RALPH S. LILLIE. 



siveness in refractory starfish eggs. Schwar/'s observations, as 

 \\cll as my own with abnormal starfish eggs, thus belong to that 

 general class of cases in which the responsiveness of cells is 

 increased by treatment with salts or low concentrations of lipoid- 

 solvents. The response of voluntary muscle to various forms of 

 chemical stimulation may be increased by brief immersion in 

 isotonic solutions of various sodium salts; in the case of salts 

 which do not precipitate calcium, this sensitizing action increases 

 with variation in the nature of the anion in the following general 

 order: Cl : Br : XO 3 < C1O 3 < CNS and I, an order corre- 

 sponding to the order of increasing effectiveness in promoting 

 colloidal dispersion. 1 Interpreted in terms of the membrane 

 theory, these facts mean that the readiness with which the plasma 

 membrane undergoes increase in permeability may be increased 

 either by altering the general state of the colloids in the mem- 

 brane, or by slightly altering that of the lipoids alone. 



\Ve conclude that the effect produced by salts and weak ether 

 solutions in increasing the responsiveness of refractory eggs t< 

 fertilization is comparable with the sensitization of irritable tis- 

 sues by these substances; also that in both cases the essential 

 change consists in an increase in the readiness with which the 

 plasma membrane undergoes the critical change of permeability 

 and of electrical polarization. 



It is to be noted that the resistance of eggs to fertilization by 

 foreign sperm may also be decreased by chemical treatment, as 

 Loeb discovered several years ago. 2 Heightening the alkalinity 

 of the medium has this effect. This characteristic and striking 

 effect is probably an expression of a very general action of weak 

 alkali. Many facts indicate that slight increase in the alkalinity 

 of the medium usually increases the readiness with which the per- 

 meability of cells is altered: cell-division is accelerated, the irritabil- 

 ity of irritable tissues and the rate of activity of automatic tissues 

 is increased, the cytolytic action of salt solutions is accelerated, 

 and in unfertilized eggs membrane formation and the initiation of 

 cleavage may be induced. 3 It remains to In determined whether 



1 R. S. Lillie, Proceedings of the Society 'rimoitnl ttiology and Mcdicin<-, 



New York, 1910, Vol. 7, p. 170. 



J. Loeb, University of California Publication*. Physiology, i<;<>3, Vol. i, p. i. 

 3 Cf. J. Loeb, Archiv fur die gesammle Physiologic, 1907, Vol. 118, p. 7. 



