Phenyl Methane Dyes 171 



Usually the calcium salt of the following: 



C,H= 



/ 

 N 



SO3 CoHi 



N_/-\_C / 

 / \_/ \/-\_S03H 

 C2H5 \_/ 



\ 

 OH 



(C27H3xNAS2)2 Ca; Mol. Wt. 1159.388 

 {An acid dye) 



This dye has rarely been mentioned in biological literature; but 

 is included by Ono (1934) among those employed for staining 

 spirochaetes; it is mentioned by McMaster and Parsons (1938) as 

 a vital stain, and by Yoe and Boyd (1939) as an acid-base and oxi- 

 dation-reduction indicator. 



n80 



Chambers (1935) has included this among several dyes which he 

 studied in connection with the uptake of dyes by cells in tissue cul- 

 ture. A cyanol, probably this one, has been used by Fautrez 

 (1936) in histochemistry, as an intracellular indicator; and by 

 Ivanov and Braun (1938) in the study of permeability of tissue 

 membranes. 



c. Hydroxy Tri-phenyl Methanes (Rosolic Acids) 



The rosolic acid dyes, as stated above, are tri-phenyl methane 

 derivatives in which the amino groups of the rosanilins are re- 

 placed with hydroxyl groups, thus giving them acidic instead of 



