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SPECU LATIONS

AND

CONJECTURES

ON THE

(QUALITIES

OF THE

NERVES,

By SAMUEL xMUSGRAVE, M.D.

. Fellow of the R o y a l Society, And Correfponding Member of the Academy of Belles Lettres at Paris,

°\

L\Q,mp^&ti9 Prinldj J^ld by P. TTlmsly, T. jfA^E, J. Robson,

M.DCC.LXXVI. [Price Two Shillings and Six Pence.]

14410

C<ra,ca£ovxL

CONTENTS.

T Introduction Page I

CHAP. I.

Of the Circulatioit of the Bloody as it is influenced by the Nerves — 20

CHAP. II.

Of Animal Heat — 41

CHAP. IIL

The Animal Fluids corrupted by Irritations of the Nerves 61

CHAP. IV.

Of the Dropfy — 70

CHAP.

iv CONTENTS.

CHAP. V.

All Diforders probably Dif- orders of the Nerves 90

CHAP. VI.

Of the probability that Me- dicines curing Diforders aEl wholly through the Nerves 107

CHAP. VII.

The fame pofttions further fupported from the Ope- ration of Mental Caufes 118

CHAP. VIII.

Of the feveral Methods of relieving Irritation 126

CONCLUSION — 140

SPE-

,r I ■' I

SPECULATIONS

AND

CONJECTURES

UPON THE

Qualities of the Nerves.

INTRODUCTION.

\ S Philofophers at prefent Introduc-

pay but little regard to any do&rines, that are not fup- ported by experiments, it be- comes neceffary for every man who follicits their attention, ei- ther to fupport his opinions by B expe-

TION.

Introduc- tion.

2 ON THE QUALITIES

experimental proof, or to {hew that the fubjed: he is treating will not admit of it. I am afraid the Art of Healing, not- withftanding the many ingeni- ous attempts to illuftrate and improve it by experiments, will be found in the end to fall un- der this latter defcription. To know the relative properties of any two fubftances, and their agency one upon another, it is neceffary to bring them both together to the teft of experi- ment. Now the fubjed of me- dicine being the living human body, upon which we cannot at pleafure make experiments, we have no way of determining

with

TION.

OF THE NERVES. 3

With philosophical exadnefs, the In™°duc- effe&s producible in it by the application of other fubftances. We may, it is true, inveftigate and perhaps afcertain the anti- feptic powers of Nitre, Cam- phor and Bark ; but in fo doing what do we difcover but the effe&s produced by them in fome third fubftance, and not in that which is the proper fub- jedt of medicine ? Our enqui- ries therefore, inftead of com- prehending both agent and pa- tient, are confined wholly to the nature of the agent. But further, were it poffible to con- quer this difficulty, another of greater confequence would ftill B 2 remain,

TION.

4 ON THE QUALITIES

Introduc- remain. It would be impoffi- ble, I fay, to come to any cer- tain univerfal conclusion from experiments made upon the living body, on account of the difference between one living body and another. Philofophers have, indeed, laid it down as an axiom, that Nature muji be u?iifor?n : and this in a ftridt metaphyseal fenfe, I fuppofe, is true ; that is, Bodies confti- tuted in the very fame manner muft undoubtedly have the very fame properties. In a popular fenfe, however, Nature is not uniform : in other words, Bo- dies, which from their agree- ment in many leading proper- ties

OF THE NERVES. 5

ties come under one fpecific ap- J pellation, are not always con- - ftituted in the very fame man- ner, and may of courfe have fome different properties, both active and paflive. Thus, for inftance, the iron of different mines is very difllmilar in brit- tlenefs and toughnefs, infomuch that to make the former forts ufeful, it is neceffary to unite them with fome of a contrary quality. In the vegetable kingdom it is well known, how much the corn, the vines, the fruit trees, and the timber trees of one country excel thofe of another ; and how much al- fo medicines, procured from B 3 the

NTRODUC- TIO>,T.

TION.

6 ON THE QUALITIES

Introduc- the fame fpecies of plant, differ in ftrength and virtue. We ought not therefore to be great- ly furprifed at finding fome, or even a considerable difparity ift different individuals of the Hu- man Species whofe greater fen- fibility muft make all fuch dif- parities more apparent. The fad; is, that almoft every hu- man fubjed: has fome peculia- rity of conftitution, juft as every face has fome peculiar features. Many inftances of this kind will occur to every reader. Nothing, however, can be more ftriking than what the learned Mr. Kalm relates from his own knowledge of the Poifon-tree in America,

which

TION,

OF THE NERVES. 7

which one perfon may handle Istroduq- as he pleafes, cut it, peel off its bark, rub it or the wood upon his hands, fmell at it, fpread the juice upon his {kin, and make more expe- riments with no inconveni- ence to himfelf ; another per- fon, on the contrary, dares not meddle with the tree, while its wood is frefh, nor can he venture to touch a hand, which has handled it, nor even to expofe himfelf to the fmoke of a fire, which is made with this wood, with- out foon feeling its bad ef- fects ; for the face, the hands, and frequently the B 4 " whole

TION.

8 ON THE QUALITIES

Introduc- « whole body fwells excefllve- cc ly, and is affe&ed with a " very acute p^in." This, how- ever, is not all. He informs us likewife that his own fervant, who foon after his arrival handled it with fafety, and for that reafon made a jeft of the extraordinary effedts afcribed to it, was however punifhed for his jefting in the following year, being greatly incommoded, and fuffering feverely from its efflu- via *. To what purpofe then would it be to make fcientific

* Kalm's Travels. Vol. I. p. 77. The whole account, which is very curious, fills five pages.

expe-

'ION",

OF THE NERVES. 9

experiments upon any living Introduce body, when that body not only differs in qualities and habitudes from the reft of the fpecies, but with refpect to thofe very habi- tudes undergoes a variety of changes, and at different times differs even from itfelf ?

I am therefore ftrongly in- clined to think, that thofe who have laboured to difcover the Theory of Dilorders, have fought that which is not to be found, and may be compared to the Taylor in the ancient fable, who was employed to make a fuit of clothes for the Moon ; which fitting it in one of its phafes,

muft

TION.

10 ON THE QUALITIES

Introduc- muft of courfe be unfit in every other. For what is Theory, but a conne&ed chain of pofltions univerfally true ? Now with re- fpedt to diforders and their cure, which depend upon the manner in which the human body is affe&ed by different external fubftances, it is plainly impof- ble to frame any pofition that {hall be univerfally true, the paffive properties of the body being in no two individuals the fame, nor permanently the fame, even in one. It is true, there is a general relation that obtains in the greater part of the fpecies, upon which fome general rules of practice may be founded :

juft

T10N.

OF THE NERVES. n

juft as in the external figure, Introduce there is a general proportion be- tween the dimensions of dif- ferent parts, which is of con- siderable affiftance to the painter and the ftatuary, although per- haps there are not two human bodies exifting, in whom the fame proportion obtains throughout. This is probably the utmoft de- gree of knowledge we are capa- ble of acquiring with refpect to the paffive properties of the human body, and with this therefore we muft be content.

However, though it be im~ poflible to afcertain the a£Hcn of any external fubftance upon the

human

TION.

12 ON THE QUALITIES

Introduc- human body, there is no great difficulty in difcovering many relations which the main com- ponent parts of the body have to one another. Thus, whatever difference there may be in the elements of the human frame, there is yet no individual in whom the heart and arteries do not propel the blood, and the veins reconvey it ; in whom the mufcles are not the immediate and the nerves the primary caufe of motion. Thefe relations are probably unalterable, and may therefore become the object of fcience ; and that fcience alfo may be encreafed by the dif- covery of new relations. It is

the

OF THE NERVES. 13

the main ddign of this Treatife Introduc- tion.

to add one more to thoie al-

ready known, by {hewing, that when the human body is dis- ordered, the firft morbid im- preffion is made upon the nerves, the other parts receiving the miafma entirely from them ; and that, on the contrary, when health is reftored, the firft falu- tary impreflion is alfo made upon them, and that they are of courfe the grand medium, through which health and fick- nefs are produced.

This theorem, if worthy of that name, is not fo barren of ufeful corollaries, as at firft

fight

TION.

14 ON THE QJJALITIES

Introduc- £ght it may appear. Firft, it opens a larger field of remedies to the practitioner. Nothing is more common at prefent than for Theorifts to treat with a fu- percilious contempt every re- medy the operation of which they cannot in fome way or other account for. Plaifters, they will tell you, are nothing more than a warm adhefive covering : Aromatic fomentations are in no refpedt better than fo much hot water : laftly, liniments and em- brocations cannot enter into the circulation, and therefore can do little or no good. True : if it be neceffary that medicines, in order to do good, fhould be

firft

TIONT,

OF THE NERVES. 15

firft incorporated with the I^troduc- blood and humours, and re- ceived into the circulation. But on the contrary, if the nerves are the grand vehicle of medi- cine, then every application to the fkin being feparated from the nerves only by a porous e- pidermis, may eaiily make an impreffion upon them, and in all local complaints effe&uate a cure.

But to give another inftance : if it be true, as I fhall endea- vour to (hew, that any irrita- tion of a nerve will caufe an immediate corruption of the fluids that are within the de- part-

TION,

16 ON THE QUALITIES

Introduc- partment of that nerve ; it may- be worth our while to confider whether the violent bilious vo- mitings, that accompany a cer- tain fpecies of the colic, inftead of caufing the irritation of the inteftines may not be the effect of it ; and whether therefore it be not bad pradice in every cafe to attempt to carry off that bile by cathartics. I fhould be cautious of ftanding fingle in the aflertion, that the bilious colic is beft cured by opiates alone ; but in this I am juftified by the authority of Dr. Warren, an authority which I quote with the greater confidence, ha- ving my felf followed his practice

with

TION.

OF THE NERVfeS. 17

With fuccefs *• Now if this be Introduc- fo, if an opiate will flop the generation of this acrimonious bile, muft not every candid en- quirer acknowledge that the ir- ritation gave rife to it ?

