THE EFFECT OF ULTRAVIOLET LIGHT ON PHOTOSYNTHESIS.

1. An unidentified unit in the mechanism of the photosynthesis of Chlorella pyrenoidosa is rendered inactive by the absorption of one quantum of ultraviolet light (2537 A wave length). 2. The same irradiation has no effect on the normal respiration of Chlorella pyrenoidosa. Experiments have not yet been made on the respiration inhibitable by HCN. 3. No chemical change was detected in the chlorophyll extracted from irradiated cells.