388 DISEASES OF THE G ASTRO-INTESTINAL TRACT. 



The resulting ulcers usually conform to the size and shape 

 of the patch involved (Figs. 178 and 179) ; especially in the 



FIG. 179. 



A typical ulcer of the intestine (diagrammatic), showing the undermined edges of 

 the ulcer and the slough still adherent : a, epithelial lining; b, submucous 

 tissue ; c, muscular coat ; d, peritoneum (Green). 



lower part of the ileum, however, the ulcers are liable to 

 coalesce, and thus involve extensive areas of the mucous 

 membrane. The solitary follicles undergo necrosis in a similar 

 manner, resulting in the formation of rounded ulcers. By 

 the end of the third week this stage of ulceration is generally 

 complete, and during the fourth week cicatrization is in prog- 

 ress, finally leaving behind thin, transparent, flexible scars, 

 which often can be recognized years afterward ; the lymph- 

 atic elements are not replaced. 



Microscopically the swelling of the patches and follicles is 

 found to be due mainly to an active proliferation of their 

 lymphoid cells; a few larger epithelioid cells are usually 

 present. 



Coincident with these intestinal lesions of typhoid, the 

 mesenteric glands, in relation to the areas most affected, 

 become swollen from a similar inflammatory hyperplasia, and 

 to an extent in proportion to the severity of the intestinal 

 lesion. 



Enlargement of the spleen is also almost constantly present 

 produced by its congestion and an increase of its lymphoid 

 elements ; large epithelioid cells are often present, as in the 

 intestinal lesions and mesenteric glands, which are actively 

 phagocytic, frequently having encysted within them fragments 

 of red corpuscles. 



The spleen, as well as the liver and kidneys, are often the 

 seat of necrotic foci. The typhoid, bacilli can usually be 

 demonstrated in large clumps, in properly stained sections of 

 the spleen (Figs. 180 and 181), though the whole organ may 

 possibly be cut up in a vain search for them. They are also 

 present in the intestinal lesions, mesenteric glands, liver and 

 kidneys, in the dejecta, and can sometimes be found in the 



