ACID-FAST GROUP 329 



a criminal in the Hawaian Islands by subcutaneous implantation 

 of leprous tissue. The belief in the pathogenicity of this organism 

 rests principally upon its presence in great numbers in the. leprous 

 tissues. 



Character of Disease and Lesions Produced. The organisms may 

 proliferate in the nerves, causing anesthetic leprosy; or in the 

 subcutaneous tissues, producing nodules resembling superficially 

 those of tuberculosis. The disease progresses slowly, the infected 

 individual surviving for years or even several decades. 



Immunity. Methods of immunization are unknown. 



Bacteriologic Diagnosis. The disease may be diagnosed bac- 

 teriologically by scraping a nodule and preparing a smear from 

 the serum so obtained. The characteristic acid-fast organism 

 may be demonstrated. In the hands of some investigators the 

 complement binding reaction (using extracts from leprous organs 

 as the antigen) has proved of diagnostic value. 



Transmission. The method of the spread of leprosy is not 

 understood. 



Non-pathogenic Acid-fast Bacteria 



Many species of non-pathogenic acid-fast bacteria have been 

 described, and from a variety of sources. Some are normal 

 inhabitants of the skin, others occur in dung and in soil. The 

 presence of these organisms upon the body, in milk, etc., frequently 

 renders a differential diagnosis necessary between them and the 

 Bacillus tuberculosis. A few of the more important types will be 

 briefly described. 



Bacillus smegmatis. This organism has been repeatedly 

 observed in the smegma from the genitals of man and animals 

 and from the skin of the axillae. Morphologically it resembles 

 the tubercle bacillus. Its isolation is accomplished with consider- 

 able difficulty and only upon media containing blood-serum. The 

 B. smegmatis is non-pathogenic. It is of importance principally 

 because of the possibility of confusion with B. tuberculosis when 

 it occurs in the urine. Although the smegma bacillus is acid fast, 

 it may be decolorized by alcohol according to most authors. 



Dung Bacillus, Grass Bacillus of Moeller, Butter Bacillus, etc. 

 Acid-fast bacteria not unlike the B. tuberculosis in morphology 

 have been isolated from a great variety of sources. They may in 



