THE THEORY OF ANESTHESIA. 359 



has made similar observations for solutions of cytolytic sub- 

 stances (haemoglobin). 1 The increase in permeability caused 

 by pure solutions of Na-salts in fish eggs is also hindered by 

 alcohol and ether, according to McClendon; 2 and Loeb has de- 

 scribed similar effects of alcohol on Fundulus eggs. 3 The most 

 conclusive evidence of a decrease in permeability during narcosis 

 is however derived from experiments on the electrical conduc- 

 tivity of narcotized cells; this appears to be decreased during 

 narcosis (McClendon, Osterhout, Hober and Joel). McClendon 

 in 1910 found the conductivity of sea-urchin eggs to be decreased 

 by chloroform, but did not investigate the phenomenon in detail. 

 More extensive experiments have been carried out on plant cells 

 by Osterhout, 4 who has succeeded in showing clearly that in the 

 presence of moderate concentrations of anaesthetic the cells of 

 the marine alga Laminaria undergo increase in electrical resis- 

 tance, indicating decreased permeability to ions; on removing 

 the anaesthetic the original conductivity returns. If too high 

 concentrations of anaesthetic were used the result was quite 

 different; conductivity underwent marked increase and the 

 effects were irreversible; the tissue had in fact undergone 

 injurious or cytolytic alteration. Evidently the change cor- 

 responding to anaesthesia is the reversible change of decreased 

 conductivity, indicating decreased permeability. Similar obser- 

 vations on blood-corpuscles have recently been made by Joel 

 under Hober's direction. 5 



Taken in its entirety the foregoing evidence indicates that 

 under the influence of a narcotizing agent the plasma-membrane 

 undergoes an increase in its general stability or resistance to 

 alteration; stimulation is prevented because this effect requires 

 ready and rapid variations of permeability, and of these the 

 stabilized membrane is no longer capable. Associated with this 

 general stabilization is a decrease in the permeability to diffusing 

 substances; the cell is more completely shut off from the disturb- 



1 Traube, Biochem. Zeitschr., 1908, Vol. 10, p. 371. See also the experiments of 

 G. H. A. Clowes, Proc. Soc. Exper. Biol. and Med., 1913, Vol. n, p. 8. 



2 McClendon, Amer. Journ. Physiol., 1915, Vol. 38, p. 173. 



3 J. Loeb, Biochem. Zeitschr., 1912, Vol. 47, p. 127; cf. p. 155. 



4 Cf. Osterhout, Science, N. S., 1913, Vol. 37, p. in; also "Quantitative Re- 

 searches on Permeability" in "The Plant World," 1913, Vol. 16, p. 129. 



6 Joel, Pfluger's Archiv, 1915, Vol. 161, p. 5. 



