SECTION ONE 



NITROSO GROUP 



Chromophore : — N = 



The nitroso dyes form a very small group. They are all acid 

 dyes. Only two, namely, naphthol green B and naphthol green 

 Y, have so far been used in biology. 



Naphthol green B is used as a stain for collagen, etc. 



Naphthol green Y has not, as far as I am aware, been used for 

 staining microscopic tissue preparations; its tinctorial properties 

 are poor. However, Ingraham & Visscher (1935) and Visscher 

 (1942) employed the dye, macroscopically, in their studies of the 

 secreting mechanism of gastric glands and pancreas. 



NAPHTHOL GREEN B 



Michrome No. 192. Molecular weight 878. An acid dye, 

 pH 6-85*. Solubility at 15° C: water 10%, absolute alcohol 3%. 



NaOgS- 



N— O 



Fe 



1% in neutral distilled water; see pages 17 and 29. 



59 



