DETECTION OF ADULTERATION 57 



older tests. A solution is made by dissolving 

 0-035 gram pure morphin sulfate in 10 c.c. of 

 sulfuric acid. This solution does not keep well. 

 A convenient amount of the sample is placed in 

 a dish or beaker, a watch-glass containing i c.c. 

 of the above solution is floated on it, and the dish 

 covered with a glass plate. The materials are 

 allowed to remain undisturbed at room-tempera- 

 ture for several hours. Formaldehyde is in- 

 dicated by the development of a color ranging 

 from pink to dark blue. A black discoloration 

 is disregarded. Bonnet found that with i part 

 of formaldehyde to 25,000 parts of sample a 

 distinct color appeared in one hour. 



In testing ice-cream and similar articles it 

 must be borne in mind that some of the flavor- 

 ing materials being aldehydic in nature may 

 simulate formaldehyde. La Wall has found 

 that vanillin may act thus. The phenylhydrazin 

 and Bonnet tests are least liable to fallacy in this 

 respect. 



Nitrites and Formaldehyde. — Mixtures of these 

 substances are now sold under fanciful and mis- 

 leading names, for milk preservatives as a 

 nitrite prevents the reactions of formaldehyde 

 with some of the tests. 



Leffmann has found that the phenylhydrazin 

 test will react promptly with formaldehyde in 

 presence of notable amount of nitrite and also 



