578 DISEASE IN WILD MAMMALS AND BIRDS 
may be aided by this unidentified bacillus especially 
in the ulcerative and septicemic varieties of Kangaroo 
disease. 
In so far as the diagnosis of this infection in the 
uncomplicated form, like lumpy jaw, is concerned the find- 
ing of streptothrix by stain seems adequate and its pres- 
ence in the gastric ulcers and hepatic necroses identifies 
this variety. The most difiicult question to decide is the 
identity of the cases without one or the other of these dis- 
tinctive features but with mucocatarrhal or purulent 
nasosinusitis followed by pneumonia or septicemia, and 
of cases of primary pulmonary involvement. These in- 
stances have been diagnosed as belonging to the same 
category because of the presence of streptothrix in the 
exudate at the site of the important lesions and because 
the type of lesion is similar to that which complicates 
accepted characteristic cases. Inability to reproduce ex- 
perimentally any of these infections limits our criteria 
for judgment in the matter. I am inclined to view these 
septicemic cases therefore as initiated by the strepto- 
thrix, growing in the nose and sinuses or inhaled into the 
lungs, aided by lower bacteria, an unidentified Gram- 
negative bacillus being the most important. 
Having reviewed briefly the bacteriology of Kangaroo 
disease, its strict pathology may be discussed more defi- 
nitely in terms of the type of infection. Reference has 
already been made to the method of pathogenesis 
employed by the streptothrix and its congeners. Whether 
or not a toxin is elaborated by these organisms is an 
unsettled question, especially for the marsupial variety 
because as yet it cannot be made to produce lesions in 
other animals. It is highly probable that all these organ- 
isms find colonization easy in the animal's body once they 
get well settled, and that they act mechanically, producing 
necroses by their gro^^i;h and by attracting leucocytes in 
such large numbers that digestion of devitalized tissue 
occurs, to an extent that resembles pus. The inflamma- 
