BACTERIUM TUBERCULOSIS 93 



135. Gabbett's method of staining tubercle bacteria. 



I. The stain (carbol fuchsin) : 



Fuchsin ... 

 Absolute alcohol 

 5 % carbolic acid 



2 . The decolorizer and counter stain : 



Methylene-blue powder 

 10% sulphuric acid . 



Stain the preparation with the first solution as described 

 (§ 100), then rinse in water and stain i minute with the second 

 solution, which decolorizes and counterstains at the same time, 

 and again rinse in water. If the film has a bluish tint, it is 

 ready for examination ; if not, it should be stained a little longer 

 in the second solution. In these preparations the tubercle 

 bacteria should appear as slender, more or less curved, rod- 

 shaped bodies of a deep reddish color, while the surrounding 

 tissue and other bacteria present are stained a more or less 

 intense blue. 



Sudan III is reported by Dorset to be a very good differen- 

 tial stain for this organism. A saturated solution in 80 (^ alco- 

 hol is used. It is reported to be effective in differentiating the 

 tubercle organism from that of leprosy and from the smegma 

 bacillus. 



