two compounds and differ from one another in the number of 

 methyl, ethyl, or phenyl groups introduced, and according to 

 whether they are introduced into the amino groups or directly 

 onto the benzene rings. 



a. Di- AMINO Tri-phenyl Methanes 



MALACHITE GREEN C. I. NO. 657 



Synonyms: Emerald green. New victoria green. Diamond green. 



Solid green. Light green N. 



_C 



{Absorption maxima: 616, [4^0] ) 



Malachite green is a rather weakly basic dye that has been used 

 in the past for various histological purposes; as by V. Beneden for 

 staining Ascaris eggs, by Petroff for staining erythrocytes, and by 

 Maas as a contrast stain following borax carmine. Today it has 

 very largely been replaced by methyl green; but it is now often 

 used by botanists for staining host tissue in plants infected w4th 

 fungi, according to the technic of Pianese (with acid fuchsin and 

 martins yellow), which was originally applied to cancer tissue. 



BRILLIANT GREEN C. I. NO. 662 



Synonyms: Ethyl green. Malachite green G. 



This is a basic dye which is generally known in the form of the 

 sulfate : 



CH3CH. SO.H / \_N 



CH2'CH3 



/ 



CH.CH3 



{Absorption maximum: 623.) 



The largest call for brilliant green at present is as an indicator 

 in media for water analysis, according to the technic of Krum- 

 wiede. It is also used for inhibiting the colon organism in stools; 

 and is added to broth for the enrichment culture of the typhoid 

 bacillus. 



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