OF THE ALLAIEXTARY TRACT 209 



active swarms in the stool when diarrhoea is pro- 

 duced by it. The mucinous material shows the great- 

 est numbers. 



Attacks of balantidial dysentery may sponta- 

 neously terminate in apparent recovery and after a 

 period, in which constipation is likely, an acute at- 

 tack may recur. Whether the organisms remain 

 within the colonic wall in these normal intermissions 

 or in case of apparent recovery or whether they are 

 then only lumen dwellers is unknown. We do know 

 that ulceration may be present without diarrhoea, 

 however, just as in the case of intestinal amoe- 

 biasis. 



CHRONIC BALANTIDIOSIS 



Much more common than the state of balantidial 

 dysentery is that in which there is an infection with 

 Balantidium coli without dysentery or even any ap- 

 parent disturbance due to it. It is unknown whether 

 in the ''carrier" state without symptoms of disease 

 the organism is purely a lumen dweller. In the com- 

 parable state in the pig, which is the rule, that is 

 apparently the case, although ulceration of the colon 

 of the pig may be produced, according to Brumpt 

 (1909). Haughwout (1918) reports Balantidium 

 coli in sections of pig's intestine in the tissues and 

 blood vessels, and gives the microscopic picture of 

 the infection as similar to that seen in human bal- 

 antidiosis. We may, it seems, infer that the organ- 



