Its most general effects upon the animal system at large, and more particularly upon that of the human species.

Previously to noticing the operation of opium on parti­cular functions, a more general question arises; whether, when exhibited internally, it acts solely by its application [Page 8] to the nerves of the Prime vie? or whether some part is also absorbed, and operates by being united with the blood? From the experiments of DR. A. MONRO, ^* where by he found, that frogs, under the influence of opium, expired sooner when the heart was left in the body and the circulation free, than they did, when it had been ob­structed by removing its ventricle, and tying its vessels, I am induced to believe, that it may operate in some degree by being absorbed and united with the blood, not as was formerly supposed, by rarifying or any way changing this fluid, (for the smallness of its dose, and its sudden operation, are sufficient proofs against such an opinion) but rather by its being suspended therein, it will have an opportu­nity of exerting its influence upon the nerves of the in­ner surface of the heart and blood vessels; and the small­ness of the dose can be no objection to this opinion, for it is as easy to conceive that the one hundredth part of a grain may produce a considerable operation upon the in­ner surface of the vascular system, as that a grain shall produce such a general effect by acting only on the ali­mentary canal.

Another question is, whether opium acts directly up­on the part to which it is applied? or whether its effects are entirely owing to its operation upon the brain? From innumerable experiments it appears, that opium destroys motion most particularly in the part to which it is imme­diately applied, and that it has this effect also upon parts cut off from all communication with the brain; hence we are led to conclude, that it may operate upon the nervous [Page 9] system without the intervention of the brain; but as opium, applied to the abdominal muscles of frogs, did not destroy the motion of the heart nearly so soon in those that had previously had their brain and spinal marrow destroyed, as it did in others in whom these parts were left entire, ^* we must also conclude, that the more general effects arising from opium must be produced mostly from its influence being communicated from the nerves of the part, to which it is applied, to the sensorium commune, and thence re­flected back upon the system at large: I say mostly in this manner, because in the same series of experiments it is proved, that some general effects may be in­duced without this interposition of the brain, for not­withstanding the heart was not affected in those in which this organ was destroyed, to such a degree as when it re­mained entire, yet its force and frequency were evident­ly diminished, as appeared by comparison with others in a similar situation, that were not under the operation of this medicine.

Having established these fundamental principles, viz. 1st, That opium acts primarily and especially upon the ner­vous system. 2d, That it exerts its effects most particu­larly upon the part to which it is immediately applied. 3d, That the general effects which it exerts upon the system at large depend upon its influence on the brain; but that 4thly, it may produce some general effects without its in­tervention, I shall go on to examine the effects of opium more particularly upon the animal economy.

[Page 10] In the ANIMAL FUNCTIONS, the operation of opi­um has always been remarkable for allaying pain, whence its general title of anodyne and paregoric; but as pain may origi­nate from different causes, so the use of opium to relieve it has been attended with different results: thus in that pain, which arises from inflammatory distention as in phrenitis, hepatitis, pneumonia, &c. though it frequently will give some temporary ease, yet, as it has a tendency, as will be shewn presently, to encrease the cause of the complaint, the pain retunrs with augmented violence; indeed some­times in these cases, it is said not even to give temporary ease, but to encrease the pain from its first operation. But in that species of pain which arises from irrita­tion, as from gravel or a stone in the bladder, or from the venereal, or from the cancerous virus, &c. it is a sure and never failing palliative. In a third species of pain, that arising from spasm, as gastrodynia, cholic, &c. Opium is not only an effectual palliative, but frequently an excellent and sovereign remedy.

Opium does not relieve pain by its causing sleep, be­cause it often has this effect without inducing that state, and when it does, the pain generally ceases first.

In the voluntary muscles, opium occasions a sluggishness and aversion to motion, and a weakness in their action, when attempted to be moved.

