348 BA OTEBIOL OGY. 



Bacillus LEPEiE. — Between 1879 and 1881 there 

 waw described by Hansen and by Neisser an organism, 

 a bacillus, that was constantly to be found in the nodules 

 characteristic of leprosy. For this organism the name 

 bacillus leprae was suggested. Though very like bacillus 

 tuberculosis in both morphology and staining properties, 

 it is, however, a little shorter, thicker, and much less 

 homogeneously stained. Its presence in the tissues and 

 secretions is demonstrated by the same method as that 

 employed for detecting bacillus tuberculosis. In sec- 

 tions of leprous nodules, stained by the ordinary Koch- 

 Ehrlich process, the bacilli, crowded together in the 

 large so-called " lepra cells," are always to be seen in 

 great abundance. It is unlikely that' bacillus leprae has 

 ever been cultivated artificially, and the disease has cer- 

 tainly never been reproduced in animals by inoculation 

 with bits of the diseased tissue, so that nothing can be 

 said of the life-history of this organism. 



Bacillus Syphilidis. — In 1884 Lustgarten de- 

 scribed an organism, the so-called "bacillus of syphilis," 

 that he had discovered in j)rimary syphilitic lesions and 

 in the secretions from syphilitic ulcers. In staining 

 reactions, but more especially in morphology, this 

 brganism is said to be strikingly like bacillus tubercu- 

 losis. He found it in the tissues usually within the 

 bodies of large, apparently swollen cells. He found it 

 not only in the primary sores about the genitalia, but 

 in the syphilitic lesions of the remote organs as well. 

 As this organism has never been cultivated artificially, 

 as the disease has never been reproduced in animals by 

 inoculation, and as many competent observers, working 

 upon the most promising material, have failed to detect 

 it, the prevailing opinion is to the effect that the organ- 



