142 



ANALYSIS OF MILK. 



TABLE XIV.— Alcohol Table (Hehner). 



The method used at the Government Laboratory for the 



-estimation of volatile acids is as follows : — 



Ten grammes of milk are neutralised to the extent of one- 



. . . N 

 half the total acidity with ---, NaOH, and a little phenolphthalein 



added. The mixture is then evaporated to dryness on a water- 

 bath with frequent stirring, and, after treatment with 20 c.c. 

 of boiling distilled water, so as to break up and thoroughly 

 detach the milk solids from the capsule, a further addition of 



N 



10 



NaOH is made, until the neutral point is reached. The 



difference between the original acidity of the milk and that of 

 the evaporated portion is regarded as acetic acid. The number 



