MEMBRANE FORMATION AND CYTOLYSIS 179 
makes the egg more permeable to alkali or the effect of the two 
substances is cumulative. This can be demonstrated by a very 
striking series of experiments. Unfertilized eggs were placed 
in 50 ¢.c. of m/2 NaCl+2c¢.c. of m/10 sodium oleate. Three 
and one-half minutes later some of them were replaced in 
sea-water. The majority of these eggs formed membranes at 
once, and subsequently many succumbed to cytolysis. A 
second portion of the eggs was transferred to 50 c.c. of sea- 
water slightly acidified by the addition of 0.5 ¢c.c. N/10 HCl 
(0.4 e.c. HCl is enough to produce a change in color of neutral 
red in sea-water). Not an egg that had been transferred to 
this slightly acid sea-water formed a membrane or cytolyzed. 
The addition of even 0.3 c.c. or still less HCl was enough to 
prevent membrane formation and cytolysis of the eggs after 
they had been transferred to sea-water. On the other hand, 
the cytolytic effect of the sea-water was greatly increased by 
the addition of alkali. The following experiment may serve 
as an example. Unfertilized eggs were placed in 50 c.c. m/2 
NaCl+0.2 c.c. m/10 sodium oleate solution. Three minutes 
later, they were transferred to the following solutions: 50 ¢.c. 
of sea-water+0.5, 0.3, 0.1, Occ. N/10 HCl; 0.5, 1.0, 1.5 
e.c. N/10 NaOH. Among the eggs that had been trans- 
ferred to the sea-water to which acid had been added none 
or extremely few formed membranes, and no cytolysis oc- 
curred. Of the eggs transferred to ordinary sea-water 95 
per cent formed membranes, and about 1 per cent of them 
cytolyzed. All the eggs that were transferred to the sea- 
water+0.5 c.c. N/10 NaOH formed membranes, and 90 per 
cent of them cytolyzed. In the cases where more NaOH 
had been added to the sea-water all the eggs fell victims to 
cytolysis. 
If our line of thought is correct, it must also be possible to —_¢* 
cause membrane formation and cytolysis in the eggs while they Ss 
are still in the soap solution, by merely making it alkaline. Andy 
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