yo MAINE AGRICULTURAL EXPERIMENT STATION. 



Whenever the fat is not quite clear, more satisfactory results 

 may be obtained by allowing the bottles to stand until the fat 

 has crystallized and then warming them by placing the bottle 

 in hot water, before taking the reading. 



TESTING MILK. 



The original method of Dr. Babcock. The bottle usually em- 

 ployed for testing milk is shown in fig. i, p. 62. It should be 

 made of heavy glass and should hold, up to the neck, not less 

 than 40 cubic centimeters. The neck is graduated to read in 

 per cent of the amount of milk used. The graduation extends 

 from o to 10 per cent, which is sufficient range for normal milk. 

 The pipette for measuring milk should hold 17.6 cubic centime- 

 ters when filled to the mark. A pipette of this size will deliver 

 18 grams of milk of average specific gravity (1.032.) The milk 

 is measured into the test bottle and the test made as described 

 on pages 66-69. 



The modified method. (Bartlett.) The method described 

 above is the original method as announced by Dr. Babcock, 

 and beginners and those who have had little experience are 

 advised to follow that method. Those who are somewhat 

 skilled in testing should use the modification of the method as 

 given in Bulletin 31 of this Station. For convenience of refer- 

 ence the method is here reprinted. 



After the milk is mixed by stirring or pouring from one vessel 

 to another, the required amount, 17.6 cubic centimeters, is 

 measured into the test bottle. It is then heated to about 70 F., 

 if not already at that temperature, by setting the bottles in a 

 tank of warm water. Twenty cubic centimeters of sulfuric acid 

 (specific gravity 1.82 to 1.825) are added, and the bottle shaken 

 by giving it a rotary motion, until the milk and acid are thor- 

 oughly mixed. The mixture is then allowed to stand not less 

 than 5 minutes. No harm is done if it stands longer than 5 

 minutes and in fact, occasionally, some kinds of milk have to 

 be given a little more time. After standing the necessary time, 

 the bottle is given another gentle shake to mix in and dissolve 

 any particles of curd that may have risen to the surface. Hot 

 water is then added nearly to the uppermost mark, the bottle 

 is put in the centrifugal machine and whirled for 5 minutes at 



