chap, xvii.] ABDOMINAL VISCERA. 337 



border of the gut, since in that place the longitudinal 

 muscular fibres are thickest. 



In one remarkable case a man was stabbed in the 

 belly. It was subsequently found that there was a 

 small puncture in the ileum, which had been plugged 

 by the mucous membrane, and further secured by 

 recent lymph. The man did well until the fourth 

 day, when he died somewhat suddenly. It was then 

 found that an intestinal worm (Ascaris lumbricoides) 

 had worked its way through the wound, breaking 

 down the adhesions, and had escaped into the peri- 

 toneal cavity. Extravasation followed, and thus the 

 worm was the immediate cause of the man's death. 



The calibre of any portion of the small intestine 

 depends mainly upon the condition of its muscular 

 wall. The tube may become much contracted when 

 empty. In peritonitis and in certain other conditions 

 the muscular coat is paralysed and the bowel becomes 

 intensely dilated by gas (tympanitis). 



deckel's diverticulum. From one to four 

 feet from the end of the ileum is sometimes seen a 

 diverticulum (Meckel's) that represents the remains of 

 the vitello-intestinal duct. It may be expected in 

 2 per cent, of the bodies examined. This diverti- 

 culum usually exists as a tube of the same structure 

 as the intestine. Its length varies. It may some- 

 times extend as a patent tube as far as the umbilicus. 

 It is more often but a few inches long, and may then 

 end in a free conical or globular extremity, or in a 

 fibrous cord. This diverticulum may cause intestinal 

 obstruction in many ways. Its end may contract 

 adhesions, and beneath the bridge thus formed a loop 

 of bowel may be strangled. It may twist itself about a 

 piece of intestine so as to form a knot around it. It may, 

 from its adhesions, so drag upon the ileum as to cause 

 " kinking " of the tube at its point of origin. In more 

 than one case it has been found in an external hernia. 

 W 4 