With these effects upon the body, opium also induces a placid tranquillity of mind, which is often followed by that weakened and depraved state of the intellectual powers, in which drunkenness consists, destroying all sense of pro­priety, reason, and prudence, and indeed almost every [Page 11] distinguishing mark of man: hence in the Indies ‘Those who are desirous of attempting some desperate action, intoxicate themselves with its smoke; in this intoxica­tion they fall upon the first object that presents itself, upon strangers as well as upon most inveterate ene­mies.’ ^*

The powers of sensation, motion, and thought, being thus diminished, soon terminate in that state which con­stitutes sleep: this constant attendant upon the use of o­pium, has been established, by the observations of physici­ans, from the time of HIPPOCRATES to the present day; and it has been confirmed, by the general consent of mankind, ever true to their observations, in giving it the term of soporific, hypnotic, and somnific: Yet there are not wanting those who, by speculative reasoning and par­tial observation, deny its possessing this power, and assert a directly opposite operation, except with persons in a state of debility: That it induces sleep in a healthy person is a fact too firmly fixed to require any proof. I shall there­fore only enquire into the foundation of the opinion of those, who contend that it sometimes induces wakefulness.

That in small quantities it will not always produce sleep, where there are powerful stimuli applied at the same time, or where the system is in a very irritable state, I allow; and I believe it is this negative operation (if I may use the expression,) of opium, which has led many to suppose that it produces watchfulness, when in fact, this disposition was caused, either by the nature of the disease or by some stimulant applied; I had an opportunity a few months since [Page 12] of witnessing a case directly in point. A convalescent, from the great irritability of her system, having past one or two restless nights, was induced, on the succeeding e­vening, to take a dose of laudanum, and with as little sleep as before; here immediately the cause of her watch­fulness was assigned to and indeed noted down in proof of the stimulant operation of opium, but unluckily for the idea, the following night was attended with the same de­gree of watchfulness, without its enlivening aid. Had this patient's irritability been so far overcome by the night succeeding the one on which she took the laudanum, as to have permitted her to enjoy a little sleep, or had the want of it on that night, not been particularly observed it would be considered an incontrovertable fact, that the person had been kept awake by opium; but from her previous and subsequent watchfulness, there can be no possibility of sup­posing that she would not have kept awake equally well without opium, and the only reason for its not produc­ing sleep must evidently have been owing to the dose not being large enough to overcome the great irritability of her system.

From the experiment of DR. I. RAMSAY upon himself, ^* it appears that thirty drops of Tinct. Theb. did not make him drowsy immediately upon taking it, but seemed to have a contrary effect, for he felt more enlivened after it; this circumstance he imputes to the operation of the opium, but I rather suppose it was owing to a very different cause; for he was prosecuting his studies, became drowsy over them and then determined to take opium: to accomplish this, required some exercise, perhaps the necessity of go­ing [Page 13] into another room, either for laudanum, or liquid, or vessel in which to take it: if so it requires no stretch of imagination to conceive his being less disposed to sleep af­ter it, than whilst he continued quietly doing over his books, for it is by no means uncommon for persons who cannot resist a continued inclination to sleep, whilst sitting up unmolested, and at case to lose all disposition thereto, by the time they have undressed themselves to go to bed: but even putting the case in the most unfavourable light possible, even supposing the laudanum and requisites for taking it all stood at his elbow, still it must be allowed, that the train of ideas which had admitted drowsiness, was broken in upon by introducing a new subject to the mind, which, besides its novelty, actually required particu­lar attention, for says he ‘I determined to try (and con­sequently to observe) the effects of opium.’ And it is easily conceivable, how such a change of thought and ac­tive employment of the mind, should overcome, for a time, a considerable disposition to sleep: however in two hours notwithstanding his determination, he found it very difficult to refrain from sleep. He then took from ninety to an hundred drops of the same tincture, which soon rous­ed him from his drowsiness, and not without cause, for the shock from the very thought of having taken such a quantity of opium, after observing such considerable ef­fects from a much smaller dose, and which had yet but just began to operate, would I conceive have been fully suffici­cient to resist the influence of a much greater dose than thirty drops of laudanum; but observe, in a short time, as soon, I suppose, as the second dose began to operate, he found himself delirious, which was soon succeeded by inability to walk, vertigo and finally sleep. From these [Page 14] considerations I am led to believe, that this experiment, can no way support the opinion of opium's having any power of keeping a person awake; for even should we al­low that the doctor had no fear or dread from taking such a large dose; yet his sanguine expectation of such an o­peration, (which he seems to have gained from an erro­neous idea of the first's having drove away sleep) would alone be adequate to the production of such an effect. DR. KUHN mentioned in his lectures, a man, who after having been bit by a dog, that was wrongfully supposed to be mad, actually had all the symptoms of Hydrophobia su­pervene; if then expectation will bring on all the dread­ful symptoms of such a disease, need we be surprised that expectation should suspend, for a time, the soporific ope­ration of thirty drops of laudanum?

