WERNER-SCHMID METHOD. 



23 



and fro a short distance over a Bunsen flame, or better, 

 by suspending it in front of a stove. 



Werner-Schmid Method. This is a very satis- 

 factory and rapid method for the determination of fat 

 and is especially suitable for sour milk. 



10 c. c. of the milk are measured into a long test- 

 tube of 50 c. c. capacity, graduated to tenths c. c., and 

 ten c. c. of strong hydrochloric acid added, or the 

 milk may be weighed in a small beaker and washed 

 into the tube with the acid. After mixing, the liquid 

 is boiled one and a half minutes, or the tube may be 

 corked and heated in the water bath from five to ten 

 minutes, until the liquid turns dark brown. It must 

 not be allowed to turn black. The tube and contents 

 are cooled in water, 30 c. c. of well 

 washed ether added, shaken, and 

 allowed to stand until the line of acid 

 and ether is distinct. The cork is tak- 

 en out, and a double tube arrange- 

 ment, like that of the ordinary wash- 

 bottle, inserted. The stopper of this 

 should be of cork and not of rubber, 

 since it is difficult to slide the glass 

 tube in rubber, and there is a possi- 

 bility, also, of the ether acting on 

 the rubber and dissolving it. The 

 lower end of the exit tube is adjust- 

 ed so as to rest immediately above 

 the junction of the two liquids. The 

 ethereal solution of fat is then blown 



