LEPROSY. 71 



geal mucosa. In the skin they are chiefly found in the derma, espe- 

 cially in connective-tissue cells and endothelial cells. They are also 

 found in the glands in relation to the superficial lesions. The bacilli 

 are found in smaller numbers in the liver and spleen. In anaesthetic 

 or nerve leprosy they are found in small numbers in the granuloma 

 tissue which affects the interstitial connective tissue of the peripheral 

 nerves. Also, rarely, in the anaesthetic spots of nerve leprosy. 



In morphology and staining reactions they are almost identical 

 with the tubercle bacillus. The main points of distinction are: (i) 

 The fact of the leprosy bacilli being found in enormous numbers, 

 especially in large vacuolated cells (lepra cells), and lying in the lymph 

 spaces. They are frequently beaded and lie in masses which have been 

 likened to a bundle of cigars tied together. It is necessary to examine 

 for long periods of time, smears made from tuberculous lesions of 

 skin before finding a single organism. (2) Leprosy bacilli have not 

 surely been cultivated. (3) Injected into guinea-pigs, they do not 

 produce lesions. 



Recently a leprosy -like disease of rats has been reported in which 

 there are two types: (i) A skin affection and (2) a glandular one. 

 In this disease acid-fast bacilli, alike in all respects to leprosy bacilli, 

 have been found. Deane has obtained a diphtheroid-like organism 

 in culture, which is nonacid-fast. This same finding has been 

 obtained in cultures considered positive in human leprosy. Quite 

 recently it has been claimed that the bacillus has been cultivated by 

 excising aseptically the subcutaneous portion of lepromata and 

 dropping the leprous tissue into salt solution. 



For diagnosis we should use both smears from the nasal mucus 

 and from ulcerated lepromata or from the scrapings from intact 

 tubercles. Some advise centrifuging with salt solution, but this is 

 rarely necessary. The best method is to excise a small portion of skin 

 or mucous membrane, fix it in absolute alcohol or Zenker's fluid. Cut 

 thin sections in paraffin. Stain with carbol-fuchsin, decolorize with 

 acid alcohol, and then stain with haematoxylin. This gives the location 

 of the bacilli. This is also a good method for tuberculous tissues. 

 It is claimed that the B. leprae stains more easily and loses its color 

 more rapidly than the tubercle bacillus. Some prefer to stain the 



