Chapter VIII: Part 8

But the _Arsenious acid_ may perchance be so mixed with various foreign matter as to render its separation by filtration difficult; in such a case, after having boiled it in distilled water, in order to procure all the soluble matter from it, the residual mass may be evaporated to dryness, care being taken that the heat applied for such a purpose never exceeds 250° _Fah._ or we shall lose the arsenic, should any be present, by volatilization. The residue thus obtained may then be submitted to a higher temperature in a subliming vessel, in order to procure the arsenious acid in its pure state. This process applies particularly to the examination of the matter vomited, or the feculent evacuations passed, by the patient. Should the arsenious acid have, in the first instance, been dissolved in oil, _Dr. Ure_ proposes to boil the solution in distilled water, and to separate the oil afterwards by the capillary action of wick threads. If the arsenious acid be mixed with resinous bodies, _Oil of Turpentine_ may be employed as their solvent, which will leave the arsenic untouched. _Dr. Black_ directed the application of alcohol for this purpose, but this is obviously improper, since arsenious acid is soluble in that fluid.

If the physician be called upon to investigate the contents of the alimentary canal after death, and the arsenious acid cannot be discovered amongst the suspected matter, the stomach itself must be cut into small pieces, and in compliance with the directions of _Orfila_, boiled in ten or twelve times their weight of distilled water, which should be renewed as fast as a portion of it flies off in vapour; this liquor should be cooled and decanted, in order to put a few drops of it into the solutions of the different re-agents which we have before described. If the precipitates should indicate the presence of arsenic, we may proceed according to the directions we have already laid down; if, on the other hand, the fluid offers no indication of poison, the mass exhausted by water should be treated, according to the process suggested by _Rose_, by boiling it for some time in a solution of potass, by which means the stomach will be partly decomposed and dissolved, and the arsenious acid, with which it might have been combined, saturated by the alkali. In this state the liquor is to be filtered, again boiled, and nitric acid added, little by little, until it passes from a dark to a clear yellow colour. The object of the acid in this stage of the process being to decompose and destroy the animal matter. The excess of acid should be saturated with potass, when an _Arsenite of Potass_ will be formed, if there really existed any arsenious acid in the stomach. This _M. Orfila_ recommends us to precipitate by the _Hydro-sulphuret of Ammonia_, and a few drops of nitric acid; (_Rose_ prefers _lime water_ for the same purpose); a yellow _sulphuret of Arsenic_ will be the result, from which the whole of the metal may be obtained, by drying it upon a filter, mixing it with an equal bulk of potass, and melting it in a small glass tube.

This complicated mode of proceeding will rarely be found necessary; but it should not be neglected, where the presence of arsenic cannot be otherwise detected in the alimentary canal of those who are suspected to have died from its ingestion, especially in the examination of a body where, from the length of time it may have been under ground, there is reason to suppose that the acid exists in a state of intimate combination with the animal matter. And we may take this opportunity to observe, that advanced putrefaction, however disagreeable it may render such researches, will not, in the case of arsenic, defeat their success; let the forensic physician, then, remember, that the length of time which may have elapsed since the death of the body, ought never to be urged as a plea for not having proceeded in its dissection. The task may be personally disagreeable, but it will be less painful than the reflections which must attend a breach of duty; upon such an occasion we would address the anatomist in the quaint but expressive words of _Teichmeyer_[262], “_Præstat enim manus quam conscientiam cruentare et contaminare._”

ARSENIC ACID, and ITS SALTS.

