746 STUDIES IN GENERAL PHYSIOLOGY 



unfertilized starfish eggs is determined by internal condi- 

 tions 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 

 accelerate the maturation oi 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 completed, 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. Fertiliza- 

 tion by spermatozoa, chemical or physical agencies, lengthens 

 the life of the egg, while the changes following the matura- 

 tion 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. 



6. 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 



