Death and Dissolution of the Organism 363 



An unusually favourable object for the study of 

 natural death is the animal egg. The egg of the starfish 

 Asterias forbesii when taken out of the body is usually 

 immature, but in the spawning season it ripens in sea 

 ■ water. The writer 1 observed that eggs which ripen 

 disintegrate very rapidly when not fertilized. This 

 disintegration may be due to a process of autolysis, 

 which sets in only after the egg has extruded the two 

 polar bodies. The writer found that by preventing 

 the maturation of the egg either by withdrawing the 

 oxygen or by replacing the alkaline sea water by a 

 neutral solution or by exposing the eggs for some time 

 to acidulated sea water, the disintegration could also 

 be prevented. 



Further experiments showed that even in the mature 

 egg rapid disintegration could be prevented by lack of 

 oxygen, and similar results were obtained by Mathews. 

 When the egg is fertilized it does not disintegrate 

 in the presence of oxygen but it gradually dies in 

 the absence of oxygen. One is almost tempted to 

 say that while the fertilized egg is a strict aerobe the 

 mature unfertilized egg is an anaerobe. This latter 

 statement, however, becomes doubtful since the pre- 

 sence of oxygen may help the disintegration only in- 

 directly by allowing certain changes to go on in the 

 egg. The important points for us are that duration of 

 life in the mature unfertilized egg is comparatively 



1 Loeb, J., Biol. Bull., 1902, iii., 295. 



