_Oxy-muriate of Mercury. Bi-chloride of Mercury._
This metallic salt is by far the most active of all the mercurial
preparations. According to the latest views of Chemistry it is a
compound of two proportionals of chlorine, and one proportional of
metallic mercury, and is therefore a _bi-chloride of Mercury_. It
generally occurs in the form of a crystalline mass, made up of very
small prismatic crystals, which undergo a slight alteration by exposure
to air, becoming opaque and pulverulent. Its taste is extremely acrid,
with a metallic astringency, occasioning a sensation of obstruction in
the throat which continues for some time. Its specific gravity is
5·1398[268]. When pulverised and thrown upon burning coals, it is
immediately volatilized, giving out a thick white smoke, of a very
pungent smell, not at all resembling garlic, but which irritates the
mucous membranes extremely, and is highly dangerous to those who breathe
it. It is soluble in eleven parts of cold, and in three of boiling
water; and this solubility may be farther increased by the addition of a
few drops of rectified spirit, or of muriatic acid. When swallowed in
small quantities it acts as a most virulent poison.[269]
_Symptoms of Poisoning by Corrosive Sublimate._
The effects, as well as the _modus operandi_, of this salt, will vary
with the quantity swallowed. We shall, therefore, first consider the
acute symptoms which supervene a dose sufficiently powerful to destroy
life in a few hours; and afterwards those which may arise from its long
continued use in small quantities, and at different intervals.
1. _Symptoms which follow a large dose._ A most painful burning and
sense of constriction is experienced in the fauces; dryness of the mouth
and lips; excruciating pain in the stomach and bowels, increased by the
slightest pressure, and generally attended with considerable distention;
excessive vomiting and purging of frothy mucus; the countenance is
frequently red and swollen, and the eyes exhibit a sparkling appearance,
accompanied by contraction of the pupils. The pulse is in general quick,
small, and hard; suppression of urine takes place, and cold sweats;
anxiety; universal pains; convulsions, and death. If the patient
survives long enough, a violent ptyalism, and sloughing of the mouth and
gums may take place.
2. _Symptoms which are produced by the repetition of small doses._ In
this case the mercurial salt acts as an “Accumulative Poison.” (_See
page_ 148). The most striking of the symptoms are those arising from its
specific action upon the salivary glands, in consequence of which an
increased flow of saliva takes place, the gums become tender and sore,
the breath intolerably offensive, and if the use of the salt be not
discontinued, the teeth loosen, and even fall out, and their loss is
sometimes followed by that of the bones of the palate, or maxillæ; at
the same time other evils, although perhaps less apparent, soon arise;
the strength and muscular powers of the body begin to fail; emaciation
proceeds rapidly; cardialgia, dyspepsia, diarrhæa, and a train of morbid
symptoms succeed; violent pains are experienced in the muscles, tendons,
or joints; tremors of the limbs, and even paralysis may result; and in
some cases, pulmonary consumption terminates the existence of the
unhappy sufferer. It has been asserted that _Corrosive Sublimate_, when
taken for a long time in small quantities, will sometimes occasion all
the symptoms of debility above enumerated, together with hectic fever,
without producing salivation. This is a truth which the author’s
personal experience will enable him to confirm. The Countess of
Soissons, mother of the celebrated Prince Eugene, was accused, at the
latter end of the seventeenth century, of having destroyed her husband
by these means. A question of considerable importance has arisen, with
regard to the specific effects of mercury, which demands some notice in
this place. _Whether salivation, after having entirely subsided, can
ever return without a fresh exhibition of Mercury?_ Two instances are
related by _Dr. Mead_ of the return of salivation, after an interval of
several months, when not a particle of mercury had been administered, in
any form, during that period.[270] _Dr. Male_, in his work on Juridical
Medicine,[271] relates an analogous case which occurred in his own
practice: “In March, 1815,” says he, “I gave a small quantity of
triturated mercury to a respectable woman in this town, who had been
long ill; she became suddenly and unexpectedly salivated. She soon
recovered, and enjoyed better health than she had done for a
considerable time. In October, without (as she informed me) having taken
any medicine whatever, the salivation returned with extreme violence,
her mouth sloughed and mortified; and in a few weeks she died.” _Dr.