Opium exerts a particular operation upon the NATU­RAL, FUNCTIONS. Inducing,

1st, In the stomach, a weaker action as is evinced by its destroying appetite; this has been established by many ex­periments, and confirmed by daily observation, particu­larly by the circumstance of its being purchased at exor­bitant prices, by the unhappy sufferers in the famine of 1770, in China, to allay the cravings of hunger. ^* Here I cannot proceed without observing, how cautiously we should avoid being captivated with any particular opinion, for we are then not only blinded to its imperfections, but we also look upon its very blemishes as ornaments; as appears by a person's having lately brought this same fact, to support a favourite opinion, in illustration of opium's encreasing the appetite. ^†

[Page 15] 2d, In the intestines, a diminution of their peristaltic motion, as appears by its constantly producing costiveness, as well as by experiments on the brute creation, in whom, (by opening their abdomens) after giving them opium, the intestinal action was not only found to be both slower and weaker than natural, but in a little time entirely to cease. ^*

3d, In the secretories and excretories of the body, a weaker action appearing in a diminution of all the se­cretions and excretions, except that of sweat.

The VITAL FUNCTIONS likewise suffer in their action by the operation of opium. The pulse and respi­ration become slower and fuller, and the heat of the body is diminished. I know that these effects are denied by some, but from an experiment made upon myself, where­by I found, that in about twenty-five minutes after tak­ing thirty drops of laudanum, the heat of my body dimi­nished 2° by the thermometer, and the frequency of my pulse, which until that time had suffered no perceptible change, was lessened four strokes in a minute, and con­tinued so near forty minutes, when sleep terminated my observation; from the same effect of a diminished fre­quency of the pulse, only in a greater degree, being ob­served by DR. BARD in an experiment upon himself, ^† as well as from the experiments of DR. LEIGH, where, in all the cases in which opium was administered alone or in an aqueous menstruum, it uniformly produced this effect, e­ven so as to lessen the pulse fourteen and fifteen strokes: ^‡ from these then, and many other observations, which [Page 16] might be adduced, if necessary, I must conclude, that this power of its diminishing the frequency of the pulse and consequently the heat of the body, is a general and con­stant effect of opium.

Should any, one say, as indeed it has already been said, in opposition to this opinion, that from several of DR. LEIGH'S experiments, it appears that the pulse was accele­rated after the exhibition of opium; I admit it, and the cause is very evident, when we consider the menstruum in which it was given, for in every case where this acce­leration of the pulse was produced, the opium had been administered in alkohol, and there is not the least doubt, but that this stimulant effect must have arisen from that menstruum, since in all the other cases, as above observed, it had a directly opposite effect. And that it must have arisen from that cause I think is also incontrovertibly proved by FONTANA who having likewise observed the vio­lent effects following the exhibition of opium in spirits of wine, resolved to make some experiments to ascertain the cause, from which he concludes, that it proceeded from the spirit, since, says he, this fluid, when exhibited alone produced all these effects more violently and quickly, than when opium was dissolved in it. ^*

From the operation of opium upon the heart being much less evident than upon the voluntary muscles, DR. HALLER concluded this organ to be entirely free from its influence; but from the above observations and experiments, and from the experiments of DR. MONRO, by which he found, [Page 17] after laying bare the hearts of frogs and injecting a few drops of a solution of opium into their veins, that, ‘as soon as the solution had entered the ventricle of the heart, that organ was rendered incapable of expelling its contents, and in less than a minute thereafter became entirely paralytic,’ we are forced to differ from that great phy­siologist, and to conclude, that the heart as well as every other living part is subject to the operation of this medicine.

