, we are able to diagnosticate with precision the
slightest lesions of any part of this important organ, and, knowing
their nature, to map out an appropriate course of treatment. With the
aid of the stethoscope, invented by Laennec and improved upon by Camman,
we are able to distinguish the slightest deviation from the normal
sounds, and, by noting the character of the sound, the time when it
occurs, the area over which It is heard most distinctly, and the
direction in which it is transmitted, to locate the lesion which
produces it. By the aid of the sphygmograph, first invented by
Herrisson, and afterward improved upon by Ludwig, Vierordt, Marey, and
lastly by Pond, of our own country, the pulsations at the wrist are
registered, and thus made perceptible to the eye.

We herewith give a cut, Fig. 1, of Pond's instrument, and two tracings
made by it. The first is a healthy tracing, and the second indicates
enlargement, technically called hypertrophy, of the heart

PERICARDITIS, or inflammation of the membranous sac which surrounds the
heart, may be either acute or chronic. The symptoms in acute
pericarditis are made up from co-existing affections, and are frequently
associated with articular rheumatism, Bright's disease of the kidneys,
or pleuritis The intensity of the pain varies in different individuals.
The action of the heart is increased, the pulse is quick, and vomiting
sometimes takes place. When this disease is developed in the course of
rheumatism, it is known as rheumatic pericarditis, and is almost always
associated with endocarditis. In some cases acute pericarditis is very
distressing, in others it is mild. The fatality is not due so much to
the disease itself, as to co-existing affections. When it does not prove
fatal, it sometimes becomes chronic.

In chronic pericarditis, pain is seldom present. The heart is generally
more or less enlarged, its sounds are feeble, the first being weaker
than the second.

ENDOCARDITIS, or inflammation of the membrane lining the cavities of the
heart, is one of the most frequent forms of heart disease. It is almost
invariably associated with acute rheumatism, or some of the eruptive
fevers, as small-pox, scarlet fever, etc., and is due to the irritation
of the unhealthy blood passing through the heart. The disease is
generally attended with little or no pain, and, consequently, if the
attending physician be not on the alert, it will escape his observation.
When associate