THE ALCOHOL TEST IN RELATION TO MILK. 25 
We can not see that the alcohol test is of any particular value in 
the control of a market milk supply except as a means of evidence 
that milk from a particular source is abnormal in some way and 
should be examined by other tests. It might be of value at a re- 
ceiving station as a means of detecting sour milk, but the test would 
be expensive compared with the use of alkaline tablets for the rapid 
determination of acidity as described by Farrington and Woll (9). 
THE TITRATION METHOD OF APPLYING THE ALCOHOL TEST. 
From the simple alcohol test in which a definite volume of a definite- 
percentage alcohol is added to an equal volume of milk there has 
developed a method in which a definite volume of milk is titrated 
with certain percentages of alcohol until a coagulation of the milk is 
produced. 
Lohnis (16) has found this titration method to be of value as a test 
for the quality of market milk. He found that there was quite a 
definite relation between the titration with 80 per cent alcohol and 
the bacterial content of market milk. He titrated 2 c. c. of milk in a 
beaker against a black background with 90, 80, and 70 per cent alco- 
hols, the titration being made at a temperature of from 15° to 20° C. 
The first appearance of flakes was considered the end point. 
We have used this method in the titration of 116 samples of market 
milk furnished with bacterial counts by Dr. Kinyoun and Dr. Dieter, 
of the Health Department of the District of Columbia. In our 
titrations of 92 samples of raw and 24 samples of pasteurized milk we 
have not found any definite relation between the titration with 90 
per cent and 80 per cent alcohols and the bacterial count. In Table 
20 is shown the acidity, bacterial counts, and alcohol titration of 92 
samples of raw milk, and in Table 21 the results of an examination 
of 24 samples of pasteurized milk. The bacterial counts of the raw 
milk ranged from 2,100 to 20,600,000 per cubic centimeter, and the 
pasteurized milk from 1,200 to 3,100,000 bacteria per cubic centimeter. 
Consequently we were able to titrate samples having a great variation 
in their bacterial content. If a study is made of the bacterial counts 
and the alcohol titrations shown in Tables 20 and 21 it will be seen 
that there is no definite relation between them. In order to bring 
this point out more clearly the titrations of samples containing more 
than 500,000 and less than 500,000 bacteria per cubic centimeter 
have been averaged, as shown in Table 22. The average titration 
with 90 per cent alcohol of 46 samples of raw milk containing more 
than 500,000 bacteria per cubic centimeter was 1.95 c. c, while the 
average titration of 46 samples containing less than 500,000 per cubic 
centimeter was 2.39 c. c. The average titration of 46 samples with 
80 per cent alcohol was 4.61 c. c. when the bacterial count was more 
