80 Biological Stains 



sections of embryos, and has been employed in the vital staining 

 of fungi and protozoa; also the supravital staining of blood 

 (Sabin, 1929). 



Soep (1927) proposes it in place of methylene blue for studying 

 reductase production in milk. 



A spectrophotometric curve of this dye is given in graph 1, Fig. 

 8, p. 79. Like other green dyes, it has two absorption maxima, 

 one in the violet and the other near the orange range. 



For use in Supravital staining of blood, see Staining Procedures, p. ID3-9. 

 For use in Lillie modification of Ziehl-Neelsen technic, see Id., p. IIIB3-II. 



c52 JANUS BLACK C. I. NO. 134 



Synonym: Diazine black. 

 CH3 



/\/=N-\/\ /~\_0H 



NH2 / \ N = N-\_/ 



CI /-\ 



C25H20N5OCI; Mol. Wt. 441.907 

 {A basic dye) 



It will be seen from the above formula that this dye, like Janus 

 green B, is an azo-safranin. It has rarely been called for in biol- 

 ogy; but according to Maheshwari and Wulff (1937), Brestlavetz 

 has employed it in vital staining pollen tubes. 



c68 METANIL YELLOW C. I. NO. 138 



Synonyms: Orange MNO or MN. Acid yellow R. Soluble 

 yellow OL. Yellow M. Tropaeolin G. 



NaSOa 



N=N_/~\_NH_ 



CisHuNaOaSNa; MoL Wt. 375.373 



{An acid dye; absorpiton maximum 536 in hydrochloric acid 



solution) 



Solubility at 26° C: in water 5.36%; in alcohol 1.45% 



In Masson's (1929) technic (see Foot, 1933) this dye is used as a 

 connective tissue stain following hematoxylin and acid fuchsin. 



For a technic adapted from Masson (1923), calling for Mucicarmine with hema- 

 toxylin and metanil yellow, see Staining Procedures, p. IA4-7. 



