200 CHAPTER XVI. 



A solution of one part of metliylen blue and one of carbonate 

 of potash in twenty of alcohol and a hundred of water is 

 evaporated down to a hundred parts. (It may be used at 

 once, or after diluting with an equal volume of anilin water, 

 for sections, which after staining may be differentiated with 

 glycol, creosol, or Unna's glycerin-ether mixture all of 

 which, as well as the polychrome methylen blue, can be 

 obtained from Grubler & Hollborn.) MICII^LTS (op. cit.) 

 makes it as follows : 2 gr. of medicinal methylen blue are 

 dissolved in 200 c.c. of water, and 10 c.c. of -^ normal solu- 

 tion of caustic soda added. Boil for a quarter of an hour; after 

 cooling add 10 c.c. of yg- normal sulphuric acid, and filter. 



Methylenazur is isolated from methylen blue by the prolonged action 

 of an alkali or of silver oxide. It seems also that it is formed in certain 

 mixtures of methylen blue witheosin (ROMANOWSKY, LAVERAN, GIEMSA 

 and others), by means of the eosin, which in these mixtures acts chemi- 

 cally, and can be replaced by resorcin, hydroquinon, and the like. It is best 

 procured from Grubler & Hollborn, who supply it pure as " Azur I," 

 and mixed with an equal quantity of methylen blue as " Azur II." See 

 further as to this dye under " Stains for Blood." 



There are several sorts of methylen blue sold, the most 

 important being " methylen blue, according to EHKLICH " ; 

 "methylen blue, according to KOCH"; "methylen blue 13X, 

 according to S. MAYER " ; " Methylenblau, medic, pur." 



The colour to be employed for intra-ritam nerve staining 

 should be as pure as possible. APATHY (Zeit. wiss. Mik., ix, 

 1893, p. 466) writes that the best in fact, the only one that 

 will give exactly the results described by him is that of E. 

 MERCK, of Darmstadt, described as " m edicinischcs Methylen- 

 blau." DOGIEL (Encycl. mik. Technik., 1st edition, p. 811) 

 has had his best results with " Methylenblau n. Ehrlich," or 

 " BX," obtained from Grubler & Hollborn. 



338. The Uses of Methylen Blue. As a histological reagent 

 it is used for sections of hardened central nervous tissue, in 

 which it gives a specific stain of medullated nerves. It 

 gives more or less specific stains of the basophilous granula- 

 tions of " Mastzellen " and plasma-cells, and the granules of 

 NISSL in nerve-cells, also mucin. It is much used in the 

 form of mixtures affording methylen azur in the study of 



