152 SPECIAL BACTERIOLOGY 



BACILLUS LEPR.E. 



This organism, discovered by Hansen in 1879, is found chiefly in 

 the interior of the peculiar round and oval cells found in leprous 

 tubercles. The bacilli have also been found in the lymphatic glands, 

 liver, spleen, testicles, and in the thickened portions of nerves 

 involved in the anaesthetic form of the disease. According to some 

 authorities they have also been found in the blood. The bacilli lie in 

 the leprous cells in great numbers, and also in the lymph spaces out- 

 side of these cells. They are not found in the epidermal layers of the 

 skin, but, according to Babes, they may penetrate the hair follicles. 



Microscopical Appearances. The Bacillus leprae resembles the 

 tubercle bacilli in form, but is more uniform in length and not so 

 frequently bent or curved, and is from 4 to 6 /u, in length, and less than 

 1 p in width ; the ends of the rods are pointed, and in stained specimens 

 unstained spaces similar to those in the Bacillus tuberculosis are present. 



Motility. Non-motile. 



Staining Reactions. The bacilli stain readily with the aniline 

 dyes, also by the Gram method and by the Cladius method (see Photo- 

 micrograph, Plate III., Fig. 17). For differential staining reactions see 

 Tuberculosis, p. 136. 



Biological Characters. It has not yet been obtained in pure 

 cultures, so that its etiological relation to the disease with which it is 

 associated is based upon the demonstration of its constant presence in 

 leprous tissues. 



Pathogenesis. Leprous tissues containing the bacillus are in- 

 fectious, and may produce this disease. Arning inoculated a condemned 

 criminal in the Sandwich Islands subcutaneously with fresh leprosy 

 tubercles, who was under observation until his death occurred from 

 leprosy at the end of five years. Positive results have also been obtained 

 in the lower animals. Melcher and Ortmari inoculated rabbits with 

 pieces of fresh leprosy tubercles in the anterior chamber of the eye, the 

 animals dying at the end of several months ; the characteristic tubercles 

 containing the bacilli being found distributed throughout the various 

 organs. 



BACILLUS SMEGMATIS. 



Found in the smegma praeputii between the scrotum and thigh 

 and between the labiae. It is also found in the cerumen, and occasion- 

 ally on the skin. 