Hamilton_, the Professor of Midwifery in Edinburgh, relates in his
lectures the case of a married lady, who had been under the necessity of
going through a course of mercury, under the care of the late _Mr.
Bennet_, who, from motives of delicacy did not enquire very minutely
into the particular circumstances; but, according to the rule of the
day, gave his patient a sore mouth. Four months afterwards she
miscarried, and salivation again came on. It was removed for a week, at
the end of which it returned, and harrassed her for about twelve
months.[272] The author, in his _Pharmacologia_,[273] has cited a case
from _Hufeland’s Journal_, (vol. ix) wherein mercurial influence, after
its complete subsidence, had been renewed by doses of opium. In the
trial of _Miss Butterfield_, at the Croydon assizes, for poisoning _Mr.
Scawen_, in the year 1775, the merit of the case entirely hinged upon
this question. See vol. 1, p. 303.
_Physiological action of Corrosive Sublimate._
When this salt is introduced into the stomach in a large dose, it
immediately exerts a corrosive action on that organ, in consequence of
which the heart and brain become sympathetically affected, and death
results from the suspension of their functions. For this view of the
_modus operandi_ of this mercurial salt we are indebted to _Mr.
Brodie_,[274] whence it would appear that its physiological action is
very different from that of arsenious acid; the former acting as a
simple _escharotic_, on the coats of the alimentary canal, the latter
requiring to be absorbed, before it can display its energies. These
observations, however, apply only to those cases in which the quantity
of poison has been so considerable as to destroy life in a few hours;
where the dose has been small, and the symptoms have arisen from its
frequent repetition, the salt produces its effects by a different mode
of operation. In this latter case it is absorbed, and carried into the
current of the blood, so as to be distributed to every part of the
living system; and it has been asserted that, after the long continued
and improper use of mercury, it has been discovered in different parts
of the body, and even in the brain, in the form of globules. In this way
then deleterious effects may arise from the external application of
corrosive sublimate, and numerous instances are recorded where such
consequences have followed the injudicious use of lotions and plasters,
into which it had entered as an ingredient.[275] In the _Medical
Repository_, for December, 1821, _Mr. Sutleffe_ has communicated the
case of a girl of five years of age, who became salivated, and died, in
consequence of an application made to the head for _tinea capitis_,
consisting of pomatum rubbed up with a few grains of _corrosive
sublimate_.
_Antidotes to Corrosive Sublimate._
After the view which we have taken of the operation of this salt in
large doses, it necessarily follows that copious dilution is the very
first object which we have to accomplish, and then the ejection of the
fluid by vomiting. _Sydenham_ relates an interesting case of poisoning
by this substance, which was successfully treated by copious draughts of
water, and repeated vomiting.[276] But it becomes a question of great
practical importance to enquire, whether there may not exist some
counterpoison or antidote which, by decomposing the salt, will at once
disarm it of its virulence? This question has been investigated in a
very masterly style by _Orfila_, who has clearly proved by experiment,
that neither the _alkaline salts_ and _earths, the sulphurets of potass
and of lime_, nor the _martial alkaline tinctures_, as proposed by
_Navier_,[277] deserve the least confidence; for although the salt may
by some of these bodies be decomposed, yet the resulting oxide will
prove as virulent as the original compound; equally inefficient are the
other substances which have been proposed as counter-poisons, such as
_sulphuretted hydrogen_, _solutions of sugar_,[278] _the infusions of
Peruvian bark_,[279] and _metallic mercury_.[280]
_M. Orfila_ having observed the facility with which _albumen_ decomposes
corrosive sublimate, and gives rise to a triple compound of albumen,
muriatic acid, and protoxide of mercury, induced him to ascertain by
experiments whether the _white of eggs_ might not prove an antidote to
that poison; the result of his inquiry has shewn that this is the case;
and that by mixing such albuminous matter, in _large quantities_, with
the diluents given to provoke vomiting, the happiest effects may be
anticipated. Many examples are recorded of the success of this practice.
In the Transactions of the King and Queen’s College of Physicians in
Ireland, an interesting case of this kind is related by _Dr. Lendrick_;
it is, however, but justice to state, that there are instances also of
the failure of this antidote. In the 41st volume of the _London Medical
and Physical Journal_, p. 204, the reader will find the case of a girl
who was poisoned by a drachm of sublimate, and who, notwithstanding the
copious administration of albumen, died in ninety hours afterwards.
