PAR THENOGENESIS 



tion of the development In the egg, therefore, fertilization 

 and parthenogenesis are variations. 



Investigations in the realm of inanimate nature have in 

 the last decades led to such a wealth of new discoveries, 

 have so shattered the foundations of the old point of view 

 that we are warned against beholding the picture of inani- 

 mate nature now offered us as final. Full well we know 

 that every day holds the possibility of new discoveries 

 which must make everything known appear in a new light. 

 Also in the investigation of living nature we may be certain 

 that we stand only on the threshold of the knowledge of its 

 deeper principles and we should avoid too quick and final 

 conclusions. 



Even when we know clearly the exact goals which living 

 nature reaches, and when we survey the chief paths which 

 it traverses to reach these goals, always does the fact that 

 there are by-paths — detours to our conditioned human 

 comprehension — take us by surprise. We should not look 

 upon this endless richness of nature's creative capacity as 

 an opportunity for us to confirm a preconceived notion or 

 theory. Rather with wide open mind should we be recep- 

 tive to this richness In all its manifold expressions. 



In calling forth a new individual, nature has not limited 

 itself to one mode; both fertilization and parthenogenesis 

 initiate development of the multicellular animal. When 

 it was found that parthenogenetic development could be 

 initiated also in the laboratory by experimental means, we 

 should have taken this discovery as a sign of the manifold 

 possibilities that inhere in an egg-cell to respond to stimuli. 

 Instead, this discovery was held to mean that the final solu- 

 tion of the problem of the initiation of development in 

 animal eggs had been reached, that the final word concern- 

 ing one biological phenomenon had been spoken — and 

 even, that man here had mastered nature, that he himself 

 could create life. The discovery of isotopes has taught us 



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