PROTOZOA IN THE DIGESTIVE TRACT 49 



that of Connal (1922) who described the course of an 

 accidental oral infection by viable mature oocysts, as fol- 

 lows: The incubation period was about six days, the onset 

 sudden, and the duration over a month. The cure was 

 spontaneous. The symptoms were diarrhoea, abdominal 

 discomfort, flatulence, lassitude, and loss of weight. During 

 the first three weeks of the illness no oocysts were found, 

 but then oocysts appeared in the faeces for nine days. On 

 the 10th, they were not seen, but reappeared on the 11th 

 and 12th days, after which they were not found again. The 

 acute signs of illness abated within one week of the finding 

 of the oocysts. The faeces contained a large amount of 

 undigested material, particularly fat which gave it a thick 

 oily consistency, showing signs of slow gaseous formation. 

 Although Isospora hominls is considered pathogenic to 

 man in some cases, it appears to bring about no lasting 

 disturbances in the majority of cases. 



Ciliata 

 1. Balantidium coli (Malmsteii 1857) 



This ciliate lives in the lumen as well as the wall of the 

 colon and caecum, and is a pathogenic parasite. It has a 

 wide geographical distribution, having been reported from 

 Europe, Asia, Africa, and South and North America. In the 

 United States a number of infections have been reported 

 in recent years. But in the Philippine Islands more cases 

 perhaps have been reported than anywhere else. Balanti- 

 dium coli occurs more often in persons who come in con- 

 tact with the pig in which it is a common parasite. Chim- 

 panzee is also liost to this ciliate. A heavy infection with 

 this organism brings about a chronic dysentery. Dysenteric 



