B.By the application of certain reagents, or tests, to its solutions.
B.By the application of certain reagents, or tests, to its solutions.
B.By the application of certain reagents, or tests, to its solutions.
It may happen that the quantity of the above substances is not sufficient to allow their metallic reduction by calcination. In that case, we must proceed to obtain a solution; but since neither the oxide, nor the carbonate, is soluble in water, it will be necessary to bring them in contact with concentrated acetic acid, so as to obtain an acetate of copper; which will furnish the following indications with the respective tests.
a.A surface of clean iron.If dipped into the solution will become coated with metallic copper, and appear as if transmuted into that metal.
b.Ammonia.This test, when added in a quantity more than sufficient to saturate any excess of acid, will strike a beautiful blue colour; in the first instance we shall obtain a deep blue precipitate, but this will be redissolved by an excess of alkali. To detect the presence of copper, therefore, in pickles, it is only necessary to cut them into small pieces, and to pour liquid ammonia, diluted with an equal bulk of water, over them in a stopped phial: if the pickles contain the most minute quantity of this metal, the ammonia will assume a blue colour. In the same manner cupreous impregnations may be discovered in the various articles of confectionary above enumerated, and in those foreign conserves which are imported into this country, and usually sold in round boxes.
c.Sub-carbonate of Potass.By this re-agent a precipitate of a pale blue colour is produced.
d.Arsenite of Potassinstantly occasions a copiousprecipitate in the acetate of copper, which is of a green colour, and is in fact an arsenite of the metal.
e.Triple Prussiate of Potass.This test gives a brown precipitate with a solution of verdegris, which is found to consist of prussiate of copper, and prussiate of iron; while the liquor contains an acetate of potass.
We have in this case the same embarrassments to encounter, as those already noticed under the consideration of arsenic. Our tests may produce their respective precipitates, but they will present different colours according to the nature of the fluids with which the substance happens to be mixed; whence the circumstance of colour, so characteristic on other occasions, cannot be received as a satisfactory indication. In such a difficulty, we may collect the precipitates, and calcine them in a crucible with charcoal, in order to obtain the metal; or we may at once evaporate the whole of the alimentary mass, and submit it to a high temperature, by which means all the vegetable and animal principles, which can form a part of the liquor vomited, will be decomposed and converted into several volatile productions, and into charcoal; this combustible body will decompose the oxide of copper, and reduce it to its metallic state.[312].
Nor is this process without its fallacies; it is often difficult to recognise the metal, dispersed as it necessarily must be, in small quantity, through a considerable mass of charcoal; in this case we are recommendedbyOrfilato place the product of the calcination in water, when in a short period, the copper, from its superior specific gravity will subside from the lighter particles of charcoal. But it would be still better to pour nitric acid upon the product of the calcination, and thereby to obtain a solution ofnitrate of copper, which by filtration might be immediately prepared for the application of appropriate re-agents.
It merits notice, however, that in certain cases of poisoning by copper, no vestiges of the substance can be found in the matters voided from the stomach. In that case,Orfiladirects that the mucous membrane of the stomach, and of the intestines, should be scraped off, dried, and submitted to the action of a strong heat in a crucible. “I have,” says this distinguished experimentalist, “twice obtained metallic copper, by calcining in this manner a portion of the membranes of the stomach of two dogs that I had poisoned with verdegris. This effect particularly takes place when the mucous membrane is of a bluish colour, hard, and strongly adhering to the substance of the stomach.”
It is clearly established by the experiments ofBayenandCharlard,[313]as well as by those ofProust,[314]that this metal possesses no poisonous properties. Its muriate, however, has been shewn byOrfilato possess highly corrosive properties. It excites violent vomiting, great depression, and death, without convulsions. Its antidote is milk, which it speedily coagulates; and by chemical combinationwith it, the poison is rendered inert. On dissection, the stomach is said to have been found corrugated and indurated, and has been compared to tanned skin, but its colour is not altered.
As this substance is never likely to become an object of forensic interest, in this kingdom, we shall pass it over without farther notice.
The ancients were acquainted with a mineral to which they gave the name ofCadmia,[315]from Cadmus, who first taught the Greeks to use it. They knew that when melted with copper it formed brass; and that when burnt, a white spongy kind of ashes was volatilized, which they used in medicine.[316]This mineral contained a good deal of zinc; and yet there is no proof remaining that the ancients were acquainted with that metal. It has a brilliant white colour, with a shade of blue, and is composed of a number of thin plates adhering together; its specific gravity is 7·1. When strongly heated in a crucible, it quickly goes into fusion, absorbs the oxygen of the atmosphere, and burns with a beautiful white flame, inclining to green, and extremely brilliant. The oxide of zinc thus formed, is diffused through the atmosphere, and is there condensed into extremely light flakes of a beautiful white appearance. This oxide was formerly known under the fanciful names ofnihil album; lana philosophorum, &c.
