28 
LABORATORY MANUAL 
Several exercises are suggested below as substitutes or additions if it is 
felt that a need for such exercises exists. Merely a brief outline, with no 
mention of observations, conclusions, or questions is given. 
EXERCISE NO. 18 
Object: To determine the influence of souring of milk on its fat content. 
Procedure: 
A. Test a lot of milk in duplicate. 
B. Measure out 17.6 cc. of the above lot of milk into each ol two 
10% milk test bottles, and set these aside until the next exer¬ 
cise. 
C. Test the two soured samples of milk by the same method used 
for sample A and compare results. 
References: F. & W. If 32; Van S. p 23; St. p 132 
EXERCISE NO. 19 
Object: To determine the variation in the fat content of the milk of one cow 
during various stages in the milking process. 
Procedure: 
A. Strip some of the first milk from each of the four quarters into 
a sample bottle. Label properly. 
B. Repeat this with another bottle when one-half through milk¬ 
ing. Label. 
C. Strip the last milk from each of the four quarters into a third 
bottle. Label. 
D. Test each of the above samples in duplicate. 
References: F. & W. If 168; Van S. p. 8; Jud. p. 35; St. pp. 49-51. 
EXERCISE NO. 20 
Object: To determine the variation in the fat content of milk of one cow from 
one milking to another. 
Procedure: Obtain a representative sample of milk from each of six 
milkings of one cow and test each sample in duplicate. 
References: F. & W. If 160-164 inclusive. Van S. p. 7; Jud. pp 35-38, St. 
p 48. 
