1. Methods are described for measuring the stickiness of cells to solid surfaces.
2. The effect of various factors such as temperature, serum concentration, sodium chloride concentration, etc., on the adhesiveness of leucocytes to solid surfaces and the phagocytosis of solid particles are compared, and certain marked differences pointed out.
3. On account of these differences it is concluded that forces of surface tension, though undoubtedly operative in determining the behavior of cells in contact with solid bodies, are not the only factors involved.
4. Ways in which changes in the structure or rigidity of the protoplasm might affect phagocytosis and adhesiveness in opposite directions are suggested.