In its metallic state it is quite inert; but late experiments byVauquelinandDeyeux, have proved that it is very easily acted upon by water, the weakestvegetable acids, some saline substances, and butter; a fact which is hostile to the proposal of employing this metal for the manufacture of culinary utensils.
This salt occurs in masses, consisting of crystals which are four-sided prisms, terminated by four-sided pyramids. Their taste is styptic, metallic, and slightly acidulous. They are soluble in 2·5 times their weight of water at 60°, and in less than their own weight of boiling water, butthey are quite insoluble in alcohol. Thus dissolved they redden the tincture of tournesol.
This salt, like tartarized antimony, from the high degree of emetic virtue which it possesses, generally proves its own antidote; still, however, it must be considered as a poison; for several cases are on record, where the most alarming symptoms, and indeed death itself, have been the effect of its ingestion.Metzger[317]mentions the case of a woman, who accidentally ate a trifling quantity of a cake, into whichWhite Vitriolhad been introduced for the purpose of shortening the days of an old man. The woman died; but the intended victim escaped, after severe vomiting.M. Orfilahas also related several cases of poisoning by this salt. The symptoms which presented themselves on these occasions were, an astringent metalline taste, a sense of constriction in the fauces, so distressing as even to excite in the patient a fear ofsuffocation; frequent vomitings; copious stools; pains in the epigastric region, extending afterwards over the whole abdomen; difficulty of breathing; frequency of pulse; paleness of the countenance, and coldness of the extremities.
We have lately heard of a case in which a noble lord swallowed a solution of white vitriol, which had been sent to him by mistake, for Epsom salts, to which it bears some analogy. Fortunately, however, the violent emetic effect which followed removed the poison from the stomach, and obviated any farther injury.
We have no well authenticated dissection of a human being who had died from the ingestion of this poison. The examination of animals[318]who have been so killed has shewn nothing more than an inflammation, not very severe, of the membrane with which it had come in contact; sometimes dark blood is observed to be extravasated upon the muscular coat of the stomach and intestines.
The chemist must remember that theWhite Vitriolof commerce always contains sulphate of iron, and sometimes sulphate of copper. When dissolved in distilled water it may be identified by the following re-agents;viz.
a.Potass, andAmmonia, precipitate an oxide of a greenish white colour, easily soluble in an excess of the latter of these alkalies. The oxide obtained by potass, being washed and dried, and calcined withcharcoal, is revived, provided the temperature be very much elevated. It should be known, that if the salt has been previously purified, the above tests will occasion awhiteprecipitate.
b.Prussiate of Potassproduces a precipitate of a rather deep blue colour; which, consists of a mixture of the prussiates of zinc and iron. If the salt has been divested of all impurity, the precipitate will be white.
c.The Hydro-sulphuretsinstantly occasion a blackish precipitate, which, like the former, will be found to be a mixture of zinc and iron, in the state of an hydro-sulphuret. If the salt, however, is pure, its colour will be white with a tinge of yellow.
This metal does not exert any influence on the living body; but its oxide in combination with nitric acid constitutes one of the most corrosive of all the metallic salts.
The usual state in which this substance occurs is in that of small cylinders, having been cast into moulds for the purpose of imparting to it a form best adapted for the purposes it is designed to answer.
Its action on animal matter is highly caustic, and when introduced in any considerable quantity into the stomach, will induce death by corroding the texture with which it may come in contact. At the same time there is reason to believe that the whole, or part of its composition, may be absorbed; for we have many instances on record where the frequentrepetition of this metallic salt, in small doses, has imparted a blue tinge to the skin, which can only be explained on the supposition that the oxide of the metal has been actually deposited in the rete mucosum[319].
We are not aware that there is any modern case of poisoning by this salt[320]. The medical practitioner, however, ought to know, that common salt, is its true antidote; indeed so completely does it decompose and separate it from water, that if a saturated solution of nitrate of silver be filtered through common salt, it may be afterwards drunk with impunity.M. Orfila, by a series of experiments, has shewn that if themuriate of sodabe administered a very short time after the ingestion of lunar caustic, it will disarm it of its virulence by transforming it into an insoluble muriate, possessing no power of acting on the animal œconomy.
