The Permeability of Normal and Malignant Cells to Water

Abstract

Direct investigation of cell permeability has been necessarily limited in its material, since most of the cells of multicellular organisms have not been available for even roughly quantitative study during their life. Hence it is that most of our knowledge of the permeability of cell surfaces has been derived from experiments with plant cells, the eggs of certain invertebrates, and erythrocytes. It will readily be realized that it would be dangerous to form generalizations as to the permeability or osmotic properties of tissue cells on the basis of studies of other scattered types of cells. Even the red blood cells of various groups of vertebrates show striking divergences in their permeability both to water and to solutes (1). Considering the permeability of cells to simple substances as one of the fundamental phenomena of life, and in view of its importance in determining the accessibility of material to cells for metabolism and growth, an attempt has been made to determine quantitatively, as accurately as conditions permit, the permeability of tissue cells to water. In the preceding paper (2), we have described a method by which the surface and volume of certain fibroblasts can be estimated, and in the present study we have followed the change in cell volume while cells are subjected to a decreasing salt concentration in the surrounding medium. As we showed in the previous paper, it is impracticable to obtain cells which are susceptible of exact measurement except in a medium of clotted plasma. In this medium a number of radially symmetrical spindle-shaped or unduloidal cells can be found and measured.