CHAPTER III.

OF POISONING WITH THE MINERAL ACIDS.

Of the mineral acids, the most important, because the most common, are _sulphuric_, _hydrochloric_, and _nitric_ acids. They are remarkably similar in their effects on the animal economy. Phosphoric acid is of much less consequence, and will be noticed cursorily.

Sulphuric acid (_vitriolic acid_, _vitriol_—_oil of vitriol_), hydrochloric acid (_muriatic acid_,—_spirit of salt_) and nitric acid (_aqua-fortis_), have been long known to be possessed of very energetic properties; and consequently cases of poisoning with them have often been observed. The instances of the kind hitherto published have been chiefly the result of suicide; a considerable number have originated in accident; and, however extraordinary it may appear, a few have been cases of murder. Tartra, in an excellent memoir on the subject of poisoning with nitric acid, quotes an instance of a woman having been poisoned while in a state of intoxication by that acid being mixed with wine and poured down her throat.[224] Valentini has related the case of a woman who was killed by frequent doses of sulphuric acid given under the pretence of administering medicines.[225] In 1829 an hospital servant was condemned at Strasbourg for trying to murder his wife in like manner, by first making her ill with tartar-emetic and then giving her sulphuric acid in syrup, under the pretence of curing her.[226] At the Aberdeen autumn circuit in 1830 a woman Humphrey was convicted of murdering her husband by pouring the same acid down his throat while he lay asleep with his mouth open.[227] On the whole, considering the powerful taste and excessively acrid properties of these poisons, it is probable that they will seldom be resorted to for the purpose of making away with another person, who is an adult, and in a state of consciousness. Of late, however, there have been several instances in our country of murder committed on infants in this barbarous manner. A woman Malcolm was executed here in 1808 for murdering her own child, an infant of eighteen months, by pouring sulphuric acid down its throat;[228] another woman Clark was tried for the same crime at Exeter in 1822; a man was executed lately at Manchester for murdering in the same way his son, a child four years and a half old;[229] and the particulars of an interesting trial will be presently noticed, that of Overfield, who was executed at Shrewsbury in 1824, for poisoning his child in the like manner.[230]

In a medico-legal point of view, the mineral acids are interesting on another account. Of late a new crime has arisen in Britain, the disfiguring of the countenance by squirting oil of vitriol on it. It originated in Glasgow, during the quarrels in 1820, between masters and workmen regarding the rate of wages,[231] and became at last so frequent, that the Lord Advocate, in applying for an act of Parliament to extend the English Stabbing and Maiming act to Scotland, added a clause which renders the offence now alluded to capital. In 1828 a woman Macmillan was tried here and condemned under that act.[232] The crime afterwards became common in England. Three cases were noticed in the newspapers as having occurred in London, in November, 1828; and two others near Manchester in the spring of 1829. It is now much less frequent.

The mineral acids are also very interesting on scientific grounds. They afford the purest examples of true corrosive poisons, their poisonous effects depending entirely on the organic injury they occasion in the textures to which they are applied. It is of use to set out, in investigating the effects of poisons, by determining the phenomena presented under such circumstances. When made aware of the rapidity with which other irritating poisons prove fatal, and the slight signs they commonly leave of their operation, one cannot fail to be struck with discovering what the animal frame will sometimes endure from these the most violent of all irritants, and nevertheless recover.

In laying down the mode of determining by chemical evidence a case of supposed poisoning with any of the three mineral acids mentioned above, it will be unnecessary to notice any of their chemical properties, except those from which their medico-legal tests are derived.

The only common properties that require notice are, their power of reddening the vegetable blue colours, for showing which litmus-paper is commonly used, and is most convenient: and their power of staining and corroding all articles of dress, especially such as are made of wool, hair, and leather. This last property is specified, though a familiar one, because it always forms important evidence in criminal cases. In order to give precision to such evidence, it is necessary to remember, that if the article of dress is a coloured one, it is generally rendered red by the mineral acids; but that the vegetable acids also will redden most articles of dress, although they do not corrode them.

I.—OF POISONING WITH SULPHURIC ACID.

