THE TROPHIC NATURE OF CHLOROGONIUM AND CHILOMONAS

¹ BIOLOGICAL LABORATORY, UNIVERSITY COLLEGE, NEW YORK UNIVERSITY

Chlorogonium (euchlorum, elongatum) is capable of indefinite autotrophic growth in a mineral medium in light, growth in nitrate being as good as in cultures containing ammonium salts. It was impossible to maintain bacteria-free cultures of Chilomonas paramecium indefinitely by subculturing them at regular intervals in a medium containing inorganic nitrogen, even in the presence of sodium acetate as a carbon source. Since November 10, 1932, both species of Chlorogonium have been cultured in total darkness in a medium containing mineral salts, sodium acetate, dextrose and proteose-peptone without losing their green color.