EX VIRIBUS VIVIMUS. 



the 'Quarterly Review,'^ and still more lately in the 

 'Fortnightly Review,'^ admirable resumes are given 

 of what is known and has been supposed with regard 

 to this possibility of human life — a subject to which 

 the term 'longevity' has had its meaning narrowed, 

 but one which will here be treated subordinately. 

 It will be unnecessary therefore to refer further to 

 authorities on this question, until their opinions are 

 discussed. Naturalists and philosophers, including 

 Aristotle, Bacon, and Haller, have incidentally given 

 expression to opinion as to the causes of the varied 

 tenure of life of organisms ; but naturally the later 

 writers have had a larger number of facts to deal 

 with, and have been able to bring a sounder scientific 

 knowledge to bear on the problem than those who 

 preceded them. The treatise of Bacon, entitled 

 ' Historia Vitse et Mortis,' contains a most admirable 

 enquiry into the causes of longevity. The question 

 is attacked from every side, and the most ingenious 

 hypotheses, with regard to animals and men, are 

 suggested and discussed with that order and pre- 

 cision which belong to the great philosopher. At 

 the same time, it must be admitted that, in Bacon's 

 time, strange traditions and superstitions held men's 

 minds, and that he actually, who shewed the means 



' January, 1868. Also see Sir Henry Holland's able Essay on 

 'Human Longevity' in the 'Edinburgh Review,' 1857, hereafter 

 referred to again. 



2 April, 1869. 



