BACTERIUM LEPUM 153 



are carried by the lymph or blood to the exposed skin 

 surfaces, chiefly the face and hands. Here they settle 

 in the subcutaneous tissues and nerves, producing a 

 chronic inflammation in which lepra cells are found. 

 These are large round or oval cells, crowded with 

 bacilli, lying irregularly throughout the inflammatory 

 tissues. Leprosy does not form definite tubercles 



FIG. 43 



Schematic representation of section through a lepra nodule: left side of 

 picture gives appearance under low magnifying power; right side, the appear- 

 ance when highly magnified. In the latter the large lepra cells are diagram- 

 matically indicated. (Abbott.) 



like tuberculosis, but the process is more diffuse; nor 

 does caseation occur. Giant cells are uncommon. 

 The bacilli produce these changes largely by poison 

 in their body and by mechanical irritation. There is 

 some reason to believe, by most recent researches, 

 that a soluble or extracellular poison is formed. The 

 bacteria are discharged from the patient by the 



