The Consistency of Ameba Cytoplasm and Its Bearing on the Mechanism of Ameboid Movement I. An Analysis of Endoplasmic Velocity Profiles of Chaos chaos

An accurate and detailed knowledge of the consistency 1 of the cytoplasm of different regions of the ameba during locomotion would seem to be of primary importance in understanding the mechanism of ameboid movement. Unfortunately, no such knowledge exists. In fact, it will be shown in this and in succeeding papers that the rheological information now available on ameba cytoplasm is at best fragmentary and largely incorrect. "Force-flow curves" (velocity gradient as a function of shear-stress (See Figs. 2, 5)) for ameba endoplasm might by themselves permit a clear decision between classes of possible mechanisms of streaming. If the endoplasm were a structureless Newtonian sol of low viscosity as has been claimed (7, 8, 16), some sort of pressure-induced flow would be the most attractive and logical possible mechanism to explore. The development of the motive force for streaming could not very well take place either at the edge of the stream or within the stream itself. On the other hand, if the endoplasm showed signs of structure (as evidenced by pseudoplastic flow), while pressure-flow would not be excluded, the possibility that all or part of the motive force for streaming might be developed in or at the edge of the stream would become more likely.