I will only add, that the capital impediment, which has hitherto retarded the improve- ment of Medicine, is, in my o- pinion, the attempt to explain it upon the principles of other fciences. Thus fome have called

* Med. Tranfaft. Vol. II. p. 68. Compare Sydenham delliaca Pafiione. proceiT. in Morb. p. 5j. De Haen Rat. Medend. Vol. I. p. 184. Ed. Lugd.Bat.

C in

TION.

18 ON THE QUALITIES

Introduc- in the aid of chemiftry, and others of mechanics and hy- draulics; and, by ftraining fome points and flurring over others, have contrived to patch up what they call a Theory ; but which to an unprejudiced eye differs as much from true Theory, as a wrong key that goes about half way thro' the lock, differs from the true key that perfedlly cor- refponds with the wards. The following pages, I hope, will fhew, that Medicine, as far as it is a fcience, is adiftindt inde- pendent fcience, founded, not upon the general properties of folid or fluid matter, like me- chanics or hydraulics ; nor upon

the

TION.

OF THE NERVES. 19

the mutual affinities of different Introdu* elements, like chemiftry ; but upon the peculiar properties of animated bodies ; properties fubtle, refined and fpiritual, like thofe of magnetic and electrical fubftances, the phenomena of which no one now attempts to explain upon the common laws of matter and motion.

C 2 CHAP,

20 ON THE QUALITIES

CHAP. 1.

Of the Circulation of the Bloody as it is influenced by the Nerves.

CHAP. npHAT the circulation of

the blood is, in a certain

fenfe, quickened or retarded by the Nerves, I fuppofe, will not be difputed. For the heart being mufcular, and its power of courfe depending upon the Nerves, it mud contract with greater or lefs force, in propor- tion as the power communicated by its proper Nerves is greater or lefs. But whether the Nerves have any power of leffening or increafing the velocity of the

blood

OF THE NERVES. 21

blood after it leaves the heart, CHAP, is a matter of greater doubt. ! — .

To determine this queftion, it will be neceffary to confider fome phenomena, which evi- dently depend upon the Nerves, becaufe they depend upon in- tellectual caufes, that is, upon the vivid impreflions which certain ideas make in the mind. The fadls I mean are the erection of the penis from lafcivious ideas, and the accumulation of blood in the face from anger or fhame.

Now that thefe phenomena

3re both produced by fome caufe

C 3 diftindt

22 ON THE QUALITIES

CHAP, diftinft from the force of the •"" heart, will appear, firft from

their locality, and fecondly from

their duration.

From their locality ; becaufe the blood being thrown to every part of the body at once by the force of the heart, whatever phenomenon is produced by that force, cannot be confined to a fingle part, but muft of neceffity affe& the whole body.

From their duration; becaufe whatever effedt arifes from the vigorous contra&ion of the heart, muft be almoft inftantly deftroyed by the arteries con- tracting

OF THE NERVES. 23

trading themfelves in proportion CHAP, to their antecedent diftenlion. ! —

It feems alfo pretty evident, that they muft arife from a con- ftri&ion of the veins, becaufe the fucceflive dilatation and contraftion of the arteries, how- ever fmart, would certainly not caufe a permanent congestion of the blood in the parts here men- tioned ; and a contra&ion fo vi- gorous as to overcome the force of the heart, would prevent the ingrefs and accumulation of it, and confequently the feveral phenomena here alluded to. It remains then, that they muft be produced by a conftri&ion of C 4 the

24 ON THE QUALITIES

CHAP, the veins, which indeed is the I,

— caufe commonly affigned for the

erection of the penis, and which being admitted to exift in one part, may with lefs fcruple be transferred to another.

Here a queftion naturally arifes — By what power, and what mechanifm this conftric- tion is produced ? It muft be owned, that genuine mufcular fibres furrounding the veins have not yet been demonftrated : notr withftanding which, it feems certain that their coats are con- tinually upon the ftretch, and have a perpetual conatus to con- trad upon the fluid that paffe$

thro

OF THE NERVES. 25

thro' them. It is from this latent CHAP.

contraction, that Baron Haller 1. —

explains fome phenomena, ob- ferved firft by himfelf, to wit, the flowing of the blood, con^ trary to gravity, and contrary to the laws of the circulation, towards any aperture of a neigh- bouring vein. This power does not, ftridtly fpeaking, depend upon life, becaufe it is not ter- minated with it, and fliould therefore, fays he, be referred to the native elafticity * of the ftretched cellular fibre. Still however it appears to be de- rived from life, becaufe he ex-

Elem. Phyfiol. Vol. II. p. 214.

prefsly

26 ON THE QUALITIES

CHAP, prefsly limits it to animals living

■ or newly dead. This being the

cafe, would it be unreasonable to fuppofe, that when the Nerves, the feat and origin of vitality, are powerfully ftimulated, they may and muft increafe every power derived from and depen- dent upon them ?

To thofe who admit, that the ereftion of the penis is caufed by a conftridtion of the veins, the following fa6t will be a de- cifive proof that the Nerves have a power of caufing fuch a con- ftri&ion. A labouring man in Devonfhire, who was taking in the corn in harveft-time, hap- pened

OF THE NERVES. 27

pened to flip from the top of the CHAP, heap, and fell to the barn floor ■ " ■ dire&ly upon his breech. Whe- ther the vertebrae of the loins were diilocated by the fall, could not be determined, though the furgeon who was called, a very fkilful and experienced practiti- oner, plainly perceived fome ine- quality in them. The fpinal marrow, however, appeared to be confiderably injured, for his legs and thighs became paraly- tic, at the fame time that he had a conftant eredtion of the penis, which never left him till death. Is it not evident in this cafe, that, as the paralyfis arofe from a violent fhock of one por- tion

I.

toff —

28 ON THE QUALITIES

CHAP, tion of Nerves, the ere&ion was caufed by a flighter fhock of another portion, fufficient to ir- ritate only, but not fufficient to j-ender them torpid ?

That the conftri&ion of the veins is influenced by the Nerves may be collected alfo from the palenefs induced by fear. Such a palenefs, it is evident, muft arife from fome change in the blood veiTels, and being not a momentary phenomenon can hardly be imputed to the con- traction of the heart and arteries being fufpended, which, except in cafes of abfolute fainting, could only be momentary. It

mufl;

OF THE NERVES. 29

muft therefore be referred to a CHAP.

diminution of the ordinary tonic 1— -

conftridion of the veins, by which means they tranfmit the blood more readily, fo that lefs of it paffes into the fmall cutane- ous veflels. In confirmation of which it may be obferved, that weaknefs is produced at the fame time, and by the fame caufes with palenefs. For it is well known, that ftrong people un- der the influence of fear become inftantaneoufly weak, and even lofe the power of fupporting themfelves, when at the top of a high building, or edge of a precipice, the view of which diforders them. Anger, on the

other

jo ON THE QUALITIES

CHAP, other hand, which reddens the

I. . — face, gives general ftrength to

the body, which under that in- fluence ufes the greateft efforts, and gives the fevereft blows.

We may therefore venture to confider the following pofltion as probable, to wit, that there is a certain tonic influence ex- erted by the Nerves upon the venous fyftem, by which it is kept in a due flate of conftric- tion ; that an increafe of this force increafes the conftridtion, and obftru&s the circulation of the blood ; and that, on the contrary, a diminution of it di- minifhes the conftri&ion, and

fuffers

OF THE NERVES. 31

fuffers the blood to flow through CHAP,

them without refiftance : whence : —

it follows in fad:, that the force with which the parietes of the veins refift the tranfmiffion of blood, is in a ftate of fluctuation, being fometimes greater and fometimes lefs, as the Nerves on which it depends are more or lefs vigorous, and more or lefs flimulated.

It adds greatly to the proba- bility of this do&rine, that the epilepfy, which is a powerful fti- mulus of the whole Nervous Syftem, is attended alfo with fo violent a conftri&ion of the veins, that the blood cannot en- ter

p ON THE QUALITIES

CHAP, ter them; fo that upon diffedt-

. ing thofe who have died in the

fit, no blood has been any where found except in the arteries ** As this is the ftroilgeft inftance that can be given of ftimulated Nerves, fo a fainting fit is the ftrongeft inftance of their relax- ation. And here again the pale- nefs of the face fhews that the cutaneous veffels are empty, and that the blood pafTes without any refiftance through the large interior veins.

* Johnftone in London Med. Obfervw Vol. II. p. 115. Haller Phyfiol. Tom. ii. p. 282. In Hydrophobo fanguis in arteriis cmnis repertus eft> ut vena inanes ejfent.

Hence

OF THE NERVES. 33

•

Hence alfo we are furnifhed CHAP,

with the folution of a phaenome- 1—

non, of which no fatisfa&ory account has hitherto been given, to wit, the great fwelling of the body that fometimes comes on after eating mufcles. It is at leaft poffible that the Nerves of the ftomach may be fo pow- erfully ftimulated by the juices of that animal, as to commu- nicate the irritation to every part of the fyftem, which, according to the doftrine here laid down, would, in every part, produce a conftri&ion of the veins ; the confequence of which muft be an univerfal fwelling. I am not now enquiring to what cir- D cum-

34 ON THE QUALITIES

CHAP, cumftance the innocence of

! mufcles at one time, and their

hurtfulnefs at another, is owing. Yet I cannot pafs by fo remark- able a phenomenon without of- fering my conje&ure, that this difference arifes partly from the different fenfibility of different ftomachs, and partly alfo, from the more or lefs vigorous ftate of the fifli ; the juices of that, which is in the fulleft health, be- ing probably the moft rich and ftimulating, and therefore the moft noxious.

I fubmit it alfo to the learned, whether the great fwelling of the veins, during the ufe of the

Pedi-

OF THE NERVES. 35

Pediluvium* has not been er- CHAP.

I. roneoufly attributed to their re- ! —

taxation, and whether it might not be better accounted for by their conftri&ion from the fti- mulus of heat. According to my idea at leaft, a general re- laxation of the veins would tend to make the fuperficial veins difappear and almoft collapfe, inftead of filling and rendering them turgid. On which ac- count too it feems .not unlikely, that the remarkable deprefiion of the mufcles of the face, commonly called the fades Hippocraticay and which is in all cafes a certain forerunner of death, may be wholly owing to D 2 the

36 ON THE QUALITIES

CHAP, the conftri&ion of the veins

J being loft, in confequence of a

total exhauftion of the vital energy of the Nerves.

