THE CIRCULATORY SYSTEM. 427 



which do not penetrate may cause death by the inflammation which they 

 excite, or they may cicatrize. 



Bullets and foreign bodies may become encapsulated in the heart wall 

 and remain so for years. 



Rupture of the heart wall occurs in various ways : 



1. Severe contusions of the thorax may produce rupture, usually of 

 one of the auricles. ' 



FIG. 225. RUPTURK OF THK HEART. 



From contusion. 



2. Spontaneous rupture occurs usually in advanced life. Eupture 

 is most frequent in the left ventricle, and, in a considerable proportion of 

 cases, near the apex. There is usually one rupture, but sometimes there 

 are more. The rupture is usually oblique and larger internally than ex- 

 ternally. The heart wall, near the seat of rupture, may be infiltrated with 

 blood, or blood may infiltrate the subpericardial fat. The heart wall 

 maybe of normal thickness, or thin; it is usually soft and in a condition 

 of fatty infiltration or degeneration. The rupture very frequently takes 

 place when the patient is quiet. Death may be almost instantaneous or 

 may not ensue for several hours. 



Fatty degeneration leading to rupture of the heart may be general, or 

 it is frequently circumscribed and due to obliterating endarteritis, athe- 



'For bibliography see Newton, Med. Record, June 17th, 1899. Also Hamilton, 

 Phila. Med. Jour., January 24th, 1903. 



