70 OTTO GLASER. 



minutes, its efficiency as a sperm-agglutinant is increased, but it 

 is decreased if the radiation is extended to fifteen minutes. 

 Moreover, regardless of radiation, the efficiency of the agglutinin, 

 like that of pepsin, varies with the square root of the concentra- 

 tion. The presence of carbon and nitrogen may be mentioned 

 incidentally. However, if the agglutinin is an enzyme, it is not 

 yet possible to suggest its taxonomic position among organic 

 catalysts. Before this can be done, we must find the process 

 which the agglutinin catalyzes. 



V. 



The last question I shall discuss is the relation of lipolysin and 

 agglutinin to the specificities of fertilization. 



We know that specificity is not absolute; it is often possible 

 to fertilize the eggs of one species with the sperm of another, yet 

 species-true spermatozoa always fertilize a much larger percentage 

 of eggs. 



The discovery that chemical entities traceable to the eggs 

 themselves intervene in fertilization however obscure such inter- 

 vention may appear has exposed the problem of specificity from 

 a new angle. Lillie has discussed the matter very thoroughly in 

 his book. 



For me, the questions involved take the following form: Is it 

 possible to substitute the lipolysin of one species for that of 

 another? Is it possible to do the same thing with the agglutinins? 

 With regard to the lipolysins, the following experiments may be 

 cited: secretion was removed from the eggs of Echinarachnius 

 until their fertility had been reduced to one half. Separate lots 

 were then inseminated in the presence of arbacia, asterias, oyster, 

 and species-true lipolysin all in a concentration of ten milligrams 

 to five c.c. of sea-water. 



The results are given in Table I. in which are listed, in separate 

 columns, the percentages of inactive eggs, those of the anomalous 

 cleavages, and those of divisions indistinguishable from the 

 normal. Apparently, it is not essential that the lipolysin be 

 species-true. More dramatic than this, of course, is Miss Wood- 

 ward's recently announced discovery that arbacia lipolysin is an 

 excellent parthenogenetic agent for Nereis eggs. 



