292 Studies in the Plijisiolofin of Fertilization 



(1) 5 cc. water, (2) 5 cc. Stroiiffi/lnceiih'utiis egg-extract, (3) 5 cc. Asterias 

 glacialis egg-extract. 5 cc. water was then added to each, and they 

 were added to separate ei|ual ainmints of Stronf/i/locentrutus eggti. Each 

 of the two experiments was dinible, two strengths of sperm being used. 



The results given in the Table show that the Asterias glacialis egg- 

 extract had the effect described by Von Dungern. Whereas the Stronyy- 

 locentrutus extract increased the fertilizing power of the sperm of that 

 form (as was previously shown in Table XII), the Asterias extract com- 

 pletely paralyzed the Strong ylocentivtus sperm, so that it was incapable 

 of fertilizing a single egg. 



7. Comparison of the effects of Strongylocentrotus and Asterias egg- 

 waters on the fertilizing power of Strongylocentrotas sperm. 



It remained, finally, to see whether this poison for Strong yloantrutus 

 sperm is given off by the eggs into the water or not. Egg-waters of 

 Strongylocentrotus and Asterias were made up of approximately equal 

 concentrations as follows. The eggs of the two forms were washed 

 thoroughly by allowing them to settle four times in finger-bowls full of 

 water. They were then placed in tubes in seven times their volumes 

 of water. After li hours the waters were drawn off the eggs and used 

 in the following experiment. 



Definite equal amounts oi Strongylocentrotus spcrni-su-spension were 

 added to (1) 2cc. water, (2) 2 cc. Strongylocentrotus egg- water, and 

 (3) 2 cc. Asterias egg- water. 10 cc. of water was then added to each 

 and they were poured separately on to approximately equal lots of 

 Strongylocentrotus eggs. The experiment, the result of which is detailed 

 in Table XXXIV, was made with two different amounts of sperm. 



TABLE XXXIV. (4.2.3.G.) 



^ , , , ( 3 drops sperm .. 



Cross: Stronqiilocentrotus Ac 



( 1 cc. sperm 



The result shows clearly that the poison is not given off by the 

 Asterias eggs into the water. On the contrary, the Asterias egg- 

 secretion stimulates the Strongylocentrotus spermatozoa to just the 

 same extent as does the Strongylocentrotus egg-secretion itself. I can 

 only explain Von Dungern's statement to the contrary on the sup- 

 position either that broken eggs were present among those from which 

 he obtained the egg-watei', or that some of the mucus from the outside 

 of the body of the Asteroid was present with the eggs. Von Dungern 