Where a particular Nerve is ftimulated, there is generally, if not always, a proportionable conftridtion of the adjoining venulce. The fimpleft inftance of this is the tumour and in- flammation occaiioned by a thorn flicking in any fenfible part. Did the veins in thefe cafes tranfmit the blood as readily and freely as ufual, there could be no fuch tumour and congeftion ; which there evi- dently is, when there is no

fever,

I.

OF THE NERVES. 37

fever, and when of courfe the CHAP, pulfations of the heart are not increafed in number. For the increafed force of the arteries, acting only alternately with the fyftole of the heart, would tend to accelerate the motion of the blood, inftead of impeding it *.

It would be unneceflary, I fuppofe, to enter into a formal proof of the Arterial fyftem

■ ———«■—■——■— — — — »

* Ut irritabilis natura ad inflammatas partes fanguinem congreget, nondum credo explicatum fuirTe, et facilius forte a vena- rum vehentium conftrictione aliqua expli- cari crediderim, etiam penis exemplo, quam ab arteriolarum minimarum quacunque vi contraclili. Haller. %Phyfiol. Vol. II. p. 214.

D 3 being

38 ON THE QUALITIES

CHAP, being fubjed to conftri&ion from

. ! — the influence of the Nerves, the

Arteries being all encircled with a mufcular coat, and every thing mufcular being actuated by- Nerves. I fhall only therefore obferve, that this conftri&ion feems to account tolerably well for the throb or increafed pul- fation of the Arteries, leading to any ftimulated part, a phe- nomenon that has given trouble to fome phyflologifts. By in- creafed pulfation, I do not mean a quicker pulfe, but a greater difference between the fyftole and diaftole of the artery, or a perceptible difference where there was none before, as in

the

OF THE NERVES. 39

the cafe of the fmaller arteries, CHAP, which in a natural ftate have ___ no pulfe. Now, as irritation is never confined to a mere ma- thematical point, but extends itfelf to all the adjoining parts, the effed: of it will always be to ftimulate the mufcular coats of the adjoining arteries, which muft of courfe render the dia- meter of thofe arteries in fyf- tole much more contracted than ufual, and their diameter in di- aftole continuing by fuppofition as before, it follows, that the difference between the diameter in fyftole and that in diaftole will be greater ; in other words, the pulfe will be increafed, or a D 4 new

40 ON THE QUALITIES

CHAP, new one created. And if the

— - mufcular coats of the arteries

are fore and tender, that pulfe will be painful as well as percep- tible ; which is precifely what conftitutes the throb, and the very phenomenon of which we are attempting the folution.

If then different affe&ions of the Nerves increafe or diminifh the power of the heart itfelf, and alfo increafe and diminifh the refiftance made to that power by the arteries and veins : there is no occafion to look out for any other caufe of the irregula- rities that happen in the circus lation.

CHAP,

OF THE NERVES. 41

CHAP. II.

Of Animal Heat.

rT^ H E heat of the human CHAP.

body was anciently fup- !

pofed to be fomething inherent in it, and hence went under the name of Calidum innatum. The moderns, who have rejecled this phrafe as unmeaning, and the dodrine itfelf as unphilofophi- cal, have however been very un- fuccefsful in their attempts to account for the phenomenon. The two prevailing opinions are, one, that it arifes from an inteftine fermentation of the

animal

42 ON THE QUALITIES

CHAP, animal juices : and the other.

II .

, ' that it is produced by the attri- tion of thofe juices with the fo- lid tubes, through which they circulate. A few fhort obfer- vations will fhew how little both thefe opinions correfpond with the real fad.

With refpedt to inteftine fer- mentation, this is generally un- derftood to be that motion, into which the elementary particles of any fluid are thrown by their mutual attraftions and repul- fions. Now if there be in ani- mal blood fuch attractions and repulfions as conftitute fermen- tation, why do we perceive no

fer-

OF THE NERVES. 43

fermentation, when it is drawn CHAP, out of the body ; the caufe of ■

thefe attra&ions and repulfions being by fuppofltion fomething reflding in the fluid itfelf ? To fay that the heat of the body contributes to it, is to make the folid containing part, and not the pervading fluid, the origi- nal fource of heat.

Secondly, That the heat does not arife from the attrition of the folid tubes with the circu- lating fluids, is evident, for the following reafons :

I. Though the preflure of folids moving by one another

fre-

44 ON THE QUALITIES

»

CHAP, frequently produces attrition,

! heat, or even fire, yet we do not

find by experience that the pref- fure of fluids againft folids pro- duces any heat at all, even the attrition they fuffer being very fmall. For the attrition being between the folid and that la- mina of the fluid which is con- tiguous to it, fliould it become greater than the tenacity with which the particles of the fluid adhere to one another, the mafs of fluid that lies within would flip away from that con-r tiguous lamina. Now the co- haefive power of all fluids being exceedingly fmall, fince other- wife they would not be fluid, it

follows

II.

OF THE NERVES. 45

follows that their attrition muft CHAP, be fo too. We fee in fa6t no marks of attrition, much lefs of heat, produced by the paf- fage of water through leaden pipes, even when it falls from and rifes to a considerable height. And we may particu- larly obferve, that water, loaded with ftony particles, does not, in paffing through leaden pipes, abrade the inner furface of thofe pipes, but, on the contrary, de- pofits the ftone in fuch quantity, as frequently to choak them up with incruftations.

There has indeed been one inftance produced, of heat gene- rated

46 ON THE QUALITIES

CHAP, rated by the attrition of a fluid

II .

* — with a folid. It is found, in

making butter with a churn, that the cream grows hot, at the time that it pafles into butter. Upon which I will only remark, that it acquires no heat till the time that it lofes its fluidity, by • the feparation of the aqueous fluid from the tenacious oil. This fa& therefore, upon which much ftrefs has been laid in the prefent queftion, is ftill perfectly conformable to our pofition, That all heat generated by the attrition of fluids, muft be pro- portionable to their tenacity. It follows, that blood in a ftate of fluidity, having but little

attri-

OF THE NERVES. 47

attrition, could from that at- CHAP.

trition derive little or no heat, 1 — .

whereas in fad its heat fome- times exceeds that of the atmof- phere by at leaft thirty degrees. Nay, fo far is the heat from being proportionable to the te- nacity, that, in putrid fevers, where the blood is in a diffolved ftate, the heat is often intenfe.

II. The warmth of the blood in different animals is not in proportion to the velocity of the circulation ; many fifhes and amphibious animals, whofe blood is cold, having a greater number of pulfes, and more ro- buft circulating veflels, than

even

48 ON THE QUALITIES

CHAP, even horfes, in whom it is

II. warm.

IIL The heat of the body appears in feveral inftances to be increafed, at the time, and in the very place where the circu- lation of the blood is obftrud:- ed. Thus it is generally al- lowed, that the ere&ion of the penis is owing to the ftri&ure of the veins preventing the egrefs of the blood. Yet at what time is its heat fo great ? Blufhing is alfo attended with a remarkable increafe of heat : yet there can be no doubt but that the circu- lation of the blood is then re- tarded ; particularly if the fa&

quoted

OF THE NERVES. 49

quoted by Haller be authentic, CHAP, that a perfon blufhing violently had a vein burft in the forehead by the fudden congeftion of blood *i

IV. If the heat of the human, body depended upon the attri- tion of the fluids in circulation, circulation and heat would be infeparable ; that is, it would be impoflible for the fluids to circulate without the body being hot, or for the body to be hot without the fluids cir- culating. Now that the cafes here fuppofed are neither of

* Haller. Phyfiol. Vol. I. p. 130.

E them

^Hfe' ON/THE QUALITIES

C H A*P. $&#i impoflible, appears from SlSi-^tlie teftimony of two very cele- brated practitioners. Thus Sy- denham informs us, that in hy- fteric paroxyfms, it is not un- ufual for the body to become near- ly as cold as a dead corpfe, pulfu nihilominus reEle fe habente *. De Haen alfo gives an inftance of the fame phenomenon, which he had carefully examined and attended to. Manum ego, qui- que circumjlant omnesy penitus frigidam et extenuatam percipi- mus ; fed fi?nul deprehenditnus 7"obufium arterice in carpo pulfumy illi> qui in altero brachio cequa-

* P, 359, Edit. III.

km ;

OF THE NERVES. 51

lem ; qirin et arteriarum juxta CHAP; digitos emaciatos fitarum pulfatio- it

nem manifeftam •. On the con- trary, that heat may exift with- out a pulfe, we learn from an- other cafe related by the fame learned author : in altera hifto- rid fine fanguinis arteriofi percep- tibtlt transfluxu pars poji fupera- turn frtgus molejle calet -f\ This however is greatly exceeded by another, of which he gives the particulars in a following part of his work %. We are there told that a man whofe heat, at

* Ratio Medend. p. 198. Ed, Lugd. 1761. •f Ibid. p. 201.

t Ibid' P- 347-

E % the

52 ON THE QUALITIES .

CHAP, the moment when he expired,

(animam efflabat) and for more

than feven minutes afterwards, was only 97, grew then hotter, fo as to raife the thermome- ter to 101 for the fpace of 84 minutes : and did not link it lower than 85, till more than 15 hours after his death, licet aer domejlicus eo tempore vix 60. o-radum notaret.

If then animal heat does not arife either from any inteftinp motion of the fluids, or from their attrition with the folid tubes, it feems clearly to follow that it refldes in the folids; and if fo, that it is not generated by

the

OF THE NERVES. 53

the folids, but inherent in the CHAP.

body, which brings us back to ! —

the old do&rine of the calidum innatum.

