BACILLUS LEPR.E 501 
investigators liaM> \\vm\v similar experiiiifiits, a few of which have 
resulted positively. The majority of such attempts have been fail- 
ures, and the consensus of opinion is that the few positive results are 
to be explained by the existence of unrecognized leprosy in the early 
stages. 
The earhest lesion appears to be an ulcer at the junction of the 
bony and cartilaginous septum of the nose. When the bacilli are car- 
ried to any tissue in the body they excite the usual inflammatory 
reaction which, however, is continued to excessive tissue proliferation. 
Granular tissue containing bloodvessels is formed, providing a good 
vascular supply, so that proliferation continues until a fair-sized 
nodule or tumor is produced. If the seat of infection is a nerve, 
a spindle-shaped thickening is produced about the nerve, which 
causes pressure, irritation, inflammation, degeneration, and finally, 
atrophy, which leads to anesthesia of the area of distribution of the 
Fig. 68.— Lepra bacilli in liver. (KoUe and Hetsch.) 
nerve. The bacilli are found both in the neuroglia and in nerve cells, 
particularly the ganglion cells. When the cell is thus infected it under- 
goes degeneration, sometimes accompanied by swelling and formation 
of vacuoles. If the bacilli become attached to arteries a proliferating 
inflammation results which causes the walls of the vessel to become 
greatly thickened and the lumen narrowed. 
The disease often displays a selective action for the skin, especially 
in the face, the extensor surfaces of the nose and elbows, and on the 
backs of the hands and feet. These areas are very apt to undergo 
ulceration. The organism makes its appearance in the skin by pro- 
ducing red spots which either disappear, leaving pigmented areas, or 
become elevated in nodules of a brown-red color. In the region of 
these nodules the subcutaneous tissue contain large numbers of 
bacilli. These eruptions are probably to be regarded as general 
inflammatory reactions in response to the irritation produced by the 
bacillus. The nodules may remain small and hard, or they may 
