The sensible qualities of this salt are too well known to require any
description. It generally occurs crystallized in six-sided prisms,
terminated by dihedral summits. It is composed of one proportional of
nitric acid, and one proportional of potass. It dissolves in seven parts
of water at 60°, and in its own weight at 212° _Fah._ Its solution is
attended with a great reduction of temperature. It is permanent in the
air, melts when exposed to a moderate heat; and, when cast into moulds,
constitutes what is known in commerce by the name of _sal prunelle_.
When mixed with inflammable matter it undergoes, in a strong heat, a
rapid species of combustion, which, in chemical language, is termed
_deflagration_. Concentrated sulphuric acid, when poured upon this salt
in powder, decomposes it at the ordinary temperature, and disengages
vapours of nitric acid, which are white, and not very abundant.
_Symptoms of poisoning by Nitre._
This salt, when taken in a large dose, acts violently on the stomach and
bowels, and occasions syncope and death. There are several cases
recorded of its having been taken by mistake for _Glauber’s salt_.
On these occasions, the patients have been seized with violent vomiting
and purging of blood, attended with severe pains in the bowels, and a
sense of burning heat, referred to the chest and stomach; cold
extremities, fluttering pulse, laborious breathing, syncope, and death.
The above effects have been produced by an ounce and a half of nitre;
although, as _Dr. Gordon Smith_ has observed, the same quantity of this
salt has been inadvertently swallowed _without_ the production of such
tremendous consequences.
From the experiments of _Orfila_, it appears that if this salt be
inserted into a wound, it occasions a fatal gangrene. Its action is
undoubtedly the effect of its acrid nature, destroying the vitality of
the textures with which it comes in contact. It is not absorbed.
_Organic lesions discovered by dissection._
In those recorded cases of death from the ingestion of nitre, the
stomach has been found red, scattered over with blackish spots, and its
mucous membrane disorganized.
_Chemical processes for the detection of Nitre._
The property which this salt possesses of deflagrating with combustible
bodies, affords a ready indication of its presence. The process also,
which we have described under the history of nitric acid, (p. 312) as
the one suggested by _Dr. Wollaston_, and adopted by _Dr. Marcet_ in his
examination of sea water, furnishes an elegant mode of ascertaining the
presence of a nitric salt.
Cl. IV. NARCOTIC POISONS.
These constitute a class of vegetable poisons, less extensive, perhaps,
but of far greater importance and interest, than the one we have already
considered. It would not be easy to enumerate the various purposes to
which the active imagination of man has applied the tribe of narcotic
plants. Medicines, poisons, intoxication, and madness, lie concealed
beneath their juices. They have, in their turn, arrested the pangs of
disease, and inflicted death upon the unsuspecting object of hatred and
revenge; they have animated the courage of the warrior, inspired the
enthusiasm of the poet, soothed the sorrows of the wretched, and
furnished the debauchee with a daily source of sensual gratification;
effects which, although apparently incompatible with each other, may be
commanded by the same substance, in a different dose. It would be
foreign to the plan of this work to enter into a physiological inquiry
into the _modus operandi_ of these extraordinary agents; and the author
relinquishes the labour with less regret, as he has already, in another
work,[415] very fully considered the several theories which have been
advanced for its explanation.
OPIUM, and its PREPARATIONS.
This well known drug is the inspissated juice of the _Papaver
Somniferum_ (Polyandria Monogynia. _Nat. Ord._ Rhoedææ, _Linn._
Papaveraceæ _Juss._) obtained by making incisions in the half ripe
capsules, at sun-set, when the night dews favour the exudation of the
juice, which is collected in the morning by old women and children, who
scrape it from off the wounds with a small iron scoop, and deposit the
whole in an earthen pot, where it is worked by wooden spatulas in the
sun-shine, until it attain a considerable degree of spissitude. It is
then formed by the hand into cakes, which are laid in earthen basins to
be further exsiccated.[416] Two kinds are found in commerce,
distinguished by the names of _Turkey_, and _East Indian_ opium. The
latter kind is regarded as being inferior to the former.
