50

Pasteur and Schrakramp have observed that the bacillus runs through
the whole course of its development in the soil. It is very probable
that spores sometimes cultivate in stagnant water rich in organic
matter. We have observed the presence of charbonous germs in water
where they have been carried by the rain.

It has been perfectly clearly demonstrated, by experiment and by
observation that charbonous germs are preserved in the soil. "By
washing suspected earth and allowing the water to settle," says Pasteur,
"then submitting the deposit so obtained to a temperature of 90º C. for
some minutes, we destroy all the germs excepting the spores of anthrax
or septicæmia, if there are any; by inoculating animals with this deposit
we get in some septicæmia, and in others charbon. In this manner the
presence of charbonous germs has been detected in earth from graves
three to twelve years after burial of animals suffering from charbon;
animals have been seen to contract charbon after having eaten herbs, etc.,
grown on graves two years after burial; forage deposited on soil con-
taining spores of charbon has been observed to commuicate the malady.
Spore formation occurs more especially in the superior layers of the soil,
but it may occur also in the deeper layers when the soil is permeable
and the temperature favourable; Soyka has noticed that it occurs more
rapidly in a humid soil than even a culture medium. it does not occur
in water deprived of organic substances (Rivolta), but the spores are
preserved in the water. In the same manner, according to the researches
of Kochstetter, whilst the bacillus is preserved three days in distilled
water, in ordinary water the spores remain for more than 154 days;
according to the researches of MM. Straus and Dubarry, the bacillus
may exist for two months in water, and the spores more than 130 days.
To sum up, these charbonous germs preserve their vitality for years in
the soil which covers charbonous animals' graves, and in the soil surround-
ing them; this soil may communicate charbon twelve years after the
burial of the carcass, and perhaps even a longer time. We may discover
germs in such graves, and may by intravenous injection of rabbits, guinea-
pigs, or sheep, which are not easily susceptible to septicæmia, with the
residue of the deposit from water with which they have been washed,
induce charbon and thus verify the suspected material.

Although the cadavers have been buried at a good depth, charbon
germs, despite the filtering action of the soil, remount to the top of the
graves, where we find them, as has already been seen; Pasteur, Feltz,
and Boilinger contend that they are brought to the surface by means of
earth-worms, but this view is denied by Koch, who claims to have proved
to the contrary by experimentally burying earth-worms in earth con-
taining the spores, and on careful examination of the casts of these
worms, finding no trace of charbonous germs of any kind. Pasteur,