4 BULLETIN 202, U. S. DEPARTMENT OF AGRICULTURE. 



When we speak of fresh, normal milk we mean fresh milk from a 

 healthy cow in the middle of the period of lactation. Milk in the early 

 period of lactation, that is, colostrum milk, or milk taken late in the 

 lactation period — "old" milk, as it is sometimes called — usually 

 coagulates with the alcohol test. Henkel (12), Metzger (17), and 

 also Auzinger (2), found that the milk from a cow in the first of the 

 lactation period, while apparently normal, may show a positive alcohol 

 test at irregular intervals. Auzinger (2) believes that the high albu- 

 men and globulin content of colostrum milk and the calcium salts are 

 responsible for the positive alcohol reaction. 



EFFECT OF COLOSTRUM AND OF "OLD" MILK ON THE ALCOHOL TEST. 



In Table 1 are shown the results of the alcohol tests which we have 

 made on colostrum milk from two cows. Three tests were made, 

 using 75, 68, and 44 per cent alcohol. The results show clearly that 

 colostrum milk gives a positive alcohol test and that the stronger the 

 alcohol the longer the test will be positive. It will be noticed that the 

 milk from' cow 16 gave a positive test with 68 per cent alcohol for 24 

 days, although the acidity was low after the fourth day. It is evi- 

 dent from these results and from those obtained by other investi- 

 gators that the coagulation of milk in the first of the lactation period 

 by alcohol is largely independent of acidity. 



Table 1. — Alcohol tests with colostrum milk. 











Alcohol test. 





Cow 

 No. 



Days after 

 calving. 



Acidity. 





















75 per cent. 



68 per cent. 



44 per cent. 



4 



2 



2.61 



i+L 



+L 



+VS 





3 



2.45 



+L 



+L 



+VS 





4 



2.25 



+L 



+M 



— 





5 



1.87 



+L 



+s 



— 





6 



1.80 



+M 





_ 





8 



1.50 



+M 



— 



— 





9 



1.70 



+M 



— 



— 





10 



1.55 



— 



— 



— 





11 



1.52 



+s 



— 



— 





12 



1.50 



+M 



— 



— 





13 



1.31 



+s 



— 



— 





19 



1.35 



— 



— 



— 





21 



2.10 



— 



— 



— 





22 



1.12 



— 



— 



— 



16 



1 



2.40 



+ L 



+ L 



— 





2 



2.20 



+L 



+s 



— 





3 



2.70 



+M 



+M 



— 





4 



2.26 



+L 



+s 



— 





5 



1.60 



+M 



+s 



— 





6 



1.84 



+M 



+s 



— 





13 



1.36 



+L 



+M 



— 





15 



1.65 



+M 



+s 



— 





16 



1.53 



+M 



+M 



_ 





19 



1.57 



+M 



+s 



— 





22 



1.70 



+M 



+s 



— 





23 



1.60 



+M 



+s 



— 





24 



1.50 



+ M 



+s 



— 





25 



1.45 



+M 





— 



i In this and succeeding tables the initial letters denoting the degree of the positive (+) tests signify: 

 L, large flakes; M, medium flakes; S, small flakes; and VS, very small flakes. Minus sign (— ) signifies 

 negative test. 



