DAIRY HUSBANDRY 
11 
SERIES B 
Testing Milk for Fat 
Materials necessary for 10 students: 
* 1—Pint Sin-acid solution. 
* 4—Ounces caustic soda or caustic potash , or washing powder. 
* A—Gallon Ethgl ether. 
* A—Gallon Petroleum ether. 
* 1—Pint 95% Elh ■ alcohol. 
* 1—Pint aqua ammonia. 
* A—gallon distilled water. 
* 10— Rohrig extraction tubes ( Rose-Gottlieb test). 
* 1 — Hood. 
* 1—Hot plate. 
1—Hot water bath. 
* 1—Sensitive balance. 
EXERCISE NO. 6 
Object: To become acquainted with the operation of the Babcock test. 
Procedure: A demonstration of the important steps in the test will be 
given by the instructor, preceding the laboratory period. In 
order that the main points may be fixed in mind, they are given 
below in the order of perform rce. 
A. (1) Procure a representative sample of milk (about 100 cc.) and 
mix thoroughly by pouring back and forth from one container 
to another at least six or more times, depending of course, on 
the condition of the sample. 
(2) Immediately after mixing, transfer 17.6 cc. of the sample to a 
10% milk test bottle. Blow the last few drops from the 
pipette. 
(3) Measure out 17.5 cc. of acid and pour into the bottle so that 
it runs down the side of the neck and rinses off adhering milk. 
(4) Mix the milk and acid thoroughly by giving the bottle a ro¬ 
tary motion. Mixing cannot be overdone. 
(5) Whirl the bottles in the centrifuge for five minutes at a speed 
which will produce 30.65 pounds pressure per square inch on 
the bottom of the bottle. Bottles should be placed so that the 
tester is balanced. (See Ex. 3, Series A.) 
(6) Add hot water (at least 140° F.) up to the neck of the bottle 
and whirl two minutes. 
(7) Add enough hot w ater (at least 140° F.) to bring the fat column 
between the 0 and 10% marks, and whirl one more minute. 
(8) If-a steam turbine tester is used, remove bottles from tester 
and with a pair of dividers read the entire fat column (including 
the low T er and upper menisci). If the temperature of the fat 
column is not within the 120°-140° F. limits, a hot water bath 
deep enough to permit the fat column to be submerged, should 
be used for four minutes. If dividers are not at hand, the per 
