Xanthene Dyes 



189 



Yellowish eosin is one of the most valuable plasma stains known. 

 It is used in various technics for staining the oxyphile granules of 

 cells (i.e., the granules having special affinity for acid dyes); these 

 cell elements, in fact, being often called eosinophile granules be- 

 cause their presence was first recognized through the use of this 

 dye. It is often employed as a counterstain for hematoxylin and 

 the green or blue basic dyes; as for example by List with methyl 

 green. Its uses, however, are really too numerous to list. At 

 the present time one of the uses for which it is in greatest demand 

 is as a blood stain in the technic of Romanovsky, with its various 

 modifications, in which it is combined with methylene blue to form 

 a "neutral" stain. 



A dye mixture sold under the name of "Triosin", was described 

 by Galigher (1934), and sold by him without stating its composi- 

 tion. The mixture proves valuable as a counterstain in some pro- 

 cedures where eosin Y alone gives less satisfactory results. Re- 

 cently Emery and Stotz (1952) used this product as an unknown 

 in a test of filter paper chromatography for dye analysis. In the 

 course of this investigation the composition of the mixture became 

 evident, and was stated by these authors as being apparently 62% 

 eosin Y, 28% orange G, and 10% erythrosin Y. A spectral curve 

 of the mixture, however, does not reveal the presence of either of 

 the two latter dyes, but seems practically identical with that of 

 eosin Y alone. 



PROCEDURES RECOMMENDED BY THE COMMISSION IN WHICH THIS STAIN IS USED* 



*Under this heading are given references to procedures described in detail in 

 Staining Procedures, edited by Conn and Darrow (1943-4). 



r8 



METHYL EOSIN 



Synonym: Eosin, alcohol soluble. 



c. I. NO. 769 



This is the methyl ester of yellowish eosin, the sodium salt of 

 which is: 



