CHAPTER XXIII. 



reading of 32 



FIG. 125. 



QUANTITATIVE ANALYSIS OF MILK, GASTRIC 

 JUICE AND BLOOD. 



(a) Quantitative Analysis of Milk. 



i. Specific Gravity. This may be determined conveniently by 

 means of a Soxhlet, Veith or Quevenne lactometer. A lactometer 

 denotes a specific gravity of 1.032. The determin- 

 ation should be made at about 60 F. 

 and the lactometer reading corrected 

 by adding or subtracting 0.1 for 

 every degree F. above or below that 

 temperature. 



2. Fat. (a) Adams' Paper Coil 

 Method. Introduce about 5 c.c. of 

 milk into a small beaker, quickly ascer- 

 tain the weight to centigrams, stand a 

 fat-free coil 1 in the beaker and incline 

 the vessel and rotate the coil in order 

 to hasten the absorption of the milk. 

 Immediately upon the complete absorp- 

 tion of the milk remove the coil and 

 again quickly ascertain the weight of 

 the beaker. The difference in the 

 weights of the beaker at the two 

 weighings represents the quantity of 

 milk absorbed by the coil. Dry the 

 coil carefully at a temperature below 

 1 00 C. and extract it with ether for 

 3-5 hours in a Soxhlet apparatus 

 (Fig. 125, p. 410), using a safety 

 water-bath, heat the flask containing 

 the fat to constant weight at a tem- 

 perature below 100 C. 

 . Calculation. Divide the weight of 



fat, in grams, by the weight of milk, in grams. The quotient is the 

 percentage of fat contained in the milk examined. 



1 Very satisfactory coils are manufactured by Schleicher and Schiill. 



410 



SOXHLET APPARATUS. 



