A MODIFICATION OF LOEFFLER'S FLAGELLA STAIN 



IVAN V. SHUNK 



Department of Botany, North Carolina State College 

 Received for publication November 20, 1919 



Although the presence of flagella on motile bacteria was 

 determined somewhat earlier, Robert Koch, in 1877, was the 

 first to demonstrate their presence by the use of stains. He 

 succeeded by using an aqueous solution of haematoxylin, and 

 dilute chromic acid as a mordant. About 1889 Loeffler, by an 

 improved method, succeeded in staining the flagella on a number 

 of organisms whose flagella had previously not been demonstrated. 



As it has been found that the arrangement of the flagella on 

 bacteria is one of the characters which varies perhaps less than 

 any other morphological characters, this arrangement furnishes 

 an easy method for classification. Certain genera are separated 

 on this one point alone as in the separation of the genus Pseudo- 

 monas from the genus Bacillus according to Migula's classifica- 

 tion. Since the arrangement of flagella is thus used in establish- 

 ing genera, it is necessary to determine definitely the character 

 of the flagella on bacteria, and hence the need of reliable and 

 simple flagella stains. 



Loeffler, in his process, allowed the cover-glass preparation 

 to dry, fixed it by passing through the flame, and then used the 

 following solutions: 



No. 1. Mordant 



parts 



Solution of tannic acid (20 per cent aqueous) 10 



Saturated aqueous solution (cold) of ferrous sulphate 5 



Saturated alcoholic solution of basic fuchsin 1 



No. 2. Stain 

 Carbol-fuchsin. 



No. 3. Corrective solutions 



A 1 per cent solution of caustic soda. 



A solution of sulphuric acid of such strength that 1 cc. will neutralize 1 cc. of 

 the soda solution. 



181 



