ESTIMATION OF FAT — ADAMS' METHOD. Ill 



taken that it is delivered into the weighing vessel at the same 

 rate and in the same manner as it was run on to the paper. The 

 papers are allowed to hang up till apparently dry ; flies must 

 not be permitted to settle on the surface of the paper, as they 

 consume portions of the fat. 



When the strips are dry enough to handle they should be 

 rolled up in loose coils of a diameter such that they will easily 

 go into the Soxhlet extractors (2 to 1 inch), and these should be 

 fastened either by a brass ring, a piece of cotton, or a small pin. 

 A number, or other mark serving to identify the sample, should 

 be placed on each, and a blank coil — i.e., one containing no milk 

 — should also be rolled up. The coils should be dried at lOU C. 

 for about an hour. 



\ sufficient number of wide-necked flasks should be carefully 

 cleaned, and allowed to stand for fifteen minutes inside the balance 

 case. The lightest of these should be placed on the right-hand 

 pan of the balance as a tare, and the others successively weii,'hed 

 against it, the weights required to produce equality being notc-d. 

 The coils should be placed in the Soxhlet extractors, the flasks 

 fitted, and a measured volume of dry ether, sufficient to fill the 

 extractor well above the upper portion of the siphon, poured 

 into each. The blank coil should be placed in a .Soxhlet ex- 

 tractor, and extracted with the same volume of ether into the 

 ■" tare." The Soxhlet extractors arc connected to upri<,'ht 

 condensers, and the ether made to boil by partially immersing 

 the flasks in water at 50° to 60° C. Extraction should be con- 

 tinued for five hours. 



The ether should be distilled off, and the flasks placed, side 

 downwards, in a drying oven at 100' C. for about twenty minutes, 

 being rotated, and air being blown in every five minutes to remove 

 the vapour of ether. This time is sufficient to dry them if dry 

 ether has been used. 



After cooling for fifteen minutes the flasks should be weighed, 

 the " tare " being again placed on the right-hand pan of the 

 balance, and the percentage of fat calculated from the increase 

 of weight. 



The "tare" is used to correct for the small quantity of 

 " extract " obtained from the paper, and to neutralise the effect 

 of any change of weight of the flasks due to handling. 



The connection between the flasks and the extractors and 

 between the extractors and condensers may be made by corks, 

 provided they have been well extracted by ether. 



The tare and the drying of the coils may be omitted, and 

 ordinary ether used in place of dry ether without greatly afiecting 

 the results. 



Dry ether is prepared by washing the commercial preparation 



