PREFACE IX 



a lecture on this subject at the International Congress of Cyto- 

 logy at Stockholm. Only the title of this lecture has ever been 

 published. This is how it happened that I was the first scholar 

 to publish these ideas, in spite of the fact that I developed the 

 same ideas later than Professor Steinbock: this has been 

 due to various circumstances, among others, also to the out- 

 break of the Second World War. This fact, however, is not 

 ultimately so im.portant for the progress of the science itself; 

 it is much more important that two researchers have reached 

 quite independently the same conclusions; and that they con- 

 tinue to collaborate in a friendly way to prepare the way for 

 the final reception of their ideas. It is unimportant that we 

 differ in several unessential points ; it seems that we will soon 

 reach an agreement even on these points. The difficulties we 

 have to overcome are great; we must struggle against inter- 

 pretations and ideas which were considered inviolate since the 

 days of the struggle for the victory of Darwinism and which 

 were supported by such an authority as Haeckel, and by 

 many other most prominent names. We must struggle against 

 interpretations which have been considered as laws, i.e. as 

 truths, and replace them by new suggestions. 



I also wish to express my warmest thanks to the distinguished 

 publishing house of Pergamon Press which has made possible 

 the publication of this book in such a full presentation. 

 I am also grateful to Dr. Janez Stanonik, the translator 

 of the present text, the original of which was written in German ; 

 he has completed his task, which has certainly not been easy, to 

 my full satisfaction. 



JOVAN HADZi 



