XII, B. 3 Manlove: Balantidial Colitis 155 



The gall bladder contains a very thick, viscid black bile, while 

 the mucosa and walls are apparently normal. 



The urinary bladder contains a small amount of amber- 

 colored urine, and the mucosa is apparently normal. 



Histologically the colon presents changes which vary from a 

 simple catarrh to extensive ulceration involving the muscular 

 coat. 



Changes in the mucosa. — The mucosa of all parts examined 

 has undergone more or less catarrhal inflammation, and in places 

 it is covered with a superficial pseudomembrane of hemorrhagic 

 and necrotic material. The capillaries are dilated, and many of 

 them are ruptured. 



Here and there may be seen distinct ulcers of 1 to 2 millimeters 

 in diameter whose base is superficial to the muscularis mucosae. 

 There are also areas of 2 to 3 millimeters in diameter where the 

 superficial epithelium has desquamated, while the epithelium at 

 the base of the glands and the interglandular papillae remain. 

 The papillae are necrotic near the surface, but in the deeper parts 

 they are thickened, fibrous, and oedematous and are infiltrated 

 with plasma cells and lymphocytes. The blood vessels in the 

 superficial parts of the papillae are widely dilated and ruptured 

 and communicate with the surface, which is covered with a 

 pseudomembrane containing balantidia. 



Where the mucosa forms the margins of the ulcers, there is 

 formation of goblet cells, desquamation of epithelium, necrosis, 

 and infiltration of plasma cells, of round cells, and of some 

 polymorphonuclear neutrophile leucocytes. The blood vessels are 

 dilated, ruptured, and partially or completely obliterated with 

 fibrin thrombi, and in many instances they communicate with 

 vessels in the submucosa showing similar changes. 



The balantidia in relation to the mucosa are found on the sur- 

 face, in the tubules of the glands, within the glandular walls, 

 in apposition to the muscularis mucosa, just penetrating the 

 glandular basement membrane, in the superficial ulcers, and 

 in the solitary lymphoid follicles. They are found both in direct 

 relation to ulcers and in mucosa which is not in close contact 

 with ulcers. In no instance is there any definite cellular re- 

 action surrounding a singly located organism. 



Changes in the submucosa.— The ulceration in places extends 

 to the submucosa, in which the change varies in degree from 

 a superficial involvement to one extending to the muscle. The 

 ulcers have overhanging, undermined edges which curl into them. 

 They are deeper at their lateral extremities, leaving a raised 

 necrotic base whose apex in some instances is level with the sur- 



