ANALYTIC PROCESSES IS 



paper. From a weighing bottle about 5 grams 

 of the milk are transferred to the coil by means 

 of a pipet, care being taken to keep dry the end 

 of the coil held in the fingers. The coil is 

 placed, dry end down, on a piece of glass and dried 

 for one hour, preferably in an atmosphere of 

 hydrogen; it is then transferred to an extraction 

 apparatus and extracted with absolute ether, 

 petroleum spirit of boiling-point about 45° or, 

 better, carbon tetrachlorid. The extracted fat 

 is dried and weighed. 



The above procedure is very satisfactory, but 

 the drying in hydrogen may usually be omitted. 

 After the coil has received at least twenty wash- 

 ings, the flask is detached, the ether removed by 

 distillation, and the fat dried by heating in an 

 air-oven at about 105°, and occasionally blowing 

 air through the flask. After cooling, the flask 

 is wiped with a piece of silk, allowed to stand 

 ten minutes, and weighed. 



Richmond states that to perform a rigidly 

 accurate determination attention to the following 

 points is necessary : The ether must be anhydrous 

 (drying over calcium chlorid and distilling is 

 sufficient). Schleicher & Schuell's fat-free papers 

 should be used, and one should be extracted 

 without any milk on it, as a tare for the others. 

 Four or five hours' extraction is necessary, and 



