SAFRANIN. 63 



/. mile. Anat., xiii, 1876, p. 263). For these the aqueous solution must be 

 acidulated with (7*5 per cent.) acetic acid; or you may stain in a neutral 

 solution, and wash out with acidulated water. Dehydrate with alcohol and 

 mount in turpentine colophonium. It is also useful for staining intra vitam. 

 See above, 93. 



For the specific staining of Ehrlich's " plasma cells " (see post, Part II). 



103. Safranin. One of the most important of these stains, on 

 account of its great power, brilliancy, and superior permanence 

 in balsam, and also on account of the divers degrees of electivity 

 that it displays for the nuclei and other constituent elements 

 of different tissues. 



The great secret of staining with safranin is to get a good 

 safranin. It is needful here to insist most urgently on what 

 was said above, 94, sub finem. Before thinking of working 

 with this important reagent, you should go to Griibler or to 

 Miinder and order the safranin you want, specifying whether 

 you want it for staining nuclei or for staining elastic fibres, or 

 for what other purpose you may require it. 



There are presumably at least a score of sorts of safranin in the market, 

 differing to a considerable extent in colour, weight, solubility and histological 

 action. Some are easily soluble in water and not so in alcohol, some the reverse, 

 and some freely soluble in both. Fourteen brands, supplied by Griibler and 

 by Miinder, have been studied by RESEQOTTI (Zeit. f. wiss. Mik., v., 3, 1888, 

 p. 320). They all gave positive results with the chromic acid method, to be 

 detailed below ; although Griibler had explained that the brands XX, 

 XXBN, TB, had not given positive results (with the usual methods). 

 Resegotti obtained his best results with the brands " Safranin wasserloslich," 

 " Safranin apiritusloslich," " XX," " XXBN," " TB," furnished by Griibler, 

 and with the brands " Rein," " 0," " FII," and " Cone.," supplied by Miinder. 



Staining. 



The majority of safranins are not sufficiently soluble in 

 water, so that solutions in other menstrua must be employed. 



A solution much used some time ago is that of PFITZNEK 

 (Morph. Jahrb., vi, p. 478, and vii, p. 291), composed of saf- 

 ranin 1 part, absolute alcohol 100 parts, and water 200 parts, 

 the last to be added only after a few days. 



The solution of FLEMMING (Arch. f. mik. Anat., xix, 1881, p. 

 317) is a concentrated solution in absolute alcohol, diluted 

 with about one half of water. 



The solutions of BABES (Arch. f. mik. Anat., 1883, p. 356) 

 are (A) a mixture of equal parts of concentrated alcoholic 



