The main points of the results of experiments made by the author are as follows: 1) When treated according to Thunberg-Ahlgren's method, an oxidizable substance decolourizes methylen blue, and oxidizes itself. This oxidation takes place faster in an alkaline medium than in an acid medium, while formalin acts as a catalase for this reaction. 2) The light-emitting test which is employed especially in our laboratory is a very sensitive one for finding out the existence of oxidizable substances and has many advantages. 3) Though researched by various methods there seems to be no difference between oxidizable substances of the male and those of the female. 4) The leaves of a maiden-hair tree and those of a platanus, and the muscles of the lower limbs of a frog all have oxidizable substance in them, but autiscorbic power is founed in the first two things only.