If a small portion of the salt can be procured it may be dissolved in distilled water, and immediately identified by the following tests.
a.Muriatic acid, or any soluble Muriate, will precipitate the muriate of silver, which is white, curdled, very heavy, insoluble in water, or nitric acid; but soluble in liquor ammoniæ; when exposed to the air it acquires a black colour.
b.Potass,Soda, andLime water, will occasion a precipitate of the oxide, of a deep brown colour.
c.Ammonia.This alkali will form anammoniuret of silver, and in consequence of the solubility of this new product, little or no disturbance is occasioned by the test.
d.Arsenite of Potass.As all re-agents must be considered as reciprocal in their operation, it is hardly necessary to state that this is one of the best tests for nitrate of silver. See the history of its effects at p.240.
If it should be necessary to discover the nitrate of silver amongst the fluids vomited, or those contained in the stomach of the deceased, we are very properly directed byM. Orfilato filter, and then assay by the appropriate tests; if, however, the different aliments should disguise the characteristic colour and appearance of these precipitates, we must proceed to desiccate and calcine them in order to obtain the silver in a metallic state.
These must be regarded as the most terrible of all corrosive poisons. Their action is so immediate and energetic, as generally to destroy the membranes of the stomach, before their peculiar antidotes can be applied. Notwithstanding the obvious suffering they must occasion, and the facility with which they may be detected, such bodies have frequently, especially in France, been the instruments of suicide and murder; whilst in this country, we have had many lamentable illustrations of their deadly force, by their ingestion from fatal carelessness. In conformity with our general plan we shall proceed to consider the individual substances included underthis general class, although the symptoms do not materially differ in the different kinds, nor are the indications of cure peculiar to any of them. There are however chemical characters which exclusively belong to each acid, with which the forensic physician must be accurately acquainted, in order that he may be enabled to detect their presence.
This acid, when perfectly pure, exists in the form of a colourless liquid, without smell, and of an oily consistence; whence its popular name. Its specific gravity is 1·85, so that, in round numbers, it may be stated that an ounce, by measure, will weigh fourteen drachms. It acquires a brown tinge from the smallest portion of carbonaceous matter; mere exposure to the atmosphere is sufficient to effect this change, in consequence of the acid disorganizing and carbonating the vegetable and animal matter suspended in the air. This fact sufficiently explains why we generally find the acid of commerce of a brown colour.
Its taste is highly acid and caustic. So powerful is its affinity for water, that upon its admixture with this fluid, a heat, sufficiently great to boil water, may be produced. When exposed in its concentrated state to the air, it will imbibe at least seven times its own weight of water, and so rapidly as to have its weight doubled in a month. Straw, wood, and all vegetable substances, when immersed in the sulphuric acid, without heat, are disorganized, softened, and blackened, and there is separated from them a certain portion of charcoal. Like the other mineral acids, theOil of Vitriolhas never been obtained in an insulated state without water; according to the latestviews ofSir H. Davy, the composition of the strongest acid may be expressed as follows. Sulphur 30, oxygen 45, water 17.
An extremely austere, acid, and burning taste; a painful heat in the fauces and throat, along the œsophagus, and in the stomach; excruciating pain; nausea, and excessive vomiting; at one time the fluid vomited is as black as ink, at another reddened by arterial or venous blood, producing in its passage through the throat, the most intense pain, accompanied with a sensation of bitterness quite intolerable; if, by chance, a portion of it should fall on the hearth or pavement, or on any other calcareous substance, it will denote its true nature by an effervescence; constipation, or sometimes bloody stools; gripes and excruciating pains over the abdomen, with a tenderness of these regions, so exquisite as not to allow the slightest pressure without torment; pains of the breast; difficulty of breathing; extreme anxiety; the pulse becomes frequent, small, contracted, and irregular; shiverings; great restlessness, dejection, and agitation; convulsive motions of the countenance; sometimes a cutaneous eruption betrays itself. Amidst all these symptoms, the intellectual powers remain unobscured. The parts about the fauces, the uvula, &c. having lost their vitality, slough, and become detached, which occasion an indescribable fetor of the breath, while they produce a perpetual cough, and the voice becomes so altered, that it resembles the sounds of a person labouring under croup.
Organic lesions discovered on Dissection.
