28 
fphere by that planet, to the exertion of its 
influence during life upon a child born ata 
particular infant? Yet with fuch reafon- 
‘ing men of the beft underftanding were 
long fatisfied! | 
Errors in {cience have almoft uniformly 
been the offspring of falfe or imperfect 
analogies; and it is curious to remark 
how a fingle idea, firft ufed by way of 
illuftration, has engendered a whole theo- 
ry, with all its appendages. ‘Thus the 
nerves have been called (as they really are 
in appearance) /irizgs : but firings are ca- 
pable of a greater or le!s degree of tea/ion, 
-and, according to this degree, vibrate with 
more or lefs force. Hence the nervous 
fyftem was faid to be braced or relaxed ; 
its functions depended upon its Zove; the 
fympathies of one nerve with another were 
cwing to fimilarity of tenfion, like thofe 
of fiddle-ftrings; nerves communicated 
their vibrations to the brain, and excited 
there tremulous motions which were the 
immediate caufe of fenfation, and fo forth. 
It is a pity that all this ingenious and well- 
connected theory is fubverted by the fim- 
ple fact, that the nerves always lie un- 
firetched in a foft bed of cellular fubftance, 
to which they are attached by means of 
innumerable threads, fo as to be utterly 
incapable of any thing like the vibration 
of a cord. 
For the purpofes of quackery and im- 
potture, a fingle word has often produced 
an admirable effel, by employing the fan- 
cy ina kind of obfcure analogy, where no 
confiftent or precife theory was meant to 
be fupported. This was remarkably the 
cafe with refpect to animal magnetifa. 
Real magnetilm was a power of nature 
very well known in its effects, though its: 
eaufe remained a fecret. A certain invi- 
fible influence proceeding from the magnet, 
exercifed a vifible {way over the iron ap- 
proaching it. Byapplying the term mag- 
netijm to the animal body, it was not pre- 
tended that the fame principle exifted there; 
but advantage was taken of the idea which 
the word excited, to infinuate that equaily 
myfterious and vunaccountable actions 
might refult from fome peculiar mode of 
operating upon one living fubjectbyanother. 
‘To this the do&trine of fjmpathy was an- 
nexed, in which mental and corporeal ac- 
tions are ftrongly blended, and a little fact 
has ferved as the bafis of much fiction. 
As it is indifputable that the image of an 
abfent perfon aéts upon the mind of'ano- 
ther through the medium of the memory, 
and that the joys and forrows of that per- 
{cn may be fympathetically communicated 
Enquirer, No. XXIII. 
_ proper influence at a diltance. 
[Feb. T, 
to his friend by letter or fpeech, fo it was 
aflumed that the bodily operations, or 
treatments, could be made to exert their 
This no- 
tion nearly refermbled that of the fympa- 
thetic cure of wounds, fo ferioufly patron- 
ized by that extraordinary chara@er Sir 
Kenelm Digby, who, however, maintained 
his fyftem more philofophically, by a fub- 
tle application of the doctrines of effluvia, 
and of the mutual attraction of fimilar par- 
ticles. 
Medical theory indeed, even in the pu- 
reft hands, has been little more than a fuc- 
ceffion of falfe or over{trained analogies. 
At one time, chemical ideas gave the 
vogue, and then every oreration in the 
animal body, found or difeafed, was afcrib- 
ed to ferments, neutralizations, volatiliza- 
tions, condenfations, and all the proceffts 
carried on in a laboratory. ‘Then mecha- 
nical and mathematical notions became 
prevalent, and the fize and weight of par- 
ticles, their free motion or obftruétion, 
the denfity or rarity, vifcidity or tenuity 
of fluids, the impelling and refitting pow- 
ers, the contractile and elaftic force of fi- 
bres, and the like, were applied to explain 
the whole animal economy. In later times, 
the living principle was taken into the ac- 
count, and the human body became a felf- 
moved eleétrical machine, fubject to excites 
ment, collapfe, overcharge, exhauftion, 
&c. Thus each fet of theorifts have had 
their favourite analogy, to which they have 
accommodated their language and reafon- 
ings, generally to the total neglect of other 
principles. 
From the preceding examples of the 
abule of analogy may be deduced the prin- 
cipal cautions to be obferved in making 
ule of this mode of argumentation. 
In the firft place, it muft be founded on 
areal, not a nominal, refemblance. In- 
ftances have been already given to fhew, 
that a lingle word laxly ufed has ferved. as 
the bafis of a faife analogy. Thefe might 
be multiplied from the effeéts of that me- 
taphorical application of terms properly 
belonging to corporeal cbje&ts, to mind 
and its qualities, which has prevailed in 
all languages. Thus the word employed 
to denote the immaterial part of the hu- 
man compound has always been that by 
which fome kind of fubtle matter, fuch as 
air, wind, breath, &c. is primarily de- 
noted. But though this is apparently di- 
vetted cf the properties of grofs matter, 
yet it remains as oppofite to the ftri@ly 
philofophical notion of /pzrit, or fome- 
thing charaéterifed by the negation of 
‘ all 
