STAINING, PRACTICAL AND THEORETICAL 



FUCHSIN ACIDt 



Michrome No. 5. Molecular weight 586. An acid triphenyl- 

 methane dye, pH 5'0*. Solubility at 15° C: water in all proportions, 

 absolute alcohol 3 % . 



H2N— /~^— 



SO3- 



CHs 



NH2 



NH2 



SOsNa 



LIGHT GREEN SF YELLOWISH 



Michrome No. 240. Molecular weight 793. An acid triphenyl- 

 methane dye, pH yi"^. Solubility at 15° C; water 20%, absolute 

 alcohol 4%. 



-O3S 



SOaNa 



SOgNa 



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



t Note: Fuchsin acid is the parent substance of a new group of dyes, the 

 fuchsinic acids, recently discovered. 



68 



