Effect of the Chemical Constitution of Soaps upon their Germicidal Properties.

Studies on the properties of soaps are of importance because of their common use as detergents, in the preparation of vaccines, in the treatment of disease, and because of their natural occurrence in the animal body where they may have some effect in determining the resistance of the animal organism to infection. Reichenbach (1908) studied the action of soaps on Escherichia coli and found that potassium stearate, pahmitate, and myristate were effective in killing this organism, while the oleate, erucate, and linoleate were inactive. Walker (1924-1926) showed that sodium and potassium soaps of the same acid did not vary greatly in their germicidal action. The lower members of the series such as the butyrate, valerate, caprylate, and caproate, had little or no germicidal effect. He found the pneumococcus to be very susceptible to laurates, oleates linoleates, and linolenates. Streptococci were killed much like the pneumococci but at higher concentrations of the soap. Escherichia coli, Eberthella typhi, Shigella paradysenteriae, Salmonella paratyphi were killed by moderate concentrations (N/20 to N/40) of the saturated soaps (laurates to stearates) but were very resistant to the unsaturated soaps. Eggerth (1926-1931) studied the germicidal action of alpha substituted soaps. He found that the soaps of the alpha bromo fatty acids were usually more germicidal than the unsubstituted. The alpha hydroxy soaps exhibited a high germicidal activity