AN ESSAY ON LONGEVITY. 135 



the offspring of a lady who certainly was alive in her 

 looth year, cannot be held to militate against the 

 general law. These are isolated cases, where unusual 

 vigour (i.e. abundant 'iriatter of life') has increased 

 longevity and the other quantities simultaneously. 

 There is not a sufficient number of trustworthy 

 records of cases of high longevity to make an ex- 

 tended testing by them of the conclusions arrived at 

 as to causes favouring longevity, likely to be of any 

 real value. 



In the course of what has been written, the ex- 

 ceedingly involved nature of the enquiry, and the 

 absence of all but the fewest data as to comparative 

 longevity, have been made sufficiently apparent. It is 

 to this condition of the subject that we would gladly 

 direct attention, as the cause of indefinite and specu- 

 lative character in an essay treating of it. It is hoped 

 that in indicating possible lines of productive enquiry, 

 and in pointing to the more prominent and reme- 

 diable gaps in information, some more practical result 

 has been attained. 



It would have been possible no doubt to carry 

 mere speculation into greater detail than has been 

 attempted here, as to the influences affecting longevity 

 in man, but the facts, such as they are, seem fairly to 

 admit of no more positive inferences than have been 

 here given. 



