THE UNIQUENESS OF THE INDIVIDUAL 



(or chromosome or organism) which has divided into two are 

 themselves capable of division, and so in turn their issue. 

 Accretionary products like shells and hair are made by living 

 cells which grow in the organic style: all additive growth is 

 subsidized by acts of multiplication. 



A lineage of cells that perpetuated itself without loss by 

 repeated binary divisions would of course increase in numbers 

 in an exponential or geometrical progression. In real life, not 

 even bacteria will increase at such a rate for long. Their growth 

 is restrained by a variety of density-dependent factors, like the 

 accumulation of inhibitory waste products or the exhaustion 

 of the supply of food. Nevertheless, growth by continuous 

 compound interest is the norm for all living systems. It is 

 departure from exponential growth that calls for comment and 

 explanation, just as with departure from uniform motion in a 

 straight line. No moving object left to itself will persevere in 

 constant linear motion, and no real organism will groAv at a 

 constant specific rate. The former circumstance no more 

 derogates from Newton^'s First Law of Motion than the latter 

 from what is sometimes called the Law of Malthus. What we 

 must ask is, in what way does the growth of organisms depart 

 from that regimen of continuous compound interest by which 

 they are theoretically empowered? 



No one has yet improved upon the answer given by the 

 American anatomist Minot. Consider a sum of money invested 

 at a rate of compound interest which, instead of remaining 

 constant, falls; and let the interest be (say) 10 per cent in the 

 first year, 9 per cent in the second, and 8-1 per cent, 7*3 per 

 cent, 6'Q per cent ... in successive years thereafter. The sum 

 does indeed grow at compound interest, but the rate of interest 

 falls progressively at a rate which progressively falls. This is 

 the organic style of growth as Minot saw it. A living system 

 progressively loses its power to multiply its substance at the 

 rate at which that substance itself was formed. Put otherwise, 



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