When a dividing echinoderm egg, in the metaphase of mitosis, is subjected to the pressure of the surface tension existing between a cover slip and a thin film of water, the entire mitotic figure, consisting of a highly viscous jelly cortex which encloses the dilute polar regions and the spindle, suddenly collapses, leaving not a vestige of the structural features of the preceding karyokinetic figure. This collapse is analogous to the sudden breakdown of certain inorganic gels, namely, of iron oxide, as described by Schalek and Szegvary, and of metallic cadmium, as described by Svedberg. In all three cases the sudden liquefaction is brought on by mechanical disturbance, in protoplasm by pressure, and in the two inorganic gels by stirring or shaking. These analogous phenomena tend to support the micellar hypothesis of the structure of gels, a structure in which the colloidal units are connected one to the other to form a three - dimensional network.

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