98 Biological Stains 



NH. HaN OH 



_N = N_/\/%_N = N_/ 



NaSOj NaSOi 



C34H25N907S2Na2; Mol. Wt. 781.726 



{An acid dye; absorption maximum 598-602 in alcohol.) 



This dye has only recently been introduced into microscopic 

 technic, Cannon (1937) having called attention to its use in gen- 

 eral histology and cytology. It proves to be a valuable stain 

 because it can be employed without mordanting or differentiation 

 and gives a very sharp clear-cut picture both of nuclear and 

 cytoplasmic structures. The black and gray tones it produces are 

 well suited for photography. 



For use as general stain in animal histology, see Staining Procedures, p. 1A4-9, 



For use as general stain in plant histology, see Id. p. IIA-6. 



For use as plant cytologlcal stain with aceto-carmlne, see Id. p. IIB-4. 



A spectral curve of this dye is given in graph 2, Fig. 10, p. 91. 

 It will be noticed that the black nature of the solution is indicated 

 by partial absorption through the whole visual range, with only 

 minor peaks at any wavelength. 



d80 SUDAN BLACK B 



_N = N _/~\_N = N _ 



C29H22N6; Mol. Wt. 554.414 

 {Absorption maximum 596-605.) 



This compound is one of the most recently developed fat stains. 

 For a fat stain it has a rather unusual chemical structure, as it 

 does not show the typical -OH group in the ortho (or beta) position. 

 It was first prepared in Germany some time in the early '30's, and 

 became available in France and England. Lison and Dagnelie 

 (1935) proposed it as a myelin stain; but it was in England that its 

 value as a stain for fats was first developed (Gerard, 1935). 

 During the second World War it achieved general recognition for 

 the purpose, both in Great Britain and in the United States. 

 Hartman (1940) and later Burdon et at. (1942) found it valuable 

 as a stain for bacterial fat. It has also been proposed for staining 

 leucocyte granules and the Golgi apparatus. 



