OF THE ALIMENTARY TRACT 207 



penetration of a normal epithelial surface of the 

 colon and of traveling in the tissues below. It ex- 

 cites a reaction of an inflammatory nature, includ- 

 ing hyperemia and mononucleosis, although some 

 record eosinophilia. Hemorrhage and necrosis oc- 

 cur, with the production of necrotic abscesses of the 

 submucosa, w^hich open through the mucosa to the 

 surface, producing an undermined or flask shaped 

 ulcer. The organisms may be seen singly, wander- 

 ing afield from these primary foci, exciting little ap- 

 parent reaction except as they accumulate. They 

 occur in tissue spaces, the lymphoid follicles, lymph 

 and blood vessels. As they multiply the abscesses 

 and ulcers are extended and may become large and 

 deep, even into the muscle coats, remaining, like 

 amoebic ulcers, undermined, ragged, bowl-shaped. 

 The manner of tissue destruction is not proven. 

 Glaessner (1908) extracted a haemolysin but no 

 proteolytic ferment. It is not unreasonable to as- 

 sume the secretion of a histolyzing ferment, in com- 

 parison to Endamoeha histolytica as the direct agent 

 of tissue destruction. 



This tissue invasion, destruction, and production 

 of characteristic ulcers, may occur from the caecum 

 to the rectum, the larger and older lesions most com- 

 mon in the former part. When active and extensive 

 particularly, probably when the rectum is involved, 

 we have the clinical state of balantidial dysentery. 



Here 'lasting from several days to several weeks 

 there may be numerous stools, of a bloody liquid 



