SWINE-PLAGUE. 421

The symptoms of swine-plague, while closely resem-
bling those of hog-cholera, may differ from them in the
existence of cough, swine-plague being prone to affect the
lungs and oppress the breathing, which becomes frequent,
labored, and painful, and associated with frequent cough,
while hog-cholera chiefly presents intestinal symptoms.

The course of the disease is usually rapid, a fatal result
often occurring in one or two days.

At autopsy the lungs are often found inflamed, and
contain numerous small, pale, necrotic areas, and some-
times large cheesy masses one or two inches in diameter.
Inflammations of the serous membranes affecting the
pleura, pericardium, and peritoneum, and associated with
fibrinous inflammatory deposits on the surfaces, are com-
mon. There may be congestion of the mucous mem-
brane of the intestines, particularly of the large intestine,
or the disease in this region may be an intense croupous
inflammation with the formation of a fibrinous exudative
deposit on the surface.

A hemorrhagic form of the disease is said to be com-
mon in Europe, but, according to Salmon, is rare in the
United States.

The bacillus of swine-plague much resembles that of
hog-cholera, and not a little that of chicken-cholera. It
is a short organism, rather more slender than its con-
geners, not possessed of flagella, and is incapable of move-
ment and produces no spores. Its vitality is low, and
it is easily destroyed. Salmon says that it soon dies in
water or by drying, and that the temperature for its
growth must be more constant and every condition of
life more favorable than for the hog-cholera germ. This
germ is said to be widely distributed in nature, and is
probably present in every herd of swine, though not
pathogenic except when its virulence has been increased
or the resistance of the animals diminished by some un-
usual conditions.

In its growth the bacillus of swine-plague is an optional
anaerobic organism.