416 SOME OTHER HISTOLOGICAL METHODS. 



transferred to alcohol, which, washes out the stain from all 

 but the plasma-cells, and may then be mounted in the resin- 

 turpentine solution. 



Mucus-cells and fat-cells are also sometimes stained by 

 these solutions. 



Other Media. In a similar way other soluble anilins may 

 be employed (in the form of a fluid containing 1\ per cent, 

 of acetic acid), primula, iodine violet, methyl violet, pur- 

 purin, safranin, fuchsin ; of these, methyl violet gives the 

 best results. 



790. Plasma-cells (NOEDMANN, Beitr. z. Kenntniss d. Mast- 

 zellen, Inauguraldiss., Helmstedt, 1884). Nordmann finds it 

 useful to employ a solution of vesuvin containing 4 to 5 per 

 cent, of hydrochloric acid. Sections should remain for a few 

 minutes in the solution, and then be dehydrated with absolute 

 alcohol. The paper quoted contains a detailed discussion of 

 the microchemical reactions of granule-cells. 



791. " Mastzellen." SCHIEFFEEDECKEE (SCHIEFFEEDECKEE AND 

 KOSSEL'S Gewebelehre, p. 329) recommends the following, 

 after OETH. A piece of mesentery of a rat is brought into a 

 solution of gentian violet in anilin water (101), which is 

 carefully heated over a flame until vapour begins to be given 

 off, and then allowed to remain for a couple of hours (or the 

 heating may be omitted, and the preparation allowed to stand 

 for twenty-four hours). It is then rinsed in water, washed 

 out until almost colourless in hydrochloric acid alcohol, rinsed 

 in water, counterstained (if desired) in carmine, and mounted 

 in balsam. Nuclei red, granules blue. 



792. Plasma Cells and Mastzellen. UNNA, in his paper, ZeiL 

 f. wiss. Mik., viii, 4, 1892, p. 475, gives the following : 



A. For Plasma Cells. 



Methylen blue ..... 1*0 

 Caustic potash ... . 0'05 



Distilled water lOO'O 



Add a few drops of this to ten, fifty, or one hundred vols. 

 of anilin water ( 101) in a watch-glass, and stain (alcohol 

 material, or at most sublimate and alcohol material, not 

 chromic material) for half an hour, several hours, or over- 



