514 Quantitative Determination of Fat in Milk [July 



methods that make it preferable In biochemical and pediatric work. 

 The time consumed is as short as in any of the above methods, except 

 the Babcock or other simple centrifugation methods, the simpHcity 

 of the apparatus compares favorably with that of any other method, 

 and the degree of accuracy with ordinary care and skill is so great 

 that it entirely suffices for all except the most precise work. 



This method was described by Dr. Arthur V. Meigs^^ before the 

 Philadelphia County Medical Society, on Feb. 22, 1882, It is, in 

 brief, as foUows : Approximately 10 c.c. of milk, after being care- 

 fully weighed, are transferred to an ordinary 100 c.c. graduated 

 cylinder, 20 c.c. of distilled water added and, after this, an equal 

 amount of ether (0.720 sp. gr,). The ground-glass Stopper is 

 inserted and the bottle shaken for five minutes. Then, after care- 

 fully removing the stopper, 20 c.c. of ethyl alcohol are added, the 

 Stopper re-inserted and the cylinder shaken again for five minutes. 

 This, as soon as settling occurs, gives two distinct strata, the upper 

 of which contains little but ether and fat, the lower contains the 

 other constituents of the milk. The upper Stratum is now drawn 

 off with a small pipette and transferred to a weighed glass dish. 

 Then 5 c.c. of ether are added and pipetted off, five successive times, 

 and these 25 c.c. are added to the ethereal Solution first removed. 

 This is done to wash off the thin layer of fat and ether which was 

 left behind at the first pipetting. The dish and contents are now 

 transferred to a safety water-bath, protected from dust, the ether 

 evaporated, and the residue placed in a hot-air oven, heated at a 

 temperature below 100° C, and finally dried in a desiccator over 

 sulfuric acid until the weight is constant. Dr. Meigs stated in his 

 report that the idea for this method was gained from a paper by 

 Hallock.i9 



The results we have obtained by this method were fairly accu- 

 rate but, in order to be absolutely sure that no lactose or protein 

 material was weighed as fat and to be certain that in both this and 

 the Soxhlet method the end-products were identical, we decided to 

 dissolve the first fat product in absolute ether, filter through a small 

 hardened filter paper, as in the Soxhlet method, into a weighed dish, 

 evaporate the ether, dry the fat and weigh. 



18 Meigs : Philadelphia Medical Times, 1882, xii, p. 660. 

 1^ Hallock : Amer. Jour. of Pharmacy, 1874, xlvi, p. 477. 



