Sterilizing Action of Acids. (V)

Abstract

I studied the sterilizing action of dibasic fatty acids CnH2n•(Co2H)2 on putrifactive bacteria, Bac. typhosus and Vib. cholerae, and also compared the sterilizing action between dibasic and monobasic fatty acids. Results are as follows: (1) At the same molecular concentration, oxalic acid (C2) is the stron-gest, malonic acid (C3) is the next, and from malonic acid the sterilizing power suddenly greatly diminishes. From C6 acid the sterilizing action of acids gradually increases, according to the increase of the number of C atom. (2) Anions of C2 to C6, acids have no sterilizing action. According to the increase of the number of C atom from C6 acid the sterilizing power of anions gradually increases, but its action is very weak. (3) Among salts of Na, Ca and N4, Ca salts have a somewhat weak sterilizing power, and NH4, salts have a somewhat long surviving period for bacteria. (4) At the same molecular concentration of acids having the same number of C atom, from C2 to C3 acids, dibasic fatty acid is the strongest, unsaturated monobasic fatty acid is the next, and saturated monobasic fatty acid is the weakest. The fact is chiefly due to pH. From C5 acid, accor-ding to the increase of the number of C atom, the sterilizing action of niono-basic fatty acids are stronger than those of dibasic fatty acids. The fact due to the effect of undissociated molecules of each acids. (5) At the same pH, sterilizing action of saturated monobasic fatty acid is the strongest, unsaturated monobasic fatty acid is the next and didasic fatty acid is the weakest of all. The fact is due to the difference of mole-cular concentration of each acids. (6) There is no special relation between the number of CO2H group and the strength of sterilizing action.