It has been stated, that the Metal Arsenic is susceptible of two degrees of oxidizement, the result of its first degree being Arseni_ous_ acid, and that of its second Arsen_ic_ acid. This latter compound, of which we are now to treat, may be obtained by the repeated distillation of white arsenic with nitric acid. In a solid state it is white, not crystallizable; of a sour, and at the same time, metallic taste; its specific gravity is 3·391; when exposed to the action of heat in a close vessel, it does not become volatile, but melts and vitrifies; thrown on burning coals, it swells, parts with its water, and becomes opaque; if the process of deoxidation be continued, it will, at length, rise in vapours, like those of arsenious acid, and which, like them, will yield an alliaceous odour, or not, according to the circumstances already explained. The _Arsenic acid_ dissolves very readily in water, and is even indeed deliquescent. With alkalies, earths, and oxides, it constitutes a class of salts, called “_Arseniates_,” all of which, as well as the pure acid, are extremely active poisons; fortunately, however, they are not much employed[263] in this country, and are not likely to become the instruments of crime. These salts, like those of the arsenious acid, are obedient to the different re-agents which were enumerated under the consideration of this latter substance, but with different results; thus the _silver_ test, instead of producing the yellow indication, occasions an equally characteristic precipitate of a red, or brick colour. The ammoniuret, and acetate of copper, furnish a bluish-white precipitate. The arsenic acid, in a solid form, or the arseniate, mixed with black flux, will, like white arsenic, furnish a metallic sublimate, when heated in a glass tube.

THE SULPHURETS OF ARSENIC.

There are two Sulphurets of Arsenic: the yellow variety known in commerce under the name of _Orpiment_, and the red sulphuret, termed _Realgar_. The bodies, as they occur _native_, do not appear to be endowed with the virulent powers which distinguish the other compounds of arsenic. _M. Renault_[264] gave as much as two drachms of the native orpiment to dogs of different sizes, from which they experienced no inconvenience. _Hoffman_[265] also offers his testimony of the inertness of this substance. The same observations apply to the _Realgar_. It is not a little singular that while these native sulphurets of arsenic should be so harmless, those which are produced by artificial fusions, are extremely virulent in very small doses. _M. Renault_ supposed that this remarkable difference of effect was owing to the arsenic being oxidized in the latter compound, and in its metallic state in the former. This explanation, however, is not considered as satisfactory by _M. Orfila_, who states that it does not embrace all the varieties of the case, for that the _sulphuret_, which is artificially obtained by pouring the arsenious acid into a solution of sulphuretted hydrogen, is as inert as the native compounds; besides which, chemical analysis has proved that there is no oxygen in any of these _sulphurets_, and that they only differ from one another, by a greater or less proportion of their two ingredients. This apparent anomaly induced _M. Orfila_ to institute a series of experiments for its investigation, but the results which he has obtained are too unsatisfactory to enable him to decide the question.

The presence of an _Arsenical Sulphuret_ is to be sought for by calcination with caustic potass, in a small glass tube. The sulphuret is decomposed in a few seconds, yielding its sulphur to the potass, while its metallic element is volatilized with the usual phenomena.

MERCURY.

Mercury, or Quicksilver[266], was known in the earliest ages. Its external characters are too familiar to require any particular description in this place. Its specific gravity is 13·568.[267] In its metallic state it exerts no action on the living system, except that which may depend upon its mechanical properties, although a different opinion has been entertained, (see _Pharmacologia_, art. Hydrargyrum.)

Several of the combinations of this metal are, however, highly destructive in small doses, and are consequently objects of forensic interest.

CORROSIVE SUBLIMATE.

_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.

RED OXIDE OF MERCURY. _Precipitate per se._

We are not aware of any instance of death having, from accident or design, taken place in consequence of the administration of this substance; indeed its red colour, insolubility in water, and comparative rarity, will protect mankind sufficiently against mistake, and at the same time render its secret administration extremely difficult. It is, moreover, mild in its effects, unless in large doses, or, under particular circumstances of constitution. It may be identified by its form, which is that of minute crystalline scales, of a deep red colour, and by exposing it to heat in a glass tube, by which it undergoes decomposition, giving out metallic mercury, adhering to the sides of the tube, and oxygen gas, which is disengaged.

RED PRECIPITATE, or _Nitric Oxide of Mercury_.

This is, strictly speaking, a _sub-nitrate_ of mercury, and is much more poisonous than the preceding substance. _Plouquet_[293] relates the case of a man, who swallowed by accident some red precipitate, when he immediately experienced violent colics, copious vomitings, a trembling of his limbs, and cold sweats. Its external characters will at once enable the chemist to identify it.

