608 RALPH S. LILLIE 



a given anesthetic may interfere with one set of processes and not 

 with another has long been known. It would appear rather, as 

 suggested above, that while chloral hydrate and the urethanes 

 impart to the plasma-membranes a degree of resistance sufficient 

 to prevent the normal changes of cleavage, this resistance is 

 insufficient to prevent the relatively violent action of the pure 

 salt-solution. The alcohols, for some reason as yet obscure, 

 protect the egg more effectively against the latter action. They 

 are, however, quite ineffective in preventing the cleavage-initiat- 

 ing and cytolytic action of fatty acids. The ability of an anes- 

 thetic to suppress or prevent a given process thus depends both 

 on the nature of the anesthetic and of the process itself. The 

 experiments with fatty acid about to be described will illustrate 

 this. 



The cleavage-initiating action of fatty acids in the presence of 



anesthetics 



The above anesthetics entirely fail to interfere with the for- 

 mation of fertilization-membranes or the initiation of cleavage 

 by fatty acids. In a number of experiments, conducted similarly 

 to those already described, in which the parthenogenetic agent 

 was sea-water containing acetic or butyric acid (2 to 3 cc. to 

 fatty acid plus 50 cc. sea-water) the results were entirely negative. 

 The addition of the anesthetic seems indeed to increase the 

 injurious action of the acid. Chloral hydrate is equally ineffec- 

 tive. The urethanes were not tried. The following series with 

 the alcohols will illustrate (Table 6). 



From these experiments it is clear that the above anesthetics 

 are completely unable to counteract the action of the fatty acid. 

 Their antagonistic influence seems to be confined to the salts. 

 Experiments with sea-water containing additional calcium and 

 magnesium chloride (without altering the osmotic pressure) 

 gave an analogous result. It was thought that possibly by 

 increasing the proportion of these salts in the medium the eggs 

 might be rendered more resistant to fatty acid. The following 

 solutions were used: 100 volumes sea- water plus respectively 



