104 Artificial Parthenogenesis and Fertilization 



result was as follows. Thirty minutes in the hypertonic solu- 

 tion was not enough, and all the eggs disintegrated except a 

 few which developed. Forty and fifty minutes were sufficient 

 and about 50 per cent of the eggs developed into larvae. The 

 eggs that had been 135 minutes and longer in the hypertonic solu- 

 tion went to pieces. None of the eggs, on the other hand, which 

 had been in the hypertonic solution with potassium cyanide (in 

 which the oxidations were inhibited) developed, whose exposure 

 to that solution had been less than 385 minutes. All such 

 eggs disintegrated in the course of the next twenty-four hours, 

 and in the same manner as eggs which are left in normal 

 sea-water, not transferred to hypertonic solutions after mem- 

 brane formation. Hence the effect of the hj-'pcrtonic solution 

 was nuUified by the addition of potassium cyanide. A small 

 number — some two to four in a watch glass containing many 

 thousands of eggs — of the eggs, which were in the hypertonic 

 solution for more than 385 minutes, developed into blastulae. 

 Again, the eggs which had been longest in the hypertonic sea- 

 water with potassium cyanide did not go to pieces so rapidly 

 when transferred to normal sea-water, as those whose exposure 

 thereto had been of shorter duration. This probably is con- 

 nected with the fact that eggs which remain longer in the 

 cyanide sea-water take up more KCN or HCN. This experi- 

 ment was repeated very often, and always with the same result. 

 Usually the addition of a sufficient quantity of potassium 

 cyanide to the hypertonic sea-water completely inhibited the 

 action of the latter. It is worthy of mention that the KCN 

 does not prevent but only retards the oxidations, and this 

 retardation is less the less KCN is added. 



It might be objected that in the previous experiment potas- 

 sium cyanide had killed the eggs, or, at all events, rendered them 

 incapable of development. The following experiment, however, 

 will overthrow this idea. 



After artificial membrane formation (by means of butyric 