_Turkey_ opium occurs in flat pieces, of a solid compact texture,
possessing considerable tenacity; its specific gravity is 1·336, so
that, when compared with concrete juices of other plants, it is heavy,
being exceeded only in this respect by opoponax and gum arabic. It is of
a reddish-brown, or fawn-colour, and has a peculiar, heavy, and narcotic
odour; its taste is acrid, bitter, and hot. By long exposure to the air,
it becomes hard, and breaks with a glimmering fracture, owing to the
presence of a few saline particles. It is plastic, and when worked with
the fingers is adherent to them. When brought near a lighted candle it
inflames, and burns with a brilliant light, but its odour at that time
is not narcotic. It is partially soluble in water, alcohol, æther, wine,
vinegar, and lemon-juice. When triturated with hot water, five parts in
twelve are dissolved, six suspended, and one part remains perfectly
insoluble, and resembles the gluten of wheat, but is of a dark colour.
The alcoholic is more highly charged with its narcotic principle than
the aqueous solution; but spirit, rather below proof, is its best
menstruum.
Few vegetable substances have been more frequently, or more ably
submitted to analysis; and the history of the successive steps by which
our knowledge respecting its composition has advanced, must encourage us
in hoping that we shall shortly be enabled to identify, by chemical
tests, the presence of opium, with as little difficulty and as great
precision as we are already capable of recognising a metallic poison.
According to the latest chemical views respecting the composition of
this body, it may be stated to consist of the following principles, viz.
resin, gum, bitter extractive, sulphate of lime, gluten, and the three
lately discovered bodies, _narcotine_, _morphia_, and _meconic acid_.
In the year 1803, _Derosne_ first obtained from opium a crystalline
substance, which he found to dissolve in acids, but he does not appear
to have instituted many experiments, for the elucidation of its nature
and properties. In 1804 _Seguin_ discovered another crystalline body,
and although he described many of its properties, what appears very
extraordinary, he never even hinted at its alkaline nature.
_Sertuerner_, at Eimbeck in Hanover, had at the same time as _Derosne_
and _Seguin_, obtained these crystalline bodies, but it was not until
the year 1817, that he first proclaimed the existence of a vegetable
alkali, and attributed to it the narcotic powers which distinguish the
operation of opium; to this body, he gave the name of _Morphia_, and it
would appear to be the same as the essential salt of _Seguin_. The salt
of _Derosne_ was also at first mistaken for the same principle, but the
experiments of _Robiquet_ have pointed out its distinctive properties,
and it has received the name of _Narcotine_.
_Morphia_, upon which the soporific powers of opium depend, appears to
exist in native combination with a peculiar acid, to which the name of
_meconic_ acid has been bestowed. The following are the essential
characters of this alkaline body, when procured in a state of
purity.[417]
It crystallizes in fine, transparent, truncated pyramids, the bases of
which are either squares or rectangles, occasionally united base to
base, and thereby forming octohedra. It is sparingly soluble in boiling
water, but dissolves abundantly in heated alcohol, giving rise to an
intensely bitter solution; in æther it is far less soluble. It has also
the characters of an alkali; affecting test papers tinged with tumeric
or violets, uniting with acids and forming neutral salts, and
decomposing the compounds of acids with metallic oxides. It unites with
sulphur by means of heat, but the combination is no sooner formed than
it is decomposed. It fuses at a moderate temperature, when it resembles
melted sulphur, and like that substance crystallizes on cooling; it is
decomposed by distillation, yielding carbonate of ammonia, oil, and a
black resinous residue, with a peculiar smell; when heated in contact
with air, it inflames rapidly, and like vegetable matter, it leaves a
carbonaceous residue. When analyzed by means of the deutoxide of copper,
it yields carbon, hydrogen, and oxygen, the atomic proportions of which
have not yet been ascertained. The nitric acid of commerce, when dropped
on _morphia_, communicates to it a beautiful red colour. _Sertuerner_
has given us an account of the effect of the alcoholic solution of
_morphia_ on himself, and three of his pupils; he found that repeated
small doses of half a grain produced at first decided excitation; then
weakness, numbness, and tendency to fainting; after swallowing vinegar
while in this condition, violent vomiting was excited; in one delicate
individual, profound sleep intervened, and on the following day he
suffered from nausea, vomiting, head-ache, anorexia, constipation, and
heaviness.[418] This case is sufficient to shew, that although _morphia_
possesses the characteristic powers of opium, its strength is by no
means commensurate with its supposed state of concentration. When
uncombined, it exerts little or no action, in consequence of its
insolubility in water, and in the fluids of the stomach. When, however,
it is combined with an acid, particularly the acetic, or the _meconic_,
with the latter of which we have before stated that it exists in opium,
it displays its properties in a very eminent degree. It is also very
soluble in oil; and, according to the experiments of _M. Majendie_, the
compound acts with great intensity.
