86 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
2. The writer pointed out in 1906 that the fertilized ege 
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 
biastulae 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 NaC] solution for 
forty-eight hours. The same could be proved for solutions of 
KCl, CaCl, MgCl,, and other salts. 
When we put fertilized and unfertilized eggs of purpuratus 
into a mixture of NaCl+KCi to which some strong base has 
been added, the fertilized eggs are destroyed much more rapidly 
than the unfertilized eggs. In fact, the unfertilized eges 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) 50 c.c.m/2 NaCl+1.1¢.c. m/2 KCI+0.2¢.c. N/10 NaOH 
(2) 50 ¢.c. m/2 NaCl+1.1¢.c. m/2 KCI1+0.2 ¢.c. N/10 NaOH 
+0.5¢.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 Chlornatriumlésung, ? 
Biochem. Zeitschr., II, 81, 1906. It is perhaps worthy of notice that the unferti- 
lized eggs of Arbacia are more quickly injured by solutions of NaCl than are those 
of S. purpuratus. 
