CHAPTER XY. 



THE COAL-TAR CHROMATIS" STAIXS. 

 A. Regressive Stains. 



272. Safranin. One of the most important of these stains , 

 on account of its great power,, brilliancy, and superior per- 

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

 of electivity that it displays for the nuclei and other consti- 

 tuent 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 ( 204). Before thinking of working with 

 this important reagent you should go to Gr abler & Hoi 1 born 

 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 histo- 

 logical action. Some are easily soluble in \vater 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 RESEGOTTI (Zeit. f.wiss. 

 Mile., v, 3, 1888, p. 320). Resegotti obtained his best results with the 

 brands " Safranin wasserloslich," " Safranin spiritusloslich," " XX," 

 " XXBN," "TB," furnished by Griibler, and with the brands " Rein, :> " 0," 

 " FII," and "Cone.," supplied by Miinder. 



The brand I have been using for a long time, and which 

 gives good results, is the " Safraniii " of Griibler & Co. 

 It should be remembered that as the processes of manufacture 

 are constantly changing, the properties of the products are 

 sure to vary somewhat from time to time. 



Staining. The majority of^afranins are not sufficiently 



