498 Veterinary Medicine. 



be sterilized in the preliminary heating process, yet the subsequent 

 mixing with milk is liable to convey the infection. 



The ideal course with milk, if the herds cannot be purified 

 from tuberculosis, would be to compulsorily remove from the 

 herd every cow that shows objective symptoms of tuberculosis, 

 or any internal disease of the udder, and to subject all the milk 

 of the remainder to Pasteurization at a temperature of 155" F. 

 for twenty to thirty minutes. This, however, requires skilled 

 and faithful management to avoid renewed contamination from 

 the lips of the vessel which may have escaped the heat, or from 

 hands, vessels and objects that were in contact with the milk be- 

 fore. The boiling temperature for fifteen minutes would be a 

 safer resort, as requiring le.ss careful handling, yet even this may 

 be contaminated after vvard under poor management. It has the 

 further drawback of the boiled milk taste and the coagulation of 

 the albumen. But the outlay for such careful sterilization will 

 soon amount to more than will the tuberculin test. 



Meat. For various reasons meat must be held less virulent 

 than milk, but mainly because it is less frequently the seat of 

 tubercle than the udder, and because it is usually cooked before 

 being eaten. The muscular tissue of the ox appears to be un- 

 favorable to colonization by the bacillus, and although the inter- 

 muscular lymph glands do not partake of this inherent resistance, 

 yet as the glands are very frequently affected from the tissues 

 which they drain, they necessarily partake in some degree of the 

 comparative immunity of the muscles. This immunity is, how- 

 ever, far from complete, as the frequent implication of the inter- 

 muscular glands (prescapular, axillary, prefemoral, etc.), suffi- 

 ciently show. Again in estimating the virulence of meat we 

 must never forget that in the great majority of cases, in ordinary 

 infected herds, the tubercle is still essentially local ; no general- 

 ization has taken place. The muscle is vascular throughout, and 

 in cases of generalized tuberculosis is infecting, yet a single 

 transient e.scape of tubercle bacilli into the blood does not ensure 

 permanent infection of that fluid, which can usually purify itself 

 in six days or less (Nocard). On the contrary, when the escape 

 of bacilli into the blood is constant, so becomes of necessity the 

 virulence of the blood and a rapid generalization ensues. Such 

 continuous escape may occur in actively advancing tuberculosis 



