202 PROTOPLASMIC ACTION AND NERVOUS ACTION 



ever, that there is no fundamental difference between 

 these two processes ; the affinity for water seems depend- 

 ent usually on the terminal or polar group of the organic 

 compound (COOH, NH2, OH, etc.), and an adsorbed 

 compound may be one in which part of the molecule has 

 an affinity for (equivalent to solubility in) water, while 

 the other part has not, but is attracted more strongly by 

 the other phase. In such cases the position at an inter- 

 face may be the chief position of equilibrium, and the 

 predominant effect may be adsorption, with limited solu- 

 tion in either phase. Such a view implies that the tran- 

 sition from adsorption to partition is a continuous one, 

 and explains why highly surface-active compounds usually 

 have high lipoid-water partition-coefficients. Such com- 

 pounds will enter into solution in the non-aqueous phase, 

 provided this is also a solvent. They may, however, con- 

 dense at the surface of material in which they do not dis- 

 solve, and in so doing influence chemical action at such 

 surfaces. Traube calls attention to the fact that the cat- 

 alytic action of finely divided non-solvent materials like 

 carbon and platinum may be thus influenced; and he 

 places narcotics in the class of ''anti-catalysers'';^ i.e., 

 they are regarded as decreasing the catalytic and hence 

 the chemical activity of living matter by some form of 

 surface-action, e.g., by occupying the interfacial positions 

 (where chemical activity appears to be greatest) in the 

 heterogeneous protoplasmic system and displacing the 

 chemically reactive compounds.^ This view, while 

 partial, may well be correct in certain cases, although it 



^ "tJber Katalyse," Arch. ges. Physiol., CLIII (1913), 309. 



* Compare Warburg, Biochem. Zeitschrift, CXIX (1921), 134; see 

 footnote, p. 206. 



