MYCOBACTERIACEiE: THE TUBERCLE BACILLUS 327 



been considered to be transmissible for a long time. It is widely 

 distributed over the earth, especially in Norway, Russia, Iceland 

 and in Turkey. In the United States there are leper colonies in 

 Louisiana, Minnesota and in Hawaii. Lepers are occasionally seen 

 in the clinics of all the larger cities. 



Leprosy is universally considered to be due to the leprosy 

 bacillus, but as to mode of transmission, whether direct from 

 man to man, or from the external world, or how, little or nothing 

 is really known. It seems certain that the disease is always con- 

 tracted in some way from a previous case, but it is certainly not 

 very readily transmitted. Segregation without absolute isolation 

 is the common method of handling lepers. The disease is not 

 ordinarily inherited. 



Bacillus Smegmatis. — This organism occurs in the smegma 

 on the genitals of man and other mammals and also in moist folds 

 of the skin where there are collections of moist desquamated 

 epithelium. It resembles the tubercle bacillus in form and stain- 

 ing properties, but is, on the average, more readily decolorized in 

 alcohol. This property cannot be relied upon to differentiate 

 the two organisms in any given case. Proper care in collecting 

 specimens for examination usually suffices to exclude this or- 

 ganism. Urines to be examined for tubercle bacilli should be 

 obtained by catheter. In doubtful cases inoculation of a guinea- 

 pig is necessary. B. smegmatis has been grown in artificial culture 

 and after a time adapts itself to ordinary media. 



Bacillus Moelleri. — Acid-proof organisms resembling the 

 tubercle bacillus in form and staining properties were fotind on 

 timothy hay by Moeller. The bacillus is likely to be found in 

 milk and other dairy products. Probably the "gutter bacillus" 

 of Rabinowitsch is identical with it or a near relative. When 

 introduced into guinea-pigs these organisms sometimes produce 

 lesions resembling tubercles, but these do not progress and kill 

 the animal and a second animal inoculated from the lesions of the 

 first gives a negative result. Cultures are easily obtained on 

 oridinary media, and the organisms grow rapidly at 25° to 30° C. 



