Bacillus Leprae, Hansen (1879). 



LEPROSY BACILLUS. 



Origin. — It is found in enormous numbers in the leprous 

 nodules of the skin; to less extent in the mucous membrane, 

 lymphatic glands, liver, spleen, marrow, etc. It usually 

 occurs in masses within the so-called leper cells. It may 

 be present in the blood in small numbers. 



Form. — Small, narrow rods, which resemble the tubercle 

 bacillus. 



Motility. — It is non-motile. 



Sporulation. — Bright bodies, are frequently observed 

 within the cell, but as in the case of the tubercle bacillus, 

 these are not spores. 



Anilin dyes. — In fresh material the bacilli can be readily 

 stained with the ordinary anilin dyes. They can likewise 

 be easily demonstrated in such material by means of the 

 method employed for staining the tubercle bacillus (p. 324). 

 The latter stain fails when the tissue has been kept in alco- 

 hol for some time. In that case Gram's method will give 

 excellent results (Chapter XV). 



Growth. — This has not been obtained on artificial media 

 with certainty. It is to be considered as a typical obliga- 

 tive parasitic organism. 



Pathogenesis. — The constant presence of this bacillus in 

 enormous numbers, in leprous tissue justifies the prevailing 

 view that it is the cause of that disease. Nevertheless, it 

 should be remembered that as yet unquestioned pure cul- 

 tures have not been- obtained, and hence, successful inocu- 

 lations are impossible. Direct infection with leprosy tissue 

 has given but few, if any, positive results. The monkey, 

 cat, dog, goat, hog, chicken, guinea-pig, rabbit, etc., are 

 apparently not affected. 



Infection. — Leprosy, as in the case of tuberculosis, may 

 be congenital. As a rule, however, it is acquired but the 

 exact mode of infection is as yet unknown. It would seem 

 that leprosy, like glanders, attacks first of all the nasal 

 mucous memiarane. The leprosy bacillus leaves the body 

 with the secretions of the nose and mouth. 



Diagnosis. — The bacillus of leprosy is to be distinguished 

 from that of tuberculosis. The inoculation of a guinea-pig 

 will decide the presence of tubercle bacilli. An examina- 

 tion of the nasal secretion, and of sputum should be made 

 in suspected cases. 



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