i8. Detection of Lactic and Glycolic Acids and a sugges- 



me. 



tion regarding the Constitution of Morph 

 By S. C. Chatterji. M.Sc Cotton College, Gauhati. 



When aeetaldehyde is added to a solution of benzidine 

 p—p diamino— diphenyl) in concentrated sulphuric acid, the 

 liquid gradually assumes a dark -red colouration. Under iden- 

 tical conditions formaldehyde brings about no perceptible 



Benzidine. 



change, or at best a slight yellowish colouration. The reaction 

 may serve both as a test for benzidine and for differentiating 

 between the two aldehydes. The fact that aeetaldehyde is 

 produced when lactic acid is warmed with concentrated sul- 

 phuric acid, enables the reaction to be employed as a test for 

 tms substance as well. It may be carried out by shaking up a 

 pinch of benzidine with about 4 cc. and then slowly adding a 



C H 



4h 4 / 



Carbazole. 



few drops of the liquid supposed to contain lactic acid. If 

 the mixture be next gentlv warmed, aeetaldehyde will be pro- 

 ceed, and the solution will assume a red colouration, its inten- 

 sity depending, up to a certain point, on the amount of the acid 

 Present. Lactic acid mav also be detected and distinguished 

 from the similarly constituted glycolic acid by the carbazole- 

 a| dehvde reaction. If about 1 gram of carbazole be added 



