DIFFERENTIATION OF LEPROSY AND TUBIRCLE BACILLI. 219 
On the Differentiation of Leprosy and Tubercle 
Bacilli, 
By 
Charles Slater, M.B.Cantab. 
In the course of an investigation of a case of tubercular 
leprosy the question arose as to the nature of certain lesions of 
the lungs. It is well known that patients suffering from leprosy 
frequently succumb to an affection of the lungs closely re- 
sembling ordinary phthisis. Whether this phthisis is the 
result of an intercurrent tuberculosis, or is of the same nature 
as the undoubtedly leprotic lesions of viscera other than the 
lungs, is still a matter of dispute. While certain observers, 
such as Hansen, Neisser, and Leloir, regard the phthisis as an 
intercurrent disease attacking a weakened patient, others, as 
Bonomé and Arning, think that the lesions are due to the 
spread of the leprotic process to the lungs. As a subsidiary 
branch of the inquiry it was thought advisable to examine the 
statements of previous investigators as to the differential stain- 
ing and morphological differences of the bacilli present in the 
two diseases, and to test their results on material supplied by 
this undoubted case of leprosy. 
The material, for which I am indebted to Dr. Delépine, con- 
sisted of various internal organs, glands, nerves, and skin from 
different parts of the body. In addition there were specimens 
of sputa obtained some three days before death. 
Distinctions between the bacilli of leprosy and tuberculosis 
have been sought by many investigators, with the general result 
that one after the other the differential criteria have been 
shown to be untrustworthy or less constant than was originally 
supposed. 
