Pbevention of Death by Fertilization 157 



and that it is entirely immaterial how lack of oxygen is pro- 

 duced, whether the oxygen is driven out by carefully purified 

 hydrogen or whether the eggs are put together in a large heap, 

 whereby only those lying on the surface of the heap receive 

 sufficient oxygen. 



It is, however, easy to show directly that the above- 

 mentioned objection is incorrect. The eggs of the star-fish can 

 easily be put into sterilized sea-water without bacterial infec- 

 tion. The following experiment was tried. The eggs of a 

 star-fish were separated into three parts: one part was put 

 aseptically into a series of flasks with sterilized sea- water; the 

 second part was put into ordinary sea- water without asepsis; 

 the third part was put into sea-water to which a large quantity 

 of a putrid culture of bacteria had been added that had 

 developed on the dead eggs of the star-fish. It was found that 

 in all three cases the mature eggs died within the same period of 

 time. The sterilization of the eggs of the first group was 

 complete, as was shown by the fact that the eggs although dead 

 preserved their form for two months, while the dead eggs in the 

 normal sea-water were completely destroyed iu a few days by 

 the action of the bacteria. 



It is, therefore, certain that the death of the star-fish eggs 

 which are not fertilized is not caused by bacteria, but by the 

 process of oxidation in the egg. If no spermatozoon enters the 

 egg, or if the egg is not caused to develop by chemical treatment 

 it perishes very rapidly. If, however, a spermatozoon enters 

 the egg, the latter remains alive ui spite of the fact that the 

 entrance of the spermatozoon causes an acceleration of the 

 oxidations in the egg. Warburg found for the eggs of the sea- 

 urchin at Naples that fertilization raises the velocity of the 

 process of oxidations to six times their original value, while 

 Wasteneys and I foimd that fertilization caused an increase 

 in the velocity of oxidations of Arbacia in Woods Hole to three 

 or four times the rate found in the unfertilized eggs. 



