rax has been a scourge of the animals of the civilized world since
the first written history we have of any of their diseases. In 1709-1712
extensive outbreaks of anthrax occurred in Germany, Hungary, and Poland.
In the first half of the nineteenth century it had become an extensively
spread disease in Russia, Holland, and England, and for the last century
has been gradually spreading in the Americas, more so in South America
than here. In 1864, in the five governments of Petersburg, Novgorod,
Olonetz, Twer, and Jaroslaw, in Russia, more than 10,000 horses and
nearly 1,000 persons perished from the disease.

_Causes._--The causes of anthrax were for a long time attributed
entirely to climatic influence, soil, and atmospheric temperature, and
they are still recognized as predisposing factors in the development of
the disease, for it is usually found, especially when outbreaks in a
great number of animals occur, in low, damp, marshy countries during the
warm seasons. It is more frequent in districts where marshy lands dry
out during the heat of summer and are then covered with light rains.
Decaying vegetable matter seems most favorable for nourishing and
preserving the virus.

The direct cause of anthrax is always infection of a previously sound
animal, either directly from a diseased animal or through various media
which contain excretions or the debris from the body of one previously
infected.

The specific virus of anthrax was first discovered by Davaine in 1851.
He recognized microscopic bodies in the form of little rods in the blood
of animals suffering from anthrax. It was not, however, till a quarter
of a century later that Pasteur defined the exact nature of the
bacillus, the mode of its propagation, and its exact relationship to
anthrax as the sole cause of the disease. In the animal body the bacilli
have a tendency to accumulate in the spleen, liver, and elsewhere, so
that these organs are much more virulent than the muscles or less
vascular tissues. When eliminated from the animal in the excretions, or
when exposed to outside influences by the death of the animal and the
disintegration of the tissues, the body of the rod is destroyed and the
spores only remain. These spores, which may be called the seeds of the
bacilli, retain their vitality for a long period; they resist ordinary
putrefaction; they are unchanged by moisture; and they are not affected
by moderate heat. If scattered with the debris of a dead a