XHa H.X_ I I If NH. 



and 



(A basic dye; absorption maximum about 521^.) 



A true Magdala red put on the market before the war under the 

 name of Magdala red echt is very expensive. According to Cham- 

 berlain (19'24 page 58) this is less satisfactory in botanical work 

 than a cheaper form of Magdala red formerly available not labeled 

 "echt." Chamberlain further states that he has been able to 

 obtain recently results with phloxine identical with those which he 

 used to be able to obtain with the less expensive form of Magdala 

 red. A sample of the latter examined by the Commission proves 

 apparently to be erythrosin, — in other words an acid dye of an 

 entirely different group and very closely related to phloxine. This 

 makes Dr. Chamberlain's failure to obtain results with Magdala 

 red echt entirely comprehensible. (See also discussion under 

 phloxine and erythrosin page 81-8'2.) 



Magdala red is used by botanists with anilin blue, in staining 

 algae. It was used by Flemming as a nuclear stain, and by Kult- 

 schitzky for staining elastic tissue. 



c. THE IXDULIXS 



Indulins are similar to safranins but are more complex: being 

 quite highly phenylated amino derivatives. The only one to 

 concern us is: 



XIGROSIX, WATER SOLUBLE C. I. NO. 865 



Synonyms: Xigrosin W, WL, etc. Gray R, B, BB. Silver gray. 



Steel gray. Induliri black. 



{A basic dye; absorption maximum about 587.) 



The exact constitution of nigrosin is uncertain. It is recom- 

 mended by Ehrlich for staining the tissue of the central nervous 

 system either alone or in combination with other stains, and by 

 Jarotsky for staining pancreatic tissue following haematoxylin . 

 Botanists use it in studying algae and fungi. Pfitzer's picro- 

 nigrosin serves as a chromatin stain. Nigrosin is also used by 

 Unna in combination with ''orange" (orange G?) in the study of 

 the process of chromolysis. 



57 



