THE THEORY OF ANESTHESIA. 343 



not demonstrate that narcotics act directly and primarily upon 

 oxidation-processes. The proper inference is rather that vital 

 processes, including those which require free oxygen, are inhibited 

 during anaesthesia. But anaesthesia may also inhibit physio- 

 logical processes which are independent of free oxygen, as Winter- 

 stein has shown in his experiments on the narcosis of anaerobic 

 animals *iike Ascaris. 1 Similarly the growth of yeast under 

 anaerobic conditions is checked by anaesthetics in the same 

 manner as in the presence of oxygen; 2 and the nerve cord of 

 Limulus, which continues to send out impulses in the absence 

 of free oxygen, is anaesthetized by ether in a typical manner. 3 

 Some more general condition which determines the rate of 

 oxidations, as well as of other metabolic processes and cell-activi- 

 ties, is more probably the one directly affected in anaesthesia. 

 This latter view would regard the suppression of oxidations as 

 secondary rather than primary, an effect rather than a cause of 

 narcosis. During anaesthesia those processes which are directly 

 dependent on oxidations are arrested, together with those not 

 so dependent. 



Various attempts have been made to refer narcosis to a decrease 

 in the external supply of oxygen, or to an inability of oxygen to 

 enter the cells. Thus anaesthesia as well as sleep were at one 

 time popularly attributed to a condition of cerebral anaemia 

 an obviously untenable view, since neither condition is confined 

 to animals with brain and circulation. That the anaesthetic 

 hinders the entrance of oxygen into cells has recently been sug- 

 gested by Mansfeld; 4 the solubility of oxygen in the lipoids of 

 the plasma membrane and hence its rate of entrance into cells- 

 was held to be diminished by the solution of lipoid-solvents in 

 the lipoids; and E. Hamburger 5 attempted to show that narcotic 

 substances actually decreased the solubility of oxygen in lipoids. 

 These views however must be regarded as unfounded (see 

 Winterstein's criticism). 6 



'Winterstein, Biochem. Zeilschr., 1913, Vol. 51, p. 165. 



2 Cf. Warburg and Wiesel, loc. cit., p. 480. 



3 A. P. Mathews, cf. the article of Tashiro and Adams, loc. cit., p. 451. 



4 Loc. cit. 



6 E. Hamburger, Pfliiger's Archiv, 1912, Vol. 143, p. 186. 

 Winterstein, Biochem. Zeilschr., 1913, Vol. 51, pp. 158 seq. 



