34O RALPH S. LILLIE. 



Probably this effect is to be related to their influence on the 

 electrical potential difference normally existing between the 

 colloidal particles and the medium. Gouy 1 found that the 

 potential-difference between mercury and sulphuric acid in the 

 capillary electrometer is lowered by the presence of many surface- 

 active or narcotic substances; similar observations were made 

 by Abl 2 for cadmium amalgam cells, and by Grumbach 3 for 

 various contact-potentials; and according to Traube the order 

 of relative action in all of these cases is essentially that of capillary 

 activity. Now precipitation or increased aggregation of colloids 

 is typically associated with decrease in the electrical polarization 

 of the colloidal particles; and capillary-active substances which 

 produce this latter effect ought therefore to further such precipi- 

 tation. A similar influence of anaesthetics on the potentials 

 shown by organic membranes like apple-skin against salt solu- 

 tions was observed by Loeb and Beutner; 4 the concentrations 

 required for appreciable lowering of potentials were, however, 

 much higher than those ordinarily required for anaesthesia. 

 Notwithstanding this difficulty Traube suggests that a decrease 

 in contact-potentials, as well as of surface-tension at the active 

 surfaces in tissues like nerve, may be an important factor in the 

 action of narcotics. To quote from Traube's recent paper on 

 narcosis: "The narcotic substances, in collecting at the boundary- 

 surfaces of cell-wall and cell-fluid, lower there the electrical 

 contact-potentials, and in so doing directly prevent the trans- 

 mission of motor and sensory impulses by means of nerve-centers. 

 . . . This retarding or inhibiting action, exerted by substances of 

 low solution-affinity (Haftdruck) to water, upon the oxidations 

 and other intracellular processes conditioned by cell-colloids, and 

 also upon the electrical phenomena at boundary-surfaces, is the 

 cause of that condition which we designate as narcosis." 5 A 

 somew T hat similar view had previously been expressed by A. B. 

 Macallum: "Chloroform, ether, alcohol, and chloral lower sur- 



1 Gouy, Annales de chimie el de physique, 1906, Ser. 8, Vol. 8, p. 291, and Vol. 9, 



P- 75- 



- Abl, Dissertation; Bonn, 1907 (cited from Traube, Pfliiger's Archiv, 1910, 

 Vol. 132, p. 521). 



3 Grumbach, Annales de chimie et de Physique (8), 1911, Vol. 24, p. 463. 



4 Loeb and Beutner, Biochem. Zeitschr., 1913, Vol. 51, p. 303. 

 6 " Theoric dcr Xarkose," p. 306. 



