XU INTRODUCTION 



which were expressed by the participants during the final general 

 discussion. 



By the extremely wide contemporary development of each field of 

 knowledge, by the application of the most diverse techniques, and by 

 study of the processes with different objects, we must not be dis- 

 appointed when there seems at first sight to be nothing in a report or 

 discussion that would appear to solve the jaroblem, or give the ini- 

 j^ression of a major qualitative leap forward. Each important scientific 

 problem is being solved step by step through the laborious investiga- 

 tion of many tens and hundreds of scientists, when the data are 

 accumulated and concepts develop. Therefore we think that the 

 summing-up of the modern points of view and of the state of the 

 jjroblem, with the simultaneous distinct demonstration of new ten- 

 dencies and ways of approach, is the most important and principal 

 result of such a symposium; these can be found in the published 

 material. Undoubtedly, too. the published material will, in many 

 respects, be a "stimulus" for a further development of science in the 

 field of primary processes produced by radiation, and by the cells- 

 reactions to irradiation. 



I should like to express my heartfelt gratitude to all the participants 

 for the efforts they made. I also consider it my duty to express my 

 cordial thanks to all who took part in preparing the materials for 

 publication, and esi^ecially, for their hard work in preparing the debate 

 and general discussion. Simultaneously with the present edition 

 the same material is being published in the Russian language by the 

 U.S.S.R. Academy of Sciences. 



G. M. Frank 



