594 BACTERIOLOGY. 
Stains with the usual aniline colors, but not by 
Gram’s method. 
Biological Characters. An aérobic, liquefying, motile 
spirillum. Upon gelatin plates the vibrio Metschnikovi 
grows considerably faster than the cholera vibrio; small, 
white punctiform colonies are developed at the end of 
twelve hours; these rapidly increase in size and cause 
liquefaction of the gelatin within twenty-four to thirty 
hours. At the end of three days large, saucer-like 
areas of liquefaction may be seen, the contents of which 
are turbid, as a rule. Under the microscope the 
colonies appear as yellowish-brown granular masses, 
which are in active movement, and the margins are 
surrounded by a border of radiating filaments. In 
gelatin stick cultures the growth is almost twice as rapid 
as the cholera bacillus. In bouillon at 37° C. devel- 
opment is very rapid, and the liquid becomes clouded 
and opaque, and a thin, wrinkled film forms upon the 
surface. On the addition of pure sulphuric acid to 
twenty-four-hour peptone cultures a distinct nitroso- 
indol reaction is produced. Milk is coagulated and 
acquires a strongly acid reaction. The spirillum does 
not clump and lose its motility with the diluted serum 
from an animal immunized to cholera. 
Pathogenesis. The vibrio Metschnikovi is pathogenic 
for fowls, pigeons, and guinea-pigs. A small quantity 
of a culture injected into the breast muscles of chickens 
and pigeons causes their death with the local and gen- 
eral symptoms of fowl] cholera. At the autopsy the 
most constant appearance is hyperemia of the entire 
alimentary canal. A grayish-yellow liquid, more or 
less mixed with blood, is found in considerable quan- 
tity in the small intestine; the spleen is not enlarged, 
