Abstract
Summary report was made on the results of mass culturing of unicellular algae using the method of "open circulation system", which was conducted during the period from 1956 to 1957. Various attempts were made in the device of culture units and the procedure of their operation, and the methods which were found to give satisfactory results were described in detail. Cultures run throughout the year, using certain strains of Chlorella and Scenedesmus gave an average daily yield of 8.6g/m2-day, which corresponds to a yield of 13 metric tons (dry weight) per acre per year.