310 BACTERIA 



tration. It causes great disfigurement. The anaesthetic 

 form causes a destruction of the nerve fibres, and so pro- 

 duces anaesthesia, paralysis, and what are called " trophic " 

 changes. Not infrequently patches occur on the skin, which 

 appear like parchment, owing to this trophic change. Bullae 

 may arise. When the tissue change is radical or far ad- 

 vanced, considerable distortion may result. The mixed 

 variety of leprosy, as its name implies, is a mixture of the 

 two other forms. 



The Bacillus leprce was discovered by Hansen in 1874. 

 He found it in the lepra cells in the skin, lymph glands, 

 liver, spleen, and thickened parts of the nerves. It is com- 

 mon in the discharges from the wounds of lepers. It is 

 conveyed in the body by the lymph stream, and has rarely 

 been isolated from the blood (Kobner). 



The bacillus is present in enormous numbers in the ski/i 

 and tissues, and has a form very similar indeed to Bacillus 

 tuberculosis. It is a straight rod, and showing with some 

 staining methods marked beading, but with others no bead- 

 ing at all. It measures 4 //. long and i /u, broad. Young 

 leprosy bacilli are said to be motile, but old ones are not. 

 Neisser has maintained that the bacillus possesses a capsule 

 and spores. The latter have not been seen, but Neisser 

 holds that this is the form in which the bacillus gains en- 

 trance to the body. There is a characteristic which fort- 

 unately aids us in the diagnosis of this disease in the tissues, 

 and that is the arrangement of the bacilli, which are rarely 

 scattered or isolated, but gathered together in clumps and 

 colonies. Bordoni-Uffreduzzi and Campania claim to have 

 isolated the bacillus and grown it on artificial media, the 

 former aerobically on peptone-glycerine-blood-serum, at 

 37 C., the latter anaerobically. But no other worker has 

 been able to do this. Hence we are not able to study the 

 bacteriology of leprosy at all completely, nor have inocula- 

 tion experiments proved successful. Nevertheless there is 



