544 BACTERIOLOGY. 



The section is , then transferred to a dish containing 

 water in order to remove the excess of dye. It is now 

 placed in 60 per cent, alcohol for 1-2 minutes, and then into 

 Bbner's solution for i minute, after which it is returned to 

 60 per cent, alcohol for another minute or two, or until it is 

 almost wholly decolored. The lig-ht pink color of the sec- 

 tion will be displaced on staining with methylene blue. 



The almost decolored section is placed in Loffler's 

 methylene blue for i minute, after which it is washed in 

 water. It is then placed in absolute alcohol for about 20 

 seconds in order to dehydrate. A longer exposure to alcohol 

 will remove the blue stain. The section is drained by plac- 

 ing the edge of the spatula or of the cover-glass against 

 some filter-paper; after which it is placed in xylol for 2 

 minutes. After removal of the excess of xylol by means 

 of filter-paper the section is mounted in Canada Balsam. 



Cedar or anise oil may be used, to clear the blue sec-, 

 tions. On the other hand, oil of cloves should be 

 avoided because it removes the blue polor. A properly 

 stained section will show deep red bacilli on a light blue 

 back-ground. . 



Ebner's solution is ordinarily used for decalcifying pur- 

 poses. The acid and alcohol present make it very useful 

 for decolorizing sections, and it is to be preferred to the 

 common procedure of treatment with nitric or sulphuric 

 acids. It is prepared according to the following formula: 



Sodium chloride, 0.5 

 Hydrochloric acid, 0.5 

 Distilled water, 30.0 

 Alcohol, 100.0 



Instead of using Bbner's solution for decoloring the 

 sections, a 2 per cent, aqueous solution of anilin hydro- 

 chloride can be employed with excellent results as it has 

 little or no tendency to decolor the tubercle bacilli (KUhne, 

 Borrel). The sections can be first stained in hematoxylin 

 or hematein for about 2 minutes. After which they are 



