184 C. M. CHILD 



temperature relations of the primary narcotic effect must be due 

 to some other factor. 



Since the temperature coefficient of distribution of benzamid 

 changes with change of temperature, in the opposite direction 

 from that of alcohol the next step is to determine how far this 

 factor is responsible for the observed results. 



When the concentration of the solution is below a certain limit 

 the benzamid does not enter the cell with sufficient rapidity or 

 in sufficient quantity to produce any appreciable physiological 

 effect; it may be oxidized or disposed of in some other way as 

 rapidly as it enters. Assuming that the substance enters the 

 cell through the lipoids, it is evident that with certain low concen- 

 trations the presence or absence or the degree of the narcotic 

 effect may depend on the coefficient of distribution. With such 

 concentrations, the higher the coefficient of distribution, the higher 

 the concentration of benzamid in the cells and the greater the 

 effect. On this basis we might interpret the greater narcotic effect 

 of the benzamid and the lower resistance of the worms at the 

 lower temperature when concentrations near the narcotic mini- 

 mum are used, as due to the higher concentration of the substance 

 in the cell at the lower temperature in consequence of the higher 

 coefficient of distribution. 



But when concentrations considerably above the narcotic 

 minimum are used it is evident that in spite of differences in the 

 coefficient of distribution, within a wide range of external condi- 

 tions the concentration of the substance in the cell is sufficient 

 in all cases to produce complete narcosis and sooner or later death. 

 In such concentrations the coefficient of distribution must become 

 a factor of minor importance and the rate of reaction in the organ- 

 ism is the chief factor. If these conclusions are correct, it is 

 evident that the coefficient of distribution is not the essential 

 factor in narcotic action in any case. The lipoids may be largely 

 responsible for the entrance of the narcotics, at least in certain 

 cases, but their effect after they have entered is apparently pri- 

 marily chemical. This conclusion is in essential agreement with 

 the most widely accepted theory of narcosis. 



With a closer scrutiny of the temperature experiments, how- 

 ever, certain obstacles to this simple interpretation appear. If 



