XIV] BACILLUS TUBERCULOSIS 359 



and glands. There is reason to believe that tuberculous 

 matter, when present in meat sold to the public, is more 

 commonly due to contamination of the surface of the meat 

 with material derived from other diseased parts, than to 

 disease of the meat itself. The same matter is found in 

 the milk of cows when the udder has become invaded by 

 tuberculous disease, and seldom or never when the udder 

 is not diseased. Tuberculous matter in milk is exception- 

 ally active in its operation upon animals fed either with the 

 milk or with dairy produce derived from it. No doubt the 

 largest part of the tuberculosis which man obtains through 

 his food is by means of milk containing tuberculous matter. 



" The recognition of tuberculous disease during the life 

 of an animal is not wholly unattended with difficulty. 

 Happily, however, it can, in most cases, be detected with 

 certainty in the udders of milch cows. 



" Provided every part that is the seat of tuberculous 

 matter be avoided and destroyed, and provided care be 

 taken to save from contamination by such matter the actual 

 meat substance of a tuberculous animal, a great deal of 

 meat from animals affected by tuberculosis may be eaten 

 without risk to the consumer. 



" Ordinary processes of cooking applied to meat which 

 has got contaminated on its surface are probably sufficient 

 to destroy the harmful quality. They would not avail to 

 render wholesome any piece of meat that contained tuber- 

 culous matter in its deeper parts. In regard to milk we 

 are aware of the preference by English people for drinking 

 cows' milk raw, a practice attended by danger, on account 

 of possible contamination by pathogenic organisms. The 

 boiling of milk, even for a moment, would probably be 

 sufficient to remove the very dangerous quality of tuber- 

 culous milk." 