If we enquire further in what fpecies or clafs of the folids it refides ; whether in the bones, the tendons, the vifcera, the nerves, and fo on : the queftion at firft fight feems difficult of fo- lution, fince, being all, as far as we can difcover, equally- warm, when united with the body, and in their proper fta- tion, and all lofing that heat when feparated from it, it fhould feem that no one part received heat from another, but all en- E 3 joyed

54 ON THE QUALITIES

CHAP, joyed it by original right, and i iJ — in equal proportion.

The matter however is more capable of inveftigation than it appears to be. For if there be any part, which being wounded, compreffed, or otherwife dif- turbed, fhall fometimes remark- ably increafe the heat, and at other times as remarkably dimi- nifK it, we may with great pro- bability infer, that heat refides in that part on which the gra- dations of it depend, and that ordinary animal heat is an affec- tion infeparably conne&ed with the ordinary ftate of it.

Such

OF THE NERVES. 55

Such a part I conceive to be C H A P.

the Nerves. One principal caufe 1 — e

of increafed heat in the body is pain, and this by an infinity of experiments appears to be an af- fedtion only of the Nerves. Thus when a thorn is fixed in the flefh, it produces a great addi- tion of heat, which muft be at- tributed not to any chemical ef~ fervefcence of juices, the thorn producing none ; nor to the at- trition of the thorn, which is unmoved, but merely to the acute fenfation of the Nerve. Many other fuch inftance^ might be enumerated, where the body neither is nor can be injured otherwife than by the irritation E 4 of

II

56 ON THE QUALITIES

CHAP, of the Nerve, which yet are con-, ftantly attended by a confide- rable degree of heat,

But perhaps the moft unex.- ceptionable inftance of heat be- ing increafed by an affedtion of the Nerves is when the caufe of the affe&ion is wholly intellect- ual. Who can imagine that grief, joy, fhame, anger, in- tenfe fludy, can dire&ly affed the bones, cartilages, tendons, epi- dermis, or the gluten, ferum, and red part of the blood ? Yet all thefe produce an eminent de- gree of heat. And that their firft and immediate adtion is up- on the brain cannot poflihly be

doubted.

OF THE NERVES. 57

doubted, as they have their ori-* c PI A P, gin in certain complex notions . and reflexions, without which the mere tangible, vifible and audible object produces at bell: but a tranfitory perception.

There is great difficulty upon any other fuppofition to account for a phenomenon frequently obferved, to wit, the produdlion . of heat by its contrary, cold. A healthy man, who walks abroad in a fharp eafterly wind, will then or foon after find a re- markable glow on his cheeks. A perfon who dabbles in fnow, or handles ice, finds the cold fucceeded inftantly by heat.

The

58 ON THE QUALITIES

The cold bath has the fame ef- fed; upon the whole furface of the body. Nothing is fo ftrik- ing an inftance, as when a blif- ter is taken off, and the unpro- tected cutis expofed in cold wea- ther. The fenfation of heat is then intenfe, and equal almoft to that of a red hot iron. How can we fuppofe this heat to arife but in confequence of a general , law, that all irritations of a Nerve, not overcoming the power of that Nerve, produce heat ?

As in thefe inftances cold pro- duces heat, fo on the contrary- it is found that fubftances pro- ducing

OF THE NERVES. 59

(ducing heat, or even adlual heat CHAP.

will not increafe, but even abate ' —

morbid heat. Thus a part high- ly inflamed with exceflive pain and heat, is frequently afluaged and cooled by a hot fomentation compofed of a decodtion of warm aromatic herbs. Thus camphorated ointments, hot in themfelves, allay the heat of a blifter : and camphor, taken in- ternally in certain forts of fevers, mitigates and abates the febrile heat.

From thefe facls it is clear that heat and cold fometimes produce in the animated body the very reverfe of thofe effedts

which

60 ON THE QUALITIES

CHAP, which they invariably have upon ' inanimate fubftances. There muft therefore be fomething in every animated body, through the medium of which external fubftances produce heat and cold, not according to their own na- tures, but according as they af- fect that medium. And what can this be but the part, which difcriminates animated bodies from all others, the fentient part of the folids, or, in one word, the Nerves ?

CHAP,

OF THE NERVES. 61

CHAP. III.

If/je Animal Fluids corrupted by Irritations of the Nerves.

T

HAT the Nerves, when C HA P.

irritated, have a power of corrupting the animal fluids, is decifively proved by the experi- ments of Baron Haller, who found that by tying the Nerve of the eighth pair near the ca- rotid, the matters contained in the ftomach of the animal, which was a rabbit, fell imme- diately into a ftate of perfed pu- trefaction. Experiment 182.

He

62 ON THE QUALITIES

CHAP. He found, alfo, that upon ty~

Hi , 1_ ing the Nerves of the fore leg in

a cat, there came on a violent

fuppuration all round, the ftench

of which was almoft infupport-

able. Experiment 183.

He tied the eighth pair of Nerves in another rabbit, the confequence of which was that the matter contained in its fto- mach degenerated into excre- ment.

The fame thing may be col- lected from many fa£ts that ac- cidentally offer themfelves.

Thus a fra&ure of the fkull,

where

OF THE NERVES. 63

where we know the injury to be CHAP

confined to the brain, produces 1_

a vomiting of bilious offenfive matter. The ftimulus of gravel in the ureters, or of a ftrangu- lated rupture, is well known to have much the fame effedt.

That the action of found is folely upon the auditory Nerve will, I prefume, be admitted. Yet Hildanus was eye-witnefs to a cafe, where a man, from hav- ing a mufket difcharged clofe to his ear, was thrown into a vomiting of crude indigefted food, which feems clearly to imply a change in the juices. And the German Ephemerides

for

64 ON THE QUALITIES

CHAP, for the year 1696 mention one$ ' upon whom inftrumental mufic of any fort produced conftantly the fame effed.

The following fa& is curious. A little boy, the fon of a mer- chant, who had received into his lungs the cutting of a pen, fhaped like the prongs of a pitch fork, had more than a year af- terward a feverifh. heat, attend- ed conftantly with fizy bloody which never left him till he luckily coughed up the irritating fubftance again : upon which he immediately grew well.

Again, the human body can- not

OF THE NERVES. 65 ;

hot emit putrid effluvia unlefs CHAP

III its juices firft undergo fome L_

confiderable change. Now there

is an inftance recorded in Hil-

danus, Cent. II. 26. of a man

who, upon receiving a violent

blow on the back part of his

neck, immediately emitted from

his body a moft abominable

foetid fmell ; although previ-

oufly to the blow he was, as

the learned author takes care to

inform us, optimo corporis habi-

tu prcedituso

It will, I fuppofe, be allow- ed that whatever effe6t is pro- duced by anger, fear, or any paflion, is produced through F the

66 ON THE QUALITIES

CHAP, the medium of the Nerves. As

III r • • , — to fear, it is notorious even to

a proverb, how much it loofens the belly, probably by render- ing the faeces more fluid, fharp, and irritating. Anger, on the other hand, feems to give a poifonous quality to the juices*: the bite of an animal in that ftate being very difficult to be healed, and often attended with fatal confequences +. Even a flight degree of paffion in nurfes, whether it be anger, fear, or furprife, is fufficient to render

* Hildanus, Cent. V. 75. J See Hildanus, Cent, I. 2$.

the

OF THE NERVES. 67

the milk bad-tafted, and im- CHAP.

III. proper for the child *. ' —

Among the many curious phenomena that attend the re- paration of blood after blood- letting, one of the moft re- markable is, that frequently the firft or fecond cup is covered with an inflammatory cruft, which is not found in any of the fubfequent. This had com- monly been attributed to the greater velocity, with which the firft ftream iffues from the

* Ephemerid. Nat. Cur. Decad. II. Vol. IX. p. 70. III. Vol. IX. and X. p. 298. £entur. Vol. I. andJI. p. 176.

F 2 \dn,

68 ON THE QUALITIES

CHAP. vein. But the late ingenious III.

■ — Mr. Hewfon obferved this dif- ference, even when there was no difference in the velocity, nor indeed, as far as he could perceive, in any other circum- ftance. He is therefore of opi- nion, that the properties of the blood itfelf are changed during the evacuation. Such a change evidently requires the agency of fome third power. For to fup- pofe the blood undergoes fo fudden a change merely by the quantity being leflened, would hardly be lefs extraordinary than to imagine, that pouring a glafs of brandy out of a bottle, would turn the reft into cyder. But

if

OF THE NERVES. 69

if we admit, what from fo many c H A P. other phenomena feems proba- '

ble, that the ftate of the fluids depends upon the ftate of the Nerves, it then becomes eafy to conceive that the febrile ftimu- lus may be fo much abated by drawing off the firft or fecond cup, that a third cup, though drawn at the fame time, may approach nearer to the ftate and appearances of healthy blood.

F 3 CHAP.

CHAP. IV.

70 ON THE QUALITIES

CHAP. IV.

Of the Dropfy.

'( T will, perhaps, be thought extravagant even to fuggeft, that the dropfy arifes from a diforder of the Nerves, and not rather from a corruption of the fluids, or elfe a rupture of the lymphatics. Yet, if it be con- fidered that the dropfy in many cafes is not an original diforder, but the confequence of fome other, fuch as fevers, or ob- ftru&ions of the vifcera, by which I mean hardnefs attended with more or lefs pain, and if it

can

OF THE NERVES. 71

can be made appear that the CHAP.

original diforder was an affeo '■ — -

tion of the Nerves, we may fafely infer that the dropfy is fo too.

Now if the Nerves be the fole feat of pain, if they be the caufe of increafed animal heat, if it be probable that the cor- ruption of the fluids is produced by fome powerful irritation; un- der one or other of thefe claffes will be comprehended all fevers, colics, dyfenteries, obftrudtions of the vifcera, and in fhort al- moft every diforder fubjed: to terminate in the dropfy,

F4 The

jz ON THE QUALITIES

CHAP. The production of a dropfy

- — by long-continued irritation,

may be illustrated by the ceder matous fwellings to which gouty people are fubjed. Here it is evident the Nerves are the ori- ginal fufferers : they are tor- tured during the continuance pf the fit with frequent returns of pain, the ceffation of which is always followed by great weaknefs. It is to this weak- nefs,arifing from long-continued or frequent irritation, that I at- tribute the produdion of the dropfy in the cafes abovemenr tioned.