In short the general effects of opium are nearly as fol­lows. Soon after being taken, it diminishes pain, except that from inflammatory distension, it brings on serenity and pleasantness of mind, followed by a state of ebriety, and attended with an indolence and aversion to all volun­tary motion, succeeded by sleep; it lessens the frequency but encreases the fulness of the pulse, it diminishes the heat of the body; it also produces costiveness and a gene­ral diminution of all the secretions and excretions, except sweat; it destroys the appetite, and it also induces a ful­ness in the large blood vessels. It is observed of this me­dicine, that it loses its force by repetition; hence a person habituated to its use will frequently find no effect from a dose, which would kill a person unaccustomed to it.

The above observations apply most particularly to the ef­fects of moderate doses of opium. When taken in large quantities, it is often immediately rejected by vomiting; if not, it soon produces symptoms of intoxication, confu­sion of the head, false vision, and delirium, which are shortly after succeeded by profound sleep, with a full and slow pulse, and great distention of the large superficial veins; at length convulsions ^* come on, which, if no relief is obtained, soon [Page 18] terminates in death. By dissection, the heart and large vessels are found greatly distended with blood, and there is generally a slight inflammatory appearance discernible in the stomach. ^*

Having pointed out the most general effects of opium, I proceed to deduce therefrom

Its Mode of Operation.

In entering upon which, I am conscious, that a man of fashion would not more surprise his modish brethren, in ap­pearing without his hat crown reared four or five inches above his head, or without half a dozen buttons strung upon each sleeve, than I shall many of the faculty in not adopting the new and fashionable opinion, that opium is a direct stimulant.

I cannot agree to its being a stimulant—1st, Because such an opinion will not account for its effects. 2nd, Be­cause all the phenomena consequent upon its exhibition, may be accounted for satisfactorily upon a different prin­ciple.

It will not account for its effects; for it appears, that by opium we are enabled to assuage the racking torture of the stone, to allay the pain of bubo, and even to deaden the force, and render life, supportable under the darting stings of an inveterate cancer: How then does it produce [Page 19] this effect? How does it alleviate pain? It is answered, by being a more powerful stimulus to the system, than either stone, venereal or cancerous virus, it deprives us of their sensation, as the sun by its superior splendor drives from our sight the glimmering stars, or as the superior im­pression of a blow on the head, deprives us of the trivi­al sensation from the extraction of a hair at the same time; but here we meet with an insurmountable difficulty; where are we to find marks of the superior stimulus of opium? The sun does not hide the stars without shewing us his greater lustre, nor does a blow fail of shewing a superior when it frees us from a lesser pain; nor can any stimulus whatever, prevent sensation from a lesser one without shewing some evident marks of its superior ope­ration; opium does not shew so great stimulant effects upon the system as stone, or venereal, or cancerous vi­rus; therefore it cannot remove their effects by any stimu­lating operation. This with many others of the effects of opium above-mentioned, particularly the experiment of DR. MONRO, where it diminished the motion and force of the heart immediately upon coming into contact with it; as well as from its constant effect in diminishing the frequen­cy of the pulse and heat of the body, and finally from its direct tendency to induce sleep; all oblige us to deny the possibility of explaining its operation from any stimu­lant power.

I have said all the phenomena resulting from the use of opium may be accounted for upon a different prin­ciple: I mean a direct sedative power, whereby it lessens the sensibility and irritability of the system, and con­sequently the motion, and the powers of motion [Page 20] in it; or in other words, that it has a direct operation upon and immediately diminishes the mobility of the ner­vous power. And in the first place, of its power of di­minishing pain; this effect, as before proved, it could not produce by any stimulant operation; but upon this prin­ciple, it is easily accounted for; it does it in the same man­ner as an intervening cloud deprives us of the sight of the stars, viz. by diminishing the power of the medium of communication: by diminishing the mobility of the ner­vous power, rendering it unfit for transmitting the sen­sation of stimuli. It was observed above, that pains ari­sing from inflammatory distention, oftentimes are not re­lieved by opium, and when they are, it is but tem­porarily, and they afterwards are augmented; this is no more than what we would expect, for from its en­creasing the fulness of the vessels, by diminishing the ex­cretions, and also, as will be shewn hereafter, from its en­creasing the quantity of fluids in the deeper-seated vessels, by diminishing more particularly the action of those on the surface, notwithstanding it may, by diminishing the sensi­bility of the system, in some degree allay the pain, yet as it tends to increase the cause, we need not be surpris­ed if instead of relieving, it should even encrease the pain.

