CHAPTER V. 

 BABCOCK TEST FOR OTHER MILK PRODUCTS. 



97. Skim milk. Each division on the scale of the 

 neck of the regular Babcock test bottle represents two- 

 tenths of one per cent. (44). When a sample of skim 

 milk or butter milk containing less than this per cent, 

 of fat is tested, the estimated amount is expressed by 

 different operators as one-tenth, a trace, one-tenth trace, 

 or one- to five-hundredths of one per cent. Gravimetric 

 chemical analyses of skim milk have, however, shown 

 that samples which give only a few small drops of fat 

 floating on the water in the neck of the test bottle, or 

 adhering to the side of the neck, generally contain 

 one-tenth of one per cent, of fat, and often more. Sam- 

 ples of skim milk containing less than one-tenth of one 

 per cent, of fat are very rare, and it is doubtful whether 

 a sample of separator skim milk representing a run 

 of, say 5000 Ibs. of milk, has ever shown less than 

 five-hundredths of one per cent, of fat. Under ordi- 

 nary factory conditions, few separators will deliver 

 skim milk containing under one-tenth of one per cent, 

 of fat, when the sample is taken from the whole day's 

 run. This must be considered a most satisfactory sepa- 

 ration. 1 



1 For comparative analyses of separator skim milk by the gravi- 

 metric method and by the Babcock test, see Wis. exp. station bull. 52 

 and rep. XVII, p. 81; Conn. (Storrs) exp. station, bull. 40; Utah exp. 

 station, bull. 96. See also Woll, Testing skim milk by Babcock test, in 

 Country Gentleman, April 26, 1902. The results obtained by the use of 

 the Gottlieb method have shown that! ether-extraction methods, as 