It is ftill more clear that

dropfies

OF THE NERVES,

73

dropfies arifing from a habit of CHAP.

drunkennefs have their origin I —

in fome injury of the Nerves. For upon what other part is it that the deftru&ive power of fpirituous liquors ads? They do not corrode the folids, becaufe nothing preferves the texture of the flefh in dead animals more effe&ually than the ftrongeft fpirits. They do not feparate the conftituent parts of the fluids, but unite and form an homogeneous mixture with the blood, the milk, the urine, and the bile. But they powerfully ftimulate all fenfible parts, give prodigious pain in all excoria- tions, and even to the tongue F 5 and:

74 ON THE QUALITIES

CHAP, and palate itfelf, when grown * tender by difeafe. Their next exertion is upon the brain, or grand origin of the Nerves. It is unneceffary to mention, as every one knows, how they per- vert the eye-fight, enliven the imagination, and inflame the paffions ; how in particular they difturb that power, which regulates and conduces the ac^ tion of the mufcles, and there- by deftroy the equilibrium of the body.

Thefe effe&s are ufually fuc- ceeded by ileep, and that by •weaknefs and languor, which after a long courfe of drunken-

nefs

OF THE NERVES. 75

nefs become fo intolerable, that CHAP.

the drunkard has no way of ' —

paffing a few comfortable mo- ments, but by repeating the ufe of the fame ftimulus. It is true this proves a temporary cure, fo that in fome cafes a tremor of the hands, produced by fre- quent intoxication, has been fuddenly carried off by a large dofe of the intoxicating liquor. However, as every debauch takes fomething from the ftrength of the Nerves^ it follows of courfe that their whole ftrength muft in time be exhaufted. And then it is that all the cavities of the body are more or lefs de- luged

76 ON THE QUALITIES

CHAP, luged and diftended with wa-

IV. & ter.

Few fimples have a more clear and evident a&ion upon the Nerves than cicuta, as every- one may judge from the giddi- nefs it produces. It has been my fortune to fee an inftance of the dropfy brought on by an overdofe of it. One Holloway, an invalid, had, by miftake, eat a large quantity of raw hemlock inftead of fallad. He found at firft the ufual confequences, i. e. great giddinefs and pain of the eyes. As foon as thefe left him, his belly and legs fwelled,

and

OF THE NERVES. <?7

and he had all the fymptoms of CHAP.

afcites and anafarca. He was — —

in a fhort time cured, princi- pally by the ufe of Dovar's pow- der ; with this remarkable cir- cumftance, that fopn after tak- ing it he felt a tingling and pricking in the parts where the f

water was collected.

If after enumerating many of the caufes of dropfies, we pro- ceed now to confider the fymp- toms, we fhall here alfo find ftrong indications of the Nerves being principally affe&ed. It is upon this fuppofition only we can account even tolerably for the frequent metaftafes of it

from

7$ ON THE QUALITIES CHAP, from one part to the other

*

IV

for inftance, from the breaft to the thighs. If we fuppofe the dropfy to be an extravafation from ruptured lymphatics, how happens it that this extravafa- tion appears in two fuch diftant parts alternately ? Does the healing of one fet of lymphatics neceffarily induce the rupture of another ? Suppofing the quan- tity of lymph to be a little re- dundant, has Nature no way to difpofe of this redundancy, with- out immediately burfting the veffels that contain it ? I fay all

* Adta Phyfico Med. Nat. Curios. Vol. IV. p. 405. Lind on the Scurvy, p. 530.

this

OF THE NERVES. 79

this upon a fuppofition, which CHAP, Anatomy does not warrant*, '

that the lymphatics are really ruptured in dropfies. Admit- ting it, however, to be fo, the idea is ftill clogged with 'many difficulties, and it is a much more natural fuppofition, that a difeafe, which fhifts its place fo rapidly, muft depend princi- pally, if not entirely, upon the

Nerves.

«

That the dropfy is connected with nervous affections, either as caufe or effed, will admit of

* For this affertion I have the authority of Dr. Hunter.

BO

8o ON THE QUALITIES

CHAP, no doubt. In an advanced

* ' — ftate it occasions great forenefs

in the integuments both of the legs and abdomen, befides be- ing frequently attended with a deep-feated pain of the limbs. It produces alfo a fever with its ufual concomitants, thirft and paucity of urine. Thefe fymp- toms, according to the do&rine here laid down, are clearly de^- ducible from a difeafed ftate of the Nerves. Or, if the reader fhould demur to this, he muft, I think, allow that blindnefs and epilepfy are affe&ions of the nervous clafs. Now that both thefe are occafionally con- nected with the dropfy, we have

fuffi-

OF THE NERVES. 81

fufficient proof. In the AEla CHAP. Phyjico-Medica of the Natures IV- Curiofi) there are two inftances of a dropfy combined with an epilepfy; andHildanus mentions a very remarkable cafe of a man only thirty years of age, ex- tremely robuft and fanguine, \ .ho fell into a leucophlegmatia, which after fome time brought on a total obftruclion of the optic Nerve *.

Buttheftrongeft poffible proof of the dropfy originating from the Nerves, is that it both ge- nerates nervous diforders, and is

• Cent. I. p. 50.

G gene-

S2 ON THE QUALITIES

CHAP, generated by them, the one

. . frequently ceaiing, as the other

begins. That it generates ner- vous diforders, was certainly obferved more than once by Hippocrates, who has laid it down as a rule of prognoftic, that an epilepfy, coming on af- ter a dropfy, is mortal * ; whick rule, as well as the matter of fa£t, Duretus, his commentator, from his own experience con- firms. Of the dropfy fucceeded by mania, Morgagni, a writer of undoubted accuracy and credit, has given a remarkable in-

Koqockcci Tlcoyvoi)(T»

ftance,

IV.

OF THE NERVES. 83

ftance *, the event of which CHAP, however was different, the pa- tient having in a fhort time af- ter recovered both his under- ftanding and health f . In my own practice, I have met with one or two inftances, where, up- on the retroceffion of the drop- fical fwelling, the patient has fallen into a delirium, termi- nated a few days after by death. In the laft mentioned cafes it is plain that the diforder exifted independent of the water, and therefore was not folely a difor-

* De Cauf. et Sedibus. Vol. I. p. 57. f See alfo Adta Phyfico-Medica Nat. Curiof. Vol. IV. p. 384.

' G 2 der

$4 ON THE QUALITIES

c ^ p- der of the fluids. And the final

feat of it being the brain, is it

unnatural to imagine the origi- nal feat of it to have been the extremities of the Nerves, which may be confidered as fo many fhoots or furculi ramifying from the brain ?

There is, on the contrary, fufficient if not equal evidence that nervous diforders are con- vertible into the dropfy. It is one of the aphorifms of Hip- pocrates, that a dropfy fuperven- ing is a good fign in the mania*:

* Sea VII. Aphorifm. 5.

which

OF THE NERVES. 85 f

which fhews clearly that he was CHAP.

well acquainted with the fa£t. L_

Gullmannus, in the A6fc of the" Naturce Curiofi *, relates the cafe of a child troubled with convulsion fits, upon the ceafing of which the child fell altnoft immediately into a general ana- farca. I was myfelf once con- fulted by a patient afflifted firft with a giddinefs of the head, and, upon the going off of this, with dropfical fwellings of the legs. In thefe cafes the dropfy was undoubtedly a confequence

* Ada Phyfico-Medica. Vol. I. p. 4.

G 3 of

86 ON THE QUALITIES CHAP, of the unfound condition of the

IV.

— Nerves ; and this being allowed,

is there not a clear poffibility of its being fo, in every other in- ftance ?

Among the many methods recommended for the cure of the dropfy, there are fome which can hardly be fuppofed to operate otherwife than upon the Nerves. Thus all the old writers, Sennertus, Riverius, and others, fpeak with confidence of the efficacy of cataplafms, plaifters and unguents, inthisdif- order. Cataplafms for the drop- fy are ftill ufed in Spain ; as ap- pears

OF THE NERVES. 87

pears by the Spanifli naval phar- CHAP.

macopaeia *. And with refped: ! —

to unguents and liniments, Dr. Oliver of Bath has related a cafe of the afcites, which, after refilling many remedies, was cured by rubbing the abdomen ^^r £f ^ with fweet oil ; a method which"^ j ^ <^ has been fince adopted by Dr. ^-i^^t* + Lind. Opium alfo has been )f*\^ *lQ found equally efficacious ; yet^^^^w- how is the action of thefe reme- dies to be accounted for, but by fuppofing the dropfy to have originated in an unhealthy ftate of the Nerves ?

* See alfo Harris Obferv. 3. Libri II.

G 4 Still

IV

88 ON THE QUALITIES

CHAP. Still perhaps we may find it - difficult to conquer the prepof- feffion, that the water colleded in the cavities of the body is the caufe of all the other morbid fymptoms. And yet, though the cafe is fimilar *, we never fuppofe the matter generated in an abfcefs, to be the caufe of that abfcefs. We know indeed it is not : we can perhaps trace the abfcefs itfelf to fome contu-

* Montanus, a phyfician of the 16th cen- tury, feems to have had the fame idea. His words are thefe ; Eft ergo hydrops abfcejjus quidam^ qui in qualibet parte corporis accidere poteft, pracipue tamen in abdomine. Confil. 263. Ed. Bafil. 1538. quoted bySchenkius, Vol. I. p. 803.

fion

OF THE NERVES. 89

fion or pun&ure, or to the lodg- CHAP.

ment of fome extraneous body : —

in the flefh. Even when this is not the cafe, we can obferve aL- moft univerfally a pain, tenfion and throbbing in the part, an- tecedent to the fuppuration. Now fetting afide our prejudi- ces, what is the real difference between the two cafes ? And why may not a morbid affection of the Nerves produce a collec- tion of ferum, as we know by experience it does of pus ?

CHAP.

9o ON THE QUALITIES

CHAP. V.

