SPENCER 



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must be the governing factor. Therefore the cost of in- 

 dividuation being higher in a well-nourished organism, 

 such an organism should be less fertile, not more fertile, 

 as Spencer assumed. 



But the amount of nutrition available is not a constant 

 quantity, so there is no necessary inverse ratio between 

 reproduction and individuation. What Spencer really 

 meant may be shown thus : 



Amount devoted to individua- 

 tion, i.e. minimum capable of 

 sustaining life. A constant 

 quantity. 



Surplus of nutrition over and 

 above cost of individuation 

 available for reproduction. 



Amount of nutrition available not a constant quantity. 



We may attach either of two meanings to the phrase 

 " cost of individuation." We may take it to mean the 

 gross amount devoted to individuation and used for 

 building and maintaining the body of the organism ; or 

 we may take it to mean the minimum amount which is 

 capable of sustaining the life of the organism. By the 

 amount of nutrition available we must understand, not 

 the gross amount lying loose in the environment, but the 

 amount which the organism can assimilate. If we assume 

 the " cost of individuation " to be the gross amount 

 assimilated, then an inverse proportion between individu- 

 ation and reproduction would mean that a well-fed organism 

 would be less fertile than an ill-fed organism. But if 

 we take the phrase to mean the minimum amount capable 

 of sustaining life, then we may assume that any surplus 

 would be available for the purposes of reproduction. But 

 this would be a direct ratio with the amount of nutrition 

 available over and above the cost of individuation, not 

 an inverse ratio with the cost of individuation. 



If we glance along the ascending grade of types from 

 unicellular organisms up to man, or, better still, to such 



