Quinone-imine Dyes 133 



ployed either, finding a stronger solution necessary in the case of 

 azocarmine B, which required more application of heat (56°C.) in 

 order to bring it into solution. 



Besides the misspelling "azan carmine" one also frequently sees 

 the name written as two words "azo carmine." The latter is not 

 a serious mistake, but it is preferred here to write it as one word, 

 so as not to imply that it is one of the azo dyes. 



For technic of Mallory-Heidenhain "azan" connective tissue stain, see Staining 

 Procedures, IB3-4. 



For technic of MolIIer's quadruple stain, see Id. p. IB3-7. 

 L35 MAGDALA RED C. I. NO. 857 



Synonyms: Naphthalene red. Naphthalene pink. N aphthylamine 



pink. Sudan red. 



This is a naphtho-safranin, and is a mixture of the monamino 

 and diamino compounds: 



I 

 / \ 



.A 



J, I I NH. ^^, H.N 



CI 



C30H20N3CI; Mol. Wt. 457.941 C30H21N4CI; Mol. Wt. 472.957 



{A basic dye; absorption maximum about 52 J^.) 



A true magdala red put on the market before 1914, and still sold 

 by Grubler and Co., under the name of magdala rot echt, is quite 

 expensive. This same company also sells a product "magdala 

 rot der Handels," and a similar type has been sold by Coleman and 

 Bell in this country. This so-called commercial magdala red is an 

 entirely different dye, erythrosin or phloxine (see p. 195)-an acid 

 instead of a basic dye, and one of an entirely different group. 

 Chamberlain (1927) states that his work with magdala red was 

 done with the latter type, hence actually with phloxine instead 

 of the dye he thought he was using; his results cannot be dupli- 

 cated with true magdala red. This means that in the well-known 

 procedure for staining algae, using this dye in combination with 

 anilin blue, one should actually employ phloxine, not magdala red. 

 (See also discussion under phloxine, p. 196.) The same statement 

 probably applies in the case of Dixon's (1920) magdala red and 

 light green stain for mycelium in plant tissue. 



A magdala red has been employed by Flemming as a nuclear 



