316 MEDICAL BACTERIOLOGY 



d. Xylene. 



e. Canada balsam. 



Bacterium cholerae (chicken cholera). Loeffler's method. 

 Bacterium tuberculosis. 



a. Weigert's method (staining with anilin oil gentian violet 24 

 hours at room temperature, or 2 to 3 hours at 40 C.). 



~b. Ziehl-Neelsen 's Method. 



1. Stain with carbol-fuchsin (12 to 24 hrs. room temper- 

 ature, 1 to 3 hrs. 40 C.). 



2. Decolorize with nitric acid (10%) a few seconds, and 

 then with alcohol (60 to 90%) until color is nearly all extracted. 



3. Counter-stain with methylen blue. 



4. Dehydrate with absolute alcohol (a few seconds). 



5. Clear with clove oil. 



6. Xylene (and examine). 



7. Mount in balsam. 

 Bacterium leprae. 



This organism is stained with the tubercle stain, unless the sections 

 have been kept in alcohol for some time, in which case Weigert 's 

 method can be employed. To differentiate this organism from 

 B. tuberculosis, stain as follows : 

 a. An aqueous solution of fuchsin 6 to 7 minutes, 

 fc. Acid alcohol (nitric acid 1, alcohol 10) 14 minute. 



c. Wash in water. 



d. Counter-stain in a saturated aqueous solution of methylen 



blue. 



e. Alcohol. 

 /. Xylene. 

 g. Balsam. 



The bacteria of leprosy stain readily by this method, tuber- 

 cle bacteria do not. 

 Bacterium mallei. 



Slow Method. 



a. Stain in Loeffler 's methylen blue 6 to 8 hours. 



&. Wash in distilled water. 



c. Tannic acid solution (10%) 4 to 5 hours. 



d. Wash thoroughly in water. 



e. Dehydrate in absolute alcohol. 

 /. Clear in xylene and mount. 



Quick method. 

 a. Stain in carbol-methylen blue 10 to 30 seconds. 



