408 
GLANDERS, ANTHRAX, PYOCYANEUS 
stated that earthworms may carry infected material from the deeper 
layers of the soil to the surface, where sporulation may occur. If these 
temperatures are exceeded in either direction, spore formation does not 
take place. The spores, which are oval, are situated at or near the 
center of the cell and measure about 0.8 micron in diameter and from 
1.2 to 1.4 microns in length. Occasional asporous strains^ are met with, 
and spore formation may be suppressed by cultivating the bacteria at 
42° C. for several hours or in fluid media containing potassium bichro- 
mate in dilutions from 1 to 5000 to 1 to 2000, or small amounts of 
phenol. 2 Lehmann^ states that long-continued transfer of cultures 
from gelatin to gelatin frequently leads to a suppression of spore forma- 
tion. Some strains become sporeless much more readily than others.* 
Spores are not formed in the intact animal body. Mature vegetative 
bacilli emerge from the spores in the presence of oxygen, if the tempera- 
ture is maintained between 15° and 40° C. The spore membrane 
merges imperceptibly into the newly formed vegetative cell; no visible 
rupturing of the spore membrane is detectable. 
-Bacillus anthracis, showing capsule formation. X 1000. (Kolle and Hetsch.) 
Bacillus anthracis stains well with ordinary anilin dyes and young 
cultures are Gram-positive. Older cultures may gradually lose their 
ability to retain the Gram's stain. Spores may be stained with the 
Ziehl-Neelsen method. (See Staining of Spores.) 
Isolation and Culture.— Bacillus anthracis grows readily upon any 
artificial media. Material is best obtained from the spleen or liver 
of dead animals, or from the blood of an infected animal. Gelatin 
is rapidly liquefied; colonies appear in gelatin plates within eighteen 
hours after inoculation, which are from 1 to 2 mm. in diameter. They 
are gray, opaque, and somewhat irregular in size. The organisms 
* Asporous cultures do not necessarily become avirulent (Chamberland and Roux: 
Compt. rend. Acad. Sci., 1883, 96, 1090). 
2 Roux: Ann. Inst. Pasteur, 1890, 4, 25. 
3 Miinchen. med. Wchnschr., 1887, 34, 485. 
4 Surmont and Arnould: Ann. Inst. Pasteur, 1894, 8, 817. 
