318 BACTERIOLOGY. 



of the transmissibility of the disease in this way, is by 

 no means conclusive; for, according to Swift, the man 

 had other opportunities for becoming infected. These 

 negative results, together with the fact that infection 

 does not more frequently occur in persons exposed to 

 the disease, may possibly be explained by the assump- 

 tion that the bacilli contained in the tubercular tissue 

 are mostly dead, or much more probably that an indi- 

 vidual susceptibility to the disease is requisite for its 

 production. 



The wide-spread idea, before the discovery of the 

 leprosy bacillus, that the disease was associated with the 

 constant eating of dried fish or a certain kind of food 

 has now been entirely abandoned. 



The relation of leprosy to tuberculosis is sufficiently 

 evident from their great similarity in many respects. 

 This is rendered still more remarkable if the ob- 

 servation recently made is true, that leprosy reacts, 

 both locally and generally, to an injection of tuberculin 

 in the same manner as tuberculosis (Babes and Kalin- 

 dero). 



Differential Diagnosis. The differential diagnosis be- 

 tween leprosy and tuberculosis is not difficult in typical 

 cases. The large numbers of bacilli found in the inte- 

 rior of the cells would point with great probability to 

 leprosy. Too much importance should not be placed 

 upon the staining peculiarities, as these are not con- 

 stant. Moreover, the two diseases not infrequently 

 occur together in the same individual. In making the 

 diagnosis, therefore, all the signs, histological and 

 pathogenic, must be considered and animal inoculations 

 made. 



