CHAPTER V. 



ORGANISMS RESEMBLING THE BACILLUS 

 TUBERCULOSIS. 



Bacillus of Leprosy. 



THE specific cause of leprosy is the bacillus of leprosy, or 

 the lepra bacillus, discovered by Hansen in 1879. It is 

 always found within the leprous tubercles, contained within 

 the cells, and is also found in the blood during the febrile 

 attacks. It is very slender, a little shorter than the tubercle 

 bacillus, straight, and has rounded ends. It does not form 

 spores, but in the stained preparation it shows unstained 

 spaces, just like the tubercle bacillus. It stains readily with 

 aqueous solutions of the anilin dyes, but retains its color 

 when treated with the mineral acids. Gram's method is also 

 applicable. It is not motile, and always occurs singly or in 

 groups (Figs. 84-87). 



Various attempts have been made to cultivate the bacillus 

 on artificial media, but the results have been extremely unsat- 

 isfactory. 



Thus far it has been impossible to transmit leprosy to ani- 

 mals by inoculation. 



Infection in man usually occurs through an abrasion of the 

 skin or the nasal mucous membrane. Infection through the 

 respiratory and intestinal tracts has never been known to 

 occur. Sticker believes that infection always occurs through 

 the nose. He bases this opinion on the facts that the 

 nasal lesion is the only constant one in both forms of lep- 

 rosy (see below) ; that the symptoms of the disease always 

 have their origin in the nose ; that the relapses begin with 

 nasal symptoms ; that it is the only characteristic lesion ; and 

 that the bacilli can be found in the leprous nodules in the 



14 Bact. 209 



