582 PATHOGENIC ANAEROBIC BACILLI. 
In stained preparations the long filaments may present a somewhat 
granular appearance from unequal action of the staining agent. 
Biological Characters.—A strictly anaérobic, liquefying, mo- 
tule bacillus. Forms spores. Grows in the usual culture media 
when oxygen is excluded—in an atmosphere of hydrogen. Grows 
at the room temperature—better in the incubating oven at 37° C. 
The spores are formed most abundantly in cultures kept in the in- 
cubating oven, but may also be formed at a temperature of 20° C. 
In the bodies of animals which succumb to an experimental inocula- 
tion no spores are found immediately 
after death, but the bacilli multiply rap- 
idly in the cadaver, and form spores 
when the temperature is favorable. 
The malignant-cedema bacillus may 
be cultivated in ordinary nutrient gela- 
tin, but its development is more abun- 
dant when one to two per cent of grape 
sugar has been added to the culture 
medium. In deep stab cultures in this 
medium development occurs at first only 
near the bottom of the line of puncture ; 
the gelatin is liquefied and has a grayish- 
white, clouded appearance ; an abundant 
development of gas occurs, and as this 
Fre. 164.—Bacillus cedematis ma. @ccumulates the growth and liquefaction 
ligni, culturesin nutrient gelatin; a, of the gelatin extend upward. <A very 
tae Leapilian naire pinnae bot- characteristic appearance is obtained 
when the bacilli are mixed in a test 
tube with gelatin which has been liquefied by heat, and which is then 
allowed to solidify. Spherical colonies are developed, in the course 
of two or three days, in the lower portion of the gelatin ; these are 
filled with liquefied gelatin of a grayish-white color, and when ex- 
amined with a low power are seen to be permeated with a network 
of filaments, while the periphery presents a radiate appearance. In 
nutrient agar growth also occurs at the bottom of a deep punc- 
ture ; it has an irregular, jagged outline and a granular appearance; 
the considerable development at. the deepest portion and gradual 
thinning out above give the growth a club shape ; in the incubating 
oven there is an abundant development of gas, which often splits up 
the agar medium and forces the upper portion against the cotton 
stopper. An abundant development of gas also occurs in cultures 
in blood serum, and the medium is rapidly liquefied ; at a tempera- 
ture of 37° it is changed in a few days toa yellowish fluid, at the 
bottom of which some irregular, corroded fragments of the solidified 
