ARTIFICIAL PRODUCTION OF NORMAL LARVAE 593 



(1) 99 c.c. sea-water +1 c.c. -fan KHO 



(2) 98 " +2 



(3) 99 +lc.c. iVnHCl 



(4) 98 " +2 



(5) 97 " +3 " 



In solution 1 almost every egg was in segmentation five 

 hours later, but the segmentation was very irregular and 

 often incomplete, and the egg showed very lively amoeboid 

 motions. Never more than 10 cells were formed. In solu- 

 tion 2 the effects were similar, but fewer eggs segmented. 

 The segmentation did not go any farther. In solutions 3, 

 4, and 5 not an egg showed any trace of segmentation, nor 

 did any egg in the normal sea-water segment. 



Some of the eggs that were put into solutions 4 and 5 

 were left there only ten minutes, and then brought back 

 into normal sea- water. Five hours later many of these eggs 

 had begun to segment. The segmentation did not go beyond 

 the first cell-division. It should be said that the sea-water 

 naturally contains some free HO ions. After a short treat- 

 ment with acid the HO ions in the sea- water were able to 

 produce an effect which they could not have had if the acid 

 treatment had not been applied. 



None of these experiments, however, led to the formation 

 of a blastula, nor did they offer any promise of the possi- 

 bility of producing blastulss in an artificial way. The ex- 

 periments were made at various periods of the spawning 

 season. After these and some other unpromising attempts 

 I tried whether an increase in the concentration of sea- water 

 would yield better results than a mere change in the propor- 

 tion of the ions. Instead of using -f n NaCl and KC1 and 

 l -n CaClg and MgCl 2 solutions I now tried *- n NaCl and 

 KC1 and 2 w MgCl 2 and CaCl 2 solutions. I do not wish 

 to give an account of all the experiments I made in this 

 direction, but prefer to confine myself to an account of one 



