AN OUTBREAK OF RABBIT SEPTICAEMIA. 
293 
THE BACILLUS OF RABBIT SEPTICAEMIA. 
In the study of the outbreak just described careful com¬ 
parative cultures were made from the bacteria obtained from 
several of the rabbits, and in all cases stained cover-glass 
preparations from the exudates were carefully examined. 
There was no difference found in the character of the bac¬ 
teria, and the evidence was conclusive that the same species 
of organisms was present in the different animals The viru¬ 
lence might have differed, but in the germs tested (those from 
three rabbits in all) this property was identical. In the de¬ 
scription of the morphological and biological characters here 
recorded, a culture from rabbit No. 500 was used. 
Morphology —A non motile bacillus with ends rounded. In 
stained cover-glass preparations made from the exudate of 
the dead rabbits it appeared as an elongated oval germ with 
more or less polar arrangement of the protoplasm. It varied 
in size from 1.2 to 1.8 in length, and from 0.8 to 1.0 g in 
width. There were frequently many involution forms which 
were especially interesting from the fact that the cellular 
substance appeared to be concentrated at one end of the 
elongated form, which frequently assumed a sack-like appear¬ 
ance. These were especially observable in preparations from 
rabb ts that were not examined until ten hours after death. 
In cultures they were slightly smaller. They stain readily 
with the ordinary aniline dyes, but do not retain the coloring 
matter when treated by the Gram or Weigert-Gram methods. 
Biology .—On agar it developed a grayish, viscid growth. 
It did not grow on potato or in gelatine. It produced no 
appreciable change in milk. It imparted a uniform cloudiness 
to alkaline bouillon, and changed its reaction in twenty-four 
hours to a strongly acid one. After several days standing a 
thin, grayish band was deposited on the sides of the tube at 
the surface of the liquid, and a.grayish, viscid sediment col¬ 
lected in the bottom of the tube. It did not develop in acid 
bouillon. In the fermentation tube containing bouillon plus 
two per cent, glucose, it imparted a cloudy appearance 
throughout the liquid. It fermented glucose but did not pro¬ 
duce gas. 
