78 MILK PRODUCTS 
Acid Mercuric Iodid——Mercuric chlorid, 1.35 
grams; potassium iodid, 3.32 grams; glacial acetic 
acid, 2 c.c.; water, 64 c.c. 
Alumina-cream.—A cold saturated solution of 
alum is divided into two unequal portions, a 
slight excess of ammonium hydroxid is added 
to the larger portion and the remainder added 
until a faintly acid reaction to litmus is obtained. 
The entire contents of the can are transferred 
to a porcelain dish and thoroughly mixed. A 
number of portions of about 25 grams are 
weighed carefully in 100 c.c. flasks. Water is 
added to two of the portions, and the solutions 
boiled. The flasks are then cooled, clarified by 
means of a small amount of the acid mercuric 
iodid and alumina cream, made up to mark, 
filtered, and the polarimetric reading noted. 
Other portions of the milk are heated in the 
water-bath to 55°; one-half of a cake of com- 
pressed yeast is added to each flask and the 
temperature maintained at 55° for five hours. 
Acid mercuric iodid and alumina-cream are 
then added, the solution cooled to room tem- 
perature, made up to mark, mixed, filtered, and 
polarized. The amount of sucrose is determined 
by formula given above. Correction for the 
volume of precipitated solids may be made by the 
double-dilution method. The total reducing 
sugar is estimated in one of the portions by one of 
