THE THEORY OF ANAESTHESIA. 339 



oxidases or oxydones. Traube also cites observations by Schry- 

 ver 1 in support of this general point of view; surface-active 

 substances retard the gelation of certain colloidal solutions, e. g., 

 of sodium cholate under the influence of calcium salts, and the 

 degree of retardation runs parallel to capillary activity and 

 narcotic action. Physical alterations of the cell-celloids may 

 thus lie at .the basis of the anti-oxidative action which, according 

 to this view, conditions the narcotic action. Other instances 

 of this effect will be considered later. Traube expresses his 

 essential view as follows: "the physical alterations of the cell- 

 colloids and by no means of the lipoids alone form one of the 

 most essential conditions for the slowing of chemical processes 

 in cells, and hence also for narcotic and other toxicological 

 processes. These physical alterations are a consequence of the 

 depressant influence which narcotics exert upon surface-tension, 

 and upon the internal pressure of the cell contents." 1 According 

 to this conception the physical alteration of the colloids would 

 be the primary effect of the narcotic, and decrease of oxidation 

 secondary; this view is more consistent with the membrane- 

 theory of narcosis, about to be described, than with the previously 

 quoted view which refers narcosis to a direct anti-catalytic action. 

 According to the membrane-theory, it is the plasma-membrane 

 which is primarily affected; and the decrease of oxidations (when 

 this occurs) is a secondary consequence of the change in the 

 membrane. This view would make the direct action of the 

 anaesthetic on oxidation-processes relatively unimportant. To 

 regard anaesthesia as dependent on a direct anti-catalytic action 

 seems insufficient, especially in view of the fact that the effective 

 anti-catalytic concentrations are much higher than those required 

 for narcosis. It should also be remembered that magnesium 

 sulphate and other salts can act as anaesthetics such salts can 

 have no such direct anti-catalytic action also that the electric 

 current may show the same influence. The action of anaesthetics 

 on oxidases will shortly be considered in more detail. 



The general fact that surface-active substances alter the 

 physical condition or state of aggregation of many colloids is, 

 however, highly important in any general theory of anaesthesia. 



1 Schryver, Proc. Roy. Soc., B, 1914, Vol. 87, p. 366. 



2 "Theorie der Narkose," p. 302. 



