712 PROTOZOOLOGY 



Mixed cultures of many free-living Protozoa are easily maintained 

 by adding from time to time a small amount of ripe hay-infusion or 

 dried lettuce powder to the collected water mentioned before. Chilo- 

 monas, Peranema, Bodo, Arcella, Amoeba, Paramecium, Colpoda, 

 Stylonychia, Euplotes, etc., often multiply in such cultures. To ob- 

 tain a large number of a single species, individuals are taken out 

 under a binocular dissecting microscope by means of a finely drawn- 

 out pipette and transferred to a suitable culture medium. 



Aside from the cultures of blood-inhabiting Protozoa, the so-called 

 protozoan cultures are by no means "pure" cultures in the bacterio- 

 logical sense, even if only one species of Protozoa is present, since 

 bacteria and other microorganisms are invariably abundantly pres- 

 ent in them. However in recent years, many holophytic or saprozoic 

 Protozoa have been cultivated in vitro free from bacteria. Glaser and 

 Coria (1930) by using a V-tube and utilizing negative geotropic 

 movement of organisms succeeded in obtaining bacteria-free sev- 

 eral species of flagellates and ciliates. Claff (1940) also using the 

 same response of certain rapidly swimming ciliates set up a "migra- 

 tion-dilution" apparatus by which he obtained organisms free from 

 bacteria. Taylor and Van Wagtendonk (1941) used a sterile viscous 

 agar medium in sterilizing Colpoda duodenaria. 



A. Free-living Protozoa 



To deal with all the culture media employed by numerous workers 

 for various free-living Protozoa is beyond the scope of the present 

 work. Here only a few examples will be given. For further informa- 

 tion, the reader is referred to Belaf (1928), Needham et al. (1937), 

 etc. 



Chromatophore-hearing fiagellates. — There are a number of culture 

 fluids. Two examples: 



(a) Peptone or tryptone 2 . gm. 

 KH2PO4 0.25 gm. 

 MgS04 0.25 gm. 

 KCl 0.25 gm. 

 FeCla trace 

 Sodium acetate 2.0 gm. 

 Pyrex distilled water 1000 cc. 



(b) Peptone or tryptone 2.5 gm. 

 KNO3 0.5 gm. 

 KH2PO4 0.5 gm. 



