On analogous effects exerted by anesthetics in physical and biological systems

Abstract

Lillie has recently demonstrated that anesthetics used in certain concentrations are capable of functioning in a manner similar to calcium salts, protecting Arenicola larvá from the destructive effect of pure salt solutions. Since calcium, on the one hand, and anesthetics, on the other, are capable of rendering a concentration film of fatty acid salts or lipoids relatively more soluble in oil and less soluble in water, it appeared possible that the agents in question protect the cell protoplasm by counteracting the destructive effect of negative ions on similar surface films formed between an external lipoid phase of protoplasm, and adjacent aqueous phases. If this theory were correct it should be possible to counteract the effect of negative ions in purely physical systems by means of anesthetics and to obtain curves corresponding with those observed by Lillie on Arenicola larvá.

To test this question an aqueous solution of NaOH of suitable concentration was delivered from a Traube stalagmometer into olive oil with and without the addition of various anesthetics at varying concentrations. The number of drops formed from a given volume of solution served as an index of the extent to which the anesthetic inhibited or promoted the destructive effect of the OH ions on the film of fatty acid salts formed at points of contact between water and oil. In all cases the curve obtained showed with increasing proportions of anesthetics, first a fall in the number of drops, and subsequently a rise, the number of drops finally exceeding that of the system employed. The fall in the number of drops indicating protection of the membrane reached a maximum with each anesthetic at approximately that concentration at which Lillie observed a maximum protective effect for Arenicola larvá.