﻿BOTANICAL GAZETTE 



the result that they have been completely confirmed. 12 These 

 experiments were made on red blood corpuscles, the permeability 

 being determined by means of electrical measurements. 



It is easy to imagine a mechanism which would respond to the 

 action of anesthetics by a decrease of permeability. Since salts 

 are less soluble in ether, alcohol, and chloroform than in water, 

 it is evident that the presence of these substances in the plasma 

 membrane in sufficient concentration would diminish the solubility 

 of salts in the membrane and consequently hinder their penetration. 

 The anesthetics might become more concentrated in the plasma 

 membrane than in the surrounding solution either by chemical com- 

 bination, by solution, or by absorption. It should be remembered 

 that such salts as Mg, Ca, Al, and La also cause a decrease of 

 permeability, and this suggests that chemical combination or coagu- 

 lation, rather than mere accumulation of an anesthetic, is respon- 

 sible for the effect. Moreover, the mere accumulation of an an- 

 esthetic at the plasma membrane (without chemical combination 

 or coagulation) could not explain the increase of permeability. The 

 best assumption is that the anesthetic combines chemically 13 with 

 the protoplasm, the effect on permeability changing after a certain 

 amount has combined. Good analogies are offered by cases in 

 which chemical combination with a small amount of substance 

 produces an effect which is reversed as soon as more combines. 

 These analogies seem fairly satisfactory in the present condition 

 of our knowledge. 



Laboratory of Plant Physiology 

 Harvard University 



12 Deutsche medicinische Wochenschrift. no. 10. 1915. 



