THE ALCOHOL TEST IN RELATION TO MILK. 5 
In order to determine whether or not the aleohol test would be 
positive in a mixed colostrum and normal milk, one experiment was 
performed. Colostrum milk from two cows 24 hours after calving 
was mixed in various proportions with fresh, normal milk which gave 
a negative alcohol test. The results of this experiment, in Table 2, 
show that from 80 to 90 percent of colostrum milk had to be mixed witli 
normal milk in order to cause a positive test with 68 per cent alcohol. 
When 75 per cent alcohol was used the test was positive with as low 
as 25 per cent of colostrum milk from cow 5, but when colostrum 
milk from cow 16 was used, a mixture of 80 per cent was required to 
give a positive reaction with 75 per cent alcohol. It seems evident 
from these results that the mixing of colostrum and normal milk 
would not cause a positive alcohol test unless a very large percentage 
of the milk were colostrum milk. 
Table 2. — The alcohol test with a mixture of normal and colostrum milk. 
Colostrum 
milk from 
cow No. 
Percentage 
of 
normal 
Percentage 
of 
colostrum 
Alcohol test 
milk. 
milk. 
75 per cent. 
68 per cent. 
44 per cent. 
5 
10 
90 
i+L 
+ L 
20 
80 
+M 
+VS 
— 
25 
75 
+M 
— 
— 
50 
50 
+s 
_ 
_ 
75 
25 
+s 
— 
_ 
90 
10 
— 
— 
_ 
16 
10 
90 
+M 
+ M 
_ 
20 
80 
+s 
_ 
_ 
25 
75 
— 
— 
— 
1 See footnote under Table 1. 
Having discussed the relation of the alcohol test to colostrum milk, 
let us consider its relation to milk drawn at the last of the lactation 
period, or what is known as "old" milk. Several investigators have 
shown that " old" milk gives a positive alcohol test. It is well known 
that milk changes in composition toward the end of the lactation 
period, and it is undoubtedly these changes which cause the coagu- 
lation with alcohol. While no definite changes have been attributed 
to the positive alcohol reaction, it is believed by some to be due to 
the high content of solids (not fat). Henkel (12), however, found 
that this could not explain in all cases the coagulation by alcohol. 
Auzinger (2) believes that on account of the variation of solids (not 
fat) the alcohol test has no significance in milk from "old" milk 
cows. 
SUMMARY OF CAUSES FOR POSITIVE TESTS IN MILK OF SINGLE COWS. 
It is apparent that fresh milk from a single cow may occasionally 
give a positive alcohol reaction with 68 or 70 per cent of alcohol. 
Colostrum milk gives a positive reaction, and the same is true usu- 
