THE DIGESTIVE SYSTEM. 547 



cloacae are formed which are often associated with other malformations of the abdom- 

 inal wall, intestines, and generative organs. 



FIG. Sio. MULTIPLE FALSE UIVEKTICUI.A OK THE I.NTKSTINE. 



Incarceration. 



1. The most common form is that in which a portion of intestine is strangulated by 

 a fibrous band. Such fibrous bands are the result of peritonitis or may be of fo?tal 

 origin. They pass from the intestines to the abdominal wall, or from one part of the 

 intestines to another. The intestine becomes in some way caught under one of these 

 bands and is compressed by it. The stricture thus produced may lead to a gradual ac- 

 cumulation of faeces in the intestine above it, and may last for a long time. before death 

 ensues. In other cases the stricture interferes at once with the circulation of the blood ; 

 the intestine is intensely congested, becomes gangrenous, and death takes place with 

 the symptoms of general peritonitis. 



2. A portion of intestine becomes caught in some abnormal opening in the mesen- 

 tery or omeutum, or in the foramen of Winslow, or between the two layers of the 

 mesentery. We have seen a case in which twelve feet of intestine had passed through 

 a small opening in the mesentery. 



3. A coil of intestine makes a half turn at its base, so that the two sides of the 

 loops cross at its base. In this way the lumen of the intestine is completely closed and 

 the vessels are compressed, so that congestion, peritonitis, and gangrene result. This 

 form of incarceration is most frequent in the ascending colon. In the small intestine it 

 may occur when the gut is fixed by old adhesions. 



4. A portion of the intestine, with its mesentery, makes one or more complete turns 

 on itself, closing the canal and compressing the vessels. 



5. A portion of the intestine makes a half or entire turn about its longer axis. 

 This is very rare, and only occurs in the colon. 



6. The mesentery of a part of the intestine is long and loose, in consequence of a 

 dragging down of the intestine by a hernia or by habitual constipation. The portion 

 of intestine thus permitted to hang down is habitually filled with faeces, and by its 

 pressure on some other part of the intestine produces an incomplete stricture. 



Intussusception. 



This change of position consists in the invagination of one portion of intestine in 

 another portion (Fig. 321). Usually this takes place in the direction of the peristaltic 

 movements, from above downward ; more rarely in the opposite direction. 



The parts are found in the following condition : There are three portions of intes- 

 tine, one within the other. The inner portion is continuous with the intestines above 

 the intussusception ; its peritoneal coat faces outward. The outer portion is continuous 

 with the intestine below ; its peritoneal coat also faces outward. The inner portion is 



