BACILLI RESEMBLING TUBERCLE BACILLI IN STAINING 317 



of the body, except in the neighborhood of the genitals. While the 

 bacillus of Lustgarten cannot resist the prolonged decolorizing action 

 of acids, but is resistant to the action of alcohol, the smegma bacillus, 

 when stained, is quickly decolorized by alcohol, but quite resistant to 

 5 per cent, sulphuric acid solution. Besides, the syphilis bacillus has 

 been found in papules, in gummata, and other syphilomata, where there 

 seems no probability whatever of the smegma bacillus having emigrated. 

 Finally, other bacilli have been described and claimed to be the specific 

 cause of syphilis, but none of these discoveries have been confirmed. 

 The latest micro-organism is discussed under protozoa. 



Syphilitic Infection. Infection of those not immune can take place 

 at any time when an abrasion, however small, is brought in contact 

 with the blood or secretions from the primary or secondary lesions of 

 syphilitics. 



The differential diagnosis of Lustgarten's bacillus must be made 

 from the tubercle bacillus, the smegma bacillus, and the leprosy bacillus. 

 According to Hueppe, the differential diagnosis between these four 

 organisms depends upon the following reactions: When stained by 

 the carbol-fuchsin method, commonly em ployed in staining the tubercle 

 bacillus, the syphilis bacillus becomes almost instantly decolorized by 

 treatment with mineral acids, particularly sulphuric acid; whereas, the 

 smegma bacillus resists such treatment for a much longer time, and 

 the lepra and tubercle bacillus for a still longer time. On the other 

 hand, if decolorization is practised with alcohol instead of acids, the 

 smegma bacillus is the first to lose its color. The bacillus tuberculosis 

 and the bacillus of leprosy are both very retentive of their color, even 

 after treatment with acids and alcohol. If, then, we treat the preparation, 

 stained with carbol fuchsin, with sulphuric acid, the syphilis bacillus 

 becomes almost at once decolorized. If it is not immediately decolorized, 

 treat with alcohol; if it is then decolorized, it is the smegma bacillus. 

 If it is still not decolorized, it is either the leprosy or the tubercle bacillus. 



By these methods the differential diagnosis can usually be made. 

 In all investigations of importance, however, animal inoculations should 

 also be made, as by this means alone can a positive diagnosis from 

 tuberculosis be established. Especial care should be observed in the 

 examination of syphilitic ulcers of the genital region, as in this situation 

 the smegma bacilli are almost always present. 



Leprosy Bacillus. 



The bacillus of leprosy was discovered by Hansen and Neisser (1879) 

 in the leprous tubercles of persons afflicted with the disease. This 

 discovery was confirmed by many subsequent observers. 



Morphology. Small, slender rods resembling the tubercle bacilli 

 in form, but somewhat shorter and not so frequently curved. The 

 rods have pointed ends, and in stained preparations unstained spaces, 

 similar to those observed in the tubercle bacillus, are seen. They stain 

 readily with the aniline colors and also by Gram's method. Although 



