an animal may disseminate the contagion after apparent recovery
which give the plague that insidious character so often spoken of, and
which greatly increase the difficulties of eradication.

_Symptoms._--The symptoms are such as would be expected with inflammation
of the lungs and pleurae, but they vary considerably, according to the type
which the disease manifests. If the attack is an acute one, as is
frequently seen in hot weather, the symptoms appear suddenly; the breathing
becomes rapid and difficult, the animal grunts or moans with each
expiration, the shoulders stand out from the chest, the head is extended on
the neck, the back is arched, the temperature is 104 deg. to 107 deg. F., the milk
secretion is suspended, there is no appetite, rumination is stopped, the
animal may bloat and later be affected with a severe diarrhea. Such cases
are generally fatal in 7 to 20 days.

Very often the attack comes on slowly and the symptoms are much less clear.
In the mildest cases there is a cough for a week or two, but no appreciable
loss of appetite or elevation of temperature. The lungs are but slightly
affected and recovery soon follows. Such animals may disseminate the
contagion for a long time without being suspected, and for that reason are
the most dangerous of all.

A more severe type of the plague is the most frequently seen. In these
cases the cough is frequent, more or less painful, the back somewhat
arched, and the milk secretion diminished. The prominence of these symptoms
increases, the appetite is affected, the animal loses flesh, the breathing
becomes more rapid, the cough more painful, pressure of the fingers between
the ribs shows tenderness, the hair loses its gloss and stands erect, the
skin becomes adherent, little, if any, milk is secreted, and the
temperature rises, varying in different animals from 103 deg. to 107 deg. F.
Animals thus affected may continue to grow worse and die in from three to
eight weeks, or they may after a time begin to improve and make an apparent
recovery. The inflammation of the lung does not, as a rule, subside and the
organ return to its normal condition, as is the case in ordinary pneumonia,
but with this disease the life of the affected portion of the lung is
destroyed, the tissue dies, and a fibrous wall is formed around it to shut
it away from the living parts. The tissue, thus encysted, gradually
softens, becomes disintegrated, and breaks down into pus. The recovery,
t