I4O J. F. MCCLENDOX. 



worms require double, and protozoa and plants six times this 

 concentration. We might conclude from this that nerves (and 

 especially medullated nerves?) are more susceptible to narcosis 

 than arc other cells. All groups of worms contain nerves, but 

 Loeb has shown that certain worms may perform coordinated 

 movements after the nerves are cut, hence the higher concen- 

 tration of the narcotic required to quiet them. However it 

 should be remembered that over-stimulation causes rounding up 

 and quiescence of Amoeba and muscle may be paralyzed by 

 increasing the permeability. The growth of plants is increased 

 by a certain concentration of ether and retarded by a greater 

 concentration. It may be that true narcosis (decreased perme- 

 ability) of protozoa and plants cannot be produced by such 

 substances as ether, etc. 



Vertebrate nerve tissues are rich in lipoids (which have similar 

 solubilities to neutral fats) and it is therefore significant that 

 Overton and also Meyer 1 found that the partition coefficient of 

 anaesthetic between olive oil and water corresponds to its anaes- 

 thetic power. Meyer 2 showed further, that with change of 

 temperature, the change in the partition coefficient between oil 

 and water, and the anaesthetic power of the substance were 

 parallel. Pohl, Frantz, Grehaut, and Archangelsky found that 

 chloroform, ether, alcohol, chloral-hydrate or acetone, became 

 more concentrated in the central nervous system than in other 

 tissues. This is probably due to the absorption of the narcotic 

 by the lipoids (especially the immense mass of myelin) in the 

 nerve tissues. 



It it could be proven that the plasma membrane consists of 

 lipoids, this solubility of narcotics might be considered direct 

 evidence for or against the permeability hypothec-, but lacking 

 such proof we must first attack the subject from another side. 



Hober 3 observed that ethyl-methane, phenyl-methane, chloral- 

 hydrate, chloroform and hypnon, in low concentration prevent 

 the production by salts, of the current of injury on muscle. 

 He showed that in lethal doses on the contrary these narcotics do 



1 Arch. exp. Path. u. Pharm., 1889, XLII., 109. 



2 Arch. exp. Path. u. Pharm., 1901, XLVI., 338. 



3 Pfluger's Arch., 1907, CXX.. 492, 501, 508. Cf. R. Lillie, Am. Jour. P/y> /./.. 

 1912, XXIX., 373. 



