SAFRANIN. 65 



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 saf ranin 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 re- 

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

 Griibler and by Miinder, have been studied by RESEGOTTI (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 " Saf ranin 

 wasserloslich," " Saf ranin spiritusloslich," " XX," " XXBN," " TB," fur- 

 nished 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 PFITZNER 

 (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 

 solution and concentrated aqueous solution (this is very much 

 to be recommended), and (B) a concentrated or supersaturated 

 aqueous solution made with the aid of heat. 



Some people still employ simple aqueous solutions. 



Lastly, there is the anilin solution of BABES (Zeit. f. wiss. 

 Mik., iv, 4, 1887, p. 470). It consists of water 100 parts, 

 anilin oil 2 parts, and an excess of safranin. The mixture 

 should be warmed to from 60 to 80 C., and filtered through 

 a wet filter. This solution will keep for a month or two. 



ZWAARDEMAKER (Zeit. f. wiss. Mik., iv, 2, 1887, p. 212) 

 makes a mixture of about equal parts of alcoholic safranin 

 solution and anilin water (saturated solution of anilin oil in 

 water; to make it, shake up " anilin oil," which is nothing 

 but pure anilin, with water, and filter). 



Any of these stains may be used with any of the following 



5 



