ESTIMA TION OF FAT 185 



181. Estimation by Adam's Paper-coil Method. 



In this method, which is the standard extraction 

 process, and capable of great accuracy, a certain quantity 

 of milk is soaked up by absorbent paper, which is 

 then dried, and extracted with ether. Special strips 

 of absorbent paper are manufactured for this process, 

 and are the most convenient to use, although blotting or 

 filter paper that has been previously extracted with ether 

 may, however, be employed, after it has been cut into 

 strips about 20 inches long and 2 inches in width. 



Ten c.c. of well-mixed milk are run from a pipette 

 upon a strip of ether-extracted paper of the size 

 mentioned above. The paper is then dried by ex- 

 posing it to the air or holding it at some distance 

 from a fire, the last traces of moisture being driven 

 off by suspending it by means of a piece of platinum 

 wire in a steam-bath at 100° C, for about an hour. 

 It is then rolled round a sinker, consisting of a 

 hermetically sealed and weighted glass tube, which 

 is then placed in a Soxhlet extractor, fitted with a 

 dry flask of known weight, and extracted with dry 

 ether for three or four hours on the water-bath. The 

 sink and paper are then removed, and as much of 

 the ether as possible distilled from the flask into the 

 extractor. The flask containing the fat is dried for 

 two hours in the steam oven at 100° C, cooled in a 

 desiccator, and weighed. On deducting the weight of 

 the empty flask, the weight of the fat is obtained, and 

 from a knowledge of the specific gravity of the milk taken, 

 the percentage of fat in the sample can be calculated. 



182. Estijnation of Fat by Gerber's Modification 



of Babcock's Process. 



Of the different methods for fat estimation depending on the 

 mechanical separation of the fat by centrifugal force, the one most 



