Abstract
The milk ordinances of two municipalities were examined. One municipality required all milk sold as “raw” to come from cattle negative to the agglutination test for Bang's disease, while the other ordinance had no such requirement. Eighteen quart samples of milk were collected from the commercial distributors of each city, representing 17 dairies in one and 18 dairies in the other. Three to 5 ce. of gravity cream from each quart was inoculated intraper-itoneally into 2 guinea pigs. The pigs surviving the inoculations were autopsied 4 weeks later. The spleen of each was cultured for Bact. abortus and the blood tested for agglutinins for this organism.
Bact. abortus was not isolated from any of the quart samples of milk from the 18 dairies in the city, the ordinance of which required raw milk to come from cattle tested for Bang's disease. Two guinea pigs, representing one dairy, died as a result of the inoculation before the end of the 4-week incubation period, so that satisfactory results could not be obtained. Agglutinins for Bact. abortus were not demonstrated in any of the milk from this city. Guinea pig inoculations of the milk from dairies supplying milk to the other city were as follows: Six pairs of pigs inoculated with milk from 6 dairies, died in from 1 to 10 days after injection and satisfactory incubation periods for Bact. abortus were not obtained. Agglutinins for Bact. abortus were demonstrated in the milk from 2 of the above dairies in the 1 :50 dilution. Therefore, milk containing these agglutinins was being used to make up these milk supplies. Usually milk from a single udder with this amount of agglutinin does not contain Bact. abortus; however, these agglutinins were no doubt diluted many times with milk from negative animals and this low agglutination of the mixed milk probably indicated infection in the herd.
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