THE INFECTIOUS DISEASES. 



255 



LEPRA (LEPROSY). 



Leprosy is characterized by the development of nodular and some- 

 times diffuse masses of tissue, consisting of larger and smaller cells of 

 various shapes spheroidal, fusiform, and branched, with a fibrous 

 stroma the whole somewhat resembling granulation tissue. The new 

 tissue is most frequently formed in exposed parts of the skin, as the 

 face, hands, and feet, but it may occur in the skin of any part of 

 the body. It is formed more rarely in the subcutaneous connective tis- 

 sue, in intrafascicular connective tissue of nerves, in the viscera, and in 

 the mucous membranes. The mucoasjnembranes most frequently af- 

 fected are those^of the eye^nose, mouth, and larynx. ~~~The nodules may 

 be very smalTor as large, as li walnutTand maylSe single or^joined to- 

 gether in groups or masses. Thelissue of the part in which th~e~Tiew 

 formation occurs may be atrophied and replaced by, or may remain in- 

 termingled with, the leprous tissue, or it may be hyperplastic. The 

 nodules may persist for a long time without undergoing any apparent 

 change, or they may_soften and break_ down, forming ulcers ; but ulcer- 

 ation, except inlhlfmucous membranes, is said usually to occur as the 

 result of injury or unusual exposure. The leprous tissue may change 

 without ulceration into cicatricial tissue, or cicatrization may__follow 

 ulcergiion. 



Various secondary lesions and disturbances of nerve function are 

 associated with the formation of leprous tissue in the nerves and central 

 nervous system, but these we cannot consider here. 



In all the primary lesions of leprosy, bacilli are said to be present, 

 mostly in the cells, and particularly in the larger transparent spheroidal 

 forms, but sometimes free in the intercellular substance. The bacilli 

 have been found in the skin, mucous 

 membrane of the mouth and larynx, 

 in peripheral nerves, in the cornea, 

 in cartilage, in the testicles, and in 

 lymph-nodes. Sometimes the cells 

 contain but few bacilli, but they 

 are frequently crowded with them. 



Characters of the Lepra Bacilli. 



The bacilli are from 4 to 6 /J. long and 

 very slender. They are sometimes pointed 

 at the ends and sometimes present spher- 

 oidal swellings (Fig. 126). In their com- 

 portment toward staining agents, as well 

 as in general morphological characters, 

 they considerably resemble the Bacillus 



tuberculosis, but they are more readily stained. They may be stained with fuschsin 

 or gentian violet by the ordinary method, or by the method employed for staining 

 the tubercle bacillus (see page 247). 



FIG. 126. THE BACILLI OF LEPROSY. 



From a nodule in the skin, showing the bacilli free 

 and within cells. 



