OLD AGE AND NATURAL DEATH 



before his cells, and a cell before its ferments have stopped 

 working. But legally, I suppose, a man is dead when he has 

 undergone irreversible changes of a type that make it im- 

 possible for him to seek to litigate.) 



Weismann believed that natural death had evolved under a 

 Darwinian regimen of natural selection. The '"utility of death"* 

 he says, is this. ""Death takes place because a worn-out tissue 

 cannot for ever renew itself. . . . Worn-out individuals are not 

 only valueless to the species, but they are even harmful, for 

 they take the place of those which are sound.' It follows that 

 'by the operation of natural selection, the life of a theoretically 

 immortal individual would be shortened by the amount which 

 was useless to the species\^ In this short passage, Weismann 

 canters twice round the perimeter of a vicious circle. By 

 assuming that the elders of his race are decrepit and worn out, 

 he assumes all but a fraction of what he has set himself to 

 prove. Nor can these dotard animals ""take the place of those 

 which are sound** if natural selection is working, as he tells us, 

 in just the opposite sense. It is curious that Metalnikov in his 

 comparatively recent La Lutte contre la Mort (1937) should 

 give these fallacies a seventy-five-year run by twice repeating 

 them with approval word for word. The problem is, why are the 

 older animals decrepit and worn out? And for this Weismann 

 had no sufficient answer. It must be obvious that, senescence 

 apart, old animals have the advantage of young. For one thing, 

 they are wiser. The Eldest Oyster, we remember, lived where 

 his juniors perished. They are wiser, too, in their experience of 

 infection, for an animal which has survived a first infection is 

 better equipped to deal with it a second time. In the majority 

 of animals 'immunological wisdom** may be a better bargain 

 than anything they may have by way of mind. We are always 

 inclined to over-estimate the value of mental wisdom, though 

 no one, I suppose, has the temerity to doubt that the giraffe 



^ The Duration of Life ^ p. 24. 



19 



