TUBERCULOSIS. 249 



gen rays kill it in an hour. The baceillus can withstand the action 

 of the gastric juice and infect the intestinal tract. In one experi- 

 ment the gastric juice of a dog failed to destroy the vitality of the 

 baceillus after it had been in the stomach for six hours. 



Tuberculosis, while comparatively common in man and certain 

 domestic animals, is rather rare in dogs. They seem to possess 

 great powers of resistanca, and are able to throw ofE the attacks 

 of thiS parasite and prevent its invasion into the system. 



Careful selection in breeding and rerpeated in breeding, thus pro- 

 ducing a very highly nervous animal, close confinement in kennels 

 or in houses where they have little or no exercise, all have a ten- 

 dency to precuspise dogs to tuberculosis. There is no doubt, how- 

 ever, that the dog, when compared with the other domestic ani- 

 mals, is to be considered remarkably free from the attacks of the 

 tubercle baceillus. 



Etiology and Pathological Anatomy. A number of observ- 

 ers agree in the fact that, as a rule, an animal affected with tuber- 

 culosis has been in the -vixnnity of -some person who was in an ad- 

 vanced stage of consumption. In one case, observed by the author, 

 the affected dog had been an inseparable companion of a woman 

 who died of phthisis. In another, the dog had frequently licked 

 the expectorations of a man in the last stages of consumption. In 

 such cases the bacilli may be introduced in the form of fine dust 

 and be respired into the lungs, or they may be taken up by the in- 

 testines, finding their way into the bowels mixed with food. In 

 one case there were tuberculous ulcers in the parotid region, and 

 also tubercular deposits in the lymphatic glands of the neck. It is 

 demonstrated that it is possible to absorb the poison through the 

 skin. The disease appears in the dog in the form of an acute or 

 local tuberculosis. The disease may be found in the lungs, the 

 mesenteric glands, the intestines, liver, kidneys, and peritoneum, 

 and in rare instances affecting the entire body. This has been 

 shown by post-mortems made by a number of observers, and espec- 

 ially by Jensen, who made post-mortems of twenty-eight tuberculous 

 dogs, and in nine cases found the lungs involved. In the same cases 

 he found accumulations of miliary tubercles, scattered and of a 

 cheesy character, varying in size between that of a millet-seed and 

 a bean. In two eases he found collections as big as an egg which 

 had undergone slight degeneration in their centres. In some cases 



