DISEASES OF THE HEART IN DOMESTIC ANIMALS 
343 
pericarditis. The point of the foreign substance is either sur¬ 
rounded by coagulated fibrin and projects freely in the cavity of 
the heart, or it presses against the opposite partition of the lin¬ 
ing, which is rent in consequence of the point gliding up and 
down during the normal action of the heart. 
The more circumscribed the myocarditis is, the more numer¬ 
ous are the above described spots. The usual termination of the 
same is induration, formation of callous scars, or suppuration. 
Upon the cadaver of the horse callous scars are often found as 
marks of protracted inflammation of the heart; they are either 
ramified, or solid white callosities of various dimensions, taking 
the place of the muscle of the heart. In the latter form they 
appear most frequently in the left ventricle toward the apex; 
they are then not as thick as the wall of the heart, sometimes-rggi 
bent outward, forming a circumscribed aneurism of the heart. % 
. . . *1 
Undoubtedly such pouch-like projections are still formed in the 
stadium of saturation as the result of a circumscribed inflamma¬ 
tion, and before‘the callous formation which seems to be brought 
about in the stadium of fatty degeneration and mollification. 
The issue of myocarditis into callous hardening often extends 
to the inner Dart of the wall of the heart, otherwise to the outer 
part with the pericardium, or to the entire wall of the heart in 
its whole thickness, including pericardium and endocardium. 
Such extended callosities which penetrate the entire thickness of 
the muscle, influence not only the increase of the positive enlarge¬ 
ment of the cavity of the heart ushered by the inflammation, but 
especially the formation of the above described pouch-like expan¬ 
sion, the true aneurism of the heart. 
The termination of carditis into suppuration is not so frequent, 
and is manifested by the presence of small abscesses in parts of 
the relaxed and discolored muscle of the heart. Especially are 
such cases known in the dog. These abscesses, which vary in size 
from a pea to a penny, are filled with thick yellow pus, and occupy 
the whole thickness of the wall between the outer and inner 
membrane, and by very small openings perforate the inner or 
outer wall of the heart; more frequently the inner. The flesh 
around the heart is always pale, very tender and soft. The form 
