THE UNIQUENESS OF THE INDIVIDUAL 



'senescence** begins then, rather than at the conventionally 

 accepted age of physical maturity somewhat later on. 



The foregoing paragraphs represent no more than a few 

 extra guesses woven in among Weismann'*s original hypothesis 

 of ageing. If what Weismann believed is true, then nothing very 

 radical can be done by way of modifying the course of growing 

 old. Scientific eugenics could in the long run give us a more 

 generous span of life; but only, it seems, by engaging life in 

 lower gear, by piecing out the burden of the years into a larger 

 number of smaller parcels, so prolonging youth symmetrically 

 with old age. But the inevitability of old age does not carry 

 with it the implication that old age must be a period of feeble- 

 ness and physical decay. If specific secretions of the ductless 

 glands fail; if assimilation becomes less efficient, so that essential 

 food factors fail to penetrate the gut wall; if chronic low-grade 

 infections persist because the defences of the body lack power 

 to overcome them; in all such cases it should be possible to 

 remove, at least for a while, any ingredients of the senile state 

 for which they may be specifically responsible. The solution of 

 these problems is a matter of systematic empirical research. 



Side by side with research of this type there should be under- 

 taken a thoroughgoing physiological analysis of the mechanism 

 of ageing. I shall sketch one possible line of analysis here, 

 because although the layman often understands the nature of 

 scientific problems and can usually grasp the principles of their 

 solution, he has, as a rule, very little idea of how scientific 

 work is actually done. 



If a physiologist were to study the problem of ageing from 

 scratch, he would not even begin to try to modify the time- 

 course of senescence by the administration of vitamins or 

 elixirs compounded of the juices of the glands. He would first 

 of all try to piece together a full empirical description of the 



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