OTHER PREPARATIONS OF MERCURY.

The various saline compounds of this metal, as the acetate, sulphate, and nitrate, are all highly poisonous, but they do not appear to us to merit a separate consideration; and more especially as we have already explained the various processes by which every variety of preparation may be identified. We may just remark that the _sulphuret_, better known by the name of _cinnabar_, or _vermilion_, has been known to occasion deleterious effects. _Dr. Gordon Smith_[294] states, upon the authority of _Mr. Accum_,[295] that “Vermilion has been detected as a poisonous ingredient in cheese:” this may be very true, but he should have stated at the same time, that the deleterious effects produced by it, did not arise from the mercurial sulphuret, but from the red lead with which it happened to be adulterated; and it is necessary to acquaint the forensic chemist, that such a fraud[296] is by no means uncommon; it may be very easily detected by burning a small portion of the suspected sample on a piece of bread in the candle, when metallic globules will announce the presence of lead; for the oxide of mercury, although revived by the process, will at the same time be volatilized. The bread by combustion affords the carbon by which the metallic reduction is effected.

The presence of very minute quantities of _vermilion_ may, according to _Mr. Smithson_, be detected by the following simple experiment. Boil a portion with sulphuric acid in a platina spoon, and lay the sulphate thus produced in a drop of muriatic acid, on a piece of gold, and then bring a piece of metallic tin in contact with both, when the white mercurial stain will be produced.

ANTIMONY.

Although the ancients were entirely ignorant of this metal, they were well acquainted with several of its combinations,[297] _Basil Valentine_, a German Benedictine Monk, was the first who described the process for obtaining it from its ore; to this work, originally written in high Dutch, and known by the title of the “_Currus Triumphalis Antimonii_,” which was published towards the end of the 15th century, we are indebted for almost all our knowledge respecting this metal.

Antimony is of a greyish white colour, having considerable brilliancy; its texture is laminated, and exhibits plates crossing each other in every direction; its _specific gravity_ is 6·7021; when rubbed upon the fingers it communicates to them a peculiar taste and smell; it is very brittle, and fuses at the temperature of 809°, but does not appear to be volatile; when fused, with the access of air, it emits white fumes, consisting of an oxide of the metal, which formerly was called _Argentine flowers of Antimony_. When the metal is raised to a white heat, and suddenly agitated, it enters into a state of combustion, and is converted into the same white coloured oxide.

According to _Thenard_,[298] antimony is susceptible of no less than six different degrees of oxidation; _Proust_, however, has shewn that they may all be reduced to two, viz. _protoxide_ and _peroxide_. The former of which alone exerts any sensible activity upon the human body; but this constitutes the basis of several preparations, which although in common use for medical purposes, are so extremely poisonous in larger doses, as to render them objects of interest to the forensic physician.

EMETIC TARTAR.[299] _Tartarized Antimony._

This saline body appears in the state of white crystals, whose primitive figure is the regular tetrahedron, although it assumes a variety of secondary forms. Its chemical composition is still involved in some obscurity; it is stated, in the different dispensatories, to be a triple salt, consisting of tartaric acid, oxide of antimony, and potass, and that it ought therefore, according to the principles of the reformed nomenclature, to be termed a _Tartrate of Antimony and Potass_. The truth of these views, however, we have already[300] ventured to question; _Gay Lussac_ has stated that in the various metalline compounds of which _Super-tartrate of Potass_ is an ingredient, this latter substance acts the part of a simple acid; an opinion which receives considerable support from the great solvent property of _cream of tartar_, and from the striking fact that it is even capable of dissolving various oxides which are insoluble in tartaric acid, of which the protoxide of antimony is an example. In such a state of doubt, a better name could not be found than that of _tartarized antimony_.

The salt, according to _Dr. Duncan_, is soluble in three times its weight of distilled water at 212° _Fah._ and in fifteen, at 60°.