All Diforders probably Diforders of the Nerves \

CHAP. \ F the poiltions here laid down „_ — are probable (for a greater de-

gree of evidence can hardly bq expelled) if I fay it be probable that the Nerves caufe great irre- gularities in the circulation, that they increafe animal heat, that they alter the nature and pro- perties of animal fluids, and laftly, that their unhealthinefs produces the dropfy, it feems no great ftride in reafoning to infer that all diforders of the body are

pro-

OF THE NERVES. 9j

produced through this medium, CHAP, and are in fad diforders of the ! —

Nerves.

This will appear ftill more likely from the following consi- derations.

I. It is now pretty generally al- lowed that obftru&ion, the caufe formerly afligned for all except nervous diforders, is wholly in- adequate to the effect. Indeed there is a pretty ftrong preemp- tion, that obftrudlion, though perhaps a fymptom of many dif- orders, is not the caufe of any : becaufe a ligature made upon a

blood

92 ON THE QUALITIES

CHAP, blood veffel, which is thegreateft — conceivable degree of obstruc- tion, produces no very bad ef- fect, much lefs any fatal difor- der *.

But neither is there any better reafon for fuppofing that all dis- orders in the body arife from a feptic nliafma ; a notion which many feem to have entertained, though no one hitherto has put it into the form of a theory.

* Morgagni Epift. Anatom. XIII. Se<5t. 30. Halleri Phyfiol. Vol. I. p. 116.

Van Swiet. in Boerh. Se<5t. 170. v. Caro- tidum.

For

OF THE NERVES. 93

For it is obvious to obferve, that CHAP.

many fubftances, which both . ! —

prevent and correal putrefaction, are very deftru&ive to the hu- man fpecies. Few things have made greater ravages in the world, than the ufe of fpirituous liquors. Yet thefe are among the moft powerful antifeptics. Salts of all kinds, which preferve the firmnefs of the dead body, have a diredt contrary effed: upon it, while living ; the few peo- ple, who have ventured to take them in large quantities, having by that continued irritation cor- rupted and attenuated their juices to fuch a degree as to fall into profufe and fatal hasmor-

rha-

94 ON THE QUALITIES

CHAP, hages *. Bark and bitters are ! — not always falutary ; and vege- table acids, vinegar in particu- lar, have fometimes brought oil incurable atrophies. Again, who has not experienced the effe&s of cold, a caufe which in its confequences has probably de- ftroyed more of the human fpe- cies than war, peftilence, and famine, though without being the objed of equal terror ? Coldj however, is a moft powerful an- tifeptic ; and this aiitifeptic qua-

* Adta Hafniens. Vol. I. p. 208. Ephe- merid. Nat. Cur. Decad. II. Vol. X. p. 214.- Dr. Lavington. Philof. Tranfaft. Vol. LV, p. 6.

lity

OF THE NERVES. 9$

lity increafes in the fame pro- CHAPS

portion that it becomes more ! — ,

and more dangerous to health and life. Laftly, it fhould not be forgotten that fixed air, which immediately reftores tainted flefh, is equally re- markable for its property of de- stroying life.

On the other hand, health is frequently preferved and restor- ed by the ufe of things which powerfully promote putrefac- tion* What, for inftance, pof- feiTes more of this quality, than a combination of heat and moif- ture ? Yet warm bathing is a very efficacious remedy in many

dif-

96 ON THE QUALITIES

CHAP, diforders, particularly rheuma- ' tifms, which the antifeptic prin- ciple, cold, fo frequently pro- duces. Tepid vapours received into the mouth, or tepid liquors drank at the beginning of a cold, have equally good effects . So that, upon the whole, if a para- doxical man fhould maintain, that antifeptics were the caufe of ficknefs, and putrefaction the cure, he might fupport his doc- trine with as fpecious reafons as any that can be alledged on the contrary fide.

Even fubftances adually pu- trid are not fo deftru&ive to ani- mal life as upon this principle

they

OF THE NERVES. 97

they ought to be. That fpecies C H A P.

of bird, called the carrion crow, L_^

is known to delight in the moft putrid food ; dogs are fre- quently obferved to eat it with fafety ; and Haller moreover relates (Elem. Phyfiol. Vol. VI. p. 190. note P.) from Oving- ton, that in Mafcata the in- habitants feed their cattle en-* tirely upon putrid fifh. The Efquimauxlndians, according to Mr. Curtis (Philof. TranfaCt. Vol. LXIV. p. 383.) ate every thing raw till of late, and pu- trefaction was deemed no ob- jection. In all but the laft of thefe cafes the putrid juices, without any correction from H fer-

$8 on The qualities

CHAP, fermenting vegetables, are how- fen — ! — ever converted into wholefome aliment, and, as far as our in- formation goes, create no dif- orders, and give no material difturbance to the animal (eco- nomy. But

II. The external caiifes, to which the greater number of diforders are univerfally, and, I think, with good reafon attri- buted, are plainly fuch whofe primary a&ion is exerted upon the Nerves,

Thus infe&ious fevers, a very numerous clafs of diforders, are moft commonly produced by

the

OF THE NERVES. 99

•

the effluvia of the fick body, CHAP,

received into the noftrils and ! —

ftomach. To the Nerves of thefe parts they are common- ly difagreeable, producing an offenfive fmell and naufea. Yet fuch is their fubtilty, that they are not the objedts of either fight or touch, and therefore by no means fufficient to give a mechanical obftruclion to the circulating fluids.

In fome cafes the contagion is propagated by the wearing of infe&ed clothes ; where it is plain the cutaneous filaments of the Nerves muft receive the iirft impreffion.

H 2 Cold

.

loo ON THE QUALITIES

CHAP. Cold is fuppofed to produce

! — its ill effe&s by flopping per-

fpiration; though ointments and plaifters, which are generally allowed to obflruft it, are worn and ufed without any ill effedt at all. It has alfo been fuppofed to coagulate the juices, though I am pofitive the fevers occa- iioned by it do not always ex- hibit fuch a coagulation. The greater probability therefore is, that the mifchief it produces is produced in the Nerves, upon which we know it has a dired and fenfible a&ion.

We know too, that wine im- mediately affe&s the Nerves,

not

OF THE NERVES. 101

not only from its ftimulating CHAP. fenfation, but alfo becaufe it in- '

vigorates more fuddenly, than the chyle produced in the in- teftines can pafs into the lac- teals, and fo on, through the thoracic duel into the blood.

III. The diforders produced by poifon appear to be caufed not by the operation of the poi- fon on the fluids and the con- veyance of it by them to the different parts of the body, but, on the contrary, by the irrita- tion and corruption of the Nerves, previoufly to the alte- rations that are produced in the fluids,

H3 As

102 ON THE QUALITIES

CHAP. As a proof of this we may

* ! — obferve, that the operation of

poifons is in fome inftances too quick, and in others too flow, to admit of our attributing the propagation of it to the circu^ lation of the fluids.

Of the former fort are the poifon of highly concentrated cherry or kernel water, which kills in an inftant ; of the fa- mous Indian arrows whofe ac- tion is equally fpeedy ; of foul corrupted air, whether produced by burning or by an accumula- tion of putrid vapour. Even the fmell of mufk, if not abfo- lutely mortal, has frequently

been

OF THE NERVES. 103

been known to produce con- CHAP, vulfions. — ~

Of the latter fort, whofe ac- tion is too flow to depend upon the circulation, may be reckon- ed, I think, the poifon of a viper, which produces indeed great pain and fwelling of the part, fuppofe the finger, almoft inftantly ; but the advance of this fwelling to the wrift, fore- arm, elbow, and arm is but gra- dual, requiring perhaps an hour or two ; whereas were the ef- fect produced on the fluids, whether blood or lymph, it muft be diffufed by thofe fluids H 4 ir\

io4 ON THE QUALITIES

CHAP, in a much fliorter time over the i ' — whole conftitution.

Secondly, the venereal poi- fon produces at firft only a to- pical evil, by which it is plain that it only affe&s the Nerves : becaufe did it a£t by vitiating the fluids of any kind, it would immediately be diffufed through the whole body by the fangui- ferous or lymphatic veflels. There would hardly be any fuch thing as a venereal com- plaint, Amply topical. The . poifon of a mad dog is in many cafes ftill more flow in its ope- ration, lying dormant in the

body,

OF THE NERVES. 105

body, as it is faid, for many CHAP.

years *. Inoculation furnifhes 1 '■ — 1

a fourth inftance equally deci- sive, the length of time between the communication of the poi- fon, and the production of the difeafe, being infinitely more than fufficient to circulate it to the remoteft parts and fineft veffels of the body.

If then the Nerves are ade- quate to the production of al- moft all morbid fymptoms ; if the other caufes affigned are plainly inadequate ; if in many

* Schenkius, Lib. VII. 54. Ephemer. Nat. Curiof. Decad. III. Vol. 6. p. 266.

cafes

106 ON THE QUALTIES

CHAP, cafes the Nerves certainly re- *, — J — ceive the firft imprefHon ; if in cafes, where the noxious caufe is certainly known, (which is only where it is poifon) the ope- ration of it clearly fhews that it principally attacks the Nerves : from all thefe circumftances there arifes a ftrong probability, that the Nerves are the fubje&s of all diforders univerfally.

CHAP,

OF THE NERVES. io7

CHAP. VI.

Of the probability that Medicines curing Diforders aSi wholly through the Nerves.

T

H E agency of medicines CHAP, received into the ftomach '

cannot but be doubtful ; whe- ther for inftance it is exerted upon the Nerves, or upon the fluids, after the medicine is by digeftion incorporated with them. Or rather, neither of thefe methods can fingly pre- vail to the exclufion of the other. Should its efficacy be pxerted only when applied to

the

jo8 ON THE QUALITIES

C H A P. Nerves, digeftion will circulate

vi. . ... J it, and bring it in contact with

a greater number. Should it

not a£t till digefted and mixed

with the fluids, it muft finally

in the courfe of the circulation

be applied to the Nerves.

