35§ PATHOGENIC BACTERIA.
one end, from which the new bacillus projects. The
spores of anthrax (Fig. 102), being large and easily ob-
FIG. 102.—Bacillus anthracis, stained to show the spores; x icon (Frankel
tainable, are excellent subjects for the study of sporula-
tion, for the action of germicides and antiseptics, and for
demonstration by stains. When dried upon threads of
silk they will retain their vitality for several years, and
are highly resistant to heat and disinfectants.
Spores of anthrax are killed by five minutes' exposure
to a temperature of 100° C., and are killed in five minutes
in a 5 per cent solution of carbolic acid, or, at least, are
deprived of their vegetative property in relation to cul-
ture-media. It is said by some that spores subjected to
5 per cent, carbolic acid can germinate when introduced
into susceptible animals. Spores are also killed by simple
wetting with i : 100,000 bichlorid-of-mercury solution.
The bacilli are not motile and are not provided with
flagella. They stain well with ordinary solutions of the
anilin dyes, and can be beautifully demonstrated in the
tissues by Gram's method and by Weigert's fibrin method.
Picro-carmin, followed by Gram's method, gives a beauti-
ful, clear picture. The spores can be stained with carbol-