40 MILK 
alcoholic solution of phenolphthalein added and 
the titration made with standard alkali. Thérner 
proposes that the number of c.c. required should 
be multiplied by 10 and the result termed the 
‘“‘degree of acidity.” Fresh normal milk will 
show figures ranging from 16 to 18. When the 
degree of acidity is 23 or over, the sample will 
coagulate on heating. 
The process involves a slight error, in that the 
addition of a notable amount of water to a milk 
sample disturbs somewhat the relation of the 
phosphates and diminishes the acidity. It may 
be advisable to titrate the undiluted milk. If 
the number of c.c. used is multiplied by 0.9 the 
lactic acid equivalent to the acidity of the sample 
is given in grams per 1000 C.c. 
