86 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



2. The writer pointed out in 1906 that the fertilized egg 

 of the sea-urchin is injured much more rapidly by abnormal 

 solutions than the unfertilized egg. Fertilized and unfertilized 

 eggs of the same purpuratus female were put into a neutral 

 m/2 solution of NaCl. From time to time specimens of these 

 eggs were transferred to sea-water to test whether or not 

 they were normal. The fertilized eggs ceased to develop into 

 blastulae when they were more than three hours in the m/2 

 NaCl; while the unfertilized eggs developed normally when 

 sperm was added after they had been in the NaCl solution for 

 forty-eight hours. The same could be proved for solutions of 

 KC1, CaCl 2 , MgCl 2 , and other salts. 1 



When we put fertilized and unfertilized eggs of purpuratus 

 into a mixture of NaCl+KCl to which some strong base has 

 been added, the fertilized eggs are destroyed much more rapidly 

 than the unfertilized eggs. In fact, the unfertilized eggs can 

 resist a much higher concentration of a strong base than the 

 fertilized eggs. That this difference is due, partly at least, to 

 the difference in the rate of oxidations (and the developmental 

 changes dependent upon these) is proved by the fact that the 

 destructive action of the alkali can be inhibited by the addi- 

 tion of some KCN. Newly fertilized eggs of purpuratus were 

 distributed into the following two solutions: 



(1) 50c.c. m/2NaCl+l.lc.c. m/2 KC1+0.2 c.c. N/10 NaOH 



(2) 50c.c. m/2NaCl+l.lc.c. m/2 KC1+0.2 c.c. N/10 NaOH 



+0.5 c.c. 1/10 of 1 per cent KCN. 



The eggs that had been in the first solution for three and 

 one-half hours were all destroyed when they were transferred 

 to normal sea-water. Those that had been in solution (2) were 

 still alive at that time and could continue to develop when 

 transferred into normal sea-water. 



1 Loeb, " Ueber die Ursachen der Giftigkeit einer reinen Chlornatriumlb'sung, ' 

 Biochem. Zeitschr., II, 81, 1906. It is perhaps worthy of notice that the unferti- 

 lized eggs of Arbada are more quickly injured by solutions of NaCl than are those 

 of S. purpuratus. 



