122 Phylum Protozoa 



grown on beef-agar slants, and the alga Stichococcus bacillaris, grown on 

 0.05% Benecke's agar slants. The bacterial slants may be used when 

 i to 5 days old; the algal slants when 1 8 to 24 days old. The quantities 

 inoculated into the culture fluid are one i-mm. loop level full of bac- 

 teria and three 2-mm. loops of algae to 20 cc. culture fluid. 



Isolation cultures may be carried on depression slides by using two 

 drops of this fluid per depression. Such cultures must be renewed daily 

 by transferring one Paramecium to freshly inoculated fluid on a fresh 

 slide. The optimum temperature is 2 7°-28° C. 



Mass cultures may be carried in cotton-stoppered flasks by using the 

 same fluid. Such cultures must be made frequently to keep the Para- 

 mecia in good condition, but the organisms will live for three months or 

 more in a greatly depressed condition without renewal of fluid. 



References 



For the culture of Paramecium aurelia see also pp. 105 and 120. 



For the culture of Paramecium multimicronucleatum see also pp. 113, 115 and 128. 



For the culture of Paramecium bursaria see pp. 55 and 105. 



PARAMECIUM MULTIMICRONUCLEATUM; MASS- 



CULTURING, MAINTAINING AND REHABILITATING 



MASS-CULTURES, AND SECURING CONCENTRATIONS 



Edgar P. Jones, University of Akron and University of Pittsburgh 



MASS-CULTURING 



VARIETY in composition is one of the outstanding characteristics of 

 infusions in which Paramecia are to be mass-cultured. There ap- 

 pears to be no single method of successful culturing. In general, small 

 quantities of materials, usually organic, must be introduced into water to 

 induce bacterial multiplication. These bacteria are the chief food supply 

 of the Paramecia, at least in the earlier stages of the culture. Liebig's 

 beef extract (Woodruff and Baitsell, 191 1), mangle beet water (Glaser 

 and Coria, 1930), sewage (Butterfield, Purdy, and Theriault, 1931), let- 

 tuce leaves (Dimitrowa, 1930), wheat (Turtox Leaflet No. 4), bananas 

 (Turtox Leaflet No. 4), timothy hay (Petersen, 1929), Horlick's malted 

 milk (Jennings and Lashley, 1914), gelatin or curd placed under earth, 

 meat, pond lily leaves, red cabbage leaves, and soil are some of the 

 materials which are reported to have been used. Such diverse organic 

 materials may be boiled in water, or they may be allowed to macerate. 

 When the infusion is ready, it may be autoclaved, especially if portions 

 are to be preserved for future use; or it may be used without sterilization. 

 Slight variations of the above techniques require the introduction of 

 algae (Raffel, 1930), yeast (Lund, 1918), or bacteria (Phelps, 1934) 



