86 PRINCIPLES AND PRACTICE OF MILK HYGIENE 
non-clinical reactors and not a single sample produced 
tuberculosis when injected into guinea pigs. Later,incon- 
junction with Brauer,!* he made a thorough test of the 
milk from 10 non-clinical reactors, inoculating guinea 
pigs, and feeding guinea pigs, calves and pigs. Not one 
of the experimental animals developed tuberculosis. 
Some of the guinea pigs in the feeding experiment re- 
ceived 66 grammes of milk daily for 5 months, or 33 times 
their body weight; 10 calves received 7 to 12 litres each 
day for 8 to 11 months and 20 pigs were given 1 to 6 
litres daily for 4 months. O. Miiller made inoculation 
tests on guinea pigs with the milk from 9 non-clinical 
reactors, and Ascher with the milk from 7, and tubercle 
bacilli were not demonstrated in a single case. Ostertag . 
contends that in those cases in which tubercle bacilli were 
demonstrated in the milk from non-clinical reactors, the 
milk was infected secondarily, and in support of this 
view he points out that in some of the cases in which 
tubercle bacilli were demonstrated in the milk no lesions 
of tuberculosis could be found on postmortem, while in 
other cases lesions of open tuberculosis were present. At 
any rate, the evidence in its entirety indicates that the 
milk of non-clinical reactors is much less likely to contain 
tubercle than the milk of cows with tuberculous udders 
or which show clinical symptoms of the disease in other 
organs. | 
Influence of Dilution While these experimental re- 
sults indicate very accurately the conditions under which 
tuberculous cows contaminate milk, it must not be for- 
gotten that they relate to the milk of individual cows 
tested separately, while in practice the milk of tuber- 
18 Zeitschr. fiir Fleisch u. Milchhy., p. 80, No. 4, vol. xxiv. 
