the pain subsides, the fever
disappears, and convalescence is apparently established, when, suddenly,
all the symptoms are renewed with even greater intensity than before.
This disease rarely proves fatal, unless the heart is involved.

CAUSES. Rheumatism is frequently supposed to be occasioned by a
suppression of the functions of the skin, and is generally attributed to
the action of cold upon the surface of the body. But this acts only as
an exciting cause. It is a disease of the blood. This form of rheumatism
usually occurs between the age of fifteen and thirty, and prevails most
extensively in changeable climates. Acute articular rheumatism seldom
terminates in the chronic form.

CHRONIC ARTICULAR RHEUMATISM. Articular rheumatism, in the subacute or
chronic form, is frequently observed in medical practice. The symptoms
are pain and more or less swelling of the joints, although not of as
grave a character as in acute rheumatism. There is frequently an absence
of increased heat and redness. As in the acute form, the different
joints are liable to be affected successively and irregularly, until,
after a time, the disease becomes fixed in a single joint, and the
fibrous tissues entering into the ligaments and tendons are liable to be
affected. The appetite, digestion, and nutrition are often good, and, in
mild cases, patients are able to pursue their daily vocations. The
disease is supposed to be the same as in the acute form, but milder,
and, strange to say, more persistent. A diseased condition of the blood
is supposed to be involved in both instances, but this morbid state is
less extended, and, at the same time, more obstinate in the chronic than
in the acute form. Sub-acute articular rheumatism is not always chronic,
and may disappear in a shorter time than in the acute form. Chronic
articular rheumatism is not generally fatal, but there is danger of
permanent deformities.

MUSCULAR RHEUMATISM. This affection is closely allied to _neuralgia_,
and may properly be called _myalgia_. It exists under two forms, acute
and chronic. In acute muscular rheumatism, there is at first a dull pain
in the muscles, which gradually increases. When the affected muscles are
not used the pain is slight, and certain positions may be assumed
without inducing it constantly; but in movements which involve
contraction of the muscles the pain is very violent. In some cases, the
disease is movable, changing from one muscle to another, but