MOUSE-SEPTICEMIA.	427
perhaps identical, organism in the erysipelatous disease
which attacks the swine of many parts of Europe.
There seem to be certain slight morphological and
developmental differences between these two organisms,
but Baumgarten, Giinther, Sternberg, and others have
regarded them as insufficient for the formation of sepa-
rate species, and have boldly described the organisms as
identical, while Lorenz has shown that immunity pro-
duced in the rabbit by one bacillus protects against the
other. The described differences are, indeed, so very
small that I think it well to follow in the path of the ob-
servers mentioned, pointing out in the description such
points of difference as may arise.
The bacilli are extremely minute, measuring about
i.o x 0.2 /* (Sternberg). Fliigge, Frankel, and Eisenberg
find the Bacillus erysipelas suis somewhat shorter and
stouter than that of mouse-septicemia: there seems to
be a "division of opinion upon this point.
Sporulation has been described by some observers, but
nothing definite seems to be known upon this point.
Motility is ascribed by some (Schottelius and Frankel)
to the Bacillus erysipelas suis, and is denied to the bacillus
of mouse-septicemia by others. The truth seems to be
that the motility of both organisms is a matter of doubt.

No flagella have been demonstrated upon the bacillus.
It grows quite well both at the room-temperature and at
the temperature of incubation. It can grow well with or
without oxygen, but perhaps flourishes
a little better without than with it. It
is killed by a temperature of 52° C. in
fifteen minutes.
The colonies upon gelatin plates can
first be seen on the second or third day,      fig. n8.—Colony
then appearing as  transparent grayish   of the bacillus   of
-	. -       .	-	*       i	/-	mouse-septicemia: X
specks   with    irregular    borders,   from   go      a*\
which many branched processes extend
(Fig. 118).     Frankel describes them  as resembling in
shape the familiar branched cells occupying the lacunae