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.c. of m/2 NaCl+2 c.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 HC1 

 (0.4 c.c. HC1 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 HC1 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-fO.2 c.c. m/10 sodium oleate solution. Three minutes 

 later, they were transferred to the following solutions: 50 c.c. 

 of sea-water +0.5, 0.3, 0.1, c.c. N/10 HC1; 0.5, 1.0, 1.5 

 c.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 

 are still in the soap solution, by merely making it alkaline. And 



