Nitro and Azo Dyes 



79 



C2H 



2"5 



N 



N 



/ 



CH, 



C2H 



N / \ N^N 



/ /\ CI 



CH, 



zns 



r 



CsoHsiNeCl; Mol. Wt. 511.053 



{A basic dye; absorption maximum about 610-623) 



Solubility at 26° C: in water 5.18%; in alcohol 1.12% 



Janus green is best known for its use in demonstrating chondrio- 

 somes, stained intra vitam, according to the technic of Michaelis 

 (1900), and as more recently developed by Cowdry, and by Bens- 

 ley (1911). It is also used by Faris (1924) with neutral red for 



I 



I 



I 



I 



bJ 

 O 



3 

 8 •-• 



400 



• I I I I • I I ^ I I I 



460 520 580 640 

 WAVELENGTH Tn>l 



Fig. 8. Spectral curves of two azo dyes: 

 1. Janus greeru 2. Congo red. 



I J 



700 



