THE LINING MEMBRANE OF THE HEART.

Endocarditis frequently occurs as a complication of rheumatism, some of
the specific or zymotic fevers, specific poisoning, etc. This is a more
frequent disease among horses than is generally known, and often gives
rise to symptoms which at first are obscure and unnoticed.

In influenza we may find the heart becoming involved in the disease, in
consequence of the morbid material conveyed through the heart in the
blood stream. In view of the fact that many affections in even remote
portions of the body may be traced directly to a primary endocardial
disease, we shall feel justified in inviting special attention to this
disease.

Endocarditis may be acute, subacute, or chronic. In acute inflammation
we find a thickening and a roughened appearance of the endocardium
throughout the cavities of the heart. This condition may be followed by
a coagulation of fibrin upon the inflamed surface, which adheres to it,
and by attrition soon becomes worked up into shreddy-like granular
elevations. This may lead to a formation of fibrinous clots in the heart
and sudden death early in the disease the second or third day.

Subacute endocarditis, which is the most common form, may not become
appreciable for several days after its commencement. It is characterized
by being confined to one or more anatomical divisions of the heart, and
all the successive morbid changes follow each other in a comparatively
slow process. Often we would not be led to suspect heart affection were
it not for the distress in breathing, which it generally occasions when
the animal is exercised, especially if the valves are much involved.
When coagula or vegetations form upon the inflamed membrane, either in
minute shreds or patches, or when formation of fibrinous clots occurs in
the cavity affected, some of these materials may be carried from the
cavity of the heart by the blood current into remote organs,
constituting emboli that are liable to suddenly plug vessels and thereby
interrupt important functions. In the great majority of either acute or
subacute grades of endocarditis, whatever the exciting cause, the most
alarming symptoms disappear in a week or 10 days, often leaving,
however, such changes in the interior lining or valvular structures as
to cause impairment in the circulation for a much longer period of time.
These changes usually consist of thickening or induration of the
inflamed structures. But while the effect