Pathogenic Bacteria

SYMPTOMATIC ANTHRAX. 457

act in a manner resembling the pulverized spinal cords
of the rabbits used in rabies, and give an almost per-
fect immunity. Roux and Chamberland have found that
filtered cultures can also produce immunity when properly
introduced into animals.

The immunity to symptomatic anthrax seems, how-
ever, to be one of degree, for Arloing, Cornevin, and
Thomas found that when the bacillus was introduced
into the animal body simultaneously with a 20 per cent,
solution of lactic acid, either the virulence of the bacil-
lus or the resistance of the tissues was so changed that
natural immunity was destroyed and the bacteria allowed
to develop and produce the disease. Roger found also
that refractory animals, like the rabbit, mouse, pigeon,
and chicken, could be made susceptible by the combined
injection of the Rauschbrand bouillon, the Bacillus pro-
digiosus, Proteus vulgaris, and other harmless organisms.

When the guinea-pig is inoculated with the bacillus of
symptomatic anthrax, it dies in from twenty-four to
thirty-six hours. The post-mortem examination shows
a bloody serum at the point of inoculation, and the mus-
cles are dark red or black, like those of the " black-leg "
of cattle. No changes are apparent in the internal organs.
The bacilli are at first found near the point of inocula-
tion in the inflammatory exudations only, but soon after
death, being motile, they spread to all parts of the body.

The peculiarities of symptomatic anthrax point to the
entrance of the bacteria into the animal body through
wounds, but the occurrence of epidemics at certain geo-
graphical points, known technically as "Rauschbrand
stations," suggests that infection may also take place
through the respiratory and alimentary tracts.

At first thought, as Frankel points out, one might
imagine that an animal dead of quarter-evil and the dis-
charges from its body might be harmless, as compared,
for example, with the cadavers and discharges of anthrax,
because of the purely anaerobic method of the growth, of
the bacillus of symptomatic anthrax and the rapidit}^ of its