702 RALPH §S. LILLIE 
containing sea-water.!° This remarkable result, which he as- 
cribed to a modification of oxidation-processes in the egg, is seen 
also in eggs treated with isotonic iodide or sulphocyanate solu- 
tions, and, to a less extent, with nitrate or chlorate. The physi- 
ological basis of this profound change in the developmental cap- 
ability of eggs with artificially formed membranes is still largely 
obscure. That oxidations play a part seems clear from Loeb’s 
admirable experiments; I am inclined, however, to attribute also 
a fundamental significance to alterations of surface permeability. 
If the above view as to the nature of the primary change in fer- 
tilization be well founded, it is clear that the increased permea- 
bility resulting from the action of the membrane-forming agency 
can be only temporary if favorable development is to follow, since 
a prolonged loss of semi-permeability must lead to the cytolytic 
dissolution of the egg-protoplasm. In fact the dead eggs, after 
the above salt-treatment, are always found laked or depigmented 
on the next day, while the living eggs retain the pigment. The 
initial increase of permeability must thus under physiological 
conditions be temporary and not too lasting; hence the inference 
seems unavoidable that one essential effect of the after-treatment 
with hypertonic sea-water is to restore the normal permeability. 
This hypothesis is an almost necessary corollary of the foregoing 
considerations. The cytolytic action followingsimple membrane- 
formation and due apparently to the persistence of an abnormally 
increased permeability is in fact prevented by subsequent treat- 
ment with hypertonic sea-water or cyanide.! A demonstrable 
consequence of the after-treatment is thus to restore a normal 
condition of permeability, and that this is the essential action 
seems highly probable. I have discussed this possibility in an- 
other paper to which I refer those who may be interested in this 
question.” 
The following experiments will illustrate the foregoing general 
description. Unfertilized eggs of Arbacia were exposed for periods 
of five and ten minutes to (1) the pure salt solution and (2) the 
same solution plus a small proportion of ¥ CaCl,. Part of the 
10 Cf. Chemische Entwicklungserregung, chapter 8, p. 60. 
11 Cf. Loeb: loc. cit., chapter 10, p. 77. 
2 American Journal of Physiology, 1911, vol. 27, pp. 295, 304. 
