370 Dr. F other gill on Longevity. 
other of the non-naturals. The animating paf- 
fions, fuch as joy, hope, love, See. when kept 
within proper bounds, gently excite the nervous 
influence, promote an equable circulation, and 
are highly conducive to health while the 
deprefling affedtions, fuch as fear, grief, and 
defpair, produce the contrary effedt, and lay the 
foundation of the molt formidable difeafes. 
From the light which hiftory affords us, as 
well as from fome inftances in the above table, 
there is great reafon to believe, that longevity 
is, in a great meafure, hereditary; and that 
healthy, long-lived parents would commonly 
tranfmit the fame to their children, were it not 
for the frequent errors in the non-naturals, which 
fo evidently tend to the abbreviation of human 
life. 
Whence is it, but from thefe caufes, and the 
unnatural modes of living, that, of all the chil¬ 
dren which are born in the capital cities of Europe , 
nearly one half die in early infancy ? To 
what elfe can we attribute this extraordinary 
mortality ? Such an amazing proportion of 
premature deaths is a circumftance unheard of, 
among favage nations, or among the young of 
other animals! In the earlieft ages, we are 
informed, that human life was protradted to a 
very extraordinary length; yet how few perfons, 
in thefe later times, arrive at that period, which 
nature 
