256 General Discussion 



of cellular differentiation as is Wislocki's contribution to the growth 

 cycle of deer antlers. When a dozen studies of similar amplitude 

 have been completed, we shall have a well-defined branch of geronto- 

 logical studio with its own generalizations and its own vocabulary. 

 Mear hile, we can only salute the pioneers. 



Wislocki's contribution to the growth cycle of deer antlers is in 

 a class by itself. His analysis is as direct an attack on the problem of 

 ageing in transient tissues as can at present be made. 



Montagna's paper was useful in presenting results derived from 

 the human female in circumstances which permitted a freer and 

 cooler discussion than is often possible. His was an extensive analysis 

 of a problem complementary to the intensive analysis of the red 

 blood cells by Lovelock and Mollison. 



Evidence from botany was presented by Yemm. I had hoped that 

 he would have told us why monocarpic plants mature seeds but 

 once and die. This he did not do. Nevertheless, his view that even 

 in senescent leaves there is an appreciable amount of synthesis and 

 respiratory activity, suggests that ageing in plants may be a very 

 laggard process indeed. 



Drawing these various lines of research together, I feel embar- 

 rassed by the existence of much scattered but suggestive evidence, 

 and the lack of a unifying conception which would make everything 

 fit into place. But I am not dismayed on this account, for science, 

 like the ageing process itself, must advance in steps and I feel that 

 this symposium has made a definite contribution to the solution of 

 the problem of ageing. 



It is true, as Professor Zuckerman once said, that genius, luck, 

 fashion and expediency always seem to underlie man's greatest 

 achievements. Luck, yes, but having heard Dr. Parkes' remarks 

 I am sure that "Fortune only favours the prepared mind". 



The coming years will bring new observations and insights, be it 

 in the directions indicated above, or along other lines. In some years 

 hence we may again be wondering where we stand and what progress 

 we have made ; let us hope that we may meet again at the Ciba 

 Foundation in London. 



