342 PATHOGENIC BACTERIA. 



5. In incipient cases the lepra bacilli were first found 

 in the nose. 



Once established in the body, the bacillus by its growth 

 produces chronic inflammatory nodes — the analogues of 

 tubercles. 



The nodes consist of lymphoid and epithelioid cells and 

 fibres, and, unlike tubercles, the lepra nodes are vascu- 

 lar, so that much of the embryonal tissue completes its 

 transformation to fibres. The bacilli are not distributed 

 through the nodes like tubercle bacilli, but are found 

 in groups enclosed within the protoplasm of certain large 

 cells — the "lepra cells." These cells seem to be over- 

 grown and partly degenerated lymphoid cells. Some- 

 times they are anuclear, sometimes they contain several 

 nuclei (giant-cells). Bacilli also occur in the lymph- 

 spaces and in the nerve-sheaths. 



Iyepra nodules do not degenerate like tubercles, and 

 the formation of ulcers, which constitutes a large part of 

 the disease, seems largely due to the action of external 

 agencies upon the feebly vital pathological tissue, which 

 is unable to recover itself when injured. 



According to the recent studies of Johnston and Jamie- 

 son, 1 the bacteriological diagnosis of nodular leprosy can 

 be made by spreading the serum obtained by scraping a 

 leprous nodule upon a cover-glass, drying, fixing, and 

 staining with carbol-fuchsin and Gabbet's solution as for 

 the tubercle bacillus. In such preparations the bacilli 

 are present in enormous numbers, thus forming a marked 

 contrast to the tubercular skin diseases, in which very few 

 can be found. 



In that form known as anesthetic leprosy, nodules form 

 upon the peripheral nerves, and by connective-tissue 

 formation, as well as the entrance of the bacilli into the 

 nerve-sheaths, cause irritation, then degeneration, of the 

 nerves. The anesthesia which follows these peripheral 

 nervous lesions is one of the conditions predisposing to 

 the formation of ulcers, etc. by allowing injuries to occur 



1 Montreal Med. Journal, Jan., 1897. 



