THE ACTION OF ETHER ON PROTOPLASM. 1 



L. V. HEILBRUNN, 



No problem in general physiology has been investigated more 

 frequently than the problem of anesthesia. Many workers have 

 attempted to discover the essential nature of the action of 

 anesthetics on living substance. Not only have animals, tissues, 

 and cells been studied, but some physiologists have even gone 

 so far as to study the effect of anesthetics on lifeless materials 

 which they believed similar to protoplasm. 



Many theories have been proposed to explain anesthesia. In 

 recent years the permeability theory has had a wide following. 

 This theory claims that anesthetics either decrease the per- 

 meability of the cell, that is to say of the plasma membrane, or 

 that they at any rate prevent an increased permeability. The 

 actual evidence in support of the theory is somewhat scanty. 

 What there is has been well summarized by Winterstein (i), 

 Hober (2), and Lillie (3), all three of whom are strong advocates 

 of the theory. 



In only a few cases has it been shown that anesthetics lower 

 cell permeability and most of these cases are doubtful, as Winter- 

 stein admits. In some instances observers have claimed that 

 anesthetics produce an increase rather than a decrease in per- 

 meability (see Hober). Perhaps the work most often quoted in 

 support of the doctrine that anesthetics lower permeability is 

 the series of conductivity measurements of Osterhout (4) on 

 plant cells. There is however a growing realization that a 

 decrease in the electric conductivity measurements of a group of 

 cells does not necessarily depend on a decrease in the permeability 

 of the plasma membranes of these cells. Many factors play a 

 part in influencing the conductivity measurement. When an 

 electric current is sent through a mass of cells, certainly a large 

 part of the current goes between and around the cells. Changes 

 in the conductivity of the spaces between cells are therefore apt 



1 Contribution from the Zoological Laboratory of the University of Michigan. 



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