THE THEORY OF ANAESTHESIA. 363 



to be studied. Recently Loewe 1 has investigated the influence 

 of a number of anaesthetics on the electrical resistance of solid 

 artificial membranes impregnated with lipoids, and he has found 

 that in some cases they cause decided decrease of conductivity, 



a change to which he refers as "narcosis of the membrane." 

 These results recall those of Osterhout on living plasma-mem- 

 branes, but whether the anaesthetic effect in living cells is so 

 direct as Loewe's experiments would indicate seems doubtful. 

 Clowes's recent interesting conception of an interchangeability in 

 the relative positions of the lipoid and aqueous phases of the 

 protoplasmic emulsion so that either the one or the other, ac- 

 cording to conditions, may form the external or continuous phase 



may throw a much-needed light on these phenomena. He 

 suggests "that anaesthetics function by promoting the continuity 

 of an external fatty or lipoid phase. The solubility of this 

 lipoid film in adjacent aqueous phases being lowered, its per- 

 meability to water-soluble substances would be diminished. 

 Since certain vital processes presumably depend upon inter- 

 mittent intercommunication between adjacent aqueous phases, 

 it may well be imagined that a temporary interruption in this 

 communication would result in anaesthesia" (loc. cit., p. 10). 

 Such a change would involve both decreased permeability to 

 water-soluble substances and greater stability of the membrane. 

 On the whole it appears highly probable that lipoid-solvent 

 anaesthetics cause their effects through some purely physical 

 change in the cell-system more particularly in the plasma- 

 membrane. Their chemical inactivity as a class indicates this. 

 Processes like solution and adsorption, rather than chemical 

 combination, probably determine their action in most cases. It is, 

 however, best not to be too dogmatic on this point, since the 

 distinctions between solution, chemical combination, and adsorp- 

 tion are. probably not absolute. There is always the possibility 

 that in certain cases the anaesthetic may form some chemical 

 combination which interferes with chemical or other changes 

 necessary to stimulation; the inactivation of haemoglobin by 

 carbon monoxide may serve as an illustration of how this is 

 possible. Hober 2 has recently suggested that in true reversible 



1 S. Loewe, Biochem. Zeitschr., 1913, Vol. 57, p. 161. 



2 Hober, Deutsche medizinische Wochenschrift, 1915, No. 10. 



