NUCLEAR STAINS WITH COAL-TAR DYKS. 177 



mid the divers degrees of electivity that it displays for the 

 nuclei and other constituent elements of different tissues. 



The great secret of staining witli safraniii is to get a good 

 xdfranin. In ordering it, from Griibler & Hollborn or else- 

 where, it is well to specify 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. The brand I 

 have been using for a long time, which gives good results, is 

 the " Safranin O " of Grubler & Co. 



Staining. The majority of safranins are not sufficiently 

 soluble in water, so that solutions in other menstrua must be 

 employed. 



PiTi'ZNER (Morph. Jahrb.i vi, p. 478, and vii, p. 291) advised 

 a solution of safranin 1 part, absolute alcohol 100 parts, and 

 water 200 parts, the last to be added only after a few days. 



FLEHMING (Arch. mik. Anat., xix, 1881, p. 317) used a 

 concentrated solution in absolute alcohol, diluted with about 

 one half of water. 



BABES (ibid., 1883, p. 356) used (A) a mixture of equal 

 parts of concentrated alcoholic solution and concentrated 

 aqueous solution (this is very much to be recommended), or 

 (B) a concentrated or supersaturated aqueous solution made 

 with the aid of heat. 



Some people still employ simple aqueous solutions. 



The anilin solution of BABES (Zeit. wiss. Mik., iv, 1887, p. 

 470) 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 (ibid., iv, 1887, p. 212) makes a mixture of 

 about equal parts of alcoholic safraniii solution and anilin 

 water (saturated solution of anilin oil in water ; "to make it, 

 shake up anilin oil with water, and filter). This, I find, will 

 keep for many months, perhaps indefinitely. 



I myself use equal parts of saturated solution in anilin 

 water, and saturated solution in absolute alcohol. 



Differentiation. For general directions see 281 and 282. 



12 



