Effects of Anesthetics. 



9 



systems by means of anesthetics and to obtain curves correspond- 

 ing with those observed by Lillie on Arenicola larvae. 



To test this question an aqueous solution of NaOH of suitable 

 concentration was delivered from a Traube stalagmometer into 

 olive oil with and without the addition of various anesthetics at 

 varying concentrations. The number of drops formed from a 

 given volume of solution served as an index of the extent to which 

 the anesthetic inhibited or promoted the destructive effect of the 

 OH ions on the film of fatty acid salts formed at points of contact 

 between water and oil. In all cases the curve obtained showed 

 with increasing proportions of anesthetics, first a fall in the number 

 of drops, and subsequently a rise, the number of drops finally 

 exceeding that of the system employed. The fall in the number 

 of drops indicating protection of the membrane reached a maximum 

 with each anesthetic at approximately that concentration at which 

 Lillie observed a maximum protective effect for Arenicola larvae. 

 Furthermore on increasing the proportion of anesthetic above 

 this optimum, the number of drops increased and finally passed 

 the normal at approximately that point at which Lillie found 

 no further protective effect for larvae. The curve indicating the 

 effect of MgCl 2 corresponded almost exactly with that of an 

 organic anesthetic, but CaCl 2 , instead of exhibiting an optimum, 

 was found to counteract the destructive effect of OH ions not only 

 at low but also at high concentrations, and also to exert a pro- 

 tective effect against Mg and organic anesthetics used at high 

 concentrations. The accompanying diagram illustrates the effect 

 of propyl alcohol on this purely physical system, and on Arenicola 

 larvae. 1 



C3H7OH. Drops. Larvae. 



nil 52 Killed. 



25 per cent 18 Uninjured. 



10 per cent 76 Killed. 



As a further confirmation of this point, it was found that propyl 

 alcohol added in suitable proportions to a solution of n/io NaOH 

 would protect mice from a lethal dose of this substance injected 

 intravenously, and furthermore that it was possible to protect 

 to a certain extent corpuscles suspended in salt solution from the 

 destructive effect of negative ions by the addition of optimum 



1 See Lillie, Am. J. of Physiology, 1913, 31, p. 255. 



