THE ACTION OF ETHER ON PROTOPLASM. 467 



the body wall of female frogs. These experiments constitute 

 the greater portion of Winterstein's evidence and the reader is 

 referred to his paper for details. As I understand the experi- 

 ments, Winterstein measured the osmotic flow into short glass 

 cylinders sealed at both ends with muscle membranes. In such 

 a system it would seem that the entrance of water w r ould depend 

 more on the distensibility of the muscle membranes than on 

 their permeability. The high concentration of alcohol and other 

 anesthetics used by Winterstein might tend to coagulate the 

 membranes and make them less distensible. This would simu- 

 late a decreased permeability. However I have not worked 

 with this sort of a set-up and I am not sure that I can judge 

 it properly. 



My results with sea-urchin eggs are perhaps more interesting. 

 With this type of material Lillie found that the shrinkage of the 

 cell in hypertonic solutions was delayed by the presence of ether 

 in anesthetic concentration. This may very well be true, but it 

 need not be due to a change in permeability to water. For it is 

 easy to show that when eggs are placed in hypo tonic solutions, 

 they expand just as readily, or even more readily in the presence 

 of ether than in its absence. This is illustrated in Fig. 2, which 

 compares the expansion of etherized and unetherized eggs in 

 hypotonic solutions. The shrinkage and expansion of a cell 

 depends on many factors. Of these permeability is one, but not 

 the only one. Other factors of importance are surface tension, 

 the rigidity of the plasma membrane, and the colloidal condition 

 of the interior. This last factor is of especial importance in 

 Lillie's experiments. Lillie found that after fertilization the 

 sea-urchin eggs showed a greater tendency to crenation and 

 shrinkage when placed in hypertonic solutions, and that this 

 increased tendency to crenation was prevented by anesthetics. 

 As a matter of fact fertilized eggs become somewhat crenate 

 even without being placed in hypertonic solutions (16). The 

 crenation is concomitant with, and doubtless dependent on, the 

 gelation of the protoplasm which follows fertilization. In view 

 of the fact that anesthetics such as ether prevent this gelation 

 (see below), it is easy to see that they would tend to hinder 

 crenation. 



