344 The Philippine Journal of Science ms 



man, I am able to demonstrate with some sections of a human 

 case of balantidiasis. The intestine from which these sections 

 were obtained is from the necropsy of one of Bowman's (1909- 

 1911) cases. In certain sections of this material, which is 

 heavily infected with balantidia, I have been so fortunate as to 

 find, in addition to open ulcerations, closed balantidial abscesses 

 situated in the thickened submucosa, which lie under the sound 

 mucosa and entirely surrounded by sound tissues, and which are, 

 consequently, probably free from intestinal bacteria. An early 

 stage of such an abscess is shown in Plate VI, consisting of a 

 small cavity filled with balantidia and the infiltration of the 

 surrounding tissues with mononuclear cells. Plate VII shows a 

 part of an advanced abscess, which is too large to be shown in 

 one field of even the low power of the microscope. Examined 

 with high magnification the "pus" of this abscess is seen to 

 consist, not of polymorphonuclear leucocytes, but of cell detritus 

 and mononuclear cells only. The tissues about the abscess show 

 round-cell infiltration, but no polymorphonuclear leucocytes. The 

 absence of polymorphonuclear leucocytes in the "pus" and in the 

 tissues surrounding the abscess confirms the opinion that the 

 abscess is free from bacterial infection. Both the abscess and 

 the sound tissues surrounding it contain many Balantidium coll. 

 Therefore, it having been demonstrated that balantidia are 

 capable of penetrating the sound intestinal epithelium, that they 

 do not invade secondarily the lesions due to bacteria, and that 

 in the submucosa the balantidia are able to produce abscesses 

 which later extend through the mucosa and become open ulcers, 

 it would appear that the primary etiologic relation of Balantidiutn 

 coli to balantidial dysentery had been proved. 



SUMMARY AND CONCLUSIONS 



1. Parasitization of man with Balantidium coli is relatively 

 common in the Philippine Islands. 



2. The balantidia appear in the stools of parasitized individuals 

 only at irregular intervals, and consequently infections, unless 

 accompanied by clinical symptoms, may frequently be overlooked. 



3. A large proportion of the pigs in and about Manila are 

 parasitized with balantidia. 



4. Balantidia are passed in the resistant encysted stage more 

 or less constantly in the stools of parasitized pigs. 



5. Morphologically Balantidium coli suis is identical with 

 Balantidium coli hominis. 



