LIPOID -ALTERANT SUBSTANCES 215 



difficult to conceive, it seems more likely that an 

 adsorption-effect is involved, similar to that observed 

 in finely divided suspensions of charcoal. It is well 

 known that the catalytic effect of such suspensions is 

 markedly influenced by surface-active compounds;^ this 

 effect indicates an alteration in the character of the 

 surface, probably resulting from adsorption. Other 

 phenomena of a related kind, e.g., the precipitation 

 produced by organic solvents in protein solutions (as 

 observed by BattelH and Stern and Moore and Roaf),^ 

 the liquefying action of these compounds on gelatine 

 gels (Traube and Kohler),^ the solidifying action on 

 lecithin suspensions, and the interference with the 

 precipitation of lecithin suspensions by electrolytes 

 (Koch, Hober and Gordon, and others) ,'' are similarly 

 referable to surface- conditions, although the special 

 nature of these conditions is not clear in all cases. It 

 is noteworthy that most of these effects are observed 

 at concentrations far in excess of those required to 

 produce reversible narcotic effects in living protoplasm. 

 To characterize the organic anaesthetics as negative 

 catalyzers, as Traube does, may place them in a class, 

 but does not explain their characteristic action on 

 living matter. 



It seems certain from the physical peculiarities of 

 these substances that they must undergo adsorption 



^ Cf. Warburg, Arch. ges. Physiol., CLV (1914), 547. 



2 BatteUi and Stern, Biochem. Zeitschrift, LII (1913), 226; Moore 

 and Roaf, loc. cit. 



3 Traube and Kohler, Internal. Zeilschr. f. physik.-chem. Biol., II 

 (1915), 42. 



4 Cf . pp. 360 ff. of my Theory of Ancesthesia, loc. cit. 



