482 PATHOGENIC BACTERIA IN MILK 



were in good physical condition and in which the diagnosis of tuber- 

 culosis could be made only by the tuberculin test. He also calls 

 attention to the fact that tubercle bacilli may not be voided contin- 

 ually by such animals, and that they may occur in the milk from 

 certain dairies and sources only on a few days during several weeks. 

 Eber has made similar observations in regard to the intermittent 

 distribution of tubercular milk by dairies in Leipzig. Schroeder seems 

 to believe that tubercle bacilli may be excreted with the feces of 

 tubercular cows and otherwise, even in the absence of open tubercular 

 lesions, but this view is certainly not shared by many. At the Eighth 

 International Congress in Washington, Bang stated that when the 

 tubercular lesions in a cow are closed no tubercle bacilli are present 

 in either the milk or the feces. When some of the lesions are open 

 and the bacilli enter into the lymph or blood circulation the bacilli 

 may be temporarily present in the milk or feces. Heymans believes 

 that Schroeder's results with the inoculations of feces into guinea-pigs 

 are not quite conclusive as to the fecal excretion of tubercle bacilli in 

 an early stage of tuberculosis in cattle. 



In considering the significance of bovine tubercle bacilli in milk 

 it must be borne in mind that the presence of a small or even a larger 

 number of bacilli sufficient to produce tuberculosis in a guinea-pig 

 by intraperitoneal or subcutaneous injection 1 may, but generally will 

 not, produce tuberculosis in man, even when ingested as food for a 

 considerable period. That this is indeed the case has been repeatedly 

 shown by a number of observers, and the following investigations are 

 of interest: 



Hess, of the Research Laboratory of the Health Department of 

 New York City, obtained specimens of raw milk in New York from 

 large forty-quart cans. He collected this milk from dealers who had 

 small children who drank the milk in a raw state. He secured 107 

 specimens, and in 17 of these tubercle bacilli able to kill guinea-pigs 

 were found; 8 stems were subsequently obtained from the dead 

 animals and 7 were found to be of the bovine and 1 of the human type. 

 This induced the author to point out that tubercle bacilli in milk 

 might occasionally be derived from man and not from cattle. Of the 

 dealers who had dispensed the milk containing tubercle bacilli, ten 

 were found to have 18 children who had been regularly fed on 

 this raw milk; 9 of the children were two years or under and only 

 1 was over five years. The children were carefully watched for 

 one year, and 16 were submitted to the Pirquet tuberculin test; 

 4 reacted in a positive manner; of the 4, 2 were perfectly healthy 

 and 2 were poorly nourished, but showed no definite signs of tuber- 

 culosis. Of the 2 in poor condition, 1 had five months previously had 



1 Knutt has shown that a tubercle-bacilli-containing-milk which would produce tuberculosis 

 in guinea-pigs in intraperitoneal inoculations of 0.00001 gram (i. e., a dose of T ^ of a milligram) 

 would only produce tuberculosis if fed in a dose of 15 grams, i. e. , one million and a half (1 ,500,000) 

 times the intraperitoneal dose. 