As this substance destroys life by simply acting as an escharotic, it is not difficult to anticipate the disorganization which dissection will display. The extent of the lesion, however, must in every case depend upon the quantity and degree of concentration of the acid, the state of the stomach in relation to its alimentary contents, and other incidental circumstances not to be exactly appreciated. The mucous membrane of the mouth, the tongue, and œsophagus, will in general be found destroyed, and converted into a pulp.
The great indications to be fulfilled in this distressing case, is the immediate dilution, saturation, and expulsion of the poison. Copious draughts of water, holding calcined[321]magnesia in suspension, should be administered without any loss of time. If this is not in readiness, soap and water should be administered; mucilaginous drinks, milk, and even warm or cold water, in the absence of more eligible potations, should not be neglected. It must be never forgotten, exclaimsOrfila, that success upon these occasions depends upon the activity of the practitioner; the delay of a few moments will entirely change the fate of the patient, as the sulphuric acid destroys the texture of the organs with a fearful celerity. After having thus neutralized the caustic, it will be our duty to obviate the effects it may belikely to occasion; the lancet must be used with boldness, and the detraction of blood repeated at short intervals; at the same time emollient clysters may be advantageously injected.
In the pure state, there can exist no difficulty in identifying it; its specific gravity, and its action on vegetable matter, will, without any other tests, be quite sufficient to fulfil our object. If heated with metallic mercury, it will disengage sulphurous acid gas; and if united with lime, a sulphate of lime will be produced, which the chemist may easily recognise by dissolving a portion in distilled water, and assaying the solution bymuriate of baryta, which will produce with the sulphate a precipitate, insoluble in nitric acid. By the last mentioned tests we shall be enabled to detect the presence of sulphuric acid, in whatever state of complication it may happen to exist with alimentary matter.
This acid, when pure, assumes the form of a limpid fluid, emitting white fumes of a suffocating odour; its taste is highly acid, and corrosive; and it is at once distinguished from all other acids, by its tinging the skin indelibly yellow. When of the specific gravity 1·5 it contains 74·895 per cent of dry acid, (whose ultimate elements are one proportional of nitrogen, and five of oxygen) the complement 25·105 parts, is water.[322]It is decomposed with violent action by all combustibles, and when mixed with volatile oils it causes their inflammation.
From the facility with which this acid undergoes decomposition, it is rarely found in commerce in a colourless condition; indeed the action of light is sufficient to impart a tawny tinge to it; when this change has proceeded to such an extent as to render the acid orange coloured, it is calledNitrous acid, or, in the language of the arts,aqua fortis, although in a chemical point of view, such a nomenclature is incorrect, for it is nothing more than nitric acid, holding nitrous acid gas loosely combined.
This acid has been so frequently swallowed in France, for the purpose of committing suicide, that it has enabled the pathologists of that country to afford a very satisfactory account of its operation, and effects. ToM. Tartrawe are particularly indebted for a very full and interesting investigation of the subject, and we shall avail ourselves upon the present occasion, of the many facts and observations with which his treatise[323]abounds. In describing the symptoms occasioned by the ingestion of this acid,M. Tartraestablishes four different gradations, viz. 1. When the death is speedy, for it is never sudden, it commonly takes place from theprimaryeffects in about twenty-four hours, varying from six to forty-eight hours. 2. When it proves fatal from itssecondaryeffects, at different intervals, from fifteen days to several years. 3. When death does not take place, but the recovery is imperfect. 4. When a perfect cure is sooner or later obtained. The first case is illustrated by thefollowing example, which will serve to convey a very just idea of the progress and intensity of the symptoms. “A man, driven by distress to commit suicide, under the greatest agitation of mind, and upon an empty stomach, swallowed, at a draught, two ounces of concentrated nitric acid. Instantly he was seized with the most excruciating pains and agitation, and could not lie in bed, but rolled himself upon the floor. Vomiting came on, accompanied by a general sensation of coldness, especially in the extremities. Every time he vomited, the matter effervesced upon the pavement. A solution of soap and oil was administered to him, and in two hours he was brought to the hospital, often having vomited, and stopped on the road to drink. On his arrival, he had emollient drinks, especially linseed tea, in great abundance. He was in continual agitation, and his countenance was greatly altered. He now vomited every instant a blackish glairy matter; he opened his mouth easily, and his tongue was white, with a tinge of yellow; he complained of acute pains in his mouth, along the œsophagus, and in his stomach. His belly, slightly tense, could not bear the slightest pressure, without great torment. The surface of the body was cold; the pulse small and frequent; he had hiccup, and the respiration was laborious.
