THE UNIQUENESS OF THE INDIVIDUAL 



growth of any wild animal living under natural conditions. 

 Fish are the only wild animals for which we are approaching a 

 predictive ecological theory of growth rate and size frequency. 

 Nor can this be counted a triumph of abstract scholarly enter- 

 prise. The pressure of necessity is behind it; it is less because 

 fish are edifying than because they are edible that we know as 

 much as we do. 



THE PATTERN OF CHANGE OF SIZE 



In spite of the compass and complexity of growth, and the 

 great variety of different processes that contribute to increase 

 of substance, the passage from germ to adult is an orderly and 

 predictable process. What rules of order does it conform to, 

 and upon what reasoning is prediction based? 



It is one thing to devise empirical formulae which describe 

 the growth of the members of one particular species; that is 

 simply a matter of measuring the growth of a sufficient number 

 under conditions sufficiently well defined. It is quite another 

 matter to try to frame general laws of growth which the 

 majority of animals are expected to conform to, and biologists 

 have set about the problem in two entirely different ways. 



Some have attempted to arrive at Laws of Growth deduct- 

 ively, starting with certain deceptively inoffensive axioms about 

 the conduct of metabolism and ending with theorems that 

 purport to describe the way in which all animals grow. I believe 

 that this approach must be classified at present as a scholarly 

 indoor pastime; that it may sometimes lead to acceptably 

 accurate answers is only marginal evidence of the truth of the 



axioms. 



The other way to go about it* is to proceed inductively, by 



* [The inductive approach is considered in more detail in my article on 

 'Size, Shape, and Age', in Essays on Growth and Form, ed. W. E. Le Gros 

 Clark and P. B. Medawar (Oxford, 1945.)] 



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