102 THE CIRCULATORY SYSTEM. 
a weakening of the heartwall by endocarditis, myocarditis, or fatty 
degeneration. The heart cavities are often found after death to con- 
tain yellow, succulent, semi-translucent masses or colorless clots. They 
are formed during the last hours of life and are of no pathological 
significance. Masses of fibrin may form upon the heart valves or in 
any of the heart cavities during life. They are usually associated 
with some valvular lesion and are of a firm whitish appearance. 
What tumors have been found in the heart ? 
Primary tumors are rare, but sarcomata, fibromata, lipomata and 
myxomata have been found. 
BLOODVESSELS. 
What forms of degeneration have been noted in bloodvessels ? 
Fatty degeneration, affecting the intima or media, or both; this 
may lead to the formation of an aneurism. 
Calcareous degeneration, affecting the intima or media, usually 
occurs in vessels otherwise diseased. 
Amyloid and also hyaline degeneration ; these forms may implicate 
the entire vesselwall. 
ARTERIES. 
What is an aneurism ? 
It is the dilatation of the coats of an artery over a larger or smaller 
part of its course. Aneurisms are named according to their shape. 
When implicating the entire vesselwall for a longer or shorter space 
there is formed a cylindrical aneurism. 
If the wall of one side of a vessel is affected, then there is formed a 
sacculated aneurism. These ordinary aneurisms are due to degenera- 
tive changes in and consequent weakening of the vesselwall. In cir- 
soid aneurism there is a dilatation and also a lengthening of the vessel, 
giving it a tortuous course. This form occurs as a rule in the smaller 
arteries. 
To what inflammations are the arteries subject ? 
(1) Acute arteritis, with an exudation of leucocytes into the vessel- 
walls. This occurs usually as the result of injury. The inner coat 
may be affected (endarteritis), or the outer coat (periarteritis). 
(2) Chronic arteritis in most cases is more marked in the intima, 
but may implicate all the arterial coats. The change consists of a 
production of new connective tissue and a thickening of the vessel- 
