ETIOLOGY 



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about eleven months. During this period his brother not merely 

 lived with him, but slept in the same bed, and, after his death, wore 

 his clothes. In about four to five years this brother showed all 

 the typical signs of tubercular leprosy, though he had only once 

 been out of Ireland, and then only to visit England. Another 

 similar case may be quoted of a person who, acquiring leprosy in 

 Tonkin, returned to Strasburg and lived with a nephew, who 

 subsequently developed the disease. Turning to the evidence of 

 history, there is the spread of lepro.^y throughout Europe, and, 

 later, the rapid spread of the disease in the Sandwich Islands, 

 where, though existing probably for many years, it increased from 

 1859, when it was hardly known, till in 1881 no less than 800 lepers 

 were isolated, and it is said that no less than one-tenth of the 

 population were affected. Another instance is the case of New 

 Caledonia, in which the disease, though now common, is believed 

 to have been introduced for the first time in i860, and Pine Island, 

 which is said to have been infected from New Caledonia; or 

 Mauritius, which was infected by a single leper, and from which, 

 later, the island of Rodriguez was infected, also by a single leper. 



As to individual cases of infection by residence among lepers, 

 the most noted is that of Father Damien de Venster, who went 

 from Belgium as a missionary to the Molokai Leper Asylum of the 

 Sandwich Islands in 1873, and who was first recognized to be suffer- 

 ing from the disease in 1882, from which he died in 1889. 



Again, the prophylactic success of even partial isolation of lepers, 

 as evinced in Europe in the thirteenth and fourteenth centuries, 

 and to-day in Norway, Sweden, and Iceland, is in favour of the 

 view that the disease passes from man to man. But it is not wise 

 to hastily conclude that this transference is direct, for any of the 

 above cases are easily explicable by the disease being conveyed 

 by food or biting animals. The success of partial isolation might 

 be simply to diminish the chance of infection by these means. 

 Moreover, the fact that the attendants of the Hendela Leper 

 Asylum of Ceylon have so far not been known to contract the 

 disease is against the theory of direct contagion. Further, though 

 there is evidence that married people may both suffer from the 

 disease, there is no proof that sexual intercourse is a means of 

 infection. Nor is there any evidence of heredity being a source 

 of infection, for never has a child been born in a leprous condition, 

 though it is said that to per cent, of the children of leprous mothers 

 become sooner or la,ter lepers themselves. 



If the germs are not carried from one person to another by con- 

 tact, sexual or germinal transmission, they might still be con- 

 veyed by air, dust, water, or food, and, indeed, all these theories 

 have their supporters. 



It does not appear likely that it is conveyed by air, otherwise it 

 would surely be spread more commonly from patients to attendants 

 in leper asylums. With regard to dust, it is quite true that, though 

 some persons report the presence of a very few bacilli in earth 



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