His symptoms increased. He uttered sighs and lamentations; his limbs became icy; a cold sweat covered his whole body; his pulse was scarcely perceptible; the pain was constant; still he could rise and make continual but useless efforts to quench his thirst, and satisfy his urgent desire to void urine, and go to stool. He continued in this state during the night; the matters vomited became more clear,and of a yellow colour. He at last made a few drops of urine. The shocking appearance of his body already resembled that of a corpse, but he retained his senses, and was speaking when he expired, nineteen hours after swallowing the acid.” The burning heat and pains which are commonly the immediate effects of the ingestion of this acid are very variable in their intensity and duration, andM. Tartraobserves that, in general, they are not in proportion to the quantity or strength of the acid swallowed. It often happens that persons who have taken only a small dose, are seized with the most excruciating and dreadful pains, and some of those who have swallowed a great quantity, two or three ounces for example, have had scarcely any suffering, but remained very tranquil. In the first case, the patients either recover, or survive a long time; in the second, speedy death is almost always the consequence; thus a young man of twenty died in twenty hours, without any agitation or signs of acute pains. On opening the body, the highest degree of disorganization appeared, perforations of the stomach, and great effusion of its contents into the abdomen. The second variety of the progress and termination of poisoning by nitric acid, exhibits, at first, the same phenomena as the preceding; but less alarming symptoms succeed by degrees; after some months, the inner membrane of the alimentary canal detaches itself in portions, the patient falls into a marasmus, and dies. We are here presented with a case ofconsecutivepoisoning, seepage147.
The third termination is in imperfect recovery. A slow and progressive amendment ensures the safety of the patient; but there still remains some complaint; obscure pains in the throat, and especially inthe epigastric region; habitual constipation, occasional vomiting, and increased sensibility of the stomach, so that it can only support light nourishment and bland liquors; in short, they continue invalids during the rest of their lives; they are subject to repeated and even habitual indispositions, and sometimes to pain and insupportable heat of the stomach; but they are able to follow their occupations, and long survive their poisoning.
The total disappearance of the symptoms produced by swallowing nitric acid; or complete and absolute recovery without leaving any consequences, is the last variety of termination.
Tartrahas furnished us with the following interesting account of the dissection of those who have died of the primary effects of nitric acid. The external appearance of the body presents no alteration; every part is sound and natural, and possesses, in a certain degree, the firmness and freshness of life. The epidermis of the margins of the lips has commonly an orange colour, more or less deep. It seems burnt and easily separates. Sometimes yellow spots are discovered on the hands and other parts of the body, caused by the contact of the acid. A yellow fluid, in some cases very abundant, flows from the mouth and nostrils, and the belly is considerably distended with air. The alimentary canal is remarkably affected. All the internal membrane of the mouth is burnt, and has sometimes a white colour, but is more commonly yellow; it is separate in some places, and adheres in others. The teeth are often loose, and have a very marked yellow colour at theircrown.The mucous membrane of the pharynx exhibits the same change, or is in a state of inflammation of a dirty red colour. The whole extent of the œsophagus is lined with a dense mass of a fine yellow colour, dry on its surface, unctuous and greasy to the touch, and which seems to be formed both of the mucous membrane, altered in a particular manner, and of the albumen contained in the viscid fluid which exudes from the membrane of the œsophagus, solidified by the nitric acid. This lining adheres in very few points, and is easily detected from the other membranes of the œsophagus, which are brown and blood-shot. When the stomach is not perforated, it has commonly a considerable size; externally, its membranes are slightly and partially inflamed, but very much towards the pylorus and beginning of the duodenum. Its colour is faded, livid, of a yellowish green, with large gangrenous spots. It adheres every where to the neighbouring parts, the diaphragm, liver, spleen, and transverse arch of the colon, by means of a concrete lymphatic exudation; its sides, which are thin and yellow in some places, and thick and black in others, exhibit net-work of dilated blood-vessels filled with black coagulated blood. Often there are several points of the stomach dissolved, and ready to burst with the slightest touch; it contains a great quantity of gas, which has a peculiar smell, resembling that of bitter almonds; it also very commonly contains a great quantity of yellow matter, of a pultaceous consistence; the substance of the stomach is generally swelled in some places, and deeply marked with black, without being dissolved; this effect is most remarkable at the great end, into which the acid seems to fall by its weight; the rugæ of the stomach are very brown, and are reduced to a mucilaginousconsistence. The other parts of the alimentary canal exhibit the same organic lesions, although the phenomena have less intensity in proportion as the part is more distant from the stomach.
