3O2 LOEB. 



of a starfish were distributed into two series of eight Masks. The 

 one series of flasks was connected with a hydrogen generator ; the 

 other with a tank containing pure oxygen. I'efore the beginning 

 of the experiment all the air in one of the series of flasks was 

 driven out by the current of hydrogen. During the course of 

 the experiment a vigorous current of hydrogen was maintained. 

 Both series of flasks contained freshly laid immature eggs of 

 Astcrias. The experiment lasted three days, and from time to 

 time a flask was removed and its contents examined. The eggs 

 which had been exposed to the current of oxygen maturated just 

 as rapidly and as numerously as those in ordinary sea water, and 

 the mature eggs soon died. In the current of hydrogen matura- 

 tion did not occur in the majority of the eggs, and these remained 

 alive. In the hydrogen cultures a rapid development of bacteria 

 occurred while in the oxygen cultures this occurred to a small 

 degree. 1 



Treatment with acids which, as we have shown above, prevents 

 the maturation of the eggs (without killing them) also prevents 

 their death and disintegration. 



Eggs which, without having been in contact with pure sea water, 

 are introduced for ten or fifteen minutes into 100 c.c. sea water 

 plus 4 c.c. 7//io HC1 maturate very slowly or not at all when 

 they are returned to normal sea water. They also retain, as long 

 as they are immature, the transparent, normal appearance of 

 living eggs until they finally become the prey of bacteria. 



If scans to follow from these experiments that the same 

 processes which underlie the maturation of starfish eggs also lead 

 to their death (if they are not inhibited through circumstances 

 which we designate by the term fertilization). I tried to see, now, 

 whether it was also possible to maintain the life of the mature 

 egg through lack of oxygen. I indeed obtained in a few cases 

 positive results in this direction. The eggs of a starfish were 

 spread in a thin layer over the bottom of a dish. After three 

 hours seventy-five per cent, of the eggs were maturated. A 

 portion of the mature eggs were carefully introduced into the 



1 Care must be taken in these experiments that the air is thoroughly 

 removed from the sea water in the hydrogen flasks before the eggs are intro- 

 duced into them. Of course the hydrogen apparatus must also be free from 

 air. 



