GENERAL DISCUSSION 



de Hevesy: I feel sure that you all share my view that we ex- 

 perienced a most profitable and exceedingly pleasant meeting. Our 

 thanks are due to all who addressed us and participated in the dis- 

 cussion, but first of all to our Chairman, Prof. Haddow, and to the 

 organizer of this meeting. Dr. Wolstenholme, to the assistant 

 secretary, Miss Bland, and to all members of the able and friendly 

 staff of the Director. 



If I am permitted to add a personal remark, I wish to say that I 

 never experienced a more pleasant meeting. 



We have traversed various territories and it is difficult to decide 

 which of the countries passed has the most beautiful scenery. One 

 may say that nothing was more fascinating than following the path 

 and fate of seeded marrow-cells as was done by Dr. Loutit which 

 revealed among others the powerful effect of radiation on immunity. 

 It really sounded like a fairytale. Some, however, may give pre- 

 ference to the discussion of the great variety of changes in the 

 enzymatic pattern produced by irradiation, in which various speakers 

 participated, and to the presentation of the philosophy of such 

 happenings put forward in such a fascinating way by Prof. Krebs. 

 Protection was one of the main fields of discussion. Formerly, a 

 geneticist as far as he was interested in the application of X-rays 

 was anxious to produce the maximum number of mutations. By 

 working on these lines very important results were obtained, among 

 others in the field of agriculture. Quantity and quality of crops were 

 improved. I doubt if any geneticist envisaged in those days that 

 the time might come when the main concern will not be to produce 

 mutations by irradiation but protect against them. Dr. HoUaender 

 reported results of his and his colleagues' endeavour to achieve 

 protection against mutative effects of radiation. This was followed 

 by an animated discussion on different aspects of genetic happenings. 



That the basic problem of radiobiology, the site of primary bio- 

 chemical lesion, is yet unsolved was emphasized by different speakers. 

 Now in view of the great variety of enzymatic changes produced by 

 irradiation one may be inclined to consider such inactivation to be 

 the primary radiation damage. What makes one doubt the correct- 

 ness of this assumption is the fact that while the same enzyme when 

 present in a radiosensitive organ can easily be inactivated, when 

 located in a less radiosensitive one proves to be refractory to even 

 large doses. We were told by Dr. Van Bekkum that when the rat is 



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