The _meconic acid_, when separated from the residuum of the magnesian
salt, as described in the process for the preparation of morphia (_note
p._ 386) does not appear to possess any medicinal activity. Its
distinguishing _chemical_ character is, that it produces an intensely
red colour in solutions of iron, oxidized _ad maximum_; and a deep blue,
with solutions of the salts of gold. _Narcotine_ is the salt originally
obtained by _Derosne_, and is supposed by _MM. Majendie_ and _Robiquet_
to be the peculiar principle which produces the excitement experienced
by those who take small doses of opium. It may be entirely removed by
macerating the extract of opium in sulphuric æther.
_Symptoms of poisoning by Opium._
In considerable doses, the primary action of this substance, as a
powerful and diffusible stimulant, is not apparent; for the powers of
life are immediately depressed, drowsiness and stupor succeed, and these
are followed by delirium, stertorous breathing, cold sweats,
convulsions, and apoplectic death.
The quantity of opium necessary for the production of such effects must
be regarded as _relative_. In no two cases can we ensure a similar
result, by the administration of the same dose. But, of all the
circumstances capable of modifying the power of this drug, habit is the
most remarkable; in illustration of which we have only to adduce the
history of the opium eater, or laudanum drinker; a species of debauchee
by no means uncommon, as every London chemist can testify, for he
frequently experiences considerable doubt and difficulty in
distinguishing persons, to whom habit has rendered large doses of opium
necessary, from such as purchase it with a view to suicide.[419] The
lowest fatal dose, to those unaccustomed to it, seems to be about four
grains; but the Turk will take three drachms in the morning, and repeat
the same dose at night, without any other effects than that of
cheerfulness and exhilaration. This temporary impunity, however, is
dearly purchased by years of suffering and sorrow. The effects of opium,
says _Russel_, on those who have been addicted to it, are at first
obstinate costiveness, succeeded by diarrhœa and flatulence, with loss
of appetite, and a sottish appearance; their memories soon fail, they
become prematurely old, and then sink into the grave objects of scorn
and pity.[420]
Where a person has, from accident, or design, swallowed a large dose of
pure opium, or laudanum, the symptoms produced are so characteristic and
striking, that the practitioner, who may be summoned to render
assistance, will have no difficulty in ascertaining their cause.
Insensibility, with a scarcely perceptible respiration, although in some
cases it is attended with an apopletic stertor; the countenance is livid
and cadaverous; the skin cold; and the muscles of the limbs and trunk in
a state of extreme relaxation. The pupils are insensible to the
impression of light, and the pulse is almost imperceptible. In some
stages, the patient, by being strongly shaken, may be roused for a few
moments from the lethargy; there is generally a narcotic odour
distinguishable in the breath. Vomiting may also take place upon the
first impression of the laudanum upon the stomach; although after its
action has been displayed upon the brain, it will be difficult to excite
emesis by the most powerful means; the reason of which may be very
satisfactorily deduced from the ingenious experiments of _M. Majendie_
on the mechanism of vomiting; by which he proves, that without the
influence of the brain, the muscles, whose actions constitute an
essential part of the operation, are incapable of performing their duty,
and that vomiting therefore cannot take place. This is a very important
doctrine, inasmuch as it suggests to the pathologist several expedients,
by which he may be enabled to occasion vomiting, by recalling the
excitability of the brain. The period which will elapse, between the
ingestion of the poison, and the death of the sufferer, may be stated to
be from six to twenty-four hours; but it will in each case be liable to
vary, not only from the quantity of opium swallowed, but from the habit
and peculiar circumstances of the individual submitted to its operation.
