480 ALVALYN E. WOODWARD 



3. Combination with the ' spermophile group' (agglutinin) of 

 fertilizin. It will be recalled that (p. 460) ' anti-fertilizin' was 

 obtained by Lillie by breaking up Arbacia eggs after most of the 

 fertilizin had been removed through washing. He observed that 

 a mixture of anti-f ertilizin and fertilizin was unable to agglutinate 

 sperm. The inhibition in this case he assumed to be due to 

 occupancy of the spermophile group of the fertilizin. 



4. Comhination with the ' ovophile group'' (lipolysin) of fertilizin. 

 That anti-fertilizin inhibits sperm fertilization as well as aggluti- 

 nation, I found in experiments where the controls produced 77 

 per cent and 82 per cent cleavages, while the eggs treated with 

 anti-fertilizin produced, respectively, 68 per cent and 21 per cent 

 cleavages. It is even more efficient in blocking autoparthenogene- 

 sis in Arbacia (table 7). 



TABLE 7 

 Inhibition of autoparthenogenesis by anti-fertilizin 



Eggs + fertilizin 2\ hours + hypertonic NaCl 20 minutes 



Eggs + antif ertilizin + fertilizin 2\ hours + hypertonic 20 minutes. 

 Eggs + boiled anti-fertilizin + fertilizin 2j hours + hypertonic 20 

 minutes 



PEBCENTAQE OP 

 CLEAVAGES 



43 

 10 



57 

 



Since it prevents autoparthenogenesis, anti-fertilizin must 

 combine with the parthenogenetic agent, lipolysin, or with the 

 egg, as well as with the agglutinin. This versatility is not sur- 

 prising when we remember that under the term 'anti-fertilizin' 

 are grouped all the egg contents to which the membrane is not 

 permeable. It must include the fatty substance with which 

 lipolysin combines. 



From the fact that this particular union with the parthenogene- 

 tic agent takes place, we should anticipate that the fatty sub- 

 stance itself would inhibit the development of the egg (table 8). 

 To obtain the fatty extract, one volume of sea-urchin eggs and 

 two or more volumes of ether were shaken and then allowed to 

 settle into layers. The solution used consisted of 0.3 cc. of this 

 ethereal extract diluted with 100 cc. sea-water. In experiment 3, 



