Miscellaneous Dyes 231 



Fl5 TITAN YELLOW G C. I. NO. 813 



Synonym: Thiazol yellow. 



S SOiNa SOiNa S 



I 

 C 



C28Hi9N506S4Na2; Mol. Wt. 695.706 

 [An acid dye) 



This dye has been recommended as an indicator for determining 

 magnesium in body fluids. After removing the organic matter 

 and calcium from such solutions the dye is added; under alkaline 

 conditions it becomes red in the presence of magnesium and the 

 color observed can be compared with that of a standard previously 

 prepared. 



Also, like the two preceding dyes, it has been employed in fluores- 

 cence microscopy; it is one of those recommended by Pick (1935) 

 and by Jenkins (1937) as a vital stain under ultra-violet illumina- 

 tion. 



Fl7 THIOFLAVINE T C. I. NO. 815 



Synonym : Thioflavine T G 



CH3_/\_S 



\ /~\_N_CH3 

 _ N=C-\_/ \ 



1\ CH3 



CI CH3 



Ci7 Hi9 No SCI; Mol. Wt. 318.861 

 {A basic dye) 



Like the other related dyes here described, this one has proper- 

 ties as a fluorochrome; thus Metcalf and Patton (1944) have em- 

 ployed it, with ultraviolet light, in insect histology. 



f20 THIOFLAVINE S C. I. NO. 8l6 



{An add dye; a methylated and sulfonated derivative of primulin) 



This is among the dyes that has recently come into use in con- 

 nection with fluorescence microscopy. Pick (1935) employed a 

 thioflavine as a vital stain, depending on its fluorescence under 

 ultra-violet light; probably he referred to this although there is also 

 a thioflavine T (C. I. No. 815). More recent authors (Jenkins, 

 1937, Levaditti, et al., 1940) definitely refer to thioflavine S, and 



