ANTAGONISM BETWEEN SALTS AND ANESTHETICS 615 



with some qualification to apply also to the resting egg-cell. 

 The removal of an inhibiting condition, whatever the means 

 employed, is the essential requirement for fertihzation. What 

 follows is determined entirely by the nature of the egg itself. 



The recent work of F. R. Lillie^^ reinforces still further this 

 general point of view. His results indicate that in fertilization 

 a union of a specific amboceptor-like substance, contained in the 

 egg-cortex, with some other specific substance, also furnished 

 by the egg, forms the primary or determinative event. The 

 spermatozoon acts by removing the hindrance to this interaction, 

 but other agents may act similarly — hence the possibility of 

 parthenogenetic fertilization. This conception makes it clear 

 why the presence of the sperm is unnecessary to the activation 

 of the egg, and suggests that in its activating capacity this struc- 

 ture plays essentially the part of a specific releasing mechanism, 

 ' in a manner which is thus closely analogous to that of a stimu- 

 lus, as already indicated. The ensuing developmental processes 

 are specific to the egg under investigation and require special 

 analysis in each case. 



SUMMARY 



The chief experimental results and general conclusions of this 

 paper may be briefly summarized as follows: 



1. The action of pure isotonic solutions of neutral salts (0.55 

 m KCNS, Nal) in inducing formation of fertilization-membranes 

 and cleavage in the unfertilized eggs of Arbacia may be pre- 

 vented by anesthetics as well as by calcium and magnesium salts. 

 The effective concentrations are those which just suffice to pre- 

 vent cleavage in fertilized eggs. 



2. The anesthetics are less effective than calcium or mag- 

 nesium, and vary characteristically in effectiveness. The mono- 

 hydric alcohols of the aliphatic series are the most favorable of 

 those tried; the order of relative favorabihty runs: i-amyl >n- 

 butyl > n-propyl and capryl > ethyl. Phenyl and ethyl ure- 

 thanes have comparatively slight action, and chloral hydrate 

 still less. Cyanide is ineffective. 



" Cf. Science, N. S., 1913, vol. 38, p. 524. 



