660 STUDIES IN GENERAL PHYSIOLOGY 



Thirteenth scries. It was evident that the KC1 brought 

 about artificial parthenogenesis, even if the osmotic pressure 

 of the sea-water was not raised. I now tried whether a pure 

 KC1 solution was able to cause artificial parthenogenesis, 

 and whether this was possible when the osmotic pressure of 

 such a solution was lower than that of sea- water. The solu- 

 tions used were as follows: 



(1) 10 c.c. 21 n KC1 + 90 c.c. distilled water 



(2) 20 " + 80 



(3) 25 " " +75 



(4) 2 " " +98 sea-water 



(5) Normal sea-water (control) 



The osmotic pressure of solutions 1 and 2 was smaller 

 than that of normal sea-water. One portion was left thirteen, 

 the other fifty minutes in these solutions. 



The next morning a large number of swimming trocho- 

 phores was found in every one of the dishes that contained 

 eggs taken from the first four solutions. The control solu- 

 tions were absolutely free from trochophores. 



Fourteenth series. -The experiment was so surprising 

 that I wished to repeat it. The following solutions were 

 prepared : 



(1) 10 c.c. 2|w KC1 + 90 c.c. distilled water 



(2) 2 c.c. " + 98 c.c. sea-water 



(3) Normal sea-water (control) 



The eggs were left in the solutions fifty minutes. The 

 water was sterilized. The next morning the eggs that had 

 been in solutions 1 and 2 contained living larvaB, while the 

 eggs in the normal sea-water were undeveloped. 



Fifteenth series. -I wished next to know whether the KC1 

 solution might be still more diluted without annihilating its 

 effect upon the unfertilized ChaBtopterus eggs. Four solu- 

 tions were used: 



