HOST-PARASITE RELATIONS I INTESTINAL PROTOZOA 



to have penetrated the healthy tissue. Two attempts to 

 infect himself per os with fecal material containing 

 balantidia were unsuccessful. 



Ziemann (1925) also found balantidia in a monkey, 

 Cercocebiis fiiliginosus, which he considers to be B. coli. 

 Several years before this, Hegner and Holmes (1923) 

 discovered a balantidium in a South American monkey, 

 Cebus variegatus, recently imported from Brazil. The 

 morphology of the balantidia in this monkey differed 

 from both that of B. coli and of B. suis but no decision 

 was reached regarding its zoological position. Recently 

 Rees (1927) has reported balantidia from Macacus 

 rhesus. 



Other lower animals. Balantidia were first found in 

 frogs and species have been described from frogs, sal- 

 amanders, fish, ccelenterates, flatworms, sand fleas, cock- 

 roaches, and snails as well as in several species of mam- 

 mals: in guinea-pigs by da Cunha (1914), in horses by 

 da Cunha (191 7), in the agouti by Buisson (1923) in 

 sheep by Hegner (i924d) and in cattle by Cooper and 

 Gulati (1926). A thorough study of the genus must 

 first be made before it will be possible to state how many 

 of these are "good" species and whether any of them 

 belong to the species B. coli. A study of the balantidium 

 in the guinea-pig by Scott (1925) indicates that this 

 form is indistinguishable from B. coli. Attempts to 

 infect laboratory animals with cysts from other hosts 

 have all been unsuccessful. Thus Graziader and Mario 

 ( 1922) failed to infect the guinea-pig and cat per rectum 

 with infected feces from man; Ohi (1923) likewise 

 failed to infect the guinea-pig, rabbit and dog with pig 



184 



