UNFERTILIZED STARFISH EGGS. 305 



explaining how the spermatazoon finds its way to the egg in 

 animals in which fertilization occurs within the body. Definite 

 directive forces are clearly not necessary, since a portion of the 

 spermatazoa must reach the ovary, through their ciliary motion, 

 by way of the uterus and Fallopian tubes. Experiments similar 

 to those made by Harper upon pigeons must yet be made upon 

 mammals. Yet there seems to be no doubt that the mammalian 

 egg of many species is also fertilized before it reaches the uterus. 

 Cases of extra-uterine pregnancy also point to the possibility that, 

 fertilization may occur at the surface of the ovary. 



VI. THE PROLONGATION OF LIFE AND THE THEORY OF FER- 

 TILIZATION. 



Our experiments seem to have proved that the mature tmfer-l 

 tilized starfish egg dies within a few hours through internal, 

 changes but that the process of fertilization saves the life of the\ 

 egg. This is true, not only of the fertilization of the starfish egg ! 

 by spermatozoa, but also for the chemical fertilization through , 

 hydrogen ions. Mr. Xeilson succeeded this year in keeping the 

 parthenogenetic larvae of starfish alive much longer than has thus 

 far been the case (over thirty days), and Dr. Fischer was able to 

 accomplish the same for the larvae produced osmotically from 

 unfertilized sea-urchin eggs. It is therefore possible that the 

 chemical or osmotic fertilization of these eggs can give rise to as 

 long-lived larvae as the fertilization of the egg through sperm. 



But how does the spermatozoon or the physical and chemical 

 means substituted for it, save the life of the egg and why does 

 the mature egg die when it is not fertilized by sperm or artificial 

 means? I believe that the answer lies in this, that the fertilizing 

 agencies accelerate metabolic processes in the egg which, before 

 fertilization, went on only slowly. After fertilization by sperm or 

 by the chemical or physical means substituted for it, the egg divides 

 and grows, which it did not do before fertilization occurred, 

 Growth is inconceivable without a preponderance of synthetical 

 over hydrolytical processes. I believe it possible that the deter- 

 mining factor in the chemical forces set in motion within the egg 

 through fertilization consists in this that the synthetical processes 

 in the egg are accelerated. If these processes are not inaugurated 



