AN ESSA Y ON LONGEVITY. 49 



expenditure is great, as a rule generative expenditure 

 will be small, and vice versa; and when they both 

 exist in large (that is, large relatively to the degree 

 of evolution) quantity, the longevity is greatly 

 diminished. A complication introduces itself here 

 in the fact that great personal expenditure, antagon- 

 izing longevity, accompanies high evolution rather 

 than low — high evolution which favours longevity. 

 The injurious influence however of the personal, ex- 

 penditure, possibly increased in some directions, is 

 counteracted by diminished expenditure in other di- 

 rections, which high structure brings to its possessor 

 in the form of advantages in securing nutritious food 

 and escaping noxious agents ; and further, the in- 

 creased personal expenditure tells almost invariably 

 upon the generative expenditure, which is small in 

 highly-evolved organisms, or organisms of high in- 

 dividuation.^ Thus the whole average expenditure 

 is not necessarily greater in highly-evolved organisms, 

 like things being compared to like. 



There are other minor and more direct influ- 

 ences affecting longevity in organisms, which may 

 possibly be brought under the general heads of 

 Evolution and Expenditure, but to which further 

 reference will be made in discussing the two pro- 

 positions inductively. 



1 This relation is clearly brought out in Mr. Spencer's chapters on the 

 Antagonism of Individuation and Genesis, and of Expenditure and 

 Genesis. — ' Principles of Biology,' vol. ii. 



E 



