33 
above described, with the result that both of them gave only slightly 
3 r ellowish solutions after heating with the reagent and the addition of 
caustic soda. In this connection it was also found that even when 
mixed with saccharin they in no way interfered with the delicacy of 
the test as ordinarily carried out. Similarity it was found that neither 
cumarin nor ethyl parasulphobenzoate gave any color test with the 
reagent. 
CONDUCT OF VANILLIN TOWARD PHENOL AND SULPHURIC ACID. 
A consideration of the possible substances which might occur 
together with saccharin in certain food stuffs and other preparations 
led to the thought that possibly vanillin might under some circum- 
stances be present along with saccharin in certain preparations, the 
one as a flavoring, the other as a sweetening agent. 
It therefore occurred to me to test the conduct of vanillin toward the 
reagent. It was found that when a minute quantity of vanillin is mixed 
with the reagent, it begins to turn yellow and then red even in the 
cold, and when kept at 160°-170° C. for live minutes, the mass first 
becomes blood red in color and finally almost black. If the mass be 
then dissolved in water and a few drops 2N sodium hydroxide added, 
the solution becomes deep purplish red in color. 
This in itself is an exceedingly delicate reaction for vanillin and is 
one which at first glance might be thought to seriously interfere with 
the use of phenol and sulphuric acid as a reagent for saccharin. How- 
ever, it is a very easy matter to distinguish between saccharin and 
vanillin by means of this reagent on account of the marked difference 
in the conduct of the two substances toward it at certain temperatures. 
As indicated in the above, the reagent begins to act on vanillin even 
in the cold, whereas it has no action on saccaharin even at 100° C. 
Advantage is therefore taken of this fact in distinguishing between 
vanillin and saccharin. That it is a very simple matter to distinguish 
between the two in this manner may be seen from the following: 
Minute quantities of vanillin and saccharin, respectively, were mixed 
with a small amount of the reagent and heated for five minutes in a 
bath of boiling water. The mass containing the vanillin became blood 
red in color under these conditions, and on the addition of water it 
gave a pink, somewhat turbid, solution which, on the addition of a few 
drops of 2N sodium hydroxide, became clear and deep purplish-red in 
color. On the other hand, the mass containing the saccharin remained 
colorless, and with water and alkali gave a perfectly clear, colorless 
solution. In spite of the fact, therefore, that both of these substances 
produce red coloring matters when heated with phenol and sulphuric 
acid, it is still an easy matter to distinguish between them by means 
of this reagent. 
