310 BACTERIOLOGY. 



III. Staining of Tubercle Bacilli in Tissues. 



Thin sections of tuberculous tissues may be stained 

 by the same methods recommended for cover-glass 

 preparations, except that it is best not to employ heat 

 to any extent. 



The Ehrlich's Method. Place the paraffin sections in 

 aniline fuchsin and leave for from one to twelve hours; 

 then decolorize by placing them for about half a minute 

 in dilute nitric acid (10 per cent.); wash in 60 per cent, 

 alcohol until no more color is given off; counter stain 

 for two or three minutes in a saturated aqueous solu- 

 tion of methylene-blue, wash in water; dehydrate with 

 absolute alcohol; clear up in oil of cedar or xylol and 

 mount in xylol balsam. 



Method of Ziehl-Neelson. Stain the section in warmed 

 carbol-fuchsin solution for one hour, the temperature to 

 be not over 45 to 50 C. Decolorize for a fe\y seconds 

 in 5 per cent, sulphuric acid, then in 70 per cent, alcohol, 

 and from this on as in the Ehrlich method. 



