General Discussion 345 



been well represented at this meeting, and at first it seemed that, 

 as has happened in previous discussions of the problem, we mif^ht 

 have continued to sit in uncompromisingly opposing camps. This 

 has most fortunately not happened ; as time has gone on the sharp 

 dichotomy between the two points of view has tended to disappear 

 and discussion has become more broadly based. 



There has, of course, undoubtedly been a trend towards the view 

 that drug resistance is to be explained in terms of genie mutations 

 rather than in terms of directed physiological variations ; indeed as 

 we heard yesterday afternoon several of our participants have 

 confessed to conversion on this point. Yesterday evening I referred 

 to these conversions as a welcome measure of the success of the 

 meeting although they might not be in the direction that one 

 wished. In these words of mine of course the welcome was the 

 response of a scientific man and the hint of disappointment that 

 of a wishfully thinking human being. If one regards drug resistance 

 not only as a biological phenomenon of academic interest but as a 

 practical obstacle to be overcome, it is naturally more encouraging 

 to think of it as a directed physiological variation than as a spon- 

 taneous mutation; the former phenomenon might conceivably be 

 subject to some sort of control; the latter, so far as I can see, can 

 only be met by rendering an essentially uncontrollable event less 

 likely to occur, that is in practice by multiple chemotherapy. 



However, conversions or no conversions, nothing but good can 

 come of the breaking down of barriers between opposing schools of 

 thought, so that a matter of controversy ceases to be a matter of 

 doctrinal disputation and becomes one for impartial scientific 

 discussion. I hope that all who have taken part in this symposium 

 will agree with me that we have indeed advanced in this desirable 

 direction, and that they will return to their laboratories feeling 

 that their time and thought, so generously given, have been well 

 spent. 



