14 
LABORATORY MANUAL 
EXERCISE NO. 8 
Object: To determine the effect of temperature of the milk and the acid on the 
color and condition of the fat column. 
Procedure: The ideal fat column should be a clear golden or amber color 
with a decided sparkle and should freely transmit light rays 
in an unbroken course within the column. A fat column lack¬ 
ing in any of the above indicates an imperfect test. There is 
no question that curd within or beneath the fat column affects 
the reliability of the results. 
A. Use 17.6 cc. of milk in each and make each of the following tests 
in duplicate: 
(1) 17.5 cc. of acid at normal temperatures (65°-75° F.) 
(2) 17.5 cc. of acid at a low temperature. (Below 55° F.) 
(3) 20-21 cc. of acid at a low temperature (Below 55° F.) 
(4) 17.5 cc. of acid at a high temperature. (98°-105°F.) 
Observations: 
Sample 
i • 
Tempe 
irature 
C. C. of 
Acid 
% fat 
Color 
Condition 
Milk 
Acid 
1 
a 
b 
a 
2 
b 
3 
a 
b 
4 
a 
b 
Conclusion: 
Questions: (1) Why should the fat column of a milk test be read so as 
to include both menisci? 
(2) What effect on the test will the practice of allowing the acid 
and milk mixture to stand for a few minutes before centrifug¬ 
ing have? 24 hours? 
(3) What may cause foam on top of the fat column? How may 
this defect be remedied? 
(4) Give the important developments which resulte4 from the in¬ 
vention of the Babcock test. 
References: F. & W. If 79, 80, 307 (Table 2), 39, 41; Van S. pp. 64-70; 
Jud. pp. 66-72; St. pp. 118-119. 
