38 HARRIETT M. ALLYN. 



alcohol in any of the experiments. Concentrations were used of 

 0.5 per cent., 2.0 per cent., and 5.0 per cent., the solutions being 

 made up with sea-water. The times varied from 3 minutes to 3 

 hours. One swimmer was found in eggs exposed to 5 c.c. alcohol 

 + 95 c.c. sea-water for forty minutes. The great majority of 

 eggs were undifferentiated. The fact that so few eggs showed 

 any signs of differentiation makes it seem possible that this 

 swimmer was not due to the alcohol, but to some chance sperm, 

 since once or twice I found a swimmer in the control. This was 

 extremely rare. 



E. Potassium Cyanide.- Twenty c.c. of n/io potassium cyanide 

 + 80 c.c. of sea-water for forty minutes induced a certain propor- 

 tion of eggs to form both polar bodies, other eggs only one. More- 

 over, the polar bodies formed while the eggs were still in the potas- 

 sium cyanide solution . No further development followed. Since 

 KCN is generally considered as an agent which suppresses oxi- 

 dation, I tried raising the oxygen content of the sea-water after the 

 eggs were removed from the potassium cyanide, hoping that this 

 would induce further development, but the results were negative. 



F. De-aerated Sea-water.- The results of the use of de-aerated 

 sea-water were very similar to those induced by potassium 

 cyanide. In both cases we supposedly have reduced oxidation 

 rate. The sea-water was de-aerated by heating to the boiling point 

 in a large flask for five minutes, then cooled in the same flask 

 (rubber stoppered), immersed entirely in water. The eggs were 

 dropped into this bottle. Some air may have re-entered during 

 the course of the experiments. As a result of putting unfertilized 

 eggs into this water a considerable number formed polar bodies, 

 as many as 50 per cent, forming both polar bodies in some 

 experiments, and 15-20 per cent, the first polar body only. The 

 polar bodies formed rather more slowly than normally. No 

 swimmers were formed. 



G. Excess of Oxygen in the Sea-water. Oxygen from a tank 

 (the ordinary commercial oxygen), washed through water, was 

 allowed to fill a wide-mouthed bottle in the bottom of which was 

 about one centimeter depth of sea-water. The bottle was then 

 tightly corked with a rubber stopper, and placed in the ice-chest 

 for two or three days, and shaken a number of times during that 



