340 KALPH S. LILLIE. 



resulting in early death or cytolysis just as occurs in eggs sub- 

 jected to a simple membrane-forming treatment without sub- 

 sequent exposure to hypertonic sea-water. 1 Eggs which begin 

 cleavage, but fragment and break down before proceeding far 

 in development, possibly belong to this latter class. If normal 

 development is to follow fertilization, the properties of the 

 plasma membrane cannot, on the present hypothesis, depart 

 \vidrly from a constant mean or physiological norm. 



The failure of the above eggs to respond normally to fer- 

 tilization, as also their resistance to cytolysis, is thus to be 

 regarded as the expression of a highly resistant condition of 

 i In- plasma membrane. The latter fails readily to undergo 

 the increase of permeability essential to these changes, probably 

 because of abnormalities in the nature, state, or proportions 

 of its chemical constituents. The essential effect of the treat- 

 ment with ether is to restore the normal properties of the mem- 

 Inane. There is, however, no reason to believe that this effect 

 is specific to ether. In some of my last summer's experiments 

 a similar though less favorable effect was produced by exposure 

 to isotonic sodium chloride solution and in one case to a o.i 

 per cent, solution of chloral hydrate in sea-water. In its general 

 form the problem relates to the essential nature of the modifi- 

 cation which these substances induce in the egg, and by which 

 the latter is brought from an irresponsive condition into one 

 in which it shows a normal response. Light is thrown on this 

 problem by the conditions in irritable tissues such as muscle 

 and nerve. 



A close analogy exists between the initiation of cell-division 

 in eggs or other resting cells, and the response of an irritable 

 tissue to stimulation. In both cases the initial or critical event 

 is apparently a temporary increase in surface-permeability, 

 with accompanying changes in the electrical polarization of the 

 limiting membranes. The means by which refractory eggs may 



1 The second part of the treatment appears to effect a return of tin- permea- 

 bility which has been increased by the membrane-forming treatment to the 

 normal (cf. Amcr. Jour. Pliysiol., 1911, Vol. 27, p. 289). Godlewski (Arthi, liir 

 Entu'icklung^mechanik, 1911, Vol. 33, p. 225) has independently reached a similar 

 conclusion with regard to the essential nature <>t the eiiei-t pnliu-ed by the hyper- 

 tonic sea-water. 