Sulphuric acid is extensively employed in very many trades, is used even for some domestic purposes, and is consequently familiar to every one. Hence it is the mineral acid which has been most commonly used as a poison, especially for committing suicide. Of 35 cases of poisoning with the mineral acids which occurred in England in the years 1837 and 1838, 32 were caused by this acid (p. 90).

SECTION I.—_Of the Tests for Sulphuric Acid._

Sulphuric acid is known as a poison chiefly in the form of the concentrated commercial acid. But a few cases of poisoning have also been produced by blue-liquor or the solution of indigo in strong sulphuric acid; and one instance[233] has been recorded of poisoning with the aromatic sulphuric acid of the Pharmacopœias, which is an infusion of aromatics in a mixture of sulphuric acid, ether and alcohol. In the following remarks on its tests, it will be sufficient to consider it _first_ in the concentrated form,—_secondly_, in a state of simple dilution,—and _thirdly_, when mixed with various impurities, more especially with vegetable and animal matter. The acid solution of indigo may be known by the tests for the concentrated acid, and its blue colour, removable by a solution of chlorine; and the aromatic sulphuric acid may be distinguished by its odour and the tests for the diluted acid.

1. _When concentrated_ it is oily-looking, colourless, or brownish from having acted on organic particles, without odour, much heavier than water, and capable of quickly corroding animal substances. If from these properties, and its effect in reddening litmus, its exact nature be not considered obvious, it may be heated with a few chips of copper; when sulphurous acid is disengaged and may be readily recognised by its odour.

2. _When diluted_, it may be distinguished from all ordinary acids by solution of nitrate of baryta occasioning a heavy white precipitate of sulphate of baryta, which is insoluble in nitric acid. Selenic and sulphurous acids, however, and also, as Mr. Alfred Taylor informs me he has lately found, the fluo-silicic acid, are similarly acted on in all respects. But selenic and fluo-silicic acids in all forms, and sulphurous acid in a state of solution, are so seldom met with, being known only in the laboratory of the scientific chemist, that they can scarcely be considered sources of fallacy. Sulphuric acid may at once be distinguished from sulphurous acid, by the latter possessing a peculiar pungent odour. From the two other acids it may be distinguished by collecting and drying the barytic precipitate, mixing this with charcoal, converting it into sulphuret of barium by heating it in a platinum spoon before the blowpipe, and then adding diluted muriatic acid to the sulphuret, so as to disengage sulphuretted hydrogen gas,—which again is easily known by its odour, or its property of blackening paper dipped in solution of acetate of lead. A much more important source of fallacy than these is the possible presence of a bisulphate in solution, or a neutral sulphate along with any other free acid; for these substances will present the same reactions with litmus and barytic salts as free sulphuric acid itself. Much has been published lately upon this point; but the difficulty has not yet been satisfactorily overcome. It may be got rid of indeed by proving, that no bisulphate or neutral sulphate is present. Their absence may be shown by no solid residuum being left on evaporating the suspected fluid, or at least no more than a mere haziness, owing to the sulphate of lead which commercial sulphuric acid always contains in small quantity. Or as Orfila suggests, we may establish their absence still better by concentrating the fluid, and finding that neither carbonate of soda, which would cause a precipitate with earthy or metallic bases, nor chloride of platinum, which would do so with potash or ammonia in combination, nor fluo-silicic acid, which precipitates soda salts, has any effect when applied to separate portions of the subject of inquiry. But suppose it appears in the course of these trials that one or more bases are actually present, how is it to be settled whether the sulphuric acid, indicated by litmus and a salt of baryta, is really free or not? To this question I must reply, that no method has yet been proposed, which is at once satisfactory and easily available. Mr. Alfred Taylor proposes to concentrate the fluid, and agitate it with alcohol, in the hope that the alcohol will remove sulphuric acid, and not a sulphate, from the water.[234] But it removes sulphuric acid from a bisulphate even when dry, and still more when a little water is present. Orfila[235] proposes, in the case of sulphuric acid in vinegar,—where there is both a vegetable acid and a neutral sulphate of lime,—to concentrate to a sixth, and agitate the residuum with four times its volume of sulphuric ether, in the expectation that this fluid will remove the free acid alone, and separate it from sulphates. But notwithstanding the authority of his name for the fact, pure ether will not remove sulphuric acid from a watery fluid; and etherized alcohol, which does remove it, takes it away also, like alcohol itself, from bisulphates. These results I have observed in some careful trials made along with Dr. Douglas Maclagan. I suspect, therefore, that where sulphates or bisulphates do exist, there is no absolutely satisfactory way of determining whether free sulphuric acid also co-exists, except by a quantitative analysis, for ascertaining whether the amount of acid and of bases corresponds with this supposition or not. And it is scarcely necessary to add, that so operose a method is scarcely applicable to ordinary medico-legal investigations.