When it is heated red hot in an earthen crucible, it blackens, and undergoes decomposition like a vegetable body, leaving a residuum of metallic antimony, and slightly carbonated potass.

_Symptoms of Poisoning by Emetic Tartar._

A question has arisen whether this salt can be considered as a poison, capable of occasioning death? In general where a large dose has been administered, it is all rejected by the vomiting which it excites; we accordingly find in the works of _Morgagni_ and other pathologists, the history of various cases in proof of the innocence of this salt. _Hoffman_, however, relates the case of a woman who experienced very severe symptoms shortly after having taken tartar emetic, and that she ultimately died,[301] and there are other similar instances recorded in the works of _Foderé_ and _Orfila_. It also deserves notice, that tartarized antimony is very liable to produce deleterious effects, where, from the insensibility of the nervous system, the operation of vomiting cannot be excited, as in apoplexy, drunkenness, and in that state of coma, which follows the ingestion of narcotic vegetables. _M. Cloquet_ communicated to _Orfila_ a case highly illustrative of this fact, in which a person, labouring under apoplexy, received into his stomach more than forty grains of tartar emetic, without exciting either nausea or vomiting. On opening the body, independent of the morbid state of the brain, which must be regarded as the immediate cause of death, extensive organic lesions were discovered in the alimentary canal, which could alone be attributed to the action of the tartar emetic. This fact will suggest a very important precaution to the practitioner, who may be called upon to treat a person labouring under a state of the system which will prevent the act of vomiting.[302].

The symptoms produced by this salt will resemble those of a corrosive poison; and where vomiting is produced, it frequently happens that although the patient may be eventually saved, an irritability of stomach, so great as to cause the rejection of all aliments, will remain for a considerable period; and _Dr. Male_ states that in the only case of poisoning by this salt which he had ever seen, the person was affected with violent convulsions, which returned at intervals for several weeks after recovery from the immediate effects of the poison.[303] _M. Orfila_, after detailing several cases of poisoning by emetic tartar, concludes by saying that the general symptoms, upon such occasions, may be reduced to the following: a rough metallic taste; nausea; copious vomitings; frequent hiccup; cardialgia; burning heat in the epigastric region; pains of the stomach; abdominal colics; inflation; copious stools; syncope; small, contracted and accelerated pulse; skin cold, sometimes intensely hot; breathing difficult; vertigo, loss of sense, convulsive movements; very painful cramps in the legs; prostration of strength,—death.

Sometimes to the above symptoms is joined a great difficulty of swallowing; deglutition may be suspended for some time. The vomiting and alvine evacuations do not always take place, the necessary consequence of which is an increase in the violence of the other symptoms.

_Antidotes._

The great indication to be fulfilled in a case of this description, is the ejection of the salt by vomiting. _MM. Orfila_ and _Berthollet_ rely very confidently upon the effects of _bark_, _strong tea_, _infusion of galls_, and other _vegetable astringents_, which have undoubtedly the power of decomposing the salt. They ought, therefore, to be employed as diluents to assist vomiting, but they are not to be considered as antidotes which can render this latter operation less indispensable.

_Physiological action of emetic tartar._

_M. Majendie_ has shewn by experiment, that if _tartarized antimony_ be injected into the veins of a dog, the animal vomits, and has frequent stools; his breathing becomes difficult; his pulse frequent and intermitting; a great degree of disquietude, and tremblings are the precursory signs of death, which generally takes place within the first hour from the injection of the emetic tartar. On opening the body great alterations are perceived in the lungs; they are found of an orange or violet colour, have no crackling, are distended with blood, and of a tight texture. The mucous membrane of the intestinal canal, from the cardia to the extremity of the rectum is red, and strongly injected.

If, instead of thus injecting the emetic tartar into the veins, it be injected into the stomach, and the œsophagus is tied to prevent vomiting, _M. Orfila_ informs us that the same alterations will be found after death. The very same effects will also arise from the application of the emetic tartar to the different absorbing surfaces, such as the cellular substances, &c.

