258 MILK AND ITS HYGIENIC RELATIONS 



having infected herds showed that the disease was found in fifty- 

 five farms which were situated in no less than thirty-six different 

 counties. 



The presence of the bacillus in milk was investigated by Schroeder 

 and Cotton. They found that the milk from apparently healthy 

 cows which did not react to tuberculin, might contain Bacillus 

 Abortus, and that these bacilli when injected into guinea-pigs 

 produced lesions similar to, but not identical with, those produced 

 by tubercle bacilli. They found that the abortus bacillus could 

 be detected in the udder when no trace of disease could be found 

 on examining the carcase. Further, they found that the excretion 

 of this organism in the milk is extremely persistent, having been 

 traced in one case for a period of eleven months after the abortion. 

 They confirm the work of MacFadyean and Stockman in regard 

 to the infection of other animals, and produced characteristic 

 lesions by feeding, in cattle, sheep, goats, mares, guinea-pigs, 

 rabbits. 



Schroeder and Cotton investigated the milk from cows on two 

 farms and also from individual cows. On one farm there were 

 140 cows tested with the tuberculin and found to be free from 

 this disease ; nineteen cows, however, showed a positive reaction 

 for the abortus bacillus. On the second farm of thirty-six cows, 

 eleven gave positive reaction, and in the total number of cows 

 investigated 14 per cent, were found to contain the Bacillus Abortus. 



Smith and Fabyan showed that the foetus obtained from a 

 guinea-pig infected with Bacillus Abortus when injected into another 

 guinea-pig gave rise to lesions simulating tubercle but in reality 

 due to the Bacillus Abortus. These lesions could be reproduced 

 at will in a series of animals. The authors believe that tuberculous 

 lesions are sometimes stated to occur which are in reality due to 

 the Bacillus Abortus. The organism was found to grow readily 

 in milk. 



Zurick and Krage investigated the milk from three cows which 

 had respectively aborted fourteen days, six months, and thirteen 

 months previously. The abortus bacillus was found in all cases, 

 but no pathological changes could be detected either in the udder 

 or in the milk. They found that if the bacilli were injected into 

 one side of the goat's udder they were excreted from the injected 

 side four or five days after the injection but not from the other 

 side. The blood of the goat showed agglutinating power for 

 the Bacillus Abortus. In other experiments the bacilli were intro- 

 duced intravenously or subcutaneously. Two of the animals 

 injected showed Bacillus Abortus in the milk within twenty-four 

 hours, a third in forty-eight hours, and the organism persisted 

 in the milk for a period of about three weeks. 



Schroeder (i), in the course of work carried out upon the nutritive 

 properties of boiled milk for guinea-pigs, found lesions in some of 

 the guinea-pigs examined, which caused him to investigate the 



