PRACTICAL CONSIDERATIONS : THE SMALL INTESTINE. 1653 



intramuscular plexus of Auerbach and the submucous plexus of Meissner, and their 

 connection with the lower seven intercostal nerves distributed to the skin and muscles 

 of the abdomen, explain (a) the abdominal rigidity and tenderness which often pre- 

 cede an extension of disease from the visceral to the parietal peritoneum ; () the 

 paresis or paralysis of the intestines which is so common as a symptom of peritonitis, 

 and which favors stasis of intestinal contents, putrefaction, and distention ; (<:) the 

 vasomotor disturbance which is an important, if not the chief, factor in the production 

 of meteorism ; (d) the vomiting, first reflex and then from irregular muscular con- 

 traction (reversed peristalsis) ; and (V) the reference of the early pains, no matter 

 what the seat of the peritonitis, to the epigastrium or umbilicus, i.e. , to the solar 

 and superior mesenteric plexuses. 



The usual cause of peritonitis of the small intestine, by infection from within, is 

 penetration of its walls by the colon bacillus, following epithelial necrosis or ulceration 

 due to catarrh or to various forms of infection, or secondary to diseases which pro- 

 duce engorgement of the terminal vessels of the portal system. It is sometimes, in a 

 less acute form, a final phenomenon in fatal cases of renal or cardiac disease. It may 

 follow tuberculosis or typhoid ulceration of the solitary or agminated lymph-nodules. 



In all cases of enterorrhaphy as after resection or anastomosis especial atten- 

 tion should be paid to the non-peritoneal area included between the two mesenteric 

 layers. The success of these operations depends primarily upon the rapid union of 

 apposed peritoneal surfaces ; hence the serous coat, including the two layers of the 

 mesentery, should be brought together through the complete circumference of the 

 bowel and accurately sutured. 



2. The Muscular Coat. Irregular or spasmodic contraction of the muscular wall 

 of the small intestine produces typical "colic," the pain being analogous to that felt 

 in a "cramp" of one of the voluntary muscles. Intestinal colic is not associated 

 with tenderness of the surface of the abdomen, or with rigidity of the abdominal 

 muscles, and is usually relieved by firm pressure, supporting and controlling the 

 affected segment of gut. The abdominal wall may be moved freely over the under- 

 lying viscera. It may thus be distinguished from the early pain of peritonitis. 



The greater thickness of the inner circular coat causes longitudinal wounds to 

 gape more than transverse ones. The latter are more apt to gape if they are at the 

 free border of the gut, where the longitudinal fibres are most numerous. As the 

 muscular coat in its entirety lessens in thickness from above downward, wounds of 

 the jejunum gape more than those of the ileum. Intestinal punctures usually, and 

 very small wounds not infrequently, are closed by muscular action, so that healing 

 takes place without extravasation of intestinal contents. Slightly larger wounds 

 may be stopped by a plug of mucous membrane. This is favored in the upper 

 portion of the tube by the presence of the valvulae conniventes and in the lower part 

 by the laxity of the submucosa. This eversion of the mucous membrane, caused by 

 muscular contraction, must always be overcome in the suture of intestinal wounds, 

 since the mucous surfaces will not unite with each other. 



3. The mttcous and submucous coats and their contained glandular and vascu- 

 lar structures are subject to many varieties of disease. If catarrhal inflammation 

 affects the mucosa of the small intestine, it is apt, if localized in the duodenum, to 

 be associated with gastritis and to extend into the bile-ducts, causing jaundice. If 

 in the jejuno-ileum, it may be mistaken for colitis ; usually, if in the small intestine, 

 the diarrhoea is less marked, the colicky pains are greater, borborygmi are fewer, 

 less mucus is found in the stools, and tenesmus is absent. Neither duodenitis, jeju- 

 nitis, nor ileitis can, however, positively be diagnosticated from one another or from 

 general intestinal catarrh (Osier). 



Ulcers of the duodenum are in the vast majority of cases (242 out of 262, Col- 

 lin, quoted by Weir) situated within 5 cm. (2 in.) of the pylorus (the most movable 

 portion of the duodenum) and are most often on the anterior wall, especially its 

 right side. The peritoneum of the right side of the first part of the duodenum looks 

 into the general peritoneal cavity, and of the left side into the lesser cavity (page 

 1647). When perforation follows, the general peritoneal cavity is therefore likely to 

 be infected, and the death of one-half of the subjects of perforating duodenal ulcer 

 from general peritonitis is thus accounted for. The second part of the duodenum is 



