226 CHARLES SLATER. 
points—a streptococcus form. Bacillus leprz does not give 
this appearance. 
It is a method inapplicable to sections, and, bearing in 
mind the well-known action of strong acids in facilitating the 
production of a streptococcus appearance in B. lepre, does not 
appear to be a reliable guide. 
Unna and Lutz, by a modification of Gram’s method, sub- 
stituting nitric acid for alcohol as the decolourising agent, 
concluded that the true form of B. leprz is a coccothrix. 
It does not appear to have been suggested as a method of 
distinction. 
The conclusions arrived at from an analysis of the work 
previously done and my own observations are— 
1. That any colouring agent which will stain the leprosy 
bacillus will also stain B. tuberculosis. 
2. That the methods proposed to stain B. lepre, while 
leaving B. tuberculosis unstained, are unreliable. There is 
no essential difference between the two bacilli in their relation 
to stains or decolourising agents. 
3. That the apparent differences in respect to rapidity of 
staining and resistance to decolorisation are due to difference 
in numbers of bacilli present. 
It has frequently been suggested that leprosy and tubercu- 
losis are closely allied, and that the bacilli present in the two 
diseases only differ in their physiological activity. It seems 
certain that no distinctions can be based on morphological 
grounds or microchemical reactions. 
As a rule, the pictures presented by the lesions of leprosy 
and tubercle are entirely different, and the nature of the 
affection can be certainly affirmed by a consideration of the 
anatomical nature of the lesion and the number and dis- 
tribution of the bacilli. In the lung, however, we have scanty 
data for these conclusions, and any help that could have been 
derived from the individual characters of the bacilli would 
have been useful. 
It may also happen that a diagnosis of the nature of a lung 
affection may be wanting during the life of the patient, and in 