Yet even in the ufe of inter- nal medicines feveral circum- ftances occur that ftrongly indi- cate their principal operation to be upon the Nerves. What elfe will account for the effeds that are every day produced by fome drugs, fuch as antimony and mercury in very fmall dofes ? A quarter of a grain of emetic tartar, of which the one half

only

OF THE NERVES. 109

only is crocus of antimony, is C H A P.

reckoned a fufficient dofe in in- ! —

flammatory fevers, and the change it makes in the patient is often aftonifhing. The lues venerea, even in a very advanced ftate, is generally cured by a- bout twelve grains of mercury fublimate, divided into dofes of a quarter of a grain each ; in which twelve grains the quan- tity of mercury can hardly be more than eight. The dofe of Dr. Ward's white drop, which is known to have performed furprifing cures, contains of mercury, the only efficacious ingredient, not fo much as the quarter part of a grain. Upon

what

no ON THE QUALITIES

CHAP, what principle can we explain — — I — the powerful adtion of fuch mi- nute dofes, unlefs we take into the account the ftimulus they may give to the fentient part of the folids ?

Again, it is often obferved that medicines, which give great re- lief to the patient when firft adminiftered, in a ithort time lofe their virtue and become wholly inert. Now if their efficacy depended upon any change made in the fluids, it ought to increafe inftead of di- minifhing by repeated exhibi- tions ; juft as every drop of acid added to an alcali brings it

nearer

OF THE NERVES. in

nearer and nearer to a neutral c H A P. ftate. But if we fuppofe that -

medicines ad: principally upon the Nerves, nothing can be more natural than that the ftimulus fhould be ftrongeft when firft applied, and gradually grow weaker, as the Nerve by habit grows more callous and infenfi- ble.

There are however many cafes in which we may pofitive- ly fay, that the cure of the dis- order arifes from fome change in the Nerves. This is evident in thofe people who are relieved by change of air, which will often cure atrophy and indigef-

tion,

ii2 ON THE QUALITIES CHAP, tion, when other means fail.

VI.

There are instances too of obfti- nate ulcers cured in this man-

ner

That a variety of diforders have been cured by mufic has been aflerted by feveral authors quoted by Haller, (Phyfiol, Vol. V. p. 305.) which I have not been able to procure. I muft therefore content myfelf with mentioning two cafes, one of a vertigo repeatedly cured by the found of a trumpet, men- tioned in the A£ta Phyfico-

A&a Hafniens. Vol. III. p. 76.

Medica,

OF THE NERVES. 113

Medica, Vol. I. p. 88. and the CHAP; other, which is very particular- ' _^

\y related in the Ephemerides, (Decad. III. Vol. IX. and X. p. 41.) of a young lady dange- rously ill of a malignant fever, who was recovered by a concert of mufic performed in her bed- chamber.

The vitriolic aether externally applied is well known to cure headachs, toothachs, and other painful complaints.

Vinegar alfo ufed externally is the moft efFe&ual difcutient known in all flight inflamma- tions and defluxions.

I Sto-

ii4 ON THE QUALITIES

CHAP. Stomachic plaiflers have great ' power in invigorating the fto- mach : cephalic plaifters are of equal fervice in vertiginous af- fections of the head : and warm plaifters of any kind fpeedily remove flatulent pains and flitches. To all this I can fpeak from my own experi- ence,

Hyfteric fits are often relieved by the penetrating effluvia of burnt feathers, matricaria, or afa foetida applied to the olfac- tory Nerve.

Trallian, in his firft book, mentions feveral cafes of the

epilepfy

OF THE NERVES. 115

epilepfy being cured by the CHAP.

fmell of rue ; and there is an _*

inftance alfo in the German Ephemerides of a hemiplegia cured by a lump of hog's dung applied to the nofe, which fo ftimulated the brain, as to rouze the patient inftantly, and re- ftore feeling to the difeafed fide, Laflly, in the fame Epheme- rides we have feveral inftances of a tertian ague being cured by the fmell of greafe, fuch as cart-wheels are greafed with. Decad. III. Vol. II. p. 120.

Moft of thefe are unqueftion- able inftances of medicines act- ing by the Nerves, and cannot I 2 but

n6 ON THE QUALITIES

CHAP, but create a fufpicion, that me- -, dicines received into the fto-

mach aft principally through

them.

Hence we may colled: how imprudent it is in fome late writers in phyfic to deny or dis- parage the efficacy of plaifters, fomentations, embrocations, and other external applications for- merly much in ufe : in fhort of almoft every thing that was not convertible into the animal flu- ids, fo as to enter tot a fub~ fkantid into the circulation. The confequence has been, in many cafes, that the patient has been deprived of effectual fuccour,

the

OF THE NERVES. n7 the phyfician has loft opportu- CHAP

nities of gaining reputation, and great advantage has been given to ignorant people, who, not knowing the theories of the learned, have therefore not been mifled by them, but have fol- lowed, what is not unfrequently a better guide, traditional ex^ perience.

I 3 CHAP.

n8 ON THE QUALITIES

VII

CHAP. VII.

The fame pojitions further fup - ported from the Operation of Mental Caufes.

C HA P. np HIS dodrine, that difor^ ders are both produced and removed through the medi- um of the Nerves, will be fome- what confirmed by {hewing, that they are capable of being produced and removed by intel- lectual caufes, whofe immediate a£tion mull be upon the Nervous Syftem. For though this is no decifive proof that material

caufes

OF THE NERVES. 119

caufes adt in the fame manner, CHAP.

it clearly fhews the poffibility —

of their doing fo.

Previoufly however to our en- tering upon this point, it may be worth while to obferve, that corporeal and intellectual ftimu- li feem in the animal oeconomy to be equivalent to each other. Thus laughter is equally pro- duced by ludicrous ideas, and by the gentle titillation of the cutaneous Nerves, when in a ftate of great fenfibility, as in children. Limpid urine, in hy- fterical people, is known to be caufed by a fudden perturbation of fpirits, as in others it is oc- I 4 cafioned

120 ON THE QUALITIES

CHAP, cafioned by drinking largely of

^~ ! weak acid liquors. Nothing

however fets this equivalency in a clearer light, than the erection of the penis, which is fome- times caufed by love or lafcivious ideas, and at other times by the ftimulus of the venereal poifon, by the acrimonious falts of can- tharides, by the rabies canina *, by a purge f , by exercife or riding, by a mere exuberance of rich nutritious juices, and laftly, in one cafe, which has been al- ready defcribed, was produced

* Cselius Aurelianus. + Ephemerid. Nat. Cur. Decad. II, Vol. X. p. 230,

by

OF THE NERVES. 121 by the {hock of the fpinal mar- CHAP.

VTT

row from a violent fall on the

breech.

1

«

Intellectual caufes will alfo deftroy and annihilate a mate- rial ftimulus, as in the cafe of drunken men, who have been made fober in an inftant by a violent impreffion of fear *. And every one I fuppofe can recol- lect inftances of the toothach being driven away by the pre- parations made for drawing the teeth.

* Ephemerid. Nat. Cur. Decad. I. Vol. II. P. 318.

It

VII.

J22 ON THE QUALITIES

wonderful that difeafes both acute and chronical, fhouldfome- times be caufed, and fometimes cured, by the paffions of the mind *. Thus continued me- lancholy* and difguft weakens the digeftion, and confumes the body as powerfully as ficknefs. Internal fatisfa&ion, on the other hand, is in many cafes the only effe&ual reftorative. Thus epi- leptic fits are fometimes brought on by affe&ions of the limbs, and fometimes alfo by terror and

* See Hildanus, Cent. I. Obf. 18. V. Obf. 72. Schenkius. Lib. III. p. 2. Obf, 56.

fur-

OF THE NERVES. 123

furprife. That wine in excefs CHAP.

•11 1 r VII. will produce a lever is not more _ .

certain than that anger will alfo do it. Laftly, a violent impref- iion of terror, grief, or joy has been known to deftroy life as completely, and as fuddenly, as the molt violent blow on the fkull ; and where it fails of do- ing this, is frequently followed by fimilar effe&s, that is, by the fame fevere pain, and con- ftant difpofition to vomit, that commonly attend a doncuffion of the brain.

But terror, though caufed by an apprehenfion of evil, does not always produce effe&s con- genial

124 ON THE QUALITIES

CHAP, genial to its caufe. If it fome-

VII. . — times kills, there are inftances

alfo, where it has reftored

ftrength to the cripple, and

health to the difeafed. I my-

felf knew a gentleman (and it

would be eafy to add many fi-

jnilar examples) whofe feet were

fo crippled with the gout as to

make it neceffary for him to be

carried on a fervant's back. In

that pofture he was going up

flairs, when an account was

brought him from above, that

his wife was fallen into a fit.

Upon which he immediately got

down from the fervant's back,

ran up ftairs without difficulty,

and by his own ftrength lifted

) his

OF THE NERVES. 125

his wife off from the bed where; CHAP,

fhe lay. Another perfon of my L_

acquaintance, a lady, was cured of a marafmus, when fuppoled by Dr. Huxham to be at the point cf death, by a fuddeir- alarm of fire *.

* See Ephemer. Nat. Cur. Decad. III. Vol. IX. andX. p. 384.

Schenkius, Lib. I. cap. 181 and 182.

CHAP.

126 ON THE QUALITIES

CHAP. VIII.

Of the fever al Methods of reliev- ing Irritation.

CHAP. r "^HE methods of relieving VIIL irritation may be referred

to two general claffes ; thofe which relax and moderate the force of the Nerves*; and thofe which deftroy the firft ftimulus by fubftituting a fecond.

* That mere relaxation will fometimes cure diforders, appears from the cafe of an old and obftinate fciatica cured by a fainting fit ; related by Foreftus, Lib. XXIX. obf. 21.

Under

OF THE NERVES. 127

Under the firft clafs are com- CHAP.

prehended bleeding, purging, L.

emollient wallies and poultices, with oily liniments. I include purging in this clafs, becaufe the effect of it upon the confti- tution is certainly to relax, though the relaxation is pro- duced by a fmart ftimulus upon the fenfible fibres of the intef- tines *. As this method of ap- pealing irritation is eafy enough to comprehend, I fhall content myfelf with barely mentioning it, and pafs on to the fecond.

