THE ALCOHOL TEST IN RELATION TO MILK. 



In order to determine whether or not the alcohol 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 per cent of colostrum milk had to be mixed with 

 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 



milk. 



Percentage 



of 



colostrum 



milk. 



Alcohol test. 



75 per cent. 



68 per cent. 



44 per cent. 



5 

 16 



10 

 20 

 25 

 50 

 75 

 90 

 10 

 20 

 25 



90 

 80 

 75 

 50 

 25 

 10 

 90 

 80 

 75 



i+L 



+M 

 +M 



+s 



+s 



+M 



+ S 



+ L 

 +VS 



+ M 



= 



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- 



