8 



The Fertilization-reactio/i 



It is a curious fact that by far the largest body of 

 data, both of observation and of experiment, on fertiliza- 

 tion relates to the end results and final consequences of the 

 coming together of eggs and spermatozoa. The phenomena 

 embracing the union of egg- and sperm-nuclei and the estab- 

 lishment of the first cleavage-figure are end-events of a 

 chain of happenings in a complex, heterogeneous and little 

 understood system and not the end-point of a single one- 

 way reaction taking place in a simple, homogeneous, fully 

 understood system. Many biological processes doubtless 

 may be explained on the assumption of an underlying sim- 

 ple, even mono-molecular, reaction so far as such in chemical 

 experiments with pure reactants be known or postulated. 

 Nevertheless, to ignore the polyphasic nature of the cyto- 

 plasm needlessly obscures the problem; comparisons of 

 cytoplasmic processes with simple or even with complex 

 reactions in test-tubes may cause serious retardation in 

 the solution of the problems of biological behavior. Chem- 

 istry, in so far as it relates to end-points, offers little help. 

 As in chemistry more information regarding the onset of 

 even the simplest reactions is desired, so here in the problem 

 of fertilization: we stand in need of more exact knowledge 

 as to the initial reaction which leads to the catenary pro- 

 cesses culminating in establishing the cleavage-figure with 

 which by rhythmical reduplication the development of the 

 egg ensues. Hence, the study of the happenings immedi- 

 ately ensuing after the mixing of eggs and spermatozoa 



184 