* See the very ingenious remark of Van Swieten. Comm.in Boerhaav. Se£t. 760.

Under

128 ON THE QUALITIES

CHAP. Under this fecond diviflon I m fliall make no fcruple of rank- ing opium and the bark, with every fort of nervous and corro- borant medicine.

That opium in reality acts by a ftimulating quality, appears from its effedts when given in an overdofe *, or when applied to a very fore inflamed part. In the firft cafe it produces vomit- ing and convulfions ; in the laft it gives excruciating pain f.

* Laudanum opiatum purgans. Ephem, Nat. Cur. Decad. II. Vol. VIII. p. 1 17, -f Schenkius, Lib. I. Cap. 296.

Now

OF THE NERVES. 129

Now was its a&ion purely and CHAP;

. VIII eiTentially anodyne, it would 1-

be anodyne in all circumftances

whatever j the greater its dofe,

and the more the Nerve was ex-

pofed to its a&ion, the more

certainly would it fucceed in

abating pain. We may venture

therefore to conclude that it

produces fleep, juft as onioiis

and tobacco do, in confequence

of a particular mode and degree

of irritation.

That the bark alfo has a de- gree of irritation, will not be denied, when it fo frequently purges, and when its tafte is fo evidently pungent upon the K tongue.

130 ON THE QUALITIES

CHAP, tongue, efpecially if fore and

VIII. j tender.

All kinds of foetid, bit- ter and aromatic medicines give equally certain marks of an ir- ritating power. Camphor in particular has a moft evident pungency.

Now there is not one of thefe fubftances that does not, in fome inftance or other, deftroy a previous fubfifting irritation. When the irritation arifes from the fuffering of a particular part, nothing fo certainly re- lieves it as opium. If from natural debility of the Nerves,

gun>

OF THE NERVES. 131

gummofe medicines ; if from CHAP,

... VIII. the attack of an intermitting —

fever, the bark iii general is an

expeditious remedy.

Wine, which is notoriously pungent and irritating, is in many cafes a fovereign cordial. Camphor alfo frequently affwages febrile heat in a very remark- able manner, and its efficacy in abating the fmarting and pain of blifters is equally undeni- able.

The medicinal powers of mer- cury may, I think, be referred to this caufe. That mercury in its own nature, and without any K 2 addi-

tji ON THE QUALITIES

CHAP, addition, is irritating, appears — from the violent effeds of cal- cined mercury, made without any admixture, by the affiftance only of gentle heat. I have known it alfo, when blended with frefh lard in an ointment, give great pain in a cafe where lard alone, and all un&uous ap- plications, gave eafe. In its natural ftate, its very fluidity is probably the reafon why it does not readily affeft the Nerves, its particles being more power- fully attracted by one another, than by any third fubftance. And yet even in this ftate I have known it produce a falivation, after having been taken fome

little

OF THE NERVES. *33

little time in the manner re- C H A R, commended by Dr. Dovar *, ,

Balfamic medicines are fre- quently found to give relief in ulcers, where mere emollients are of no fervice. Whence but from their heat and pungency?

Vinegar is one of the moft powerful repellents that we know of, that is, it prevents the fluxion, which other ftimu- lating caufes or external injuries tend to produce. Yet who cloes not know that vinegar it-

* See alfo Mead on Poifons, Effay IV,

K 3 felf

i34 ON THE QUALITIES

CHAP, felf is very ftimulating; even on

VIII. i i T

„ the tongue, and mucn more on

a raw wound ?

When we apply a blifter to the fide, in a pleurify, or vola- tile falts to the nofe, to cure a nervous headach, what do we do but apply a new ftimulus to deftroy that which prae-exifted ? And is not the cure by aether, which gives a burning fenfation to the part, of a fimilar na- * ture ?

That the cure depends upon the ftimulus may be inferred with great plausibility from fome cafes recorded in the laft

volume

OF THE NERVES. 135

volume of the Edinburgh Effay *. CHAP.

VIII. We have there an account of a ! —

man who repeatedly removed his fits of the gout, by eating one or more fait herrings at bed- time, and afterwards abftaining from drink ; while, on the con- trary, others who tried the fame method, but were unable to en- dure the intenfe heat and thirft it occasioned, and endeavoured to affwage it by drinking, en- tirely loft the benefit of the re- medy, and failed of their cure. *

I do not however mean to infinuate that, provided fome

* P. 462. K 4 new

136 ON THE QUALITIES

CHAP, new ftimulus is applied, it is

VIII s- ! — wholly indifferent of what kind

that ftimulus may be. And yet even in this there is great lati- tude. Thus, with refped to air, it is a common obfervation that changing from a clear air to a foul and loaded one has fometimes a falutary effe£t ; and I particularly remember an inftance of a child that pined and wafted in the country, and afterwrards recovered its ftrength and appetite, upon being brought to lodge in a crowded ftreet, in a town. This, however, does not obtain in all cafes, and therefore the utmoft I can pre- tend to fay is, that fuch methods

of

OF THE NERVES. 137

of cure as do not depend upon CHAP, evacuations and emollients, de- , pend univerfally upon fome kind of ftimulus or other,

That this is an eflential cir- cumftance may be collected as well from fome cafes already re- lated, as from the effects now and then produced by a mere mechanical ftimulus. I fhall not infift upon the practice of whipping chilblains with holly, having no better authority for the efficacy of it than vulgar opinion. There is not the fame obje&ion to the account Hilda- nus * gives us of the gout be-

^— ^— ^— ■ 1 ■!— ■ ■— — — — m*

* Ccntur. I. Qbf. 79.

ing

138 ON THE QUALITIES

CHAP, inor in feveral inftances cured by V1IL

— -^— the torture ; nor to the (lory re- lated by Frederick Loflius, a practitioner in the laft century at Dorchefter, of obftinate ver- tiginous complaints removed by a violent blow on the head from a fall f: ; nor, laftly, to the cure of an epidemic dyfentery, effect- ed in two patients by a fevere fcourging, as Kellnerus teftifies in the A6ta Phyiico-Medica -f . The fimilarity of thefe fadts, re- corded by men of different ages and countries, is a ftrong con- firmation of their truth ; and

* Fredcrici Loflii Obfervat. Medicinal Lib. I. Obf. 8. t Vol. IV. p. 450.

being

OF THE NERVES. i39

being; true, they are not the lefs CHAP.

t r i VIII. worthy or our attention on ac-

count of the ludicrous idea they excite ; or rather, their Angularity gives them a ftronger claim to our notice, as it fhews they do not depend upon the more familiar laws of nature, but upon fome unknown or un- heeded principle.

CON-

j4o ON THE QUALITIES

CONCLUSION.

Conclu: T P O N a review of this SI0N* ^~"^ whole argument I cannot difcover any obje&ion it is lia- ble to, unlefs perhaps I fliould be thought to have laid too much ftrefs upon fome extraor- dinary fadls, {q much out of the common road, as to bring an imputation of credulity upon all \vho believe them.

Now this imputation of ere-* dulity fits, I confefs, rather eafy upon me, as it certainly proceeds often from men, who have no other meafure of pro-

bability^

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OF THE NERVES. 141

bability, than their own very Conclu- limited experience, or fome lame and defective theory, efpoufed without any experience at all. To fuch men, and particularly to thofe, who can ftill believe that an obftru&ed circulation is the univerfal caufe of diforders, many of the fafts here related muft appear entirely unworthy of credit. But the true philo- fopher, I am perfuaded, will not think it reafonable, upon fo flight a foundation as this, to fet bounds to the powers of Nature, and where his fpeculative no- tions are contradi&ed by pofitive teftimony, will not be hafty to rejecft that teftimony, till he has

at

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142 ON THE QUALITIES

Conclu- at leaft reviewed his theory and fully convinced himfelf of the truth of it.

In medical enquiries this cau- tion is more peculiarly neceflary, as it is acknowledged on all hands that the pra&ice of phy- fie prefents every day phenome- na that feem wholly unaccount- able. Yet this obfervation, even the individual, who feels the truth of it, applies but un- willingly to the experience of his neighbour : not refle&ing that unaccountable means only a thing which we cannot account for, and does not always im- ply falfity or abfurdity, but fre- quently,

SlOtf.

OF THE NERVES, 143

quently, perhaps more frequent- Conclu- ly, the imperfed knowledge and erroneous ideas of the theorift.

Of the extraordinary fads here cited, the greater part are extraded from books, the au- thors of which have been long iince dead, and are now in ge- neral forgotten. It is impofli- ble therefore at prefent to bring any vouchers for their accuracy : but, on the other hand, their teftimony has this advantage, that it cannot be charged with partiality or unfairnefs, as they only relate the naked fad, with- out any fufpicion of the infe- rence that would be drawn from

it.

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144 ON THE QUALITIES

Conclu- it. Had I therefore been able to fupport every polition by liv- ing vouchers, I am not fure whether I fliould not on this occafion have preferred the evi- dence of recorded fads.

One principal fource of my materials has been the tranfac-^ tions of the Naturce Gurioji in Germany, publifhed under the different titles of Ephemerides, Centurias, Ada Phyfico-Medi- ca, and Nova Ada. The au- thors, who have furniflied out this collection, being for the moft part unknown in England, might perhaps be considered as a fet of ignorant dreamers, did

we

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OF THE NERVES. 145

we not find among them the Conclw- names of Heijier and Morgagni, men whofe accuracy and faga- city is undoubted, who would neither have fuffered their names to appear in an unlearned lift, nor their writings to be inferted in a colle&ion of legendary- tales.

Now if it be admitted, which no one, I think, can reafonably deny, that the witnefles here produced are competent, the lingular nature of the fads, in- ftead of invalidating our general do&rine, is a great prefumption in favour of it. For what can more ftrongly evince the truth

L of

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. 146 ON THE QUALITIES, &c.

Conclu- of any fpeculative principle, than that it furnifhes a ready fo- lution of the moft irregular phae- nomena ? as, on the other hand, nothing fhews the imperfection of a theory more clearly, than that it is encountered every day by atteftations of miraculous fads, which the theorift, from being unable to explain, is ob- liged to difcredit.

FINIS.

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