130 THE ESTIMATION OF FAT. 



Marpmann has proposed the use of cotton-wool, Ganntter of 

 wood-fibre, and Duclaux of sponge ; the principle of these 

 methods is the same as that of Adams. 



Fernandez-Krug and Hampe mix a measured volume of milk 

 with a finely-divided mineral substance usually 5 c.c. of milk 

 with 7J grammes of washed and dried kaolin and add 5 grammes 

 of finely-powdered anhydrous sodium sulphate. The sodium 

 sulphate absorbs the water contained in the milk, and, after 

 stirring well, the residue is quite dry ; this is transferred to 

 a flask holding 100 c.c. and 25 c.c. of ether added ; after shaking 

 for five minutes, an aliquot portion is withdrawn by a pipette, 

 over the point of which a piece of cotton-wool is wrapped, and 

 the fat estimated by evaporation and weighing. 



Froidevaux precipitates the casein and fat with a solution 

 containing 35 grammes of calcium phosphate and 6 c.c. acetic 

 acid per litre ; 90 c.c. of this solution are mixed with 10 c.c. of 

 milk, and the fat determined as in the Eitthausen process. 



Calculation Method. This has been referred to on p. 90, 

 and Tables XVIII. to XXII. may be used (pp. 91-95). 