_Physiological action of Opium._
It is still a question for the decision of future physiologists, whether
the narcotic principle of opium destroys the functions of the nervous
system by a local impression upon the stomach,[421] or by being
absorbed,[422] and brought into contact with the brain in the course of
the circulation. We are inclined to adopt this latter opinion, and have
therefore placed _opium_ in the second division of our classification;
at the same time, we think that it may occasionally produce an effect
upon the nervous extremities of the stomach, and we have accordingly
placed an _asterisk_ against the word, by which we denote this double
mode of operation. But, by whatever medium it may act, it is evident
that it occasions death by destroying the functions of the brain; in
consequence of which the muscles of respiration, no longer supplied with
nervous energy, cease to contract, and the animal dies in a state of
suffocation.[423]
_Of the treatment in cases of poisoning by Opium._
The first object is the evacuation of the stomach by vomiting; for which
purpose, the patient should be made to swallow from fifteen grains to a
scruple of _sulphate of zinc_; or, from five to ten grains of _sulphate
of copper_ dissolved in water; and the vomiting should be kept up for a
considerable time, and urged by irritation of the fauces. Where the act
of vomiting cannot be established, in consequence of the paralysed state
of the nervous system, cold affusion, applied by means of a shower bath,
has been said to restore the energy of the brain, and thus to render the
patient susceptible of the stimulus of an emetic.[424] Venesection has
also, under the same circumstances, been greatly extolled; and, as
vascular congestion in the brain is one of the effects of this poison,
it is reasonable to conclude that, by unloading the vessels of this
organ, we may restore its lost sensibility. _Tissot_ has strongly
recommended the practice,[425] and the experiments of _Orfila_ have
shewn that it never aggravated the symptoms of poisoning by opium, nor
accelerated the moment of death; but on the contrary, that in some
instances he found that it restored the animals which would have died,
if it had not been put in practice. Where the operation is performed,
the blood should be drawn from the jugular vein, in preference to any
other. Should these means prove insufficient to provoke vomiting, _M.
Orfila_ asks, whether one or two grains of _tartarized antimony_,
dissolved in one or two ounces of water, might not be injected into the
veins? It was formerly proposed by _Boerhaave_ to empty the stomach of
its poisonous contents, by the introduction of a syringe; an operation
which, it is said, has been lately performed with success.[426] Vinegar
and vegetable acids were long considered as _antidotes_ to opium; but
the experiments of _M. Orfila_ have clearly established that, as long as
any portion of the opium remains in the stomach, these potations, so far
from relieving, aggravate the symptoms of poisoning by this narcotic, in
consequence of the power which they possess of dissolving it. Where,
however, the opium has been expelled by vomiting, these acid drinks
possess the property of _diminishing the consecutive symptoms_, and of
thus realising the expectations which _Virgil_[427] has so poetically
raised,
----“_quo non præsentius ullum
Auxilium venit, ac membris agit atra venena_.”
The powers of the habit should, at the same time, be supported by
brandy, strong coffee, and cordials. The sufferer should be kept awake;
and, if possible, in a continued gentle motion. _Dr. Currie_[428] has
recommended the affusion of warm water at 106°, or 108°, for removing
the stupor.
A case is recorded by _Dr. Marcet_, in the first volume of the
Medico-chirurgical Transactions, where six ounces of laudanum were taken
by a young man, and remained for five hours in the stomach before any
remedies were applied for its removal; a strong dose of sulphate of
copper, however, provoked vomiting, and by judicious treatment he
eventually recovered.
_Organic lesions discovered on dissection._
It has been very truly remarked that although the instances in which
opium has proved fatal to human life have been very numerous, yet that
the accounts which we have received of the appearances of the body _post
mortem_, are by no means so satisfactory as we could desire. _M. Orfila_
asserts that no alteration can be discovered on dissection, in the
digestive canal of persons who have swallowed any narcotic poison; and
that if facts contrary to this assertion be met with in various authors,
it is because there have been administered irritating substances capable
of producing inflammation.[429] The lungs, however, frequently exhibit
morbid phenomena; their colour is sometimes violet, and frequently a
deeper red than in the natural state. Their texture is also more dense,
and less crepitating; and they are marked by livid spots. The blood
contained in the ventricles of the heart, and in the veins, is said to
be found in a liquid state; but _Orfila_ advances a diametrically
opposite opinion, and asserts that it is frequently coagulated. The
brain and its membranes often exhibit a state of vascular congestion; in
the case recorded by _Mr. Stanley_, in the sixth volume of the
_Transactions of the College of Physicians_, the cellular tissue of the
pia mater was found to contain water.[430]
_Of the detection of Opium._
There is no mode of identifying opium, whether in a liquid or solid
form, so satisfactory as that which is at once afforded by its powerful
and highly characteristic odour. In fatal instances, we shall always
meet with it in the contents of the alimentary canal, and in such
quantities as will leave no doubt as to its nature. The chemist may also
proceed to a farther examination, by obtaining _morphia_ from its
solution, by a process which we have already described under the
chemical history of opium.