112 



ACTIONS OF NARCOTICS 



convincingly in favour of the idea that narcotics are 

 acting upon a single site when acting upon brain tissue. 

 It is possible that the results would have conformed 

 more precisely to theory had the brain tissue been in a 

 normal condition, instead of being in slices. But, never- 



TABLE XXII 



THE CONCENTRATIONS OF NARCOTICS PRO- 

 DUCING A GIVEN DEGREE OF NARCOSIS IN THE 

 RAT (i.e. EQUINARCOTIC CONCENTRATIONS), 

 AND THE PERCENTAGE INHIBITION OF THE 

 RESPIRATION OF RAT BRAIN SLICES PRODUCED 

 BY THESE CONCENTRATIONS OF NARCOTIC 



theless, one cannot help being highly suspicious of a 

 simple theory of action on one site. 



Further investigations by Quastel have shown that 

 the effects of narcotics on respiration are probably pro- 

 duced by their effect on carbohydrate metabolism, which 

 is of exceptional importance in the respiration of brain. 

 But he found that in the low concentrations producing 

 narcosis in mammals, there is no significant direct effect 



