54 EX VIRIBUS VIVrMUS. 



lO. Inductive. 



We may now endeavour to see how far observation 

 supports the deductive hypothesis that longevity is 

 favoured by high individuation, and small expendi- 

 ture, both personal and generative. And here again 

 we must allude to the profound ignorance in which 

 we are as to the exact potential life-period, by what- 

 ever standard it be given, of any animal. Those 

 which we have under observation we influence ab- 

 normally, and those which we have not under 

 observation we know little about. We must then, 

 as well as we can, make allowance for abnormal 

 influences, and depend largely on general impres- 

 sions. A list of statements as to the longevity of 

 different groups of organisms is hereto appended, 

 derived from the works of many authors, and from 

 private sources of information. It is by no means 

 a satisfactory accumulation of data, but it is believed 

 that under present circumstances nothing better can 

 be drawn up.^ Lord Bacon's chapter on the same 

 subject is added in full, in order that the reader may 

 appreciate the state of knowledge in his time as to 

 the question. It will be seen from many of his 

 remarks that he had the notion that bulk favours 

 longevity, and that personal and generative expen- 

 diture antagonize it. 



• Any trustworthy additions to these statements will be very acceptable 

 to me. 



