32 
and the best results are obtained by intimately mixing the very small 
amounts of saccharin employed in the tests with the smallest amount 
of the reagent that can be got on the tip of a small glass rod by just 
touching the glass rod to the surface of the reagent. In order to 
arrive at some exact notion respecting the delicacy of the reaction the 
following tests were carried out, with the following results: 
An aqueous solution of Merck’s saccharin was prepared containing 
0.5 milligram of saccharin in each cubic centimeter. In order to 
determine the delicacy of the reaction, known amounts of this solution 
were evaporated to dryness in a small porcelain dish. To the residue 
small amounts of the reagent were added in the manner indicated 
above. This was then thoroughly stirred into the residue by means of 
a glass rod, and the dish with its contents was then put in an air oven 
heated to 150°-170° C. and allowed to remain therein for five or ten 
minutes. When heated for this length of time at this temperature 
the mixture takes on a purplish-red color if saccharin be present. 
After heating the desired length of time, the dish was removed from 
the oven and allowed to cool and water added. The results obtained 
with various amounts of the standard solution of saccharin are given 
in the following table: 
Cubic centi- 
meters of sac- 
charin solution 
used. 
Quantity of 
saccharin 
present, in 
milligrams. 
Color with alkali. I 
0.5 
0. 25 
Dark purplish-red. 
2 
. 10 
Decided purplish-pink. 
. 1 
. 05 
Distinctly pink. 
. 05 
.025 
Do. 
This last test was repeated three times with the same result. In 
testing for such minute quantities of saccharin, however, care should 
be taken to use only very small amounts of the reagent. It will also be • 
found advantageous with these very small amounts to keep the tem- 
perature between 145°-160° C. 
It should be borne in mind, of course, that orthophthalic acid and 
its derivatives, and also orthosulphobenzoic acid and its derivatives 
other than saccharin, would yield colored compounds with this reagent. 
This, however, is of no consequence, inasmuch as none of these are 
used in the preparation and preservation of food stuffs, and, further- 
more, these compounds differ from saccharin in not having a sweet 
taste, so that, taking into consideration the facts as we know them, it 
narrowed itself down to determine whether such substances as benzoic 
and salicylic acids give a color by heating with this reagent, which 
might be confused with that obtained with saccharin. The conduct of 
these acids toward the reagent here employed was tested in the manner 
