AN ESSAY ON LONGEVITY. 99 



In addition ito these classes of evidence, we have 

 experiments and observations on individuals which 

 are of little value. Were sure post-mortem signs of 

 yearage — not of wearage only — traceable, we might 

 have a class of evidence from examination of dead 

 bodies.^ But there are no sufficiently definite signs 

 known, though Professor Rolleston's investigation of 

 the Anglo-Saxon interments at Frilford shews how 

 such evidence may be of use in regard to average 

 longevity or mortality. Cases of individual longevity 

 in any race or condition of men carry little scientific 

 value, and none that are recorded appear to assist 

 in the discussion of the general question as to 

 causes, but belong to the subject of abnormal lon- 

 gevity, of which a few words will be said before 

 concluding. The incompetence of travellers to bring 

 home facts as to longevity is obvious. They cannot 

 make direct observations, or take a census of the 

 peoples they see ; hence Messrs. Wallace, Bates,^ 

 Darwin, Livingstone, and others, able observers as 

 they are, give no information of use. Even in our 

 own colonies, where civilized men are in close contact 



' Were there any laws known, such as BufFon and Flourens have 

 tried to lay down, of an exact ratio of age to growth, much might be 

 expected in this way, and the whole enquiry facilitated. 



^ Mr. H. W. Bates informed the writer that he saw many great-grand- 

 fathers on the Amazons, but that is all the information he could afford. 

 This kind of evidence is clearly of no use at all when we want to know 

 to a nicety of a year what is the expectation of life of men at 50, 60 

 years of age, and upwards. 



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