1802. ] 
impair the vigour of the body. By. the: 
exertion of any of the organs of fenfe, 
proportional fatigue of that organ 1s in- 
duced by the temporary wafte of the /e7- 
forial power or excitability; but thefe 
effects are removed by reft, during which 
ftate the excitability is re-accumulated : 
and the frequent ufe of the intellectual 
powers, by increafing the number of ideas, 
and multiplying their combinations, ren-, 
ders every fucceeding exertion lefs an. 
effort,and confequently lefs fatiguing. But, 
independent of a theory which I believe 
cannot be difproved, I can, produce a 
living proof of the truth of my pofition, 
which will probably be confidered to be 
more conclufive than any reafoning from 
principles, of which the mafs of mankind 
are yet totally ignorant, although an ac- 
quaintance with the laws that govern his 
exiftence, even as far as they are already 
known, muft be of the highelt importance 
to man. The proof, at which I have 
hinted, is the venerable poet and philofo- 
pher, Dr. Darwin, who, after having pro- 
duced three extenfive works, one of which 
alone (Zoonomia) was the fruit of twenty 
years’ labour, is ftillina green old age, and 
enjoys,or did lately enjoy, a degree of health 
equal to that of moft men in the prime of 
life, with a mind as fit as ever to pene- 
trate the veil which nature is faid to have 
thrown over the moft fublime of her ope- 
rations, or add to the pleafures of talte, 
by the beautiful flights of his enchanting 
Mufe! In addition to this, it is recorded 
of Waller, the poet, that, to the age of 
eighty-two, when he died, ‘ his intellec- 
tual powers continued vigorous, and that 
the lines which he compofed, when he 
Sor age could wetther read nor write, are 
not inferior to the effufions of his youth.’’* 
It mutt beremembered,that Wailer, like Dr. 
‘Darwin, drank water. Other examples 
might-be adduced to corroborate thefe, but 
Dr. Darwin, from his comparative old age, 
furnithes the mot ftriking inftanceon record 
of great mental exertion not being injurious 
to health, but; on the contrary, produc; 
tive of the moft happy confequences to 
himfelf, his cotemporaries, and pofterity. 
One or two examples more, however, will 
give additional weight to the proofs al- 
ready brought forward. Mr. Godwin, 
whofe perfeverance and vigilance in the 
detection of error has probably never been 
equalled, befides having conceived feveral 
works of moft exquifite imagination, has 
developed the principles of moral fcience 
in a work, which few who have read it 
_® Jobnfon’s ‘Lives of the moft eminent 
Englith Poets.” 
Mental Occupation net defiruBive to the Body. 
3 
will doubt to be ihe moft ftupendous and 
valuable that. the human mind ever pro- 
duced; yet there is no reafon to believe 
that he has fuffered by his intellectual ex- 
ertions, great as they muft have been to 
produce fo rich a harveft! Nor does it ap- 
pear, that the wnceatfing labour of Dr. 
Betldoes to develope the laws of living na= 
ture, and excite mankind to attend to 
thefe laws, have impaired his corporeal 
vigour; on the contrary, by increafing 
his knowledge of the agents that a& to the 
deftruGtion or prefervation of health and 
life, have they not given him affurance 
of enjoying an unulual prolongation of ex- 
iftence? 
Tris needlefs to multiply examples.— 
From the faéis which have been adduced 
I think it may be fairly concluded, that. 
intellectual exertion can never be injurious 
to ike body: and it will be found, that zz 
all thofe cafes uebere the health has been 
conceived to be impaired by intellefual pur- 
fuits, the caufe bas been inattention to the 
wants of the body, the principal of which 
are exercife, ret, aud food, at proper times 
and in proper quantities. 
The oblervation, that perfons eminent 
for their intelle¢tual acquirements have 
been ufually, more than others, fubjeéted 
to the ravages of lingering and fatal 
difeafes, is undoubtedly too well founded. 
It is a truth, infinitely to be regretted, 
if regret would remedy the evil, that 
many of the greateft ornaments of our 
fpecies have been cut off from fociety by 
a premature death, and the benefits which 
polterity might have derived from their 
after-exertions for ever loft; but the caufe 
is obvious: the laws of nature cannot be 
violated with impunity, whether by inat- 
tention to the neceffaries of life, or the 
direct application of noxious agents; and 
as lone as mankind negle& the cultiva- 
tion of the art of living, 10 long will they 
continue to be the victims of their igno- 
rance. ‘ 
It is unneceffary to extend thefe ob- 
fervations toa greaterlength. 1 have only 
to add, that, however they may at prefent 
be received by thofe who have imbibed an. 
oppofite opinion, I truft that they will not 
ultimately be ufelefs:—<* caufes and effedts 
are conneéted in an endlefs chain, fo that. 
no honeft effort can be loft, but will ope- 
rate to good, centuries after its author is 
configned to the grave.”* The deftruc- 
tion of the prejudice which I have endea- 
voured to combat is of the utmott im- 
* Godwin’s «© Enquiry,” ol. 2. p. 438. 
portance 
