80 Phylum Protozoa 



Using methods described above the senior author has kept Amoeba 

 proteus in continuous culture since 1923, a total of 12 years, and the 

 Amoebae are still in excellent condition. 



Bibliography 



Chalkley, H. W. 1930. Stock cultures of Amoeba. Science 71:442. 



Dawson, J. A. 1928. The culture of large free living Amoebae. Amer. Nat. 62: 



453 



Hahnert, F. H. 1932. Studies on the chemical needs of Amoeba proteus: A cul- 

 ture method. Biol. Bull. 62:205. 



Hopkins, D. L. 1926. The effect of certain physical and chemical factors on loco- 

 motion and other life processes in Amoeba proteus. J. Morph. and Physiol. 



45:97- 

 Hopkins, D. L., and Johnson, P. L. 1928. The culture of Amoeba proteus in a 



known salt solution. Biol. Bull. 56:68. 

 Mast, S. O., and Johnson, P. L. 193 1. Concerning the scientific name of the 



common large Amoeba, usually designated as Amoeba proteus (Leidy). Arch. /. 



Protist. 75:14. 

 Pace, D. M. 1933. The relation of inorganic salts to growth and reproduction in 



Amoeba proteus. Ibid. 79:133. 

 Schaeffer, A. A. 1916. Notes on the specific and other characters of Amoeba 



proteus Pallas (Leidy). A. discoides spec. nov. and A. dubia. spec. nov. Ibid. 



37:204. 

 1926. Taxonomy of the Amebas with description of thirty-nine new marine 



and fresh water species. Cam. Inst. Wash. Dept. Mar. Biol. 24: i. 



CULTURING AMOEBA PROTEUS AND A. DUBIA 



H. R. Halsey, Columbia University 



BOTH Amoeba proteus and A. dubia are found in freshwater ponds 

 and streams among aquatic plants such as Cabomba or Elodea, or 

 in the debris on the bottom of such bodies of water, particularly among 

 rotten leaves. Large individuals are often found in considerable numbers 

 among Sphagnum. 



Place small amounts of such material in finger bowls or large petri 

 dishes, cover with spring water or with water from the source, and add 

 2 or 3 grains of uncooked rice, or an equal number of one-inch lengths 

 of boiled timothy hay stalks. Do not place too much of the material in 

 a single dish. This results in decay, and in the appearance of large 

 numbers of bacteria which cause the death of any Amoebae that may be 

 present. 



Amoebae will appear in considerable numbers in successful cultures 

 within a week or ten days. The decaying organic material is then 

 removed and the Amoebae cultured by the following method. Make*a 

 hay infusion of 8 one-inch lengths of timothy hay stalks in 100 cc. of 

 spring water, boil for 10 minutes and allow to stand for 24 hours. At 

 the end of this time add large numbers of small Protozoa such as Col- 



