Parameciidae 119 



and one strain (in liquid medium) which was transferred every 20 days 

 thrived for over 2% years. 



Bibliography 



Glaser, R. W., and Coria, N. A. 1930. Methods for the pure culture of certain 

 Protozoa. J. Exper. Med. 51:787. 



■ — ■ ■ 1933. The culture of Paramecium caudatum free from living microorgan- 

 isms. J. Paras. 20:33. 



1934a. The culture and reactions of purified Protozoa. Amer. J. Hyg. 21:111. 



— — ■ — ■ 1934b. The partial purification of Balantidium coli from swine. J. Paras. 



21:190. 

 Cleveland, L. R. 1928. The suitability of various bacteria, molds, yeasts and 



spirochaetes as food for the flagellate Tritrichomonas fecalis of man, etc. Amer. 



J. Hyg. 8:990. 

 Schumaker, E. i 93 i. The cultivation of Balantidium coli. Ibid. 13:281. 



THYROID CULTURES OF PARAMECIA* 



AT VARIOUS times the writer has had occasion to make some thyroid 

 l\ cultures of Paramecium caudatum. It was noted that these animals 

 found this habitat more favorable to existence and reproduction than the 

 ordinary hay infusions. 



Such a Paramecium thyroid culture may easily be made by mixing 

 about 2 grams of Armour's Desiccated Sheep Thyroids (U.S.P.) with 

 2,500 cc. spring water. This mixture should be slightly stirred and al- 

 lowed to stand exposed to the air for half an hour. Several pipettes full 

 of fluid containing Paramecia are then introduced. If the culture jar 

 is covered with a top and carefully sealed with vaseline an excellent, 

 clear culture will be obtained. After several days it may be noticed that 

 the animals are evenly distributed throughout the liquid, and are not 

 congested about the top of the jar as in ordinary cultures. The cultures 

 usually need but little attention. However, it is sometimes found desir- 

 able to add a little fresh water every week or ten days. 



M. E. D. 



A COMBINED CULTURE METHOD AND INDICATOR FOR 



PARAMECIUM** 



BRAGG AND HULPIEU (1925) describe the effect of a stain obtained 

 from red cabbage leaves as an indicator of the acidity of the food 

 vacuoles of Paramecium. I have been unable to secure similar satis- 

 factory results with the races I am using, but have found that a dilute 

 infusion of red cabbage leaves (about 30 grams to 1 liter of water) is an 

 excellent medium in which the animals reproduce rapidly; at the same 



* Reprinted with slight changes from an article in Science 58:205, 1923, by William L. 

 Straus, Jr. 



**Reprinted with slight changes from an article in Science 62:351, 1925, by Robert T. 

 Hance, University of Pittsburgh. 