In those cases where the stomach is found perforated, its bulk is very small; the holes commonly occur in the large and small extremities; their form is circular, and their edges thin, and as if dissolved. The urinary bladder contains no urine, although the patient have not discharged any.
The appearances upon dissection of those who die of thesecondaryeffects are entirely different from those above described. It would be difficult to find an example of greater emaciation, more advanced consumption, or more disgusting form. Nothing is equal to the degree of withering, and decrepitude of the whole organs; their colour is faded; the internal cavities do not contain the usual serum; the cellular and muscular systems are almost annihilated; the bones become dry, as in persons of advanced age, and break with extraordinary facility; but these changes are general and secondary, and depend upon local organic derangement of the alimentary tube. The stomach and whole intestinal canal are contracted to an extremely small size; the intestines are not larger than the little finger, sometimes not exceeding a thick writing quill; their coats are very thick, their cavity almost obliterated, and containing only a little mucosity. The stomach, which often resembles a portion of a small intestine, appears sound externally, and only presents some adhesions to the neighbouring viscera; internally, the most remarkable change is the contraction of the pylorus, the passage through which will scarcely admit a probe; and the membranes of the stomach itself are so thickened and compactedaround it, that they have lost all their natural suppleness. On the internal surface, there are irregular spots, or rather smooth and red places, which seem to be covered with a regenerated mucous membrane, less villous than that which had been destroyed by the action of the acid; these cicatrices are particularly large and numerous in the great end of the stomach, and around the circumference of the pylorus.
If the acid be in any quantity, and without mixture, there cannot exist any difficulty in demonstrating its presence. If added to copper filings, there will be a copious disengagement of orange-coloured fumes, and a nitrate of copper of a blue colour will remain, as the product. If it be saturated with potass, we shall at once obtain by due evaporation the well known substance, nitre; this salt will announce its nature by deflagrating with charcoal or sulphur. This latter test is the one we must employ for the detection of nitric acid, when mixed with vinegar, and other liquids. Where the acid has combined with the animal matters with which it may have come into contact, they must be boiled for an hour in a solution of pure potass, when the solution will assume a reddish appearance; this must be filtered, and evaporated in a capsule of porcelain, when the mass so obtained will leave a residuum of nitrate of potass.
Dr. Marcet, in a paper just published in thePhilosophical Transactions,[324]on the composition of seawater, employed a new mode of assaying the solution for nitric acid, and for which he acknowledges himself indebted toDr. Wollaston. Having concentrated thebitternin a glass vessel, until it began to deposit solid matter, he added sulphuric acid and gold leaf, and boiled the mixture; the gold leaf was not in the least acted upon, nor was any smell of nitric acid perceived; but on adding the smallest quantity of nitre to the same mixture, the gold was dissolved, and the smell ofaqua regiainstantly perceived. The rationale of the experiment is obvious, gold, although insoluble in muriatic acid, is instantly dissolved on the addition of nitric acid, in consequence of the developement of chlorine.
The liquid acid, of which we are about to treat, is a solution of muriatic acid gas in water; when of the specific gravity 1·16, according toDavy, it contains 32·32 per cent. of the gas, which recent experiments have proved to be a compound ofChlorine(oxy-muriatic acid) andhydrogen, in equal volumes. It has accordingly received a name expressive of its composition, and is calledHydro-chloric acid. Its odour is strong and peculiar; when exposed to the air it emits white fumes; its taste is intensely sour and caustic; it is, however, the weakest of the three mineral acids, and no remarkable elevation of temperature is produced by dilution. It readily combines with potass, soda, &c. and furnishes a class of salts which may be easily recognised by their characters.
As the effects of muriatic acid do not differ from those which have been described, as the consequencesof poisoning by the other mineral acids, it will be unnecessary to enumerate them.Orfila, however, remarks, that the patients who have swallowed a certain quantity of it, emit, in the first moments of the accident, a thick smoke of a white colour, and very pungent smell.
This acid, in its free state, immediately announces its nature by the fumes which it emits. When the acid, however, exists in a more questionable shape, as in the matter vomited by the patient, or in that found in the digestive canal after death, it will be necessary to saturate the liquid part with pure potass, and to boil it for some time, when we shall obtain a fluid, from which the nitrate of silver will throw down a dense precipitate. By evaporation, we shall obtain a crystallized muriate, which may be identified by the following tests: 1, When concentrated sulphuric acid is poured upon it, a brisk effervescence is immediately occasioned, and the muriatic acid is disengaged in the form of white vapours, which are thick, and of an excessively pungent smell. 2, If instead of employing concentrated sulphuric acid, this acid be used in a state of dilution, and the muriate be mixed with some substance which easily yields its oxygen, the muriatic acid will be decomposed, its hydrogen, combining with the oxygen so as to form water, while the chlorine will be disengaged, and by its pungent and peculiar odour at once announce the nature of the acid under examination.
