The Nutritional Requirements of Paramecium: Axenic Media

Abstract

The exact nutritional requirements of Paramecium had to await the creation of precise, chemically defined axenic culture methods in which the medium, of course, is free of any other organisms save paramecia. Begun over 60 years ago, the earlier attempts at developing axenic cultures now appear relatively crude. For a review of these earlier studies, the reader is referred to Chatton and Chatton (1923a,b) Hall (1941), Lwoff (1923, 1925), Oehler (1921, 1922, 1924), A. W. Peters (1921), and Wichterman (1953b). Why were these early axenic culture methods unsatisfactory? Most were so complicated or unreliable that it would be exceedingly difficult to exactly duplicate a given procedure. Yet these pioneering efforts were necessary to show the direction or general areas where paramecia required the basic neutralities for life. The attempts to obtain a bacteria-free medium involved considerable experimentation—the substitution and replacement of chemicals or organic substances believed to be required for growth.