No. 4.] CATTLE COMMISSIONERS. 487 



dangerous to cattle, nor can it be looked upon as a factor in the 

 introduction of tuberculosis into a healthy herd of cattle. Even 

 if the tubercle bacilli of cattle and of man are very closely related 

 and have the same ancestry, as we all must admit, if we regard 

 the two as mere varieties, which may eventually under very favor- 

 able conditions pass one into the other, the condition in which the 

 bacillus leaves the lungs in sputum is evidently such as to inter- 

 fere, under ordinary circumstances, with any development in the 

 bovine body. It would fall a speedy prey to destruction. 



It is interesting to notice that this work of Dr. Smith's 

 confirms the conclusions arrived at by Dr. Frothingham a 

 year ago. In last year's report, page 57, Dr. Frothingham 



says : — 



From these facts we are certainly justified in concluding that 

 calves are apparently not particularly susceptible to the human 

 tubercle bacillus ; but whether this non-susceptibility is due to a 

 bacillus of diminished virulence for the bovine, or to the age of the 

 animals experimented upon, or to some other cause, further exper- 

 iment must demonstrate. 



While it may be conceded that bovines are not suscep- 

 tible to human tubercle bacilli from sputum, yet it by no 

 means follows that human beings are therefore not suscep- 

 tible to that of the bovine. At the same time, the great 

 danger of the use of the milk and flesh of cattle suffering 

 from tuberculosis has undoubtedly been greatly exaggerated, 

 for the reason that human tuberculosis has been steadily 

 decreasing during the last thirty-five or forty years, while 

 the bovine tuberculosis has undoubtedly increased during 

 the same period. 



It cannot be denied that cows with tuberculous udders or 

 that are extensively diseased, even though no lesion can be 

 detected in the udder, give tubercle bacilli in the milk ; and, 

 until it is clearly demonstrated that these bacilli are harm- 

 less to the human race, such animals must be looked upon 

 as dangerous to the public health. 



From the flesh of tuberculous animals there is much less 

 danger than from the milk, as in this community meat is, as 

 a rule, sufiiciently well cooked to destroy the vitality of 

 these germs ; while, on the other hand, it is customary to 

 use milk in an uncooked condition. In fact, the danger 



