FERTILIZATION REACTION IN ECHINARACHNIUS PARMA. 15 



is a simple matter by exercising care to procure, as mentioned 

 above, from ovaries in sea-water clean egg suspensions entirely 

 free from bits of tissue; these eggs as a class (which to avoid 

 circumlocution I designate "ovary eggs") show wide variations 

 and are inferior to dry or shed eggs, i. e., those deposited by ani- 

 mals in clean dry dishes. Except for eggs mentioned on page 

 (21) as normally resistant to fertilization, dry eggs produce 

 more agglutinin than "ovary eggs" but show less variation. 



The following observations from a large body of recorded data 

 may now be cited. 



1. July ii, 9:30 A.M.: To 1/2 c.c. of dry eggs sea-water was added to the 10-c.c. 

 mark. At 10:10 7 c.c. of the supernatant sea-water was withdrawn and filtered. 

 Tested with freshly prepared I per cent. Echinarachnius sperm, this withdrawn 

 agglutinin charged sea-water was negative at 1/3,200 dilution and gave an 8 second 

 reaction at 1/1,600. 



2. July ii, 9:40 A.M.: Ovaries of 8 females in 20 c.c. of sea-water strained. 

 Sea-water added to 100 c.c. Eggs settled at the 7 c.c. mark. At 10:20, 90 c.c. of 

 supernatant sea-water decanted and filtered, which when tested on sperm came 

 negative at 1/400 and gave a 6 second reaction at 1/200. 



3. July 10, 10:30 A.M.: To 1.5 c.c. of dry eggs 8.5 c.c. of sea-water were added. 

 11:00 A.M. 8 c.c. of supernatant sea-water decanted and filtered, 8 c.c. being added 

 to the eggs. 11:00 A.M. to 12:10 P.M., supernatant water of the second washing 

 gave a 6-second reaction at 1/12,800 dilution. 



Comparison of (i) and (2) shows that a 5 per cent, suspension 

 of dry eggs yielded fertilizin of 1/1,600 power while a 7 per cent, 

 suspension of ovary eggs contained fertilizin of but 1/200 power. 

 Also, (3) shows us that after a second washing a 15 per cent, dry 

 egg suspension gave fertilizin rated at 1/12,800 power. Without 

 exception, the most powerful fertilizin suspensions were from 

 shed eggs. These results are typical of a large number of obser- 

 vations. 



(&) Fertilizin Production by Washed Eggs. Lillie has shown 

 that in Arbacia it is practically impossible by washing to remove 

 all the fertilizin ; as long as the egg lives it produces the aggluti- 

 nating substance. The egg of Echinarachnius is not so hardy 

 as that of Arbacia; becoming physiologically inert after remaining 

 in sea-water for a time, it ceases to give off fertilizin though far 

 from dead. This cessation is gradual, with each successive 

 washing the fertilizin produced being less. Two experiments 

 are cited. 



