No. 4.] CATTLE COMMISSIONERS' REPORT. 519 



mission of the disease to man by the ingestion of animal food that 

 the present commission is concerned. 



The results of their entire inquiry into this matter are 

 summed up by the Royal Commission as follows : — 



We have obtained ample evidence that food derived from tubercu- 

 lous animals can produce tuberculosis in healthy animals. The pro- 

 portion of animals contracting tuberculosis after experimental use of 

 such food is different in one and another class of animals; both car- 

 nivora and herbivora are susceptible, and the proportion is high in 

 pigs. In the absence of direct experiments on human subjects, we 

 infer that man also can acquire tuberculosis by feeding upon materi- 

 als derived from tuberculous food animals. 



The actual amount of tuberculous disease among certain classes of 

 food animals is so large as to afford to man frequent occasions for 

 contracting tuberculous disease through his food. As to the propor- 

 tion of tuberculosis acquired by man through his food or through 

 other means we can form no definite opinion, but we think it proba- 

 ble that an appreciable part of the tuberculosis that affects man is 

 obtained through his food. 



The circumstances and conditions with regard to tuberculosis in 

 the food animal which lead to the production of tuberculosis in man 

 are, ultimately, the presence of active tuberculous matter in the food 

 taken from the animal and consumed by the man in a raw or insuffi- 

 ciently cooked state. 



Tuberculous disease is observed most frequently in cattle and in 

 swine. It is found far more frequently in cattle (full grown) than 

 in calves, and with much greater frequency in cows kept in town cow 

 houses than in cattle bred for the express purpose of slaughter. 

 Tuberculous matter is but seldom found in the meat substance of the 

 carcass ; it is principally found in the organs, membranes and glands. 

 There is reason to believe that tuberculous matter, when present in 

 meat sold to the public, is more commonly due to the 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 tubercu- 

 lous disease, and seldom or never when the udder is not diseased. 

 Tuberculous matter in milk is exceptionally 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. 



