408 OTTO GLASER. 



ing, as well as more directly from the experiments themselves, 

 that the r61e of the egg secretion (fertilizin) experimentally added 

 to induce development was exactly the same as the role of any 

 other parthenogenetic agent, and that it united with the egg 

 receptors, no more than do the electricity, heat, cold, mechanical 

 shock, osmotic pressure, or what-not. On the other hand, like 

 these, the egg-secretion by affecting permeability, brings about 

 conditions under which the ovum is freed from its inhibitors and, 

 in a sense, enabled to fertilize itself. From this standpoint all 

 parthenogenetic methods are methods for inducing auto-parthe- 

 nogenesis, and fertilization with sperm differs from auto- 

 initiation simply in the fact that the fertilizin which unites with 

 the egg receptors has itself previously united with the sperm in 

 the jelly, or the water about the egg. 1 



SUMMARY. 



1. The egg-extracts as well as the egg-secretions of Arbacia 

 and Asterias, in addition to characteristic effects on spermatozoa, 

 are permeability increasing agents, and initiate development. 

 For the type of initiation here dealt with I have chosen the term 

 auto-parthenogenesis. 



2. Auto-parthenogenesis is blocked in Arbacia by washing the 

 eggs in sea-water. 



3. A group "Purple X" which may be split off from the sperm 

 of Arbacia, and which also appears in boiled egg-secretion, 

 blocks parthenogenesis in low concentrations and fertilization in 

 high concentrations. 



4. Prevention of parthenogenesis by washing can hardly be 

 the result of an absence of fertilizin ; prevention by Purple X may 

 be the result of occupancy of the egg-receptors. 



5. It is not unlikely that all cases of parthenogenesis are in 

 reality instances of auto-parthenogenesis. 



6. With certain minor modifications it appears possible to 



1 According to F. R. Lillie's account, the sperm unites with the fertilizin in the 

 egg. This however seems incredible, for the affinity between sperm and fertilizin 

 is very great, and since the egg jelly, through which the sperm must pass on their 

 way to the ovum is heavily charged with the fertilizin, it is difficult to see how any 

 unbound sperm could reach the egg. This change in the geographical location 

 of the sperm-fertilizin reaction however makes absolutely no difference in essentials. 



