LIPOID-ALTERANT SUBSTA.NCKS 213 



general relation, pointed out by Overton and Meyer, 

 between the lipoid-content of tissues and their suscej)ti- 

 bihty to narcotic action; and (4) the ana'sthetizing action 

 of compounds, such as Mg and K salts, which are without 

 surface-activity in the foregoing sense. Traube's theory 

 in fact, in emphasizing the importance of a single })hysical 

 factor, seems to disregard other possible factors, and on 

 the whole to underestimate the complexity of the 

 physiological conditions. 



Hober,^ Vernon,^ and others have pointed out 

 various exceptions to the rule that isocapillary solutions 

 have equal physiological action. Tliis rule cannot be true 

 in any precise sense, since an organic compound may 

 affect the conditions at the various interfaces in a complex 

 system Kke protoplasm, and at an air- water interface, 

 quite differently; and other factors, incluchng viscosity, 

 solubihty in the protoplasmic phases, and specific 

 chemical affinities enter to modify the simple surface 

 conditions. In cases where the conditions are simple, 

 the increase from compound to compound in a homolo- 

 gous series may be very regular; a good example is 

 seen in FUhner's observations on haemolysis by solutions 

 of alcohols;^ the critical hcTmolytic concentrations for 

 the first five alcohols are as follows : 



m.-sol. 



Methyl 7-34 



Ethyl 3-24 



Propyl I ■ 08 



Butyl 0.312 



Amyl o . 09 



^ Hober, Physik. Chan. d. Zelle, p. 415- 

 2 Vernon, Biochem. Zeitschrift, LI (19 13), i. 



3Fuhner and Neubauer, Arch, expcr. Path. n. PharmakcL, lAI 

 1907); 2>32,- 