It has lately been discovered that vegetable _gluten_, as existing in
wheat flour, is capable of producing upon corrosive sublimate the same
chemical decomposition, as that which we have stated to arise from the
action of albumen; whence the administration of wheat flour and water
has been suggested as a ready antidote. On the trial of _Michael
Whiting_, for administering poison (_corrosive sublimate_) to his
brothers-in-law, _George_ and _Joseph Langman_, the housekeeper,
_Catharine Carter_, stated in evidence, that the flour, (which was
subsequently proved to contain corrosive sublimate) could scarcely be
made into dumplings with milk[281]; and another witness, _Mrs. Hopkins_,
a neighbour who took charge of the dumpling that had not been boiled,
described it as “_a comical sort of paste; like glazier’s putty more
than paste, though not greasy_.” In order to ascertain the correctness
of this statement, we mixed powdered sublimate with wheat flour, and
proceeded to make it into dough with milk; when the same difficulty as
that stated by the above witnesses, embarrassed the process, and
satisfied us of the truth of their testimony. The phenomenon would
appear to depend upon the mutual chemical changes which arise in the
gluten and mercurial salt.
_Organic Lesions discovered on Dissection._
The œsophagus and stomach will be found inflamed, and sometimes eroded,
as in poisoning by arsenic. _Salin_ has asserted, that this salt never
produces perforation of the intestinal tube; this, however, is not the
fact; and we know not of any exclusive appearances, by which the organic
lesions inflicted by this poison can be distinguished, unless indeed it
be the black appearance of the stomach, as if it had been burnt, which
occasionally presents itself.
_Of the Chemical Processes by which the presence of Corrosive Sublimate
may be detected._
As the chemist, devoted to forensic enquiry, will be required to
identify this substance under very different states of mixture and
combination, we shall proceed to enumerate the various obstacles that
may possibly oppose his researches; and, at the same time, to suggest
the expedients by which they may be successfully evaded. Unlike
arsenious acid, corrosive sublimate is so readily decomposed by various
alimentary substances, that, when we attempt to demonstrate its presence
in such mixtures, we shall be more frequently compelled to rest our
proof upon the products of the analysis, than upon the actual
reproduction of the salt.
We shall proceed to consider the best modes of establishing the presence
of this salt, in the different forms in which it may occur, viz. 1, _In
the solid form_; 2, _Dissolved in water or spirit_; 3, _In various
coloured liquids_; 4, _In a state of mixture with various solids_; 5,
_Combined with solid or liquid aliments, by which it undergoes
decomposition_; 6, _In a state of combination with the textures of the
alimentary canal_.
1. _The sublimate is in its solid form._ The external characters by
which this salt is distinguished will go far to establish its identity;
but the fact should always receive the support of a chemical proof; and
as this is to be derived from the phenomena afforded by its solutions
through the intervention of various tests, it will meet with full
consideration in the following section, viz.
2. _The salt is in the state of solution, in water, or spirit._ Let us
then suppose that we have a solution of some body in distilled water,
which we suspect to be corrosive sublimate, by what means are we able to
identify it?
(_a_) _By its metallization, through the agency of galvanism._ We are
indebted to _Mr. Sylvester_ for first suggesting the mode by which
galvanic electricity might be applied for the detection of minute
quantities of corrosive sublimate in solution. His method is as follows.
A piece of zinc or iron wire, about three inches in length, is to be
twice bent at right angles, so as to resemble the greek letter π, the
two legs of this figure should be distant about the diameter of a common
wedding ring from each other, and the two ends of the bent wire must
afterwards be tied to a ring of this description. Let a plate of glass,
not less than three inches square, be laid as nearly horizontal as
possible, and on one side drop some sulphuric acid, diluted with about
six times its weight of water, till it spreads to the size of a
halfpenny. At a little distance from this, towards the other side, next
drop some of the solution supposed to contain corrosive sublimate, till
the edges of the two liquids become joined; and let the wire and ring,
prepared as above, be laid in such a way, that the wire may touch the
acid, while the gold ring is in contact with the suspected liquid. If
the minutest quantity of corrosive sublimate be present, the ring, in a
few minutes, will be covered with metallic mercury on the part which
touched the fluid.
