Abstract
I. A brief direct current or a single break induction shock causes the protoplasm to pull away from the cell wall. The effect is usually cathodal; sometimes anodal, particularly when the aboral part of the cell is toward the anode. Sometimes the effect is seen simultaneously at both poles.
The phenomenon gives the impression of contraction and breaking of the strands of protoplasm attached to the cell wall or pellicle. A clear area looking like a blister filled with liquid is formed, the shape being dependent on the extent of protoplasm pulled away from the wall and the resulting disturbance of protoplasmic stresses. If the bleb is small, it may be pinched off later without further deformation of the organism. If the bleb is large, gradually the protoplasm pulls loose all the way around, the strands being seen to give way one or a few at a time. Finally the whole protoplasm shrinks into a shapeless mass around the oral end. Recovery is sometimes possible, but probably involves the formation of a smaller cell with new cell wall.
It appeared certain that the strands are solid structures along which a considerable tension is exerted.
A short tetanizing current gives blisters at both poles.
II. If such a dye as phenolsulphonpthalein was placed in the sea water between the cells of a dense culture, the color could be observed for fifteen minutes or more. But if a break shock or short tetanizing current was passed, the color disappeared at once. The cell juice of Noctilucca is strongly acid (Ethel Brown Harvey, Carncgie Reports, Marine Biology, 1917). Stimulation caused increased permeability and the acid diffused out. This effect could not b.z obtained with currents too weak to cause the Me13 formation previously described.
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