PRESERVATION OF THE LIFE OF THE EGG 285 



which are placed for ten or fifteen minutes in 100 c.c. of sea- 

 water +4 c.c. N/10 HC1, without coming into contact with 

 alkaline sea-water, ripen much more slowly, generally not at 

 all, when after that time they are replaced in normal sea-water. 

 They retain also, as long as they are unripe, the full normal 

 appearance of living eggs, until they eventually fall victims 

 to bacteria. Unripe eggs too, when placed in neutral sea-water, 

 do not ripen for the most part, and retain their normal appear- 

 ance if they remain immature. 



It appears to follow from this experiment that the same 

 process which lies at the bottom of the maturation of the star- 

 fish egg also leads to its death, unless it is prevented by those 

 measures which we designate as fertilization. I now tried 

 whether it is possible to keep the ripe eggs alive longer through 

 lack of oxygen. In fact I obtained some positive results in 

 this connection. Starfish eggs were spread out in a thin layer: 

 After three hours 75 per cent of the eggs had ripened. A 

 part of the ripe eggs was immediately placed in narrow 

 glass tubes, in which the deeper layers suffer the same lack 

 of oxygen. A second portion was placed in small flasks, 

 through which was led a constant stream of pure oxygen. 

 Next morning, fifteen hours after the eggs were placed in the 

 oxygen, the different portions of eggs were tested. Those eggs 

 placed in the current of oxygen showed in one dish 98 per cent 

 of ripe, dark, and dead eggs, and 2 per cent of unripe, living 

 eggs. The eggs remaining in normal sea-water contained as 

 before some 78 per cent of ripe eggs, which, however, were all 

 black and dead, with the exception of a few which had begun to 

 divide and were alive. The unripe eggs were also living. On 

 the other hand, those eggs which had been in the glass tubes, in 

 complete, or relatively complete, lack of oxygen, were nearly 

 all alive. This observation, in fact, indicates that the same 

 process which leads to the maturation of the egg also causes the 

 death of the egg unless it is prevented in time. In this way 



