Studies on the metabolism, particularly of the oxidation of the Typhoid bacillus caused by these four substances. Analytic determination made of the amount of oxygen consumption of Salmonellas 57R and 58R cultured on synthetic media, by using Glucose, Gluconic acid, Phospho-glyceric acid, Lactate, Pyruvate, Acetate, Saccinate and Glutamate as the basic substances, by means of the Warburg manometer. The results were as follows. 1) The said four substances extracted from Salmonella 57R had not any influence like the smooth type upon the rough type. 2) Nucleic acid, Des-oxy-ribo-nucleic acid and Polypeptide extracted from Salmonellas 57S and 58S, and Salmonella typhi Nakagawa and Salmonella typhi Murakami had considerable effect and accelerated either oxidation like the smooth type or beyond the smooth type upon the rough type, nevertheless Polysaccharide had only a little influence upon them. 3) Acceleration of the oxidation due to these four substances seemed to begin in about 40 minutes. 4) No difference was to be noted by an amount added of these substances.