4 
88 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
mixture of 50 ¢.c. m/2 NaCl+2.5 ¢.c. m/2 CaCl, the fertilized 
eggs of Arbacia were injured after three hours and ten minutes 
to such an extent that they were not able to develop after they 
were transferred to sea-water. All the fertilized eggs of the 
same female if kept the same length of time in the same solu- 
tion free from oxygen developed and many reached the pluteus 
stage. Some of the eggs taken out after seven hours from this 
solution free from oxygen were still able to develop into larvae. 
The addition of five drops of a 1/10 of 1 per cent KCN solution 
to 50 c.c. of the abnormal solution acted just as well if not 
better than lack of oxygen. (This may have been due to the 
fact that the solution was slightly alkaline which often acts 
beneficially in solutions’ containing Ca.) The same could be 
shown for analogous solutions in which the CaCl, was replaced 
by MgCl, SrCl,, or BaCl,. 
In a mixture of 49 ¢.c. 6/8 m grape sugar+1 c.c. sea-water 
which was exposed to oxygen the eggs were injured to such an 
extent after three hours that practically no egg was able to 
develop when transferred into sea-water. Eggs which had 
been for three hours in the same solution freed from oxygen 
were practically all able to develop. 
In this case we were dealing with solutions of substances 
for which the egg is normally impermeable. It was of consider- 
able interest to find out whether lack of oxygen has the same 
life-saving effect if the harmful substance diffuses easily into 
the egg. For this purpose distilled water and narcotics were 
selected. Newly fertilized eggs of Arbacia were distributed 
into the following solutions: 
(1) 27.5 c.e. sea-water+22.5 c.c. distilled water 
(2) 27.5 ¢.c. sea-water+22.5 c.c. distilled water+5 drops 1/10 of 
1 per cent NaCN. 
The eggs in the first solution had suffered in five hours and 
forty minutes to such an extent that no egg was able to develop 
into a larva, after they were transferred to sea-water. The 
