Tuberculosis in Cattle. 5 



Rats and mice readily contract the disease from feeding in the 

 mangers of tuberculous cattle and swine, and in their turn 

 carry the disease from manger to manger and from barn to barn. 



Rabbits, Guinea pigs and goats when left at large do not readily 

 contract the disease but are very susceptible to the infection 

 when it is convej'ed to them experimentally. 



Horses, asses, dogs, cats and sheep do not readily contract the 

 disease under ordinar}- circumstances, but this cannot be 

 attributed mainly to insusceptibility since one and all take it 

 easily when inoculated. The habitual immunity is therefore 

 largeh' due to the absence of opportunity for infection, and in 

 some degree also to the outdoor life and the well developed state 

 of the muscular system and blood. For the house dog and cat 

 infection has often come from eating scraps from the plate of 

 tuberculous people and in some instances from licking up the 

 expectoration. At Alfort only 40 dogs were found tuberculous 

 in g, 000 post mortem examinations. 



TUBERCULOSIS CONTAGIOUS. 



That this disease is contagious was recognized by many of the 

 medical lights of the i6th to the i8th centuries. Morgagni, 

 Laennec, Cullen, Wickman, Valsalvi and Sarconi, and for ani- 

 mals, Ruhling, Krunitz, Fromage, Huzard and others leave evi- 

 dence corroborating this belief. The civil and ecclesiastical 

 laws joined in forbidding the use of the meat from tuberculous 

 animals, and in prescribing the destruction or disinfection of 

 articles that might have become infected from tuberculous 

 persons. 



This was placed on a solid basis by the many successful experi- 

 mental inoculations of the disease by Villemin in 1865 and by 

 his numerous followers, who conveyed the disease by feeding 

 tuberculous matter, and b}^ causing the animals to inhale tuber- 

 culous liquid in the form of spray. Finally, Robert Koch, of 

 Berlin, completed the demonstration, placing the keystone in the 

 great arch of evidence, by the discovery of the tubercle bacillus, 

 which he invariably found in the diseased tissues and in no 

 others, ?nd which he cultivated in pure culture in glycerine 



