ON STAINING FLUIDS, AND STAINING. 93 



Float a thin glass cover upon which sputum has 

 been spread or immerse sections, as in the former 

 process, in this fluid, for twenty minutes. 



Decolorise in a 33 per cent, solution of nitric acid 

 in distilled water, wash free from acid and float the 

 cover upon, or immerse the sections for a few 

 minutes in, a saturated solution of chrysoidin in 

 distilled water ; when they are stained brown, wash 

 them in distilled water, place them in absolute 

 alcohol for a short time. Clear the sections in 

 xylol and phenol, and mount in xylol balsam. 



If a small crystal of thymol is dissolved in absolute 

 alcohol and added to each of the solutions in the 

 above two formulas it will tend to their preservation. 

 Each of these solutions should be filtered into the 

 staining saucers when used. 



EHELICH'S PROCESS. 



Make a saturated solution of phenylamin in 

 distilled water. This is done by prolonged shaking 

 up the water with the floating anilin and filtering ; 

 add to the filtered mixture a saturated solution of 

 fuchsin in absolute alcohol until a brilliant red 

 colour is obtained. Now, as in the former processes, 

 spread a thin layer of sputum upon a thin glass 

 cover and dry, and fix it over a spirit lamp or 

 Bunsen's gas burner. Float the cover upon the 

 fuchsin solution for from fifteen to twenty minutes, 

 wash it in distilled water and float it upon a 33 per 

 cent, solution of nitric acid in distilled water for a 

 few seconds, when it will be found quite colourless. 

 Now float the cover for a few minutes, on solution 

 No. 2, of formula No. 1. Wash in distilled water, 

 dehydrate in absolute alcohol, mount in xylol 

 balsam. 



