MODE OF TRANSMISSION. 2/3 



years later, well-marked tubercular leprosy appeared and led to a 

 fatal result. This experiment, however, is open to the objec- 

 tion, that the individual before inoculation had been exposed to 

 infection in a natural way, having been frequently in contact 

 with lepers. In other cases inoculation experiments on healthy 

 subjects, and inoculations in other parts of leprous individuals 

 have given negative results. It has been supposed by some 

 that the failure to obtain cultures and to reproduce the disease 

 experimentally may be partly due to the bacilli in the tissues 

 being dead. That many of the leprous bacilli are in a dead 

 condition is quite possible, in view of the long period during 

 which dead tubercle bacilli introduced into the tissues of ani- 

 mals retain their form and staining reaction. There is also the 

 fact that from time to time in leprous subjects there occur 

 attacks of a certain amount of fever, which are followed by a 

 fresh outbreak of nodules, and it would appear that especially 

 at these times multiplication of the bacilli takes place more 

 actively. 



The facts stated with regard to cultivation and inoculation 

 experiments go to distinguish the leprosy bacillus all the more 

 strongly from other organisms. Some have supposed that 

 leprosy is a form of tubercle, or tubercle modified in some way, 

 but for this there appears to us to be no evidence. Both from 

 the pathological and from the bacteriological point of view the 

 diseases are distinct. It should also be mentioned that tubercle 

 is a not uncommon complication in leprous subjects, in which 

 case it presents the ordinary characters. 



The mode by which leprosy is transmitted has been the 

 subject of great controversy, and is one on which authorities still 

 hold opposite opinions. Some consider that it is a hereditary 

 disease, or at least that it is transmitted from a parent to the 

 offspring ; others again that it is transmitted by direct contact. 

 There appears to be no doubt, however, that on the one hand 

 leprous subjects may bear children free from leprosy, and 

 that, on the other hand, healthy individuals entering a leprous 

 district may contract the disease, though this rarely occurs. 

 Of the latter occurrence there is the well-known instance 

 of Father Damien, who contracted leprosy after going to 

 the Sandwich Islands. In view of all the facts there can be 

 little doubt that leprosy in certain conditions may be transmitted 



