PATTERN OF ORGANIC GROWTH AND TRANSFORMATION 



recording as many instances of gro\\i:h as possible and trying 

 to find out the properties they share in common. May we not 

 aiRrm, for example, that animals increase in size as they grow 

 older, until growth ceases altogether? We may, of course, but 

 only if room is left for reservations. All animals grow smaller if 

 undernourished — a trivial exception — but some animals (like 

 flatworms, nemertines and colonial sea-squirts) ''de-grow'* with a 

 deep-seated anatomical retrogression and may even revert to 

 an embryonic level of simplicity. Negative growth of this kind 

 has a special adaptive value. It is not a significant violation of 

 the law of general increase because negative growth is not a 

 reversal of the processes that led to enlargement, as if meta- 

 bolism has simply been engaged in a reverse gear. Nor is it a 

 significant exception that men and women are shorter in old 

 age than in the physical prime. It is indeed so, and Dr Morant 

 is satisfied that this shrinkage is not just an actuarial artifact 

 due to an earlier death of taller people, nor to the fact that the 

 older people we measure to-day were born longer ago than 

 their juniors and therefore in perhaps less propitious times for 

 growing. (Morant finds that Englishmen a hundred years ago 

 reached the same maximum height as they do at present, but 

 took about five years longer to achieve it.)* Loss of height is 

 probably due to a shrinkage of intervertebral discs. This, too, 

 is not a reversal of synthetic processes; and it may be observed 

 that the luxury of living to an age at which one can indulge in 

 physical deterioration is an artificial by-product of domestica- 

 tion, and a state of afi'airs that has no parallel in the world of 

 animals at large. 



It has long been recognized that biological growth is multi- 

 plicative in style, and not accretionary or additive. That which 

 results from biological growth is itself endowed with the power 

 of further growing. In the general case the progeny of a cell 



* [Dr J. M. Tanner has since told me that there is clear evidence of a 

 genuine secular increase in height as well as in growth rate.] 



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