_Mr. Brodie_[304] has also thrown considerable light upon the action of this salt. He observes that the effects of emetic tartar so much resemble those of _arsenic_, which we have already described, and those of _muriate of baryta_, which will form a future subject of inquiry, that it would be needless to enter into a detail of the individual experiments which he made with it. When applied to a wound in animals which are capable of vomiting, it usually, but not constantly, operated very speedily as an emetic; in other respects he found no material difference in the symptoms produced in the different species of animals, which he had been in the habit of employing as subjects of experiment. The symptoms were paralysis, drowsiness, and, at last, complete insensibility; the pulse became feeble, but the heart continued to act after apparent death, and was maintained in action by means of artificial respiration; but never for a longer period than for a few minutes. Whence it would appear, that this poison acts by being absorbed, and that it directs a sedative influence upon the heart, as well as the brain, but that its principal action is on the latter. The length of time which elapses, from the application of the poison to the death of the animal, varies; in some instances _Mr. Brodie_ found that it did not exceed three quarters of an hour, but in others, it was two or three hours, or even longer, before death took place. When a solution of emetic tartar was injected into the stomach of a rabbit, _Mr. Brodie_ observed the same symptoms to take place, as when it was applied to a wound.

_Organic lesions discovered by dissection._

_Mr. Brodie_, in his examination of animals poisoned by _emetic tartar_, sometimes found the stomach bearing the marks of inflammation, but at other times, its appearance was perfectly natural. In no case did he discover any traces of inflammation in the intestines. The reader must compare this account with that already given by _M. Majendie_, at p. 282.

1. _Tests for the detection of emetic tartar._

1. _The poison is in a solid form._ Dissolve a portion of the suspected salt in about fifteen times its weight of boiling distilled water; if it be emetic tartar, the following reagents will identify it, viz.

(_a_) _The hydrosulphurets_ will occasion a reddish-yellow precipitate, which is a combination of _oxygen_ and _antimony_, proceeding from the emetic tartar; and of _hydrogen_ and _sulphur_, from the reagent employed. If it be dried on a filter, and mixed with charcoal and the potass of commerce, it gives, by the action of heat, a cake of metallic antimony.

(_b_) _Tincture of galls._ This is regarded as the most sensible test of this salt, affording a precipitate of a curdled, dirty white colour, inclining to yellow.

(_c_) _Lime water._ This reagent produces a white precipitate, which is extremely thick, and is easily redissolved by pure nitric acid. In this case the lime forms an insoluble tartrate, and the tartrate of antimony, thus rendered insoluble, subsides along with it.

(_d_) _Concentrated sulphuric acid_ gives a white precipitate, which consists of the oxide of antimony retaining a small portion of the acid. It redissolves in an excess of the precipitant.

(_e_) _Vegetable extractive_, occasions in the solution of this salt, a reddish-yellow precipitate, which has been found to consist of _oxide of antimony_, and a portion of vegetable matter.

2. _It is mixed with various alimentary substances._

If our attempts should fail to procure a solution of the salt by filtration, answering to the above reagents, we must rely upon the proof of metallic reproduction. Various circumstances may invalidate the action of our tests, such, for instance, as the ingestion of some vegetable infusion or decoction, especially that of galls, or yellow bark.

With respect to the other preparations of antimony, it is unnecessary to waste our time in their consideration; the precepts already given will afford the practitioner every requisite hint for the prosecution of the enquiry.

COPPER.

This metal, with the exception of gold and silver, and perhaps tin, was known earlier than any other metal; but its applications were entirely confined to the arts. It was first discovered by the Greeks in the island of Cyprus, whence its name; and we learn from _Homer_, that even during the Trojan war, the combatants had no other armour but what was made of bronze, which is a mixture of _copper_ and _tin_.[305].

The external characters of the metal are too well known to require minute description. Its taste is styptic and nauseous; and the hands when rubbed for some time on it, acquire a peculiar and disagreeable odour. When melted, its specific gravity is 8·667; but after being hammered it is 8·9. It is only susceptible of two degrees of oxidation. If the protoxide be _native_, it is red; if _artificial_, orange coloured. The peroxide is black.

