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 (ace 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. 
