EGG SECRETIONS OF ARBACIA AND ASTERIAS 



477 



B, eggs of which 50 per cent or more matured, were treated side 

 by side, to obtain the egg extract and to precipitate it. The pre- 

 cipitate from A was so shght that it produced only a faint cloud- 

 iness. That from B, when dried, nearly filled a Syracuse 

 watch-glass. 



A sample of lipolysin prepared by this method from Arbacia 

 eggs in August, 1915, was examined and tested in June, 1916. 

 Its color had changed from white to a grayish violet, it had be- 

 come compact, and it was much less soluble than when first made. 

 Its efficiency as a parthenogenetic agent will be seen in table 6. 

 Other samples of the precipitate, now a year old, do not show the 

 physical changes noted in the 1915 sample. 



TABLE 5 

 Lipolysin as a parthenogenetic agent 



Eggs from lot. 



Control, unfertilized 



Eggs + sperm 



Eggs + hypertonic 20 minutes 



Eggs + hypertonic 30 minutes 



Eggs + lipolysin 2 hours + hypertonic 30 minutes . . . 

 Eggs + lipolysin 170 minutes + hypertonic 20 min- 

 utes 



PERCENTAGE OP CLEAVAGES 





 99 



31 





 99 



44 





 99 



53 







95 







4 



20 







18 







7 



17 







81 











7 



1 In this and in the following tables a vertical column represents the results 

 from the eggs of a single female or from a thoroughly mixed batch of eggs. 



In 4:B practically all the eggs which divided developed into 

 swimming larvae. In 6^, 12 per cent swam; in QB, 10 per cent, 

 and in SA also a number swam. It will be noted that fresh 

 Asterias lipolysin is more efficient with Arbacia eggs than is the 

 old Arbacia precipitate. 



This parthenogenetic development was not caused by impur- 

 ities, for the lipolysin does not contain a trace of barium, as proved 

 by careful spectroscopic tests; neither does it contain acetone, 

 alcohol, or ether, all of which were carefully removed. 



Both the lipolysin and sperm agglutinin may be obtained from 

 the same sample of egg secretion. In order to do this, BaCU is 

 added first, and the precipitate saved for extraction of the lipo- 



