538 PATHOGENIC AEROBIC BACILLI 
slightly iridescent; the deep colonies are spherical, opaque, and homo- 
eneous. 
. The growth upon the surface of nutrient agar is abundant and rapid, of 
ashining milk-white color, and cream-like in consistence. An abundant 
development forms along the line of puncture and the culture medium is 
split up by gas bubbles. In glycerin-agar the evolution of gas is very abun- 
dant and the culture medium acquires an intensely acid reaction. 
On potato the growth is abundant and rapid at a temperature of 20° to 
30° C., forming a thick, semi-fluid mass of a milk-white color. 
I have not obtained any evidence that this bacillus forms spores; the 
cultures are sterilized by ten minutes’ exposure to a temperature of 160° F. 
When cultivated in bouillon to which five per cent of glycerin has been 
added the culture medium acquires a milky opacity, and there is a copious 
precipitate, of a viscid consistence, consisting of bacilli; during the period 
of active development the surface is covered with gas bubbles, as in a sac- 
charine liquid undergoing alcoholic fermentation, and the liquid has a de- 
cidedly acid reaction. 
Pathogenesis.—Pathbogenic for rabbits and for guinea pigs when injected 
into the cavity of the abdomen—one to two cubic centimetres of a culturein 
bouillon. The animal usually dies in less than twenty-four hours. The 
bacilli are found in the blood in rather small numbers, and are frequently 
seen in the interior of the leucocytes. The spleen is enlarged, the liver 
normal, the intestine usually hyperzemic. 
BACILLUS CUNICULICIDA HAVANIENSIS. 
Obtained by the writer (1889) from the contents of the intestine of yellow- 
fever cadavers, and also from fragments of yellow-fever liver preserved for 
forty-eight hours in an antiseptic wrap- 
ping—my bacillus x, Havana, 1889. 
Morphology.—This bacillusresembles 
the colon bacillus in form, but is some- 
what larger, from 2 to 4 “ in length and 
from 0.8 tol “ in diameter ; sometimes 
associated in pairs; may grow out into 
short filaments—not common. The ends 
of the rods are rounded, and under cer- 
tain circumstances vacuoles are seen at 
the extremities, especially in potato cul- 
tures. 
Stains quickly with the aniline colors 
usually employed, and also by Gram’s 
method. 
Biological Characters.—An aérobic 
and facultative anaérobic, non-lique- 
Fig. 150.—Bacillus cuniculicida Havani- fying bacillus. Under certain circum- 
‘ensis, from a sinzle colony in nutrient gela- stances may exhibit active movements, 
tin. x 1,000. From a photomicrograph, yt is usually motionless. 
Sternberg.) A very curious thing with reference 
: : to this bacillus is that it presented ac- 
tive movements in my cultures made directly from yellow-fever cadavers, 
but that these movements were not constant, and that since my return to 
Baltimore I have not, as a rule, observed active movements in cultures from 
the same stock, which, however, preserved their pathogenic power and other 
characters. In Havana these movements were usually not observed in all 
the bacilli in a field under observation, but one and another would start from 
a quiescent condition on an active and erratic course; sometimes spinning 
actively upon its axis, and again shooting across the field as if propelled by 
a flagellum, 