Oxalic Acid.Acid of Sugar.[325]
This salt occurs in small crystals, whose form is that of a four sided prism. It is extremely acid to the taste, so that by applying the tongue to one of its crystals, its nature may be immediately discovered. It dissolves in twice its weight of cold, and in an equal weight of hot water; it is also soluble in boiling alcohol which takes up about half its weight; the solutions act powerfully on the vegetable colours, and at once denote their acid properties. On account of the strong resemblance which the crystals of this acid bear to those of sulphate of magnesia, orEpsomsalts, many fatal accidents have occurred. We are not aware that it is ever purchased, in retail, for any other purpose than as a detergent, to clean the tops of boots; in the large way, it is an article of extensive trade with the calico printers. Its salts[326]are likewise employed for various purposes in the arts.
Amongst the many schemes which have been proposed to secure the public against the possibility of mistaking this acid for Epsom salts, there does not appear to be one which admits of successful application; nor are we able to propose any test of discrimination which is not far inferior in accuracy and convenience, to that which is afforded by the mere taste of the crystal; indeed we cannot understand how soacid a solution can be swallowed, without an immediate discovery.
From the history of the many cases on record, it appears that this acid produces all the grievous symptoms, which characterise the action of a corrosive poison; its operation upon the stomach is similar to that of any other powerful acid; and dissection displays the same destruction of parts, as that we have already described under the consideration of the mineral acids.
We should endeavour to form as quickly as possible an insoluble oxalate of lime; copious draughts of lime water, or magnesia and water, should be administered; and vomiting immediately excited.
If any of its crystals can be obtained, we shall be immediately able to identify them. They dissolve very readily in water, and since the oxalic has a greater affinity for lime, than any other acid, and forms an insoluble salt with it, we have thus a ready test of its presence, for it will decompose all the calcareous salts, not even excepting the sulphate.
Many cases are recorded of the death of children from the ingestion of boiling water; an accident which will be always liable to occur, as long as the peasant allows his family to quench their thirst by drinking the cold water through the spout of the tea kettle. It has been very generally supposed that fataleffects have, on these occasions, supervened the high state of inflammation produced in the æsophagus and stomach by the boiling liquid.Dr. Marshall Hallhas, however, lately published a very interesting paper on this subject, in the twelfth volume of theMedico-Chirurgical Transactions; from which it would appear, that the patient, under these circumstances, actually dies of suffocation as in croup; and that the boiling water is arrested in its progress to the stomach by the convulsive action of the muscles of the pharynx. In passing, however, to the posterior part of the mouth, it scalds theepiglottis, andglottis, which afterwards become more and more swollen, until at length therima glottidis, or orifice into the larynx, becomes completely obstructed. Here then we have a new instance in which the operation of laryngotomy, or of tracheotomy, may be performed with the effect of preventing impending suffocation, and perhaps of saving life.Dr. Marshall Hallrelates four cases in illustration of this interesting fact; of which one recovered from imminent suffocation immediately after screaming[327]; two died from suffocation, one 10, the other 17 hours, after the accident; the fourth was completely relieved by the operation of tracheotomy, and survived 34 hours, but died, exhausted by the irritation produced by the primary affection.
An instance stands recorded in the history of the destruction of the Eddystone-light house, by fire, where a quantity of melted lead fell into the mouth,and was swallowed by a person who was attentively watching the conflagration. It is very singular, that this man lived many days after the accident; a fact which at least shews what extensive injury the stomach will occasionally sustain, without the immediate destruction of life. The lead taken out of the stomach after death, in this case, weighed exactly seven ounces, five drachms, and eighteen grains.[328]
These bodies are distinguished by a highly corrosive and peculiar taste; they change the blue[329]juices of vegetables to a green, and the yellow to a brown; they are soluble in water, and have the power of imparting the same property to oils, by combining with them, and thus forming saponaceous compounds. With the different acids they constitute peculiar salts. When applied to the flesh of animals they act as powerful caustics, destroying its texture, and ultimately dissolving it; they are accordingly arranged with great propriety under the head of corrosive poisons.