The above experiment may be beautifully simplified in the following
manner[282]. Drop a small quantity of a solution, supposed to contain
the salt in question, on a piece of gold, and bring into contact a key,
or some piece of iron, so as to form a galvanic circuit; when, if
sublimate be present, the gold will immediately be whitened.
A solution of _nitrate of silver_ will, under similar treatment,
occasion on gold a white precipitate; but as no amalgamation takes
place, it is readily wiped off, and cannot therefore occasion any
fallacy.
(_b_) _By precipitating metallic mercury from its solution, by the
contact of a single metal._ It should be generally known that, by virtue
of superior affinity, certain metals will decompose the solution of
corrosive sublimate, with different phenomena; in those cases where the
precipitating metal is capable of forming a direct union with mercury,
we shall find the precipitates to consist of an amalgam of the metal
employed; where no such combination takes place, the mercury may be
frequently seen standing on the surface as a metallic dew. This is
particularly striking when iron or steel has been employed. In the
evidence given on the trial of _Mary Bateman_[283], better known by the
name of the “Yorkshire Witch,” _Mr. Thomas Chorley_, surgeon at Leeds,
stated that he had received from his assistant, _Mr. Hammerton_, a jar
which he had carefully preserved in his possession, and of the contents
of which he gave the following account. “Upon tasting a portion, it was
very acrid, styptic, and permanent upon the tongue; I then took a small
quantity of it upon a clean knife, and rubbed it with my finger; a
change of colour immediately appeared; _further rubbing produced
numerous globules of quicksilver_, and the knife was, at the same time,
blackened by it; this change of colour led me to suspect that it must be
a mercurial composition, and having made a solution of it, and subjected
it to a series of tests and experiments, it is my opinion, that the
mixture in the pot did contain _honey_, and _corrosive sublimate of
mercury_. In order, however, more fully to satisfy myself upon this
point, a mixture was made of these ingredients, when it was found to
yield the same results.” In the above experiment, the steel knife
decomposed the sublimate, forming a _chloride of iron_, while the
mercury, thus disengaged in its metallic form, being unable to
amalgamate with the iron, appeared in globules[284] upon its surface. At
the same time the knife _became blackened_ owing to the precipitation of
carbonaceous matter from the steel.
(_c_) _Carbonate of Potass._ A saturated solution of this salt, added to
that of corrosive sublimate, will produce a _deep brick coloured_
sediment, which is stated to consist of per-carbonate of mercury[285];
while a muriate of potass will be found to remain in solution. The
_sub-carbonate of potass_ will occasion a somewhat different
precipitate, of a _clear brick_ colour, and consisting of a mixture of
the carbonate, and oxide of the metal.[286]
(_d_) _Ammonia._ A solution of the volatile alkali produces a _white
precipitate_, which is an insoluble triple salt, composed of muriatic
acid, ammonia, and oxide of mercury; being heated it grows yellow; it
passes afterwards to red, and according to _Orfila_ gives out ammoniacal
gas, nitrogen, calomel, and metallic mercury. In this operation the
oxide of mercury is supposed to be deoxidized by the hydrogen which
results from a portion of the decomposed ammonia.
(_e_) _Lime water._ This reagent may be said to decompose corrosive
sublimate more perfectly than any alkaline body; occasioning a
precipitate of a deep yellow colour, which will be found to be a
peroxide of mercury; unless indeed the quantity of lime water be very
small, when it will be a sub-muriate of the peroxide.
(_f_) _Nitrate of Tin._ According to _Dr. Bostock_[287] this test is
capable of detecting the three-millionth part of a grain in solution. A
single drop will produce an immediate and copious dark-brown
precipitation.
All the above precipitates, if rubbed on a bright plate of copper, will
render its surface silvery white, in consequence of the amalgamation
which takes place.
