Abstract
Studies on the photoreaction of eosine in the water-alcohols and -ketones have been made both in the presence and in the absence of oxygen. The corrected rate equations, giving the satisfactory explanation for the data obtained, have been presented. Analysis of the experimental results so far obtained, on the basis of these rate equations, has led to the conclusion unambigously that the primary process of the aerobic photobleaching of eosine in the aqueous solution is the attack of oxygen on the triplet state of dye.