HOST-PARASITE RELATIONS! INTESTINAL PROTOZOA 



The primary site of infection is the large intestine; 

 the small intestine may also be inhabited, and Pons 

 (1925b) has reported specimens from the vagina, but 

 this was probably due to contamination from the intes- 

 tine which was infected in this case. Much of what has 

 been stated above regarding the cysts of other protozoan 

 species and of flagellate diarrhea applies likewise to C. 

 mesnili; on this account and because of the meager condi- 

 tion of our knowledge regarding this species it would be 

 fruitless to discuss these subjects further. 



Chilomastix has been reported from various species of 

 lower animals but so far as we know these are all specifi- 

 cally distinct from that living in man. Kessel (1924) 

 seems to have inoculated monkeys with C. mesnili from 

 man, but there is always a possibility when monkeys are 

 used for experimental purposes that they may already 

 have had an infection since Chilomastix has been re- 

 corded in monkeys by both Bach (1923) and Hegner 

 (i924d). 



(2). EMBADOMONAS INTESTINALIS 



This is apparently a rare species in man (Fig. 11 a, 

 lib), but has been found in widely separated regions 

 and hence probably occurs in all parts of the world. 

 Nothing is known regarding its relations to man except 

 that both trophozoites and cysts pass out of infected 

 hosts in the feces, and that infections may last for at 

 least six weeks ( Wenyon and O'Connor, 19 17). Embado- 

 inonas has been reported from a number of lower ani- 

 mals but the specific rank of these forms is still in doubt. 

 A second species from man was described by Faust and 



170 



