IN SUSCEPTIBLE ANIMALS. 519 
This bacillus grows as well in an acid medium as in one which is slightly 
alkaline. In gelatin plates, at the end of eighteen to twenty-four hours, 
colonies are formed which under a low power are seen to be spherical and 
to contain a quantity of shining granules; the following day, at a tempera- 
ture of 15° to 17° C., the colonies may be as large asa pin’s head and still 
remain spnerical or slightly oval, but 
the outline is no longer so uniform, 
and between the shining points in the 
interior a confused network may be 
seen; as the colony becomes larger it 
_is raised above the surface of the gela- 
tin, becomes opaque, and has a pearly 
lustre like that of Friedlander’s bacil- 
lus. In gelatin stab cultures the 
growth resembles that of Friedlin- 
der’s bacillus—‘‘ nail-shaped growth.” 
Upon the surface of nutrient agar a 
rapidly extending, semi-transparent 
layer is formed. Spon potato, at 15° 
to 17° C., at the end of twenty-four 
hours transparent drops are seen in 
the vicinity of the point of inocula- 
nee ‘aie Tier a ane shining, color- ie 
ess layer, of tough consistence, is ra 
formed, which gradually extends over on pci ae ato sacs ag 
the surface. The growth upon blood  guzzi) E seeeds 
serum resembles that upon nutrient : ee . 
agar, and the blood serum is not liquefied. In liquid blood serum or in 
bouillon the bacilli are isolated—not in filaments; they cause a clouding of 
the liquid, and an abundant deposit accumulates at the bottom of the tube, 
while a film of bacilli forms upon the surface. The cultures never give off 
a putrefactive odor. : f 
Pathogenesis.—Pathogenic for dogs and for mice, less so for rabbits and 
for guinea-pigs. Agar cultures grown in the incubating oven at 32° to 37 
C. are more pathogenic than cultures in gelatin at the room temperature. 
A small quantity of a recent culture injected subcutaneously in mice causes 
their death in from one to four days, according to the quantity and age of 
the culture; the recent cultures are most virulent. When the animal lives 
more than twenty-four hours it has a mucous diarrhea. At the autopsy the 
spleen is found to be much enlarged and dark in color ; the lymp atic 
glands are also swollen and hemorrhagic, the liver and kidneys hyperemic; 
in the vicinity of the point of inoculation is a subcutaneous cedema of jelly- 
like appearance and numerous punctiform hemorrhages are seen. The ba- 
cillus is found in great numbers in the effused serum from the subcutaneous 
tissues, in the blood, the contents of the intestine, and in the parenchyma of 
the various organs. When examined at once the bacilli in the subcutaneous 
cedema and in the lymphatic glands are usually quite short, and even spherical, 
while in the blood they are somewhat longer and may appear as short fila- 
ments with swollen ends, surrounded by a capsule. When the examination 
is made some time after the death of the animal longer filaments are quite 
numerous. Rabbits and guinea-pigs are killed by the intravenous injection 
of comparatively small amounts of a recent culture, but quite large doses 
are required to producea fatal result when the injection is made beneath 
the skin. From two to three cubic centimetres of a recent culture injected 
into the circulation of a dog give rise to symptoms of toxzemia, and the ani- 
mai usually dies on the second day. At the autopsy the abdominal organs 
are found to be hypereemic, the mucous membrane of the intestine swollen, 
red in color, and covered with bloody mucus. The bacillus is found in the 
blood and in the various organs. When smaller doses are injected into a 
vein (a few drops) the animal, after a few hours, has a mucous diarrhoea and 
