PERICARDIUM, HEART. 99 
THE CIRCULATORY SYSTEM. 
PERICARDIUM. 
Aside from inflammatory changes, what pathological conditions 
may be observed in the pericardium ? 
It may be perforated or it may be ruptured. The pericardial sac 
may contain a quantity of serous fluid usually clear and of a light- 
yellow color. The sac may contain blood from hemorrhage, or there 
may be small extravasations of blood into the walls of the sac. ‘The 
condition pneumatosis may occur from perforating wounds with the 
entrance of air into the cavity of the pericardium. 
What forms of inflammation occur in the pericardium ? 
Exudative and Tubercular. 
Name and describe the different forms of exudative pericarditis. 
“1. Pericarditis with the production of fibrin. In mild cases of this 
class the pericardium is congested and its surface covered with a thin 
layer of fibrin. In more severe cases the layer of fibrin is thicker, 
with fibrinous adhesions between the parietal and visceral walls of the 
pericardium. The walls may be infiltrated with leucocytes. The 
fibrinous adhesions may be absorbed or may be replaced by new con- 
nective tissue. 
2. Pericarditis with the production of fibrin and serum. In these 
cases the changes are the same as above with the addition that there is 
a large effusion of serum into the pericardial sac. 
3. Pericarditis with the production of fibrin, serum and pus. This 
form may begin as one of the varieties just described or it may be pur- 
ulent from the start. ‘These cases are apt to run a chronic course. 
What is to be said of tubercular pericarditis ? 
It may occur as a primary inflammation, but is usually associated 
with tubercular inflammation of other parts. It may occur in the form 
of miliary tubercles scattered diffusely or limited to certain portions of 
the pericardium. Sometimes the pericardium is thickened. 
What tumors have been observed in the pericardium ? 
Fibromata, sarcomata and carcinomata (usually of secondary 
origin) and endotheliomata. 
HEART. 
Aside from degenerative and inflammatory changes, what patho. 
logical changes are found in the heart? 
The heartwall may be penetrated or ruptured. The heart may be 
