552 



THE DIGESTIVE SYSTEM. 



of irritant poisons. The mucous membrane may be the seat of superficial 

 necroses, sometimes in patches, and the pellicle may consist largely of 

 mucus with necrotic epithelium. Fibrin may be present and fibrin and 

 extravasated leucocytes and serous fluid may infiltrate the submucosa. 

 Exudative or Suppurative Enteritis is rare. Purulent foci, usually 



Ffe. 327. TUBERCULOUS ULCERS OF THE SMALL INTESTINE. 



In the larger ulcers the mucous membrane is almost entirely gone, leaving the muscularls exposed at the 



bottom. 



metastatic in origin, may form in the wall of the intestine. A more dif- 

 fuse suppuration may follow infection after obstruction or strangulation. ' 

 Tuberculous Enteritis. The lymph -nodules and Peyer's patches are 

 often involved in intestinal tuberculosis and often ulcerate (Fig. 327). 

 Miliary tubercles maybe present with cheesy degeneration (Fig. 328) and 

 the subperitoneal lymphatic vessels are often involved and may appear 

 as white, nodular, branching, slightly elevated cords, running around the 



FIG. 328. -SECTION OF A TUBERCULOUS ULCER OF THE SMALL INTESTINE. 



Showing tubercle tissue with miliary tubercles and caseation at the bottom of the ulcer. There are miliary 

 tubercles beneath the serosa. (See Fig. 329.) 



gut (Fig. 329). Tuberculous ulcers are apt to extend most rapidly in a 

 direction transverse to the axis of the gut (Fig. 330), differing in this 

 respect from typhoid ulcers (see page 230). But to this there are fre- 



1 For reference to bacterial excitants of enteritis see footnote, p. 560. 



