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as tending to impede its operation, and fhorten its exig¬ 
ence. Simple life,” he fays, “ will not only furvive 
fenfation, but will furvive it longer, if the animal is killed 
by deftroying the nervous fyftem, than if it had been de- 
ftroyed by haemorrage, fuft'ocation, or other violence. If 
a filh, immediately upon being taken out of the water, be 
llunned by a violent blow on the head, or by having the 
head crufhed, the irritability and fvveetnefs of the mufcles 
will be prelerved much longer than if it had been allowed 
to die with the organs of fenfe entire. 1 his is fo well 
known to fifhernien, that they put it in pradlice in order 
to make them longer fufceptible of the operation called 
crimping. A faint on is one of the fillies lead tenacious of 
life, infotnuch that it will lofe all figns of life in lefs than 
half an hour after it is taken out of the water, if fuffered 
to die without any fafther injury ; but if, immediately af¬ 
ter being caught, it receives a violent blow' on the head, 
the ntufcles will {hew vifible irritability for more-than 
twelve hours afterwards.” 
1 o the fame purpofe, he cbferves, that in warm-blooded 
animals an exceHive exertion cf voluntary motion imme¬ 
diately before death, prevents the ntufcles from being ri¬ 
gid when cold, and renders them more prone to putre¬ 
faction. Thus, if an ox is killed immediately after being 
oCer-driven, the carcale will not become ftiffwhen it grows 
cold, nor is it capable of being preferved by means of fait. 
In confirmation of the lame hypothefis, it may be oblerved, 
that in Come diforders of the brain, fuch as hydrocephalus, 
and apopleCt’C pally, in which the functions of the brain 
are lufpenced, the office of digeftion is fometimes better 
performed than in health. From all which Dr. Blane and 
Mr. Hunter conclude, that the exercife of fenfation is ini¬ 
mical to life, and that a fort of fatigue is induced by this 
as well as by voluntary motion ; “ fo that all that inter- 
courfe carried on through the nerves, whether towards 
the brain in ’lie cafe of fenfation, ox from the brain in 
affs of volition, tends io wear out the animal powers. 
And, as intenfe and long-continued thought, though not 
terminating in any outward action, tends alfo to produce 
an inability for farther exertions, it would appear that the 
brain or fenforium is more particularly the organ which 
is fubjeCt to that fpecies of fufierar.ee called fatigue. From 
thefe facts we perceive the neceffity of fleep, which con- 
filts in a temporary fufpenfion of fenfation, volition, and 
thought, and is a refource of nature, w hereby the powers 
of life recover themlelves after fatiety and fatigue, which 
are provided as guards to warn its when nature is in dan¬ 
ger of being drained, either by repletion or over-exertion; 
and it is evident that fuch barriers w ere abfolutelymecef- 
fary, in order to let bounds to opera-ions which are only 
occafionally requifite, -and which would otherwife depend 
oti the caprice of the will. The exercife of fenfation and 
voluntary motion in a moderate degree is conformable to 
the intention of nature, and therefore falutary; and it is 
only -when they are exccflive that they tend to wear out 
the powers of life, and more efpecially if thefe are not 
duly recruited by fleep. It follows, from the fame prin¬ 
ciple, that when life is threatened by certain difeafes, of 
which the chief fymptom is irritation, any means by which 
fenfation, w hether natural or morbid, and mufcular mo¬ 
tion, whether voluntary or involuntary, convulfive or fpaf- 
mofiic, can be Toothed or fufpended, will prove falutary, 
by allowing the powers of life to rally as it were, and to 
recover themfelves. In th ; s confifis the operation of nar¬ 
cotic medicines, fuch as opium; which, in complaints both 
of a general and local nature, proves ufeful, not merely as 
a palliative, by the removal of temporary pain or fpafm, or 
by procuring fleep, but as a principal jnftrument of reco¬ 
very, by allowing the powers of life to exert their natural 
action,. in confequence of the removal of irritation.” In 
treating tltis fubjeft, the dodtor conliders the effeils of 
opium as afiedting fimple or fenfitive life; and to deter- 
mine this, he made the following experiments: Having 
made a folutionof opium in water, he put into one portion 
of it force found living eels, and others with their heads 
O M Y. 
i 
bruited ; and, in a number of trials, it was found that the 
found eels generally died much fooner than the bruifed 
ones. This, however, was the cafe only when the folu- 
tion was of a certain degree of ftrength, fuch as half a 
grain of opium to at leaf! to an ounce of water; for, when 
only about half this ftrength, the found eels lived much 
longer, the time being then protracted to that in which 
the bruifed eels would have died merely in confequence 
of their injury ; but it muft be oblerved, that even the 
wounded eels died confiderably fooner than when put into 
plain water. 