Opium has been extolled for inducing a serenity and cheerfulness of mind, in those who have taken it, even to such a degree sometimes, as to make them express that "they feel as though they were in heaven." This state arises chiefly from the relief from pain, for which the opium was given, for LOCKE very well observes, that pleasure always is the the consequence of the remo­val [Page 21] or lessening of pain, ^* and hence SOCRATES express­ed his having a great sense of pleasure in that part which had lately been freed from the painful impressions of his galling fetters, and hence also is that same enrap­tured expression of ‘feeling as though they were in hea­ven,’ so frequent in the mouths of women, on being relieved by delivery from the distressing pangs of a pain­ful labour.

Should it be said that this pleasant state of mind is in­duced in persons who do not suffer under any particular pain or distress, yet, as has been observed, ^† from the or­dinary necessities of our lives, accidental harms, and fan­tastical uneasinesses, which habits, acquired by fashion, ex­ample and education, have settled in us, and a thousand other irregular desires, which custom has made natural to us, we are seldom at perfect ease, for no sooner is one uneasy action dispatched, but another is ready to set us to work: Therefore it is very possible, that in persons la­bouring under no evident distress, opium may bring plea­sure by suspending these many little uneasinesses.

Should it be even asserted that in an actually indifferent state of body and mind, a state entirely free from pleasure or pain, opiuim will induce pleasure, I admit it; for as pleasure clearly consists in a certain degree of relaxation of the system, as has been shewn by an ingenious au­thor, ^‡ it would be no way surprising that opium in trans­porting the system over to sleep, should carry it through the limits of this pleasurable state. The luxurious use of [Page 22] the warm bath by the ancient Romans, and also by many of the eastern nations at this day, as a great source of plea­sure, produces this effect, in a somewhat similar manner to opium, viz. by its relaxing and enervating power, and the same delicate pleasure, that follows the use of opium, DR. RUSH in his lectures mentions, often also arises from blood-letting, and it is by nearly the same means, viz. by debilitating the system.

This pleasant situation is not permitted to be long en­joyed, for opium still continuing its deadly influence, goes on encreasing weakness in the mental powers, bringing on an irregular train of unconnected thoughts, as is evinced by a stammering and almost inarticulate speech. This is the state which the East-Indians bring on when they "are desirous of committing some desperate action," for the moral faculty ceases to restrain them, and all their sense of conscience is extinct, the powers of memory also fail them, they cannot recollect the object of their ven­geance, for they fall upon the first that presents itself whe­ther strangers or enemies. It is this state of mind in which the Turks are said to shew their greatest courage, and I do not doubt but that in this foolish situation, they may be led up to the muzzle of a cannon, like an ox to the slaugh­ter; ignorant of the consequences, they run on and are punished, whilst in their sober moments, like wiser men, they would have foreseen the danger and avoided it.

During this effect upon the mind it also gradually dimi­nishes the powers of the body; the weakened muscles first become indolent and sluggish in their motion, until at length, if a person attempts to walk, he finds them una­ble to support his tottering body; these, accompanied with [Page 23] imperfect sensibility, are followed by stupor and terminat­ed by sleep. Here then we find that opium in the ANI­MAL FUNCTIONS, gradually and regularly lessens their strength, until finally it forces them down into the quiet bonds of sleep.

This sedative operation is particularly observed in the stomach and intestines, diminishing their actions and produc­ing want of appetite and cosuveness: it also diminishes the operation of the secretary and excretory vessels, by ren­dering them insensible to the usual stimulus of their con­tained fluids.

