198 



TUBERCULOSIS IN SWINE 



in accordance with the nature of the lesions rather than their 

 distribution in the body. 



The fact is worthy of consideration, that very often cattle 

 killed after reacting to tuberculin do not show extensive dis- 



FiG. 43. A photoo;rapli of a section of a tiibeyculoHS uher, from a 

 core's intestine, shozuing infltration tindef tlie marginal mucosa. 



tribution of lesions. Frequently animals are killed soon after 

 infection has taken place, in which case the lesions are re- 

 stricted to a single lymphatic gland or other organs. In other 

 cases old lesions of considerable proportion are found as shown 

 in Fig. 36, where the heart muscle is entirely encased in a 

 thick calcareous tuberculous deposit. In this case, the animal 

 was in good fle.sh and killed for beef without a suspicion that 

 it was in any way diseased. 



TUBERCULOSIS IN vSWINE 



?^ 



144. Channels of infection. It is stated that among 

 swine young animals belonging to the precocious breeds seem 

 to be more liable to tuberculosis than others. In nine eases 

 out of ten the animals are infected by ingestion. The pig 

 easily becomes tuberculous when fed on material rich in tuber- 

 cle bacteria. If pigs are fed on the refuse from dairies and 

 cheese manufactories in districts where there is much tubercu- 



