DETECTION OF ADULTERATION 47 
5% solution of uranium acetate, shake well, al- 
low to stand for five minutes and filter. To 10 c.c. 
of the clear filtrate (in the case of cream use the 
total filtrate, which will be less than 1oc.c.) adda 
mixture of 2 c.c. saturated ammonium molyb- 
date and 8 c.c. dilute hydrochloric acid (1 part 
25% acid and 7 parts water), and place in a 
water-bath at a temperature of 80° for five minutes. 
If the sample contains sugar the solution will 
have a prussian blue tint. This should always 
be compared in a colorimeter with the standard 
prussian blue solution prepared by adding a few 
drops of potassium ferrocyanid and 5 drops of 
10% hydrochloric acid to a solution of 1 c.c. of 
0.1% ferric chlorid in 20 c.c of water. 
It has been claimed that pure milk will give 
this test. Occasionally samples of pure milk will 
give a pale blue, but this can be entirely removed 
by filtration, and the filtrate will be green; while 
the color due to sucrose will pass through the 
filter, giving the blue solution characteristic of 
adulterated samples. The color is due to re- 
duction of molybdic acid, and is caused by 
levulose and dextrose as well as by sucrose. 
Solutions of 1 gram of lactose, levulose, dextrose 
and sucrose in 35 c.c of water were used in com- 
paring the amount of color produced when heated 
with the molybdenum reagent for five minutes. 
Lactose produced no color, levulose gave a heavy 