The effects of opium upon the VITAL FUNCTIONS are very clearly elucidated upon our idea of its action. In the former part of this dissertation it appeared, that not­withstanding opium produced some particular operation on the part to which it was immediately applied, yet that its general effects mostly proceeded from its influence upon the brain: we conclude then, that when taken into the stomach, it particularly lessens its tone, and also diminish­es the energy of the sensorium commune, which must be felt without doubt most especially in the parts most dis­tant from its seat; whence, as well as from their sympathy with the stomach, the vessels of the superficies must be most particularly weakened in their action, which must of course give rise to an accumulation in the larger vessels; hence the large veins appear distended; from this accumulation of blood in the larger vessels, an increase of its natural stimulus is applied to the heart, from whence in conjunc­tion with the vis insita which this organ possesses in a great degree, we can easily account for its not being so evidently affected by opium, as the voluntary muscles are; yet by [Page 24] the diminished frequency of the pulse, we find that the mo­tion of the heart is lessened: its irritability being diminish­ed, it suffers a greater dilatation from the accumulated blood, before it contracts; this, with the relaxation of the arteries, gives rise to the great fulness of the pulse. The flower circulation sufficiently accounts for the diminished head of the body. ^*

That the motions of the extreme vessels are more par­ticularly affected, and that a preternatural accumulation takes place in the larger ones, are not mere conclusions from speculative reasoning, but facts established by actual observation; for Dr. MONRO, by the assistance of his mi­croscope, found the action of the extreme vessels in frogs, under the operation of opium, entirely to cease, while that of the heart still continued; and Dr. WHYTT ^† says, by opening a frog, that had taken opium, he found the heart and large vessels leading to it unusually filled with blood.

From an encreased quantity of fluids in the system, by an obstruction of the other evacuations, and from the a­bove mentioned causes supporting the force of action in the heart and large vessels, with a loss of the resisting pow­er in those of the surface, the sweating, induced by this medicine is easily and satisfactorily explained.

Convulsions often follow from a large dose of opium; they also follow profuse hoemorrhages; here then we see the same effects induced by the abstraction of a stimulus, as [Page 25] by diminishing its force, by rendering the system insensible to its application.

By diffection after death, the stomach appears slightly inflamed; the convulsive pressure of the muscles, as also the before mentioned causes, force the blood internally, whereby the vessels of this organ, which are particular­ly relaxed by the immediate contact of the medicine, are especially distended, and give rise to this appearance.

The effects of opium being diminished by continued use, perfectly correspond with an established law of the animal oeconomy, whereby ‘all impressions which do not excite to action lose their force by repetition.’

Should it be asked, since there are so many facts, direct­ly in proof of the sedative operation of opium, and since all its effects are so clearly and rationally accounted for up­on such a principle; what has given rise to, and what has supported the doctrine of its being a direct stimulus? I answer that it originated chiefly with a person, who has endeavoured to make himself eminent in medicine, by boldly hazarding some new opinions, in opposition to an­cient and well established truths. ^*

Novelty, which is so powerful in influencing the hu­man mind, even, as Dr. HUXHAM observes, to have held Asclepiades out in his absurd and cruel practice of denying drink to persons in a fever, gained also supporters to this doctrine.

Let us examine the arguments advanced in favour of the [Page 26] stimulant operation of operation of opium. Such an operation has been inferred from its analogy with spirituous liquors; thus say they, do spirits produce a pleasant disposi­tion of mind? do they make the distressed ‘forget his po­verty and remember his misery no more?’ do they ‘overthrow the minds and understandings of all that will be trying masteries with it?’ do they make men forget their friends and familiar acquaintances, and finally to draw their swords upon their nearest relations? they surely do, and so in some degree does opium. This may be, and yet it is no proof of any stimulant operation in opium. Should any one ask whether I deny spirits being possessed of a stimulant power? I answer, no, but that they also exert a powerful sedative operation particularly on the mental faculties, every one of the above effects clearly proves: and hence the wisest of men SOLOMON, says, ‘It is not for kings to drink wine nor princes strong drink, lest they drink and forget the law and pervert the judg­ment of any of the afflicted.’ ^* It was from their weaken­ing the mind, and exposing every flaw and imperfection in it, that the poet observed,

I have said I do not deny that spirituous liquors are stimulants, and should it be asked, whether opium like them, increases the appetite, produces strength of body, watchfulness, an increased force and frequency of the pulse, with quick breathing, and raises the temperature of the body? I answer, no; and I trust the foregoing observa­tions have fully proved it to have a directly opposite effect.

