ANESTHESIA 191 



between the behavior of alcohol and the other anesthetics 

 investigated may be only one of degree. It is probable 

 that there is some recovery in ether, chloroform, and 

 chloral hydrate, but that it is so slight and so transitory 

 as to be difficult to detect. 



It is evident that suitable concentrations of anesthetics 

 produce a marked decrease of permeability.^ This con- 

 dition may be maintained for a long time if the concentra- 

 tion is not too high; with higher concentrations the 

 period is shortened and may become so short as to be 

 observed with difficulty. This decrease of permeability 

 can be easily and quickly reversed by replacing the tissue 

 in sea water. It does not seem to produce any injury 

 if the concentration is not too high. The relative con- 

 centrations necessary to produce this result, correspond 

 closely with those required to produce anesthesia, being 

 least for chloral hydrate and greatest for alcohol. 



On the other hand, the increase of permeability, 

 (except in the case of alcohol, within certain limits) pro- 

 duces permanent injury and is not reversible. It cannot 

 be regarded, therefore, as the characteristic effect of the 

 anesthetic. The characteristic effect must be regarded as 

 in some way connected with decrease of permeability.® 



' The amount depends somewhat on the condition of the material. 

 Material in poor condition generally shows less rise in resistance than 

 good material. 



' Winterstein (1916) says that these experiments are not convincing 

 because the anesthetic may act on the interior of the cell rather than on 

 the surface of the protoplasm. This objection can hardly apply, since the 

 interior of the cell is filled with cell sap': this is surrounded by a thin 

 layer of protoplasm (see page 197). If the anesthetic decreased the con- 

 ductivity of the cell sap to any marked degree, this effect would be observed 

 in the material immediately after death: this, however, is not the case; 

 if any rise in resistance occurs in dead tissue it is much less than in 

 living tissue. Loewe, (1913) states that anesthetics decrease the con- 

 ductivity of artificial lipoid membranes. See also Moore and Roaf (1905). 



