Ophryoglenidae 107 



Ca(HC0 3 )2 0.00055 M. 



MgS0 4 0.00015 M. 



KH0PO4 0.00030 M. 



NaH 2 P0 4 0.00015 M. 



Since ordinary distilled water is frequently very toxic, it is best to use 

 twice distilled water for preparing Peters' medium. 



Glaucoma pyrijormis, Colpidium campylum, or Colpidium colpoda, 

 carefully washed free of their medium, and added in sufficient amounts 

 (an excess), will support growth of Stentor coeruleus in this medium for 

 about four weeks (Hetherington, 1932). After this they degenerate. 



Bursaria truncatella behaves similarly, but degenerates much more 

 promptly. Addition of Gonium pectorale, a green form, Chilomonas, a 

 colorless flagellate, and several kinds of washed bacteria, does not alter 

 behavior in the least. Bursaria truncatella, in the presence or absence 

 of washed food, dies in physiological medium exactly as described for 

 Pleurotricha lanceolata by Penn (1935, p. 126-27). 



Accordingly, the present status of our knowledge concerning these 

 ciliates indicates that suitable food -f- pure physiological medium do not 

 meet their requirements, that certain metabolites of growing bacteria are 

 essential for the continued survival of the larger ciliate Protozoa. Further 

 progress with these animals awaits solution of this problem. 



References 



For the culture of Glaucoma ficaria see p. 54. 



For the culture of Colpidium see also p. 63. 



For the culture of Colpidium striatum see p. 54. 



For the culture of Colpidium campylum see also p. 54. 



Bibliography 



Butterfield, C. T. 1 929. A note on the relation between food concentration in 



liquid media and bacterial growth. U. S. Pub. Health Repts. 44:2865. 

 Chatton, E., et Chatton, M. 1929. Les conditions de la conjugaison du Glaucoma 



scintillans en cultures lethobacteriennes. Action directe et specifique de certains 



agents zygogenes. C. R. Acad. Sci. 188:1315. 

 Elliott, A. M. 1933. Isolation of Colpidium striatum Stokes in bacteria-free 



media. Biol. Bull. 65:45. 

 1935- Effects of carbohydrates on growth of Colpidium. Arch. f. Protist. 



84:156. 

 Giese, A. C, and Taylor, C. V. 1935. Paramecia for experimental purposes 



in controlled mass cultures on a single strain of bacteria. Ibid. 84:225. 

 Glaser, R., and Coria, N. A. 1935. The culture and reactions of purified Protozoa. 



Amer. J. Hyg. 21:111. 

 Hetherington, A. 1932. The constant culture of Stentor coeruleus. Arch. 



f. Protist. 76:118. 



1933- The culture of some holotrichous ciliates. Ibid. 80:225. 



1934a. The sterilization of Protozoa. Biol. Bull. 67:315. 



1934b. The role of bacteria in the growth of Colpidium colpoda. Physiol. 



Zool. 7:618. 



