LIPOID-ALTERANT SUBSTANCES 209 



tions produce irreversible structural change or cytolysis. 

 Such facts indicate, in general, that in the narcotizing 

 solutions the plasma membranes become more resistant 

 to alteration. Hober's observations on the action of 

 anaesthetics in hindering the production of injury- 

 currents in muscle by potassium salts illustrate the same 

 condition; the local negativity (an index of increase of 

 permeability) develops much more slowly in the presence 

 of ether, urethane, and other narcotizing compounds 

 than in the pure solution/ 



A decrease of permeability to water-soluble diffusing 

 substances and ions, and also in some cases to water, is 

 an effect of a related kind. The entrance of water- 

 soluble dyes into plant cells {Spirogyra) is retarded 

 during anaesthesia;^ neutral salts may also produce 

 this effect both in animal and plant cells.^ Decreased 

 permeability to ions is indicated by decreased electrical 

 conductivity; this has been demonstrated by Osterhout 

 in Laminaria, by McClendon in sea-urchin eggs, and by 

 Joel in blood corpuscles. "* In Laminaria a reversible 

 decrease of conductivity is found only in moderate 

 concentrations of ether and other anaesthetics, corre- 

 sponding to the anaesthetizing concentrations; stronger 

 solutions cause marked and irreversible increase of 



^Hober, Arch. ges. Physiol., CVI (1905), -^99. 



^ Lepeschkin, Ber. deuisch. botan. Ges., XXIX (191 1), 349. 



3 Szucs, Jahrh. wiss. Botanik, LII (191 2), 85. Cf. also the recent 

 observations by Miss Irwin, Jour. Gen. Physiol., V (1923), 223, 727. 

 Mg salts decrease the rate of penetration of dyes into Arenicola larvae 

 {American Journal of Physiology, XXIV [1909], 26). 



4 Osterhout, Science, XXXVII (1913), in; The Plant World, XVI 

 (1913), 129; McClendon, Popular Scientific Monthly (1915), p. 569; and 

 Joel, Arch. ges. Physiol., CLXI (1915), 5. 



