3IO UNFERTILIZED STARFISH EGGS. 



VII. CONCLUSIONS. 



1. Our observations and experiments seem to show that in the 

 same sea water and under otherwise identical conditions, mature 

 but unfertilized starfish eggs soon die, while immature as well as 

 mature but fertilized eggs live longer. 



2. It seems certain that the rapid death of the mature unfer- 

 tilized starfish eggs is determined by internal conditions connected 

 with maturation and not by the bacteria contained in the sea water. 

 The proofs for this are: First, mature eggs die just as rapidly in 

 sterilized sea water free from bacteria as in unsterilized water, 

 and secondly, when maturation is prevented artificially the eggs 

 may continue to live in water containing many bacteria. 



3. We have shown that oxygen and free hydroxyl ions acceler- 

 ate the maturation of starfish eggs ; that lack of oxygen and a 

 neutral or faintly acid reaction of the sea water inhibit or prevent 

 maturation. The fact that the eggs which remain immature in 

 the ovaries of the starfish maturate when brought into sea water 

 seems to find its explanation in part at least through this. 



4. When the maturation of starfish eggs is prevented artificially 

 through lack of oxygen or the addition of an acid to the sea water 

 they remain alive much longer than when they maturate. The 

 eggs in which maturation has already begun or has just been com- 

 pleted seem also to be saved from rapid death by these means. 



5. It seems to follow from these facts that the same chemical 

 processes do not necessarily underlie the process of maturation 

 and the process of fertilization. Fertilization by spermatozoa, 

 chemical or physical agencies lengthens the life of the egg, while 

 the changes following the maturation of the egg lead, sooner or 

 later, to death (through autolysis?). It is in harmony with what 

 has been said that the same treatment with acid which brings about 

 artificial parthenogenesis in mature starfish eggs inhibits the 

 process of maturation when used upon immature starfish eggs. 



7. These facts corroborate a suggestion which I have made 

 before, that the fertilizing action of the spermatozoon consists in 

 this, that it carries into the eggs substances which accelerate the 

 course of certain (synthetical?) processes in the egg. Such an 

 acceleration might, for example, be brought about through certain 

 ions (for example, the hydrogen ions of nucleic acid), yet the 



