■12 6 EX VIRIBUS VIVIMUS. 



There is not within the cognizance of the writer a 

 single fact of any antiquity to help us materially in 

 the enquiry, unless it be thought that the limitation 

 of life to seventy or eighty years in the Psalms is 

 a smaller span than such a writer would now assign ; 

 but this supposition is not worth further consideration. 

 It is very well ascertained that average longevity 

 has immensely increased since the middle ages in 

 Europe ; the question, however, of mortality clearly 

 does not come within the limits of this Essay. It 

 would be very satisfactory could some general re- 

 lation between high average longevity and high 

 potential longevity among men — i. e. small death- 

 rate at early and late ages— be established, but the 

 facts are conflicting, and deductive analysis renders 

 it improbable that any constant relation does obtain, 

 as was pointed out in treating of longevity in organ- 

 isms generally. 



20. The Influence of various States of Civilization. 



We have seen that the influence of civilization 

 cannot be fairly examined inductively, but the facts 

 quoted, and the conclusions they offer, warrant us in 

 supposing that a civilization of the highest order, in 

 which the efficiency of the community and the effi- 

 ciency of the component individuals is greatest — in 

 which there is the most harmonious action, the 

 greatest happiness for the greatest number, the least 



