STUDIES UPON THE RELATIONSHIP BETWEEN SURFACE TENSION AND THE ACTION OF DISINFECTANTS, WITH SPECIAL REFERENCE TO HEXYLRESORCINOL

Abstract

A brief summary of reasons for supposing surface tension to play an important role in disinfection precedes the experimental part. The experiments are of 2 sorts. (1) Various quantities of bland surface-tension reducent (soap or ethyl acetate) are added to dilutions of phenol and hexyl resorcinol and the disinfecting powers compared with similar dilutions not containing surface-tension reducents. Suitable controls on the blandness of the reducents are included. It was found that (a) adding an excess of sodium oleate, the action of the disinfectants is entirely inhibited; (b) adding small, more nearly optimum amounts of the reducents, the bactericidal power of the disinfectants is considerably increased. These results confirm and extend the work of Hansen and others. The inhibitory effect of the soap is attributed to the formation, by adsorption, of a solid film of soap around the organisms which protects them from the disinfectants. (2) The reduction of surface tension was accomplished by the disinfectant itself. The phenol coefficients and surface-tension reducing powers of 2 series of 21 resorcinol derivatives were determined. Within certain limits, the power to kill bacteria was accompanied by power to reduce surface tension. These results confirm and extend the work of Berczeller and others. A discussion of the role of mechanical and electrical adsorption in disinfection by phenolic compounds and substances like HgCl2, is appended.