless use is made 

 of crates, or of some other satisfactory means of restraint, it ia 



