and vagina, in cows;
diphtheritic inflammation of the small intestine of calves. Among horses it
is the agent in the production of necrotic malanders, quittor, and
diphtheritic inflammation of the large intestine. In hogs it has caused
necrotic or diphtheritic processes in the mucous membrane of the mouth,
necrosis of the anterior wall of the nasal septum, and pulmonary and
intestinal necrosis, accompanying hog cholera. Abscesses of the liver,
gangrenous processes of the lips and nose, and gangrenous affections of the
hoof have all been caused in sheep by this organism.

_Pathology._--The principal lesions in necrotic stomatitis occur in the
mucous membrane of the mouth and pharynx. The alterations may extend to the
nasal cavities, the larynx, the trachea, the lung, the esophagus, the
intestines, and to the hoof. The oral surfaces affected are, in the order
of frequency, tongue, cheeks, hard palate, gums, lips, and pharynx. In the
majority of cases the primary infection seems to occur in the tongue. (Pl.
XLIII.)

Infection takes place by inoculation. Some abrasion or break in the
continuity of the mucous membrane of the mouth occurs. Very likely the
origin may be connected with the eruption of the first teeth after birth,
or, in animals somewhat older, the entrance of a sharp-pointed particle of
feed. Gaining an entrance at this point, the bacilli begin to multiply.
During their development they elaborate a toxin, or poisonous substance,
which causes the death, or necrosis, of the epithelial, or superficial,
layer of the mucous membrane and also of the white blood cells which have
sallied forth through the vessel walls to the defense of the tissues
against the bacillary attack. This destruction of the surface epithelium
seems to be the essential factor in the production of the caseous patch,
often called the false membrane. From the connective-tissue framework below
is poured forth an inflammatory exudate highly albuminous or rich in
fibrin-forming elements. When this exudate and the necrosed cellular
elements come in contact, the latter furnish a fibrin ferment which
transforms the exduate into a fibrinous mass. This process is known as
coagulation necrosis, and the resulting fibroid mass, containing in its
meshes the necrosed and degenerated epithelium and leucocytes, constitutes
the diphtheritic or false membrane. Did the process cease at this point it
would be properly called a diphtheritic inflammation, but it doe