178 
PRINCIPLES OF BACTERIOLOGY 
The Smegma Bacillus 
The smegma bacillus is a harmless (saprophytic) or¬ 
ganism, which occurs around the genital organs of both 
male and female, and is important because it may be 
readily confused with the tubercle bacilli. The best 
method of differentiation between the two is that of 
Pappenheim. 
Fig. 36.—The smegma bacillus. Smear preparation of smegma, x 1500. 
(Hewlett —Manual of Bacteriology.) 
1. Make smears and fix by heat in the usual manner. 
2. Stain with Zeihl’s carbol-fuchsin solution (steam¬ 
ing) for two minutes. 
3. Pour off the stain, and without washing, pour the 
following mixture: 
4. Wash in water. Smegma bacilli will be decolorized, 
but the tubercle bacilli will be stained bright red. 
Rosolic acid .1 gram 
Absolute alcohol .100°C. 
Methylene blue added to saturation. 
Glycerine (added after other ingredients 
have been mixed).20°C. 
This mixture is poured on and off several times. 
