640 
RICHARD MIDDLETON. 
era. Such was actually the case, for they withstood re¬ 
peated inoculating; with chickens which had not received in¬ 
jections of the calf virus, the result was directly opposite. 
Htippe and Kitt arrived at the same conclusion in experi¬ 
menting with rabbit septicaemia; chickens and geese were in¬ 
oculated with attenuated cultures of chicken cholera, and 
thereby received immunity from rabbit septicaemia, which is 
otherwise equally as fatal to fowl as to rabbits. These inter¬ 
esting experiments speak for the fact that the oval bacteria of 
the several diseases herein mentioned are identical, but they 
do not prove it. 
In the abstract, it is possible that two different diseases 
may give immunity one from the other, especially when the 
bacteria which produce them are very similar; Roux and 
Chamberland have proven this by inducing immunity in 
guinea-pigs from malignant oedema by injecting virus of the 
carbuncle disease (French charbon symptomatique). Con¬ 
cerning the occurrence of these oval bacteria in nature, there 
is little known; the microbe of rabbit septicaemia is isolated 
from all putrid substances and impure water. Gamaleia 
always found in the intestinal contents of pigeons a bacteria 
similar to that of chicken cholera; these were only slightly 
irritating to poultry, but more so to rabbits ; when these were 
\ 
passed through several rabbits they increased in virulence so 
that a point was reached at which chicken cholera was in¬ 
duced therewith in poultry and pigeons. Salmon found a 
bacteria in the nasal mucous of a sound swine, that could 
cause the death of a rabbit in one day; I have also found 
similar and more or less pathogenic bacteria (i) in the sto¬ 
machic mucous of diphtheritic calves, (2) in the intestinal con¬ 
tents of a sound mouse, (3) upon a necrotic and thickened 
portion of a horse’s lung, (4) in the pus that escaped from the 
abscess in a case of periostitic suppuration of the middle region 
of the foot. 
All these oval bacteria agree so exactly—when we over- 
lgok the symptoms induced—that it is impossible to deter¬ 
mine one from the other. They are characterized try the fol¬ 
lowing peculiarities : They are immobile ; they grow slowly 
