ii8 RESEARCH IN PROTOZOOLOGY 



grown on the Trichojiionas medium. Cleveland's technique for 

 establishing Trichomonas in pure culture of bacteria may also be 

 applicable to this protozoon, if it is possible to maintain Chilomastix 

 at room temperature. 



When cysts are available they could be washed free of bacteria 

 or possibly treated with a disinfectant or acid solution to free them 

 of bacteria. If this proved possible, the cysts of Chilomastix could 

 then be hatched at 37.5° C. (Hegner, 1927) in media that had 

 been previously seeded with a single species of bacterium. This is 

 only a suggestion. It might also be possible to induce encystment in 

 cultures (Cunha, 1927) as has been done with Endamwha his- 

 tolytica. 



The cultivation of Endamoeha histolytica (Chap. XIX) will not 

 be discussed here, but it may be suggested that cysts are readily 

 produced in cultures and may be freed from bacteria by treating 

 with N/20 hydrochloric acid and washing in sterile distilled water 

 (Dobell, 1928). It would, therefore, be easily possible to test 

 the suitability of various bacteria as food for these organisms and 

 to determine their influence upon cultivation of the amoebae. 



Balantidium coli cysts have been cultivated by several investi- 

 gators (Chap. XXIV). If cysts were available, it might be pos- 

 sible to induce these organisms to develop in pure cultures of 

 bacteria. It might also be possible to free the trophozoites from 

 bacteria, by methods already described. 



The solution of the problems suggested above would no doubt 

 provide much information regarding the interrelations of intestinal 

 protozoa and bacteria, the relations of an animal's food to the 

 specificity of protozoan parasites and the identity or individuahty 

 of species found in different animals. 



