THE THEORY OF ANESTHESIA. 35! 



Winterstein's experiments with urethane) reflex irritability re- 

 turns promptly on the removal of the anaesthetic. There is no 

 evidence that nerve-cells can resist lack of oxygen for any such 

 time. There is, however, ample evidence from other sides that 

 during narcosis the normal resting oxidations of tissues continue 

 uninterruptedly. Winterstein also finds that the oxidative re- 

 moval of acid products of asphyxia takes place equally readily in 

 normal and in narcotized nerve-cells. The central nervous sys- 

 tem of the frog, which normally exhibits an alkaline reaction to 

 litmus, becomes acid during asphyxia; if oxygen is then restored 

 the alkaline reaction returns; but narcosis was found to have no 

 influence on this effect; clearly therefore, narcosis does not inter- 

 fere with these oxidations. 1 



Such observations should be correlated with those of Vernon, 

 Warburg, Battelli and Stern cited above, indicating that tissue- 

 oxidations are directly influenced only by relatively high con- 

 centrations of anaesthetics. Taken in conjunction with the other 

 instances just cited, of anaesthesia with essentially unaltered 

 rate of oxidation, they indicate that a direct suppression of 

 intracellular oxidations (or asphyxia) is probably not the essential 

 basis of anaesthesia. Apparently the latter condition does not 

 depend on any alteration of purely chemical conditions, but on 

 some influence exercised by the anaesthetizing agency on the 

 structural or organized (or "living") substratum in which the 

 chemical processes take place and by which their character and 

 rate are controlled. The evidence of this will now be considered. 



There appears to be a general relation between degree of 

 organization and susceptibility to narcosis. Plants and lower 

 organisms require higher concentrations of anaesthetic than 

 higher animals (Overton) ; in vertebrates the cells most suscep- 

 tible to narcosis are those of the higher brain-centers. Such cells 

 are distinguished by high irritability and rapid variations in their 

 activity, peculiarities which are undoubtedly a function of their 

 special structure. It is true that if organization is destroyed 

 many of the chemical processes of protoplasm (oxidations and 

 fermentations) may still continue (autolysis), and may then be 

 slowed by anaesthetics; but as already shown, much higher con- 



1 Winterstein, ibid., 1915, Vol. 70, p. 130. 



