THE PROBLEM AND METHODS OF INVESTIGATIOX 69 



with these authors that decrease in oxidation is an incident or a 

 result of narcosis which may or may not occur, and that the funda- 

 mental feature must be sought in some other change. As regards 

 some of these experiments, however, certain possible sources of 

 error exist and further investigation may alter the results. At 

 present it is difficult to conceive how narcosis can occur without 

 decrease in oxidation. 



Arguing from the observed parallehsm between the fat solu- 

 bihty of various substances and their narcotic power, Meyer and 

 Overton advanced the theory that the cell membrane consisted 

 in at least a considerable part of lipoid or fatty substances and 

 that the action of the narcotics was determined by their solubiUty 

 in these substances. This theory has undergone development and 

 modification at the hands of later investigators, and the question 

 as to the nature of the narcotic action of the substances which 

 enter the cell by dissolving in the Hpoids of the membrane has 

 received various answers. Some have held that the hpoids of the 

 membrane were responsible only for the entrance of the narcotics, 

 which once inside the cell acted chemically or otherwise. Others 

 believe that narcosis is the result of the changes in the lipoids of 

 the membrane produced by the narcotic substances. Warburg 

 considers the physical condition of the lipoids to be of great impor- 

 tance in connection with narcosis. According to Hober, narcosis 

 occurs when the narcotics have collected to a certain molecular 

 concentration in the cell Hpoids, because the narcotics then inhibit 

 a change in colloid aggregate condition of the lipoids which is 

 characteristic of excitation. R. S. LiUie finds that narcotics de- 

 crease the permeabiUty of the cell membrane or its ability to 

 undergo increase in permeabihty, and so decrease or inhibit the 

 increase in permeabihty which he beheves to be the essential 

 feature of stimulation. 



Some forty years ago Claude Bernard suggested that narcotics 

 brought about a partial reversible coagulation of the protoplasm 

 of the nerve cell. Later Dubois advanced the hypothesis that the 

 narcotics bring about loss of water from the protoplasm and so 

 decrease metabolic activity. Recently J. Traube has concluded 

 •on the basis of extensive experimentation that the narcotic etlect 



