PREFACE 



The following discussion of the problems of fertili- 

 zation is an outgrowth of the writer's own studies in 

 this field. It is an attempt to present the actual 

 status of the various problems in a critical but not in an 

 exhaustive manner, and is thus to be regarded as a point 

 of departure for future work as much as a brief summary 

 of attained results. The necessary limits of the volume 

 have imposed restrictions which have permitted scant 

 justice to numerous excellent pieces of work with which 

 all special students are familiar; for this the absence 

 of textbook intention and style may perhaps be addi- 

 tional excuse. The part of the subject that deals 

 with the basis of biparental inheritance is purposely 

 treated more summarily than other problems, because 

 so much that is really extraneous to the problem of ferti- 

 lization proper is involved in the discussion. 



The inevitable conflict between the strictly biological 

 and the physicochemical methods of analysis of bio- 

 logical problems emerges in typical form in the problems 

 of fertilization. It is the writer's opinion that it will 

 long continue to exist, but that there is an ultimate 

 reconciliation, if not in sight, at least in prospect, on logi- 

 cal grounds. An equal hospitality to the results of both 

 methods of inquiry is therefore adopted. The tendency 

 toward excessive simplification of the physicochemical 

 school is constantly being checked by the biological 

 school, and the conservatism of the latter has been more 

 than once rudely shaken by the former. These mutual 



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