A plasmorytic method for determining the amt. of solute present in plant cells was devised and was applied for the epidermal cells of the hypocotyl of Helianthus seedlings. The amt. of solute present was cor-related with the enlargement of the cells. The production of solute was found to be proportional to the growth of the cell. The production of solute apparently facilitates the growth of the cell wall but cannot legitimately be regarded as the prime cause of growth by cell enlargement.