TOTAL SOLIDS. 19 



A better plan is to use a 5 c. c. pipette and to wash 

 out that which adheres to the glass with a little water. 

 The specific gravity of the milk being known, the 

 amount taken can be calculated. The milk should be 

 as near 6o°F. as possible. 



ASH. 



The residue from the determination of total solids is 

 heated cautiously over the Bunsen burner, until a white 

 ash is left. The result obtained in this manner is apt 

 to be slightly low from loss of sodium chloride. This 

 may be avoided by heating the residue sufficiently to 

 char it, extracting the soluble matter with a few c. c. 

 of water, and filtering (using paper extracted with hy- 

 drofluoric acid.) The filter is added to the residue, the 

 whole ashed, the filtrate then added and the liquid 

 evaporated carefully to dryness. The ash of normal 

 milk is about 0.7 per cent, and faintly alkaline; if the 

 milk be watered the ash will be less. It will be seen 

 by the detailed statement of composition that it is prac- 

 tically free from sulfates, and hence a quantitivc deter- 

 mination of these may detect the adulteration "with 

 water containing sulfates. For this purpose, not less 

 than 100 c. c. should be taken. A marked degree of 

 alkalinity and effervescence with hydrochloric acid, will 

 suggest the addition of a carbonate. 



FAT. 

 The method introduced by Wanklyn for the deter- 

 mination of fat by extracting it with ether from the 



