The experimental material consisted of fifteen serial sections, each 1·o mm. in length, cut from the apex towards the base of the bean root. Proteolytic enzymes were assayed at various pH levels on corresponding groups of sections. Values per section were converted to average values per cell by dividing each by the number of cells occurring in the section. Evidence was obtained for the presence of two proteolytic enzymes or groups of enzymes with different pH optima. Maximum activity of proteolytic enzymes is shown by cells which have ceased to grow and in which the level of protein and certain other enzymes is falling. The significance of these observations in the interpretation of a mechanism of cell growth is discussed.