DAIRY FARMING DAIRYING. 377 



Some of the conclusions drawn are the following : " The evidence we have to 

 prove that tubercle bacilli derived from cattle cause tuberculosis — and fatal 

 tuberculosis — among human beings is direct and irrefutable. The evidence we 

 have to prove that the milk from tuberculous dairy herds frequently contains 

 living virulent tubercle bacilli is equally direct and irrefutable. Hence no 

 medical milk commission should consent to the certification of milk unless it is 

 obtained from cows that are free from tuberculosis and that are kept in an 

 environment free from tuberculosis infection. . . . Pasteurization should be 

 recommended for all milk that is not certainly free from the germs of tubercu- 

 losis or those of other diseases .... Until commercial pasteurization has been 

 placed under ofljcial supervision, home pasteurization seems to be the best 

 solution." 



Tubercle bacilli in market milk in Philadelphia, H. C. Campbell {U. 8. 

 Dept. Agr., Bur. Anim. Indus. Rpt. 1909, pp. 163-111). — Data on the percentage 

 of fat, total solids, specific gravity of milk, and the number of leucocytes and 

 bacteria in the market milk of Philadelphia are presented in tabular form. 



In a study of the presence of streptococci and tubercle bacilli, subcutaneous 

 inoculations were made on guinea pigs. In the ordinary market milk, many 

 cases where the pigs died of septic peritonitis a microscopic examination 

 revealed the presence of streptococci. Of 123 samples of market milk with 

 which inoculations were completed, 18 were found to contain tubercle bacilli, 

 or 14.6 per cent. It is stated that if all the experimental animals had lived 

 sufficiently long for the lesions to develop the percentage found would probably 

 have been even higher. 



In " pasteurized " milk obtained from dealers known to have pasteurizing 

 machines the number of bacteria present in most of the samples indicated that 

 either the milk was not properly pasteurized or that it was placed under bad 

 conditions after the process was completed. Inoculations showed that 1 sample 

 out of 12 contained virulent tubercle bacilli. In other market milks claimed 

 to be pasteurized a large number of bacteria were found, and the great increase 

 in the count of leucocytes after heating to 60° C. suggested that pasteurization 

 had not been practiced in the majority of the samples. Inoculations of these 

 milks likewise showed that 1 sample out of 12 contained virulent tubercle 

 bacilli. 



" The method of commercial pasteurizatipn used in the trade can not be 

 relied upon as a means of destroying disease-producing bacteria. If pasteuriza- 

 tion is to be used as a means of purifying milk, it should be done under legal 

 regulation and official supervision. A microscopic examination for determining 

 the presence of tubercle bacilli in milk is of little value." 



The viability of tubercle bacilli in butter, J. R. Mohlee, H. J. Washburn, 

 and L. A. Rogers {U. S. Dept. Agr., Bur. Anim. Indus. Rpt. 1909, pp. 179-185, 

 fig. 1). — Butter was made from milk inoculated with tubercle bacilli, packed in 

 glass jars, and sent by express to Chicago. After remaining in storage for 

 periods varying from 10 days to 6 months, guinea pigs were fed the butter and 

 others were inoculated with it. 



It was found that the storage of butter at ordinary temperatures during a 

 period approximating the length of time that market butter is usually held 

 will not destroy the vitality of tubercle bacilli within the product. The experi- 

 ments also indicated that the organisms were not distributed uniformly through- 

 out the product, and it is stated that the test should cover a considerable 

 length of time, since negative results may lead to erroneous conclusions if not 

 properly controlled by subsequent experiments. For example, certain samples 

 failed to cause tuberculosis in the experimental animals when the butter was 



