Abstract
1. Although many experimenters have studied the regenerative power of different kinds of protozoa no one has observed the variations in this power at different age periods after division.
2. Uronychia transfuga is a marine hypotrichous ciliated protozoon about 100μ in length. It may be cut in any plane with a fine pointed scalpel and the pieces will live for several days, thus showing a hardiness which makes it a good subject for experimentation.
Under conditions of culture in the laboratory (at Roscoff, France) the cell divides about once in 36 hours, the period between divisions being marked by definite changes in size of the cell and in arrangement of the nuclear elements (macronucleus and micro-nucleus).
3. Experiments to test the regenerative power were made upon cells immediately after division; on cells from 12 to 18 hours after division; on cells immediately before division; and on cells during division. The cells, in all cases, were cut with a scalpel under a microscope, full records of 75 experiments being kept.
Get full access to this article
View all access options for this article.