BACILLUS .OF LEPROSY 221 



fixation gives some information and is growing in favor as assist- 

 ance in obscure clinical cases. 



BACILLUS OF LEPROSY 



Mycobacterium Lepra. Hansen. 



Lepra Bacillus. 



The original description is of a pointed, curved, acid fast rod 

 occurring in groups within lepra cells. In recent years several 

 different organisms have been isolated on media containing trypto- 

 phan. They have a few features in common: frankly acid 

 fast or decolorized with difficulty. Gram positive, non-motile, 

 non-spore forming, staining shows beading or barring, polar 

 bodies, all capable of pleomorphism. They have been grouped 

 into 4, (i) acid fast bacilli varying from coccoid to filamentous 

 shapes, not easily isolated but growing well after once accustomed 

 to media; growth yellow or orange; (2) acid fast, non-chromogenic, 

 plump bipolar rods, short and long, growing with great sparsity 

 on laboratory media; (3) diphtheroid bacilli staining solidly, or 

 beaded, growing best at 37C. in a yellow- white manner on agar 

 and with a pellicle on broth; (4) anaerobic bacilli of more solid 

 staining character and growing feebly as a dry band on media. 

 Very marked variations in luxuriance and color production are 

 noted on different media. 



To cultivate the leprosy organisms bits of tissue are stripped 

 off and allowed to digest with trypsin on blood serum or agar 

 plates. When the tissue has softened and the bacilli multiplied, 

 transfers are made to serum glycerine media or those containing 

 tryptophan. It is best alkaline in reaction. 



Pathogenesis. The bacilli are seen in enormous numbers in 

 lepra cells and elsewhere in diseased tissues and have been found 

 in the blood. The lepra cells are large and vacuolated, and literally 

 crammed full to bursting with bacilli. In general the leprous 



NOTE. Tubercle bacilli causing avian and fish tuberculosis, and other acid fast bacilli 

 exist, but not being pathogenic for man, are not described here. 



