600 RALPH S. LILLIE 



Nevertheless, the after-treatment with hypertonic sea-water 

 initiates development in a certain small proportion of these 

 eggs, some of which form blastulae, though most stop short of 

 this stage and undergo cytolysis. It is clear from the altered 

 character of the response to hypertonic sea-water that some 

 persistent modification has been produced bj^ the previous treat- 

 ment with salt-solution. What the nature of this modification 

 is can only be surmised at present. The most probable general 

 hypothesis seems to be that the plasma-membrane has been al- 

 tered in some definite way — possibly rendered more permeable or 

 more susceptible to alterations of permeability under changed 

 external, conditions. A changed state of electrical polarization 

 would presumably accompany such a modified condition. On 

 this view the increased responsiveness to hypertonic sea-water 

 is analogous to the increased responsiveness of frogs' voluntary 

 muscle which has been sensitized by brief exposure to isotonic 

 solutions of (e.g.) sodium citrate or other sodium salt.^^' This 

 form of sensitization is almost undoubtedly dependent on a 

 surface-alteration, since it is produced within a few seconds by 

 salts which either do not penetrate the normal plasma-mem- 

 brane or do so with extreme slowness." 



The degree of protection afforded by the above alcohols may 

 be decidedly greater than that shown in the above series. The 

 following experiments (table 2) are especially favorable in this 

 respect. These experiments also bring out clearly the effective- 

 ness of anesthetics in inhibiting the characteristic action of 

 hypertonic sea-water. Ethyl alcohol and phenyl urethane were 

 used in addition to the anesthetics of table 1. 



It will be seen from an examination of table 2 that the pro- 

 tective action of the alcohols is well-marked, while that of the 

 urethanes, especially phenyl urethane, is comparatively slight. 

 Amyl alcohol is distinctly superior to the others. These results 

 are typical, as an examination of table 5 will show. A small 

 proportion of the protected eggs remain unaffected by the after- 



i»Cf. J. Loeb, Am. Jour. Physiol., 1901, vol. 5, p. 362. 



" Cf . my paper in the Proceedings of the Society for Experimental Biology and 

 Medicine, 1910, vol. 7, p. 170. • 



