Phenyl Methane Dyes 141 



The individual dyes of this series are substitution products of these 

 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 



m50 malachite green C. I. NO. 657 



Synonyms: Victoria green B or WB. New Victoria green extra, 0, / 

 or II. Diamond green B, BX, or P extra. Solid green 0. 



Light green N. 



Various brands denoted: Malachite green A, B, BX, 4B, J3E, 

 J3ES, NB, NH, or NJ. 



CH3 



/ 

 CH3 CI /~\_N 



\ I /\_/ \ 



N_/~\_C CH3 



CH3 \_/ 



C23H25N2CI; Mol. Wt. 364.903 

 {Absorption maxima: 617-619, [425]) 



See Fig. 18 for spectral curve. 



Malachite green is a rather w^eakly 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; see Krause 

 (1926-7), p. 1353. Today it has very largely been replaced by 

 methyl green; but it is still called for in special procedures, of 

 w^hich the following might be listed by way of illustration: w^th 

 acid fuchsin and martins yellow in the Pianese (1896) technic 

 which w^as originally applied to cancer tissue but is now much 

 more widely used in plant pathology; in its reduced (leuco) form, 

 by Chapman and Lieb (1937), as a reagent (although less sensitive 

 than crystal violet) for bacterial polysaccharides; as a bacterio- 

 static or amebicidic agent (Verona, 1935; Tsuchiya, 1936); as a 

 vital stain for nulei of epidermis stains of the onion (Bank, 1938); 

 by Schaeffer and Fulton (1933) as a bacterial spore stain; in place 

 of methyl green in the Pappenheim stain, when combined with the 

 Gram stain (Sandiford, 1938); also as a constituent of certain 

 bacterial stains. 



For technic of Pianese IIIB stain for fungi In plant tissue, see Staining Pro- 

 cedures, p. IIA-12. 



For technic of SchaeflEer and Fulton method of spore staining, see Id. p. IIIA2-IO. 



For technic of Laybourn modification of Albert stain for diphtheria (which calls 

 for this dye, mixed with toluidine blue), see Id. p. IIIA2-n. 



