Abstract
Plant cells of cabbage, Cornus and Catalpa in the frost hardened and unhardened states show parallel resistance to drought, frost and plasmolysis respectively. The maximum plas-molysis that can be withstood depends on the point at which an irreversible stiffening, presumably coagulation, of the cortical zone of cytoplasm occurs. The maximum resistance of cells to the other modes of dehydration probably depends on the same property and this in turn on the hy-drophily of the protoplasmic colloids.