ACUTE COLITIS. 



383 



necrosis ; the resulting ulcers may be superficial, or deep and 

 ragged in outline, spreading rapidly, so that there is but little 

 of the mucous membrane unaffected. In many cases the 



FIG. 174. 



Appendix containing two fecal concrements : case of perforative appendicitis, the 

 perforation opposite the distal concrement (Museum, Carnegie Laboratory). 



mucous membrane is covered with a grayish or brownish 

 pseudo-membrane, either in isolated patches or less frequently 

 as a uniform coating diphtheritic or croupous dysentery. 