[Page 27] The above first mentioned analogy of the operation of opium with spirits, (at the same time considering every effect of the latter as arising from a stimulant power) as­sisted by partial observation where the nature of disease in producing watchfulness has been assigned to its operation, as also by results of experiments, where it has been charg­ed of producing effects, that have been clearly proved, to have arisen from the stimulating menstruum in which it was exhibited, is the only slender basis upon which the doctrine of the stimulant operation of opium is support­ed, and which I trust must give way to the superior evi­dence of a contrary opinion, as soon as time shall have worn off its dazzling tinsel of novelty, so as to permit the cool eye of reason to investigate its inherent quality.

I do not think, with the eminent Dr. CULLEN, (whose name I mention with respect, and from whose opinion I vary with diffidence) that any of the effects of opium even require us to call in the aid of the vis medicatrix naturoe, for their explanation; and since ‘wherever it is admitted, it throws an obscurity upon our system,’ ^* and also as ‘no more causes of phenomena are to be admitted than are sufficient to explain them,’ ^† and as I think all the phenomena from the use of this medicine have been sa­tisfactorily explained upon its simple sedative operation; I have therefore entirely rejected that facultas incognita from this dissertation.

The Uses of Opium.

The limited nature of my dissertation, will particular­ly affect this part of my subject; for to do justice to it [Page 28] alone would require more pages than this treatise [...] consist of; having however enumerated its general effects, and thence deduced its modus operandi, I shall proceed to give, what I conceive, a rational explication of its use in medicine.

In the first place, Front its power of diminishing the sen­sibility of the system to stimuli, it is usefully employed in allaying the pains From the venereal disease, cancers, stone in the bladder, when extraction may be improper, and also to soothe the pungent pain following chirurgical operations, attending compound fractures, &c. &c. also ner­vous head aches, &c.

From its power of diminishing the irritability of the mus­cular fibres, it has been attended with the happiest effects in allaying any preternatural action in them; thus in the heart it relieves palpitation, if it is not symptomatic of a dis­ease that may forbid its use; in the lungs it cures asthma when it is purely spasmodic, and is of use in the chin-cough, after the sebrile symptoms are gone off.

In the stomach it is the best remedy for pyrosis and gas­trodynia, and for vomiting, when this does not proceed from any matter proper to be evacuated, or when it is not accompained by any affection which may be augmented by its use. In this organ as well as.

In the intestines, it relieves cholera a morbus, is a power­ful assistant in the cholic, in the dysentery it also allays the pain and troublesome tenesmus, takes off the constriction of the colon and thus paves the way for the more sure operation of gentle purgatives, as a radical cure. The action of the intestines in simple diarrhoea seems to be con­tinued, by the increased irritability to their contents, from an abrasion of their natural mucous covering from the [Page 29] original cause of the disease, and possibly also in some de­gree by habit; here then we would at once conclude opi­um to be, as in fact it has proved, a very valuable remedy, for by its first diminishing the irritability of the bowels, it allays for a time their encreased action, thereby coun­teracting the powers of habit, during which time, it also by its peculiar operation of thickening excreted fluids, as is particularly evinced in catarrh, it furnishes them with their proper defensive coat; thereby proving not only a palliative, but often a radical cure.

In the uterus, it quiets the efforts threatening abortions, after the plethora has been removed by bleeding, also false pains and spasms during labour; it is a sovereign remedy in pains following delivery called after pains, it relieves the pains that sometimes attend menstruation; it has also prov­ed of great use in taking off the increased action of the uterine vessels, which arises from great irritation, and thus checking the immoderate flow of the catamenia.

Opium, by its relaxing power, is very useful in favour­ing the expulsion of calculi from the ureters and urethra, and concretions from the biliary ducts, also in taking off the constriction and permitting the return of incarcerated hernix.

In the voluntary muscles, opium has been used in tetanus, and from its antispasmodic power, it may prove a pallia­tive; yet, as the celebrated Dr. RUSH ^* has proved, that this disease originates in debility, we should not expect it to give any permanent relief, therefore it should be accom­panied with proper stimulants and tonics. As epilepsy is so often owing to a turgescence of the vessels of the head, and as opium greatly favours this, not only by its general operation of accumulating the blood in the larger and in­ternal vessels, but also by its particularly filling those of the [Page 30] head, by obstructing the refluent blood by a slow respira­tion, it must of course frequently be injurious; but when the disease arises from a particular irritation, as from an aura a epileptica, great pain, or from passions of the mind, it has proved a valuable remedy, and when given a little before an expected accession, it has frequently put off the fit. ^† In convulsions not attended with coma as particu­larly the chorea sanctiviti, it has generally been found of great service.

