314 BACTERIOLOGY. 



mata, suggests that the bacilli found in such lesions were, 

 perhaps, tubercle bacilli, and represented a mixed in- 

 fection. This may have been true of some cases, no 

 doubt, as the differentiation of new-growths of tertiary 

 syphilis and tuberculosis is often difficult; but the differ- 

 entiation of the two bacilli can usually be made by their 

 different powers of resistance to the decolorizing action 

 of acids. Finally, other micro-organisms have been 

 described and claimed to be the specific cause of syph- 

 ilis, but none of these discoveries have been confirmed. 

 From this it appears that though there is no conclusive 

 proof of the fact, there is some possibility, but hardly 

 a probability, that Lustgarten's bacillus is the true cause 

 of syphilis. Its position at present is too doubtful to 

 make its detection of any diagnostic value. 



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 employed in 

 staining the tubercle bacillus, the syphilis bacillus be- 

 comes 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 tuber- 



