Frost—Bacteriological Control of Public Milk Supplies . 1363 
teria, in connection with the “pipettometer” is; described, and 
the results for B. coli in milk are discussed. 
A study of the inhibiting action of milk on the amount of gas 
produced in the fermentation tube, when compared with results 
obtained in ordinary lactose media, shows that while this reaction 
is pronounced in the case of milk that it does not apparently 
modify the results when a cubic centimeter or less of milk is 
added to a fermentation tube of other lactose medium. 
A modified form of a common test for the streptococci in milk, 
other than those of sour milk, is suggested, together with experi¬ 
mental data of its value. 
A modification of Savage’s method for a quantitative test for 
Bact. Welchii is described. 
A description of a new form of fermentation tube is given. 
This tube collects the gas from a constant amount of the medium 
and is especially useful in the study of anaerobes, and was used 
to test out certain doubtful cultures of Bact. Welchii. 
Thirty samples of certified milks were analyzed from eight 
different sources. 
Thirty-two samples of inspected milks were examined from 
seven different sources. 
Thirty-seven samples of pasteurized milks were studied from 
six different sources. 
Forty-two samples of raw milk were tested from ten different 
sources. 
On all of the samples the following tests were made: 1) Total 
number of bacteria growing at 21° C.; 2) gas production in lac¬ 
tose media; 3) Bact. Welchii, quantitative; 4) spores or bacteria 
resisting heat at 80° C. for 10 minutes. 
On part of the samples the following additional tests were run: 
5) streptococci; 6) character of the curd at 38° C. 
The analyses of these milks under winter conditions, presum¬ 
ably the most favorable for both producer and consumer, show 
that the raw milks have a bacterial content ranging from 30,000 
to 14,400,000 per c. c. The average count of milks sold in a raw 
state was found to be approximately 2,000,000 per c. c.; the aver¬ 
age count of raw milks to be pasteurized in bulk was practically 
the sarnie, while the average count for the milks to be pasteurized 
in bottles was 532,000 per c. c. The inspected milks have an aver¬ 
age count of 159,560 per c. c. and the certified milks of approxi¬ 
mately 20,000. 
