Vol. XLI. August, 1921. No. 2. 



BIOLOGICAL BULLETIN 



FERTILIZATION AND EGG-SECRETIONS. 1 



OTTO GLASER, 

 AMHERST COLLEGE. 



I. 



The newer work on fertilization is directly traceable to the 

 investigations of Frank R. Lillie. 2 It was he who first drew our 

 attention to egg-exudates: later, the loose ends of observation 

 and experiment united, in his mind, into a scheme whose novelty 

 has played the part of an intellectual ferment. If we can ask 

 new questions and for that matter, answer them too, more 

 precisely than we could in 1913, this is largely due to the catalytic 

 effects of the fertilizin hypothesis. 



From a large list of besetting problems most of them only 

 solved in part I shall select for discussion merely those that 

 have interested me particularly, and first among these is the 

 question whether egg-secretions have anything whatever to do 

 with fertilization. 



Skeptics, now and again, have been caught coquetting with the 

 inevitable difficulty that egg-secretions can be discovered and 

 analyzed in only one kind of egg at a time. By insisting on this 

 point they appear to attach comparatively little value to the 

 distinctions between prevalence and importance. However, we 

 are no longer terrorized by one who brandishes the single case. 

 Today, exudates are known not only from the eggs of one 

 echinoderm and one annelid, but frorn every one of the ten 

 species of echinoderms that have been tested. Not merely this, 

 but additional cases have been reported from annelids, molluscs 

 and tunicates. To the list of previously recognized instances, 



1 Read before the American Society of Zoologists at a symposium on Fertiliza- 

 tion, held in Chicago, December 30, 1920. 



2 An excellent summary of all the investigations in this field is to be found in 

 Lillie's "Problems of Fertilization," University of Chicago Press, 1919. 



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