MORBID ANATOMY 



1847 



scarred by old dark-coloured cicatrices, indicating the position of 

 the healed ulcers of a previous dysentery. More rarely the cica- 

 trization may have proceeded to such an extent as to cause narrow- 

 ing of the lumen of the gut, and still more rarely may the process 

 lead to abscess formation in the adherent omentum, the pus of this 

 abscess slowly working its way into the anterior abdominal wall, 

 and so to the exterior. The caecum and other parts of the bowel 

 may show polypi protruding from the mucous membrane, a con- 

 dition often called ' colitis polyposa.' 



In the epidemic diarrhoea of infants, the lesions which may be 

 found are classifiable into hyperplasia of the agminated and solitary 

 glands, superficial ulcers, lesions resembling those described above, 

 or invisible lesions. 



Fig. 767. — The Colon in a Case of Bacillary Dysentery. 



Microscopically, there is at first an exudation of fluid containing 

 but few cells into the submucosa, while the mucosa is congested, 

 but the glands are seen to be quite normal. A little later the 

 exudate into the submucosa is seen to have formed fibrin, and the 

 vessels of this coat are noted to be dilated, to contain numerous 

 polymorphonuclear leucocytes, which may be seen undergoing 

 diapedesis into the surrounding tissue. In this stage the exudate 

 has also affected the mucosa, the glands and tissue of which may be 

 seen to be undergoing coagulative necrosis. In a still later stage 

 nothing is to be seen of the mucosa, and in bad cases of the sub- 

 mucosa, except fibrinous exudate, mixed with cells and blood- 

 vessels. Often, however, the submucosa shows dense collections 