To its procuring sleep, it owes many of its virtues in cer­tain diseases, but in none more particularly than in typhus fever, where a constant watchfulness seems to be hurrying away the fleeting powers of life: opium checks this fatal career by bringing a refreshing sleep, the want of which wears down the strength faster than almost any other cir­cumstance whatever; it may therefore frequently be ad­vantageously combined with other medicines in this disease.

From its encreasing the fulness of the vascular system, opium must be injurious in all diseases accompanied with an inflammatory diathesis, for this is supported by, (and every indication of cure is to remove) the too great quantity of fluids already in the vessels. But as with this operation, it also often procures a free perspiration, by overcoming the resisting power of the cutaneous vessels, it has even been proposed in inflammatory fevers, and where this effect can be rendered certain, by the union of emetics and neu­tral falts, it has frequently been found a valuable remedy particularly for the cure of the acute rheumatism. From this power of overcoming the resistance in the extreme vessels, it proves so effectual in taking off the burning heat and shortening the hot fit of intermittents. ^‡

From its effect in allaying the operation of the secretory [Page 31] and excretory vessels, it is usefully employed to check a sa­livation from mercury, and it very probably, from this power of diminishing the irritability of the excretories at large, may expedite the cure of the venereal disease by mercury, by allowing the system to retain more in it at a time, than it otherwise would. By this operation it also renders excreted fluids of a much thicker consistence; hence, as observed before, it is of use in catarrh and diarrboea; and it is from this cause, that it changes the ichorous dis­charge of irritable ulcers to a well concocted pus, and hence its great use, as observed by SYDENHAM in the suppura­tive stage of the small pox.

Notwithstanding my having arranged the diseases in which opium is employed, as being relieved by some one of its effects, yes I do not thereby mean to assert that its usefulness in them solely depends upon such a particular part of its operation, for every one the least conversant in medicine must conceive, that a diarrhoe [...] and catarrh, beside the particular effects, under which they are men­tioned, may also in part owe their cure to opium's deter­mining to the surface; a cholera morbus, to its diminish­ing the secretion of bile; a typhus to its relaxing the spasm of the extreme vessels, &c. &c. all I had in view, was to shew on what particular quality of opium the cure of certain diseases chiefly depends.

There are many other diseases in which opium may be employed, but having shewn form what particular effects we are to expect advantage in some, and also from what effects we are to fear its use in other important complaints, I flatter myself the ingenious reader will not be at a loss to decide upon the propriety of its use in diseases in general.

This medicine may be employed either internally or ex­ternally: internally either by the mouth, in doses from one [Page 32] grain to a much larger quantity, the dose is however to be governed chiefly by the force of the irritation, which it is to allay, for in great pain, as from chirurgical operations, as well as from violent spasms, as in tetanus and from in­carcerated hernix, &c. patients will bear and often require such doses of opium, as would have destroyed per­sons in health. Or in the rectum: in this way it is proper, where a continued vomiting prevents its retention in the stomach, as also in tenesmus, and more particularly in the dy­sentery, where by being more directly applied to the part, it will allay the encreased action of this intestine and take off the constriction of the colon, without so materially prevent­ing the operation of purgatives, as if exhibited by the mouth. When opium is given in this manner it must be in double the quantity that would have been necessary if taken into the stomach.

It has been externally applied to the abdomen to relieve spasms of the stomach and intestines: to the mouth to check salivations: ^* to the cheek to relieve tooth ache, &c. &c.

When a person has taken too large a dose of opium, we should endeavour to procure its evacuation as soon as possible by exhibiting a quick emetic as twenty or thirty grains of vit. alb. and tickling the sauces with an oiled feather; we should use all means in our power to keep him awake. Blisters and sinapisms should be applied; and vinegar has been recommended to be exhibited internally, but from some experiments by LEIGH its utility is rather doubtful; I should put more dependance on the stimulus of val. alk.

Since severe pain has been observed greatly to resist its operation, may it not be induced with advantage to pre­vent its deleterious effects in this case?