398 
commonly difficult. For it is obvious, 
that the fhorter the time an idea remains 
-in the mind, the lefs likely is it to leave 
any deep or durable impreffion. And.ac- 
cordingly we find, that men in whofe 
minds the current of thought feems {6 
fluggifh as even every moment to threaten 
an abfolute ftagnation, are almoft univer- 
fally gifted by nature with memories the 
moft faithful and tenacious. 
In the 3d place: Cafes frequently oceur in 
which perfons are obferved, by thofe who 
happen to be near them, to fpeak, or in 
fome other way to give notice of an impref- 
fion upon their minds, although, upon 
awakening, they are unable to recollect any 
con{cioutfnefs. 
In the 4th place: We have reafon 
to ‘believe, that thought is uniformly 
connected with a vaft variety of mo- 
tions, where it is at the fame time of 
fo fubtle a nature, as nearly to elude our 
confcioufnefs. It feems, for inftance, ne- 
ceffarily to precede every ftep that we take 
in the longeft journey ; fince we find, that 
if the attention be at any time ftrongly bent 
upon a fubject that 1s unconnected with 
the motion cf our limbs, this motion will 
uniformly be interrupted. ‘The fame re- 
mark may be applied to the a& of fwal- 
lowing our food, and perhaps, in fome 
cafes, even to the function of refpiration. 
Now, if by the aid of reafoning we are 
able to dete&t the prefence of thought, 
where we had leaft fufpeéted its exiftence, 
why fhould we be unwilling to fuppofe 
that it uniformly accompanies fleep, al- 
though, in fome cafes, it may be fo eva- 
nefcent, as altogether to efcape our recollec- 
tion? . 
It may be afked, how can we account 
for the very fenfible refrefhment which the 
mind ufually derives from fleep, whilft we 
allow that it is then as’ continually occu- 
pied as in our wakeing ftate ? 
There are feveral circumfiances, which, 
if we were properly to attend to them, 
would enable us, I think, to reply to this 
queftion in a manner that is fatisfactory, 
and, at the fame time, perfectly compa- 
tible with the opinion we are endeavouring 
to fupport. 
1. Sleep, by entirely fufpending the 
exertion of. the voluntary mufcles, pro- 
motes the repofe of the body; and this, 
from the intimate fympathy that exifts be- 
tween the intelle€tual and the corporeal 
part of our frame, will be fufficient to ac- 
count, in a confiderable degree, for the re- 
frefhment of the mind. : 
2.448 any occupation which is monotonous 
Enquirer, No. XXIV. 
“its exertion. 
[June ry, 
induces premature fatigue, fo we find, onthe 
other hand, that we may protraé the pe- 
riod of our mental, as well as of our cor- 
poreal, vigour to a very unufual degree, 
by fufficiently diverfifying the manner of 
May we not then apply this 
obfervation to the ftate of fleep, which, by 
varying incefiantly the fubje&t of our 
thoughts, in part fecures us againft the 
fatigue which otherwife we fhould fuffer 
from continued thinking. It is remark- 
able, that our ideas when we are inthis 
ftate feldom remain long in the fame train; 
no fooner does one image offer itfelf to the 
contemplation of the mind, than it is re- 
moved from our obfervation by another, 
which in general bears no refemblance to, 
and feems not to have any kind of con- 
nection with, the preceding. 
3. Although in fleep the mind be con- 
tinually occupied, in a ftate of vigilance 
only does it appear properly adive ; it 
receives ideas indeed in the former fate, 
but feldom with any effort either to me- 
thodife or to detainthem. Now from the 
experience of our waking hours we learn, 
that it is efforts of this kind, and not im- 
preffions pafitvely received ; or, in other 
words, that it is voluntary attention, and 
not mere ¢hought, that is calculated to in= 
duce fatigue. Ideas that are quite uncon- 
nected with the will might pafs through 
the mind, I fhould conceive, for an almott 
indefinite period without exhaufting it; 
unlefs, indeed, they happen to be affoci- 
ated with fome violent emotions, or lead 
us to laborious exertions of the body, both 
of which tend equally, whether weare afleep 
or awake, to wear away the vigour of our 
frame. 
In the fituation of a maniac, no cir- 
cumftance impreffes us with fo lively an 
idea of his mifery as the nearly conftant 
vigilance to which that unfortunate being — 
is in moft inftances condemned. Sleep, by 
which almoft every other kind of unhappi- 
nefs is at times interrupted or alleviated, is 
comparatively feldom allowed to this laft 
of ail human calamities. And yet it is 
remarkable, that the mind of an infane 
perfon rarely appears exhaufted prema- 
turely by this continual occupation of 
it; at the fame time that he is, in nearly 
every cafe, a prey to the corroding in- 
fluence of a morbidly acute fenfibili- 
ty. 
ty not this fingular faé&t be in fome 
meaiure explained, by confidering the ftate 
of mind in mania as approaching very 
nearly to that which occurs in dreaming 
or reverie, in both of which the en 
. 
