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Nitrogenous Bodies. 



Since indol and skatol have been known as constituents of essential 

 oils, efforts have been made to determine the presence of these bodies 

 by the clearest possible reactions. As stated in our last Report 1 ) 

 F. Weehuizen has utilized Steensma's colour- reaction of indol for the 

 purpose of determining their presence. The process published by 

 C. Gautier and T. Noyer 2 ) is based upon the same principle, with the 

 exception that chloroform is used for extracting. This method makes 

 it possible to detect the presence even of traces of the two bodies 

 referred to. 5 cc. of the liquid under examination are shaken up with 

 5 cc. of a 5% alcoholic solution of p-dimethylamido benz- 

 aldehyde, next diluted with 1 cc. of pure concentrated hydrochloric 

 acid and the solution extracted with 5 cc. chloroform. If indol - is 

 present the chloroform assumes a carmine colour; if skatol, it turns 

 blue 3 ). In the presence of a mixture of the two bodies the chloro- 

 form acquires a violet tint. The spectra of the two colours also differ. 



x ) Report April 1909, 140. 



2 ) Compt. rend. soc. biol., 19 Dec. 1908. Quoted from Bull. Soc. chim, IV. 5 

 (1909), 256. 



3 ) Weehuizen in his paper has already referred to this blue colouring. 