_Brugnatelli_ has lately proposed a method of distinguishing _corrosive
sublimate_ from _arsenic_, which we have repeated to our satisfaction;
but the experiment requires some nicety of manipulation to secure its
success. Take a quantity of fresh wheat starch, mix with water, and add
a sufficient quantity of _iodine_ to give the liquid a blue colour; if
either of the above poisons be now introduced into it, the colour will
be destroyed, and assume a reddish tint; but if the change has been
effected by the latter substance, a few drops of sulphuric acid will
restore the blue colour; whereas if it has been produced by the former,
it is not recoverable by such means.[288]
3. _It is dissolved in various coloured liquids._ Under this subdivision
we have to consider the corrosive sublimate as existing in a state of
solution, in liquids, whose colour will be liable to obscure the
characteristic indications which the several reagents would otherwise
occasion. It has been proposed to obviate such impediments by the
previous addition of chlorine, which will discharge the colour in
question. _Orfila_ recommends such a process, where the salt has been
dissolved in wine. The same objections which we urged against this mode
of proceeding, under the consideration of arsenic, appear to us to apply
to corrosive sublimate.
It will be preferable on these occasions to precipitate the salt by an
appropriate reagent, and then to assay the precipitate for metallic
mercury; or to evaporate the solution, and to submit the matter so
obtained to the process of sublimation, when the sublimate may be
dissolved in distilled water, and examined by the tests above described.
This circuitous process may, however, in many cases be rendered
unnecessary, by dropping the solution on the surface of white paper, and
in such a situation proceeding to its examination by tests; when the
colour of the precipitate will rarely be exposed to any optical fallacy.
The Galvanic process of metallic reduction will also furnish a
satisfactory solution of the problem.
4. _It is mixed, or combined, with some medicinal body in a solid form._
As persons have been poisoned by empirical remedies, and other medicines
containing sublimate, accidentally or by design, it is necessary to
point out the readiest mode by which the investigation may be pursued.
If it should form part of a plaster, it will be adviseable to cut it up
in small pieces, and boil them for a quarter of an hour in distilled
water; this fluid, after standing for some time, should be filtered, and
examined as we have before directed. It is evident that, if the
sublimate is neither decomposed, nor strongly retained by the materials
which compose the plaster, it ought to be found in the above solution;
if, however, no such result can be obtained, the solid portion should be
dried in a capsule, and mixed with potass; and in this state submitted,
in the usual manner, to the process of sublimation, when the appearance
of metallic globules will announce the existence of the salt in
question, or, at least, of the presence of some mercurial preparation.
5. _It is united with alimentary substances which have effected its
decomposition._ It has been frequently stated during the course of the
present inquiry, that corrosive sublimate is easily susceptible of
decomposition, and that various alimentary substances, of animal as well
as vegetable origin, have the power of converting it into
_calomel_.[289] This important fact was first noticed by
_Chaussier_[290] and has been more fully investigated and confirmed by
_Orfila_.[291] Where the quantity of mercurial salt has been
considerable, we may generally obtain, on washing the alimentary matter,
a sufficient portion for experiment; but where the dose has been small,
or where it has been ejected by frequent vomiting, the whole residue may
be decomposed; in which case we must seek to establish the fact of
poisoning, through the detection of metallic mercury, by the processes
of calcination and sublimation.
6. _It is decomposed, and a part exists in intimate combination with the
membranes of the alimentary canal._ If all the preceding experiments
have failed in detecting the presence of corrosive sublimate, it becomes
our duty to examine the textures with which it may be supposed to have
come in contact; the coats of the canal should be cut into pieces, and
calcined with potass, when, if they have been acted upon by sublimate,
they will yield metallic mercury by sublimation. “The alimentary canal,”
says _M. Orfila_, “acts upon the sublimate like all other animal
substances; muriatic acid is disengaged, and muriate of mercury _ad
minimum_ (_calomel_) is formed, which combines with the substance of the
viscus.
It may be objected,” continues this distinguished experimentalist, “that
this chemical action does not take place in the living animal; that our
texture, while endued with the vital principle, is not subservient to
the same laws as inorganic substances: I am not ignorant of the extent
to which this objection is well-founded; but admitting the justice of
it, the conclusion is not less true, that if the stomach contains
corrosive sublimate at the moment of death, this body will, from that
moment, act on the texture of the viscus itself. If the stomach contain
a large quantity of aliment, the effects of such an action may be
scarcely perceptible; but on the contrary, they will be easily
applicable, should the viscus be empty, and especially if the
examination of the body takes place several days after death.”[292]
In conducting experiments upon this, and indeed all other mineral
poisons, the chemist must be prepared to meet with anomalies depending
upon the impurities or adulterations of the substance under examination.