There are three[330]alkalies—potass,soda, andammonia. To the two former the epithetfixedhas been applied, since they require a very high temperature for their sublimation; while to the third, that ofvolatilehas been assigned, because, when uncombined, it exists in a state of gas.Potass, as it was considered the product of vegetation, has received the name of thevegetablealkali, whilesoda, as the base of rock salt, has been distinguished by that ofmineralalkali. The distinctions, however, originally established byAvicenna, must now be abandoned, for they have not the slightest foundation in truth;potass, so far from being the exclusive product of vegetation, exists as a constituent part of theGranite, which forms the foundation of our globe; it has also been discovered in thePumice stone; in some minerals of theZeolitefamily; in theLeucite; in the aluminous ores ofLa Tolfa, &c. and, although potass is undoubtedly procured by lixiviation from the ashes of burnt wood, and other vegetable substances, yet there is ample grounds for supposing that the living plant receives it from the soil in which it vegetates.
Liquor Potassæ—Potassa Fusa, orKali Causticum—Lapis Infernalis—Causticum commune acerrimum.Potassa cum Calce—Potassæ Sub-carbonas, orSalt of Tartar—Potash—Pearl ash.
Potass is rarely met with in a pure form, except in the laboratory of the philosophical chemist, and istherefore not likely to become an object of judicial enquiry; but in various states of mixture, as presented in the different preparations above enumerated, it may become the accidental, as well as criminal means of poisoning; we shall therefore consider the chemical history of these different preparations separately, and then describe the symptoms which they generally occasion.
This may be considered as a nearly pure solution of potass, although, as it is usually prepared, it contains small portions ofmuriateandsulphate of potass,silica, andlime. It is a limpid, dense, colourless solution; when rubbed between the fingers it feels soapy, in consequence of a partial solution of the cuticle. As it constitutes a medicine in common use, and, moreover, forms the basis of manyquack medicines, as well as of those preparations which are sold under the name ofDepilatories, it may readily become the accidental instrument of mischief.
There cannot exist any difficulty in this investigation; its highly alkaline characters will be immediately announced by its effects on the vegetable test papers, and by its power of saturating acids; while the particular species of alkali may be readily identified by the following reagents.
(a)Carbonic acid; or water saturated with the gas.This will not produce any[331]disturbance in the solutionof potass; a fact which at once serves to distinguish this alkali from the earths,barytaandlime.
(b)Deuto-muriate of Platinaoccasions a canary-yellow precipitate, consisting of the deutoxide of platina, potass, and muriatic acid; as this precipitate is, to a certain extent, soluble in water, the test may fail through dilution. With soda, this reagent will not occasion any precipitate, a fact which depends upon the solubility of the triple salt formed, and affords an easy method of distinguishing the fixed alkalies from each other.
(c)Tartaric acid.If an excess of this acid be added, we shall obtain crystals of abi-tartrate; a phenomenon which will not take place if soda be the alkali employed.
This substance, which occurs in sticks, or cylinders, is an extremely caustic and deliquescent substance; it is principally employed in surgery, to establish an ulcer; or, instead of incision, to open a tumour. SeePharmacologia. As it differs from potass, only in the degree of purity, it is unnecessary to offer any farther remarks.
This is a mixture of the preceding substance with lime, which is added with a view to diminish the deliquescent property of the alkali, and thus to render it more manageable as an escharotic. There will be no difficulty in separating these ingredients. Their different solubilities will furnish an easy mode of effecting it to a certain extent, and we may then precipitatethe remaining portion of lime, by carbonic acid.
Although potass becomes comparatively mild, by its union with carbonic acid; yet the present preparation retains so much causticity as to render it poisonous, if administered in any considerable dose.Plenckreports a case of this kind, where a patient having swallowed an ounce ofsalt of tartar, was shortly afterwards seized with a violent vomiting, which continued for forty-eight hours, followed by a violent inflammation of the stomach; from which, however, he ultimately recovered.
A styptic, urinous, and caustic taste; a severe heat in the throat; violent vomiting, generally of alkaline matter, turning the syrups of violets green, and where the alkali has been in the state ofcarbonate, effervescing with acids; sometimes the matter thus ejected is mixed with blood; copious alvine evacuations; severe pain in the epigastric region; excruciating tormina of the bowels; depravation of the intellectual faculties, and death. It will be easily perceived that the above symptoms merely indicate the operation of a corrosive poison. They offer no characteristic peculiarities which can enable us to decide upon the particular substance that has been swallowed, unless, indeed, the matter vomited can be submitted to examination.