736 STUDIES IN GENERAL PHYSIOLOGY 



contained many bacteria. Even after three days, when the 

 water was exceedingly foul and cloudy, a portion of the eggs 

 which had lain in a heap, that is to say, without oxygen, 

 were immature and living. They were introduced into fresh 

 water and spread out into a thin layer. They maturated and 

 developed into swimming larvae upon the addition of sperm. 

 It is self-evident of course that even immature eggs finally 

 become the prey of bacteria, and so go to pieces in the sea- 

 water. 



The same experiment can be made in a somewhat more 

 complicated way with pure oxygen and hydrogen. The 

 freshly laid eggs of a starfish were distributed into two 

 series of eight flasks. The one series of flasks was connected 

 with a hydrogen generator ; the other with a tank contain- 

 ing pure oxygen. Before 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 experi- 

 ment a vigorous current of hydrogen was maintained. Both 

 series of flasks contained freshly laid immature eggs of 

 Asterias. The experiment lasted three days, and from time 

 to time a flask was removed arid its contents examined. The 

 eggs which had been exposed to the current of oxygen 

 maturated just as rapidly and as numerously as those in ordi- 

 nary sea-water, and the mature eggs soon died. In the cur- 

 rent of hydrogen maturation 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 



!Care must be taken in these experiments tbat the air is thoroughly removed 

 from the sea-water in the hydrogen flasks before the eggs are introduced into them. 

 Of course the hydrogen apparatus must also be free from air. 



