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DISCUSSION 



rotblat: Dr. Upton's results show the complexity of this problem. We have had a 

 number of results given to us in papers which seemingly disagree with otlier findings, but 

 we must remember that they don't involve the same conditions. If one finds an agent 

 which brings forward the time of death naturally one says that it is similar to ageing, it 

 produces the same results as ageing, but aU of us who have been working on these 

 problems know that the different causes of death may be due to the fact that the different 

 treatments were made at different ages and therefore, by calculating at the age at wliich 

 the exposiu-e was done and on the dose-rate you get different effects. I don't think that 

 these results necessarily contradict each other, it simply indicates that this is a very 

 complex problem. 



UPTON: I should Uke to emphasize the same tiling. The fact that not all age-dependent 

 changes are affected in the same way or to the same extent need not contradict the argu- 

 ment that the effects of radiation and the effects of time have certam basic factors in 

 common. It is our job to try to see how much one can generalize, what the similarities 

 and differences may be and to try to learn sometbdng about radiation and about ageing 

 from these similarities and differences. 



MOLE: All I want to do is to make a plea to dissociate ageing from death. I tliink mental 

 deterioration may lead to my having to retire, but it is more than likely that I wiU die 

 from sometliing else. I tliink that ageing, if you really think about it seriously, ought to be 

 dissociated from what are really the accidental things that kill people. 

 MULLER: In fact no one dies of old age. It seems to me that we are takmg the right way, 

 mortahty is an index of ageing since mortaUty from so many causes rises with ageing; 

 that we can judge from morphological and physiological criteria. It seems to me it is quite 

 legitimate to make tliis association. Why not? 



mole: If you take this seriously you have got to say that if there is a peak of mortality 

 from boys falling off their bicycles, or being involved in traffic accidents, at 13, there are 

 some sections of the population that will already have peaked at 12 and their grand- 

 fathers who die of thrombosis will also die a year earUer, and their little brothers who 

 swallow ferrous sulphate tablets wfil also die a few months earlier. 

 MULLER: I don't thing so because there are both environmental and genetic causes, and 

 certainly the environmental causes may change. Actually you will find that if you 

 subject populations of different ages to test whether they are accident prone, that rises 

 in the same way as everytliing else. 



MOLE: Oh, no I beg to differ; if you look at the results of the London Passenger Transport 

 Board investigation of bus drivers, you wiU find that accident proneness goes down with 

 increasing age. 



