CHAPTER XXXI 

 LEPROSY 



Bacillus Leprae (Hansen)* 



Synonyms. — Bacterium leprae; Mycobacterium leprae. 



General Characteristics. — A non-motile, non-flagellate, non-sporogenous, 

 chromogenic, non-liquefying, non-aerogenic, distinctly aerobic, parasitic and 

 highly pathogenic, acid-resisting bacillus, staining by Gram's method, and culti- 

 vable upon specially prepared artificial media. It does not form indol, or acidu- 

 late or coagulate milk 



Leprosy very early received attention and study. Moses in- 

 cluded in the laws to the people of Israel rules for its diagnosis, for 

 the isolation of the sufferers, for the determination of recovery, and 

 for the sacrificial observances to be fulfilled before the convalescent 

 could once more mingle with his people. The Bible is replete with 

 miracles wrought upon lepers, and during the times of biblical 

 tradition it seems to have been an exceedingly common and malig- 

 nant disease. Many of the diseases called leprosy in the Bible were, 

 however, in all probability, less important parasitic skin affections. 



Distribution. — ^At the present time, although we hear very little 

 about it in the northern United States, leprosy is a widespread dis- 

 ease and exists much the same as it did several thousand years ago 

 in Palestine, Sjnria, Egypt, and the adjacent countries, and is com- 

 mon in China, Japan, and India. South Africa has many cases, 

 and Europe, especially Norway, Sweden, and parts of the Mediter- 

 ranean coast, a considerable number. In certain islands, especially 

 the Sandwich and Philippine Islands, it is endemic. In the United 

 States the disease is uncommon, the Southern States and Gulf coast 

 being chiefly affected. 



A commission of the Marine-Hospital Service, formed for the 

 purpose of investigating the prevalence of leprosy, in 1902 re- 

 ported 278 existing cases in the United States. Of these, 155 

 occurred in the State of Louisiana. The other States with numerous 

 cases were CaUfornia, 24; Florida, 24; Minnesota, 20; and North 

 Dakota, 16. No other State had more than 7 (New York). Of the 

 cases, 145 were American born, 120 foreign born, the remainder 

 uncertain. 



Etiology. — ^The cause of leprosy is, without doubt, the lepra 

 bacillus, discovered by Hansen in 1879. 



Morphology. — The bacillus is about the same size as the tubercle 

 bacillus. Its protoplasm commonly presents open spaces of frac- 

 * "Virchow's Archives," 1879. 

 739 



