142 H. J. CONN 



These stains may be grouped in the following three categories : 



Methyl violet 

 Methyl violet B 

 Methyl violet 2B 

 Methyl violet BS 

 Methyl violet BN 

 Methyl violet BO 

 Methyl violet BBN 

 Dahlia B 



Under these designations are sold certain mixtures of the tetra- 

 methyl and pentamethyl compounds, in varying proportions, 

 sometimes also containing the hexamethyl compound as well. 

 The letters following the name are used in the trade to indicate 

 the shade, methyl violet B and methyl violet 2B, for example, 

 each being progressively deeper in shade than plain methyl 

 violet. The trade designations do not refer to chemical compo- 

 sition except in so far as the deeper shade indicates a more 

 highly methylated compound. 



ir 



Benzyl violet 

 Methyl violet 5B 

 Methyl violet 6B 

 Methyl violet 7B 



These dyes are benzylated compounds, generally mixed with 

 some of the purely methyl compounds above mentioned. The 

 number of B's in the trade designation indicates the depth of 

 violet produced in dying. 



Ill 



Crystal violet 



This dye is the pure hexamethyl compound. It is the most 

 readily obtained in pure state of the whole group, and there is 

 less confusion in regard to its composition than in regard to any 

 of the others. 