Copper, on exposure to a moist atmosphere, becomes tarnished, absorbs a portion of its oxygen, and passes into the state of an oxide, which shortly unites with the carbonic acid of the atmosphere, and forms a greenish carbonate of copper.

Metallic copper, perfectly pure, does not possess any deleterious properties. We have already cited instances[306] sufficiently conclusive to establish this fact. It becomes, therefore, a subject of no little interest to enquire, under what circumstances it may become poisonous by combination. _M. Orfila_ observes that it has been long maintained, that milk heated, or allowed to remain in vessels of copper not oxidized, dissolved a portion of this metal, and acted as a poison. _Eller_, a philosopher of Berlin, has, however, very clearly proved such an opinion to be incorrect. He boiled in succession, in a kettle well freed from verdegris, milk, tea, coffee, beer, and rain water; after two hours boiling, he found it impossible to discover, in any of these fluids, the least vestige of copper. _M. Drouard_ has also shewn that distilled water, left for a month together on the filings of this metal in a glass bottle, did not dissolve an atom of it. The celebrated toxicologist above cited, after relating these important facts, concludes by observing, that the phenomena are very different, if, instead of pure water, we substitute that which contains a certain quantity of muriate of soda. _Eller_ has demonstrated the presence of a very small quantity of copper in water, which contained 1/20th of its weight of muriate of soda, and which had been boiled in a brass kettle. This fact is of the highest importance, for it will explain the reason why highly seasoned aliments have proved deleterious, when cooked in vessels of copper. But we are indebted to _Mr. Eller_ for a still more important discovery; he found that if, instead of heating a simple solution of common salt in copper vessels, the salt be previously mixed with beef, bacon, and fish, the fluid resulting from it does not contain an atom of copper.[307] In relating this fact, _M. Orfila_ observes, “however astonishing it may appear, it is quite correct, _M. Eller_ was the first to announce it, and I have several times ascertained the truth of it; it is probable,” continues _Orfila_, “that the combination of several kinds of aliments destroys the effect of the solution of the muriate of soda; which consequently ought to render the cases of poisoning by aliments cooked in copper vessels, _which are not oxidized_, extremely rare.”

Copper combines with sulphur, and affords a black sulphuret.

OXIDE OF COPPER.

By oxidation, copper becomes poisonous. The substance may be easily recognised by the change of colour which it produces in ammonia; this alkali will dissolve it instantly, and assume a beautiful blue colour. It is wholly insoluble[308] in water. In oils and fatty matter it is easily and copiously dissolved at the ordinary temperature of the atmosphere. Such bodies also, when boiled in vessels of perfectly clean copper, facilitate their oxidation, especially if left to cool a few minutes before they are poured out.

GREEN CARBONATE OF COPPER—_Natural Verdegris_.

This substance forms spontaneously on surfaces of copper and brass; it differs from the oxide in its green colour, and in effervescing with dilute sulphuric acid; with ammonia, however, it demeans itself in the same manner, and is likewise insoluble in water. It is poisonous.

From the above history of these substances the medical practitioner will easily perceive under what circumstances, and by what bodies, metallic vessels of copper may be rendered dangerous. The oxide and carbonate, formed in them, will easily dissolve in acidulous and oily aliments, whence it follows that all preparations of such food, if conducted in vessels whose surfaces have contracted this change will be liable to prove deleterious.[309] If the vessels be perfectly clean, acid preparations may be safely boiled in them, but they must be poured out immediately, and not suffered to remain sufficiently long to allow the copper to become oxidized. To the formation of the oxide of copper, and to the acetic acid contained in the wine, vinegar, beer, and cider, _M. Orfila_ attributes the production of the _acetate_ which forms about the corners of the cocks in vessels containing these liquors. Upon the same principle the _soda water_ sold in this town, in a draught, from the pump, is liable to metallic impregnation, as we have fully satisfied ourselves.