ACTION OF THE HYPERTONIC SOLUTION 105 



acid) the eggs of a female were divided between two dishes, 

 each containing 50 c.c. of sea-water +8 c.c. of 2J m NaCl. To 

 one dish 2 c.c. of 1/20 of 1 per cent KCN were added. Samples 

 of the eggs were transferred at intervals of ten minutes from the 

 hypertonic to normal sea-water. 



We will consider first the behavior of the eggs which had 

 been in the hypertonic solution without potassium cyanide. 

 None of the eggs transferred from the hypertonic to normal 

 sea-water before thirty-five minutes had elapsed developed; 

 some 5 per cent of those transferred to normal sea-water after 

 thirty-five minutes developed into good larvae; practically 

 all of those transferred after forty-five minutes developed, and 

 the majority to normal larvae. Of those transferred after 

 fifty-five minutes practically all developed, but only 20 per cent 

 gave rise to normal larvae, while with eggs left still longer in 

 the hypertonic solution the results became worse with increasing 

 length of exposure. 



Not a single one of the eggs which had been in the hyper- 

 tonic sea-water with potassium cyanide for from thirty-five 

 to fifty-five minutes developed when transferred to normal 

 sea-water; the majority disintegrated in the course of the next 

 twenty-four hours. But the greater part of the eggs which 

 had been taken from the hypertonic sea-water with KCN after 

 fifty-five minutes were then placed not in normal sea-water, 

 but in hypertonic sea-water (50 c.c. sea-water +8 c.c 2J m 

 NaCl), which this time contained no potassium cyanide. 

 Samples of these eggs were transferred to normal sea-water 

 20, 30, 40, 50, and 60 minutes later. Of these eggs taken out 

 of the hypertonic sea-water after forty minutes, some 5 per cent 

 developed, of those taken out after fifty minutes some 30 per 

 cent, while practically all of those transferred after sixty min- 

 utes developed, though some already showed the effects of 

 over-exposure by abnormal cleavage. This experiment, which 

 was repeated several times with the same result, shows that the 