Upon the whole, Dr. Blane concludes, that “ the "reat 
malfes of mufcle in the trunk and extremities of the body 
are the inftruments of the mind in adting upon external 
bodies'; and we may therefore rank in the lift of ftinmli 
the nervous power by which the will and the paftions ex¬ 
cite external motions. This is a function Diffidently im¬ 
portant for the nerves, without admitting them as the 
principle on which irritability depends.” 
Having difclaimed all inquiry into the connection be¬ 
tween mufcular motion and volition, the doCtor proceeds 
to conftder the effeCts of the different paftions upon the 
mufcles. Though thefe are diftinft from the motions di¬ 
rectly produced by the will, yet he conliders them amoiw 
thole arifing from confcioufnefs; “ for there are emotions 
ot the heart which have vifible and powerful effeCts upon 
the mind and vafcular fyftem, which are organs entirely out 
of the reach of the Will. Not to mention the well-known 
effeCts ot grief, fear, and joy, which affeCt the whole cir¬ 
culation, there are certain paftions and fentiments which 
produce partial and local effeCts. Thefe are eftabliftied by- 
nature, cither to anfwer fome important purpoie in nature, 
as in the cafe of the congeftion of the fluids in the parts of 
generation, in confequence of the venereal appetite, or to 
lerve as natural expreftions, as in the cafe of bluffiing or 
weeping. One of the molt ftriking effeCts of the paltTons 
upon mufcular aCtion, is tite influence they have upon tlte 
ftrength or mechanical force of the voluntary mufcles. 
Fear-produces debility almoft amounting to pally. Courage 
and order of mind, on the contrary, add to the natural 
ftrength. When the mind is agitated by fome interefting 
object, and calis upon the body for an extraordinary exer¬ 
tion to effeCt its end, the mufcles are thereby enabled, as it 
were by magic, to perform aCts of ftrength of which they 
would be entirely incapable in cold blood. In circum- 
ftances of danger, for inftance, where life or honour are 
at (fake, exertions are made for overcoming mechanical re¬ 
finance which feem incredible, and would be impoflible, 
were not the mind in a fort of phrenfy; and it is truly ad¬ 
mirable in the oeconomy of nature, that an idea in the mind 
fhould- thus in a moment augment the powers of motion, 
and infpire additional refources of ftrength adequate to the 
oceafional calls of life. Thefe considerations would almoft: 
lead us to doubt whether or not the accounts we have of 
the great feats of ftrength aferibed to individuals in the 
heroic ages, be fabulous or not. It is alfo worthy of re¬ 
mark, that, in great and lading exertions of ftrength, to 
which men are impelled by aCtive and generous affections, 
fatigue is not induced in the fame proportion, by many 
degrees, as by the fame quantity of mufcular aCtion in the 
cool and deliberate aCtions of common life.” 
Having thus difeuifed the fubjeft of internal ftimuli. 
Dr. Blane next proceeds to take notice of the fecond clafs, 
viz. fuch as are external. Thefe are either immediate or 
remote, viz. fuch as are excited by mechanical means, or 
by acrimony directly and artificially applied to a mtifcular 
fibre; or fuch as occur in the inftances of fympathy, and 
in the cafe of thofe inflincts which nature has inftituted 
for the purpofe of felf-prefervation in brutes, and in the 
early part of human life. “ There are certain habitudes 
betw een outward ftimuli and the moving powers whereby 
natural propenfities are conftituted, equally neceffary to 
the fupport of life as the internal fundtions.” 1 bus, in a 
new-born animal, the firit contaft of the external air ex¬ 
cites tlte aCt of refpiration, and the contact of the nipple 
excites 
/ 
