Experimental studies on nuclear and cell division

Abstract

During several seasons extensive experiments were made on the segmenting eggs of Crepidula plana. These experiments included a study of the influence on nuclear and cell division of hypertonic and hypotonic sea water, of ether, alcohol, etc., of the lack of oxygen, of the electric current, and of pressure and shaking. The following general conclusions may be drawn from this work:1. Under the same treatment the effects may be extremely varied, owing, probably, to the different stages of cell division acted upon.2. A dividing cell is much more easily disturbed or rendered abnormal than is a resting one; the mitotic figure in particular is very easily altered and most of the abnormalities observed arise from this source.3. The earlier stages of cleavage are much more easily altered than are the later ones.4. Certain general abnormalities occur after the most varied treatment, e. g., the general results both of concentration and of dilution of sea water are to produce polyasters and to prevent the cleavage of...