ABSTRACT
Woodruff and other workers claim on the basis of experiment that a single protozoan can be cultured indefinitely without conjugation. Other observers, chiefly centred around Calkins, claim also with experimental support that unless conjugation takes place the protozoa finally die. A review of this controversy and its historical setting is given in Wilson’s The Cell, and nothing is to be gained by its repetition. Less disinterested reviews have been made by Woodruff (1925) and Calkins (1926). Woodruff called attention to the very important fact that, as culture methods have improved, the length of life of the protozoa has been increased. This significant observation is completely omitted by Calkins and the evidence for it will be briefly reviewed here.
