382 MILK AND DISEASE 



Dallar the following as being the percentage found in various places: 

 England, 20 per cent.; Denmark, 31 per cent.; Sweden, 42 per cent.; 

 Norway, 8.4 per cent.; Belgium, 60 per cent.; Massachusetts (1897), 

 58.9 per cent. 



It is a general conception that tubercle bacilli occur only in milk 

 obtained from animals suffering with tuberculosis of the udder; this 

 is not strictly true as is seen from the following conclusions by 

 Mohler: 



"The tubercle bacillus may be demonstrated in milk from tuber- 

 cular cows when the udders show no perceptible evidence of the 

 disease either macroscopically or microscopically. 



"The bacilli of tuberculosis may be excreted from such udder in 

 sufficient numbers to produce infection in experimental animals 

 both by ingestion and inoculation. 



"The presence of the tubercle bacilli in the milk of tubercular 

 cows is not constant, but varies from day to day. 



"Cows secreting virulent milk may be affected with tuberculosis 

 to a degree that can be detected only by the tuberculin test. 



"The physical examination or general appearance of the cow 

 cannot foretell the infectiveness of the milk. 



"The milk of all cows which have reacted to the tuberculin test 

 should be considered as suspicious and should be subjected to sterili- 

 zation before using." 



Shroeder, however, concluded that only 40 per cent, of the cows 

 which react to the tuberculin test actively expel tubercle bacilli. 



Market milk often contains the tubercle bacilli, as may be seen 

 from the following table compiled by Parker. 



~i~~ r .v^ -, ~^ Percentage 



"lace. Investigator. examined. positive. positive. 



England Macfayden 77 17 22.1 



Germany Muller 1596 97 6.2 



Germany Beatty 272 27 10.0 



Liverpool Delepine 12 22 17.6 



1897 Liverpool ' Hope 228 12 5.2 



1900 London Klein 100 7 7.0 



St. Petersburg Scharbekow 80 4 5.0 



Kiew Pawlowsky 51 1 2.0 



Krakow Bujwid 60 2 3.3 



Naples Marconi 14 7 50.0 



Berlin Petri 64 9 14.0 



Berlin Beik 56 17 30.3 



Schev Ott 27 27 11.1 



Koniesburc 1 .To<ror 1 nn 7 79 



1908 

 1905 



10.5 



2. 7 



oeram Smit 1584 45 2.8 



Washington Anderson 223 15 6.7 



Louisville Field 119 46 29 5 



New York Hess 105 17 16.2 



Philadelphia Campbell 130 18 13.8 



Chicago Tonney 144 15 10.5 



Rochester rinlor 0*7 in 12.6 