3. It is seldom that the medical jurist is called on to search for sulphuric acid in either of the states already mentioned. Much more generally it has mingled with and acted on various organic substances. The circumstances in which it has usually to be sought for in the practice of medical jurisprudence are twofold,—on the one hand, in stains on clothes,—and on the other, in vomited matter, the contents of the stomach, or organic mixtures generally.

_Process for analyzing stains on clothes._—When sulphuric acid is thrown upon your clothes, it produces a permanent red, reddish-brown, or yellowish stain, destroys the cloth entirely or renders it brittle, and in consequence of its strong attraction for water keeps the stain long in a moist state. In the course of the decomposition of the cloth a part of the acid is itself decomposed, sulphurous acid being disengaged. But it is an important medico-legal fact, that after a time the change either goes on very slowly, or is arrested altogether, possibly by the dilution of the acid with moisture from the atmosphere; and that consequently it may be discovered in a free state in stains after a much longer interval than would _à priori_ be expected. In the case of Macmillan formerly alluded to, Dr. Turner and I, who were employed by the crown to examine the different injured articles of dress, found on a man’s hat, stock, shirt-collar and coat many discoloured and corroded spots, which were sour to the taste fourteen days after the crime was committed; in the subsequent case of Mrs. Humphrey I discovered six-tenths of a grain of free sulphuric acid in two small spots on a blanket seven weeks after the crime; and from an express experiment on the same blanket with two drops of acid of known strength, it appeared that only one-half of the acid disappeared in seven weeks. It may therefore be inferred, that, in every instance where stains have been produced by concentrated sulphuric acid on clothes, at least on woollen clothes, and no attempt has been made to remove the remaining acid by washing or neutralization, a sufficient quantity will be present even after several weeks to admit of being satisfactorily detected by chemical analysis.

The following are the steps of the process which appear to me the most delicate and equivocal. Cut away the stained spots; boil them for a minute or two in several successive small portions of distilled water; and filter if necessary. Next prove the acidity of the fluid by litmus, and likewise by the taste if the quantity of solution is large enough to allow of so coarse a test being used; and with a few drops ascertain the existence of sulphuric acid in one form or another by nitrate of baryta and nitric acid, as mentioned in the process for the pure diluted acid. If no precipitate appears, the search for sulphuric acid is at an end. But if a precipitate is produced, ascertain the absence of bisulphates and sulphates by proving the absence of bases, according to the method described in the process for the simple diluted acid. If, however, bases be found in material proportion to the acid, the analysis is subject to all the difficulties mentioned above in speaking of the detection of the diluted acid in similar circumstances.

_Process for the contents of the stomach and other complex mixtures._—When sulphuric acid has been mixed with various mineral and organic substances, it may in no long time cease to exist in the free state. Part may be decomposed by organic matter in the way formerly mentioned. Or the whole may be neutralized at once by earthy or alkaline carbonates, administered purposely as antidotes. Or it may also be neutralized more slowly by the gradual development of ammonia in consequence of the decay of the animal matter co-existing in the mixture. Thus in a case mentioned by Mertzdorff of a child killed in twelve hours with sulphuric acid, the contents of the stomach did not redden litmus, but on the contrary had an ammoniacal odour; and they contained a considerable quantity of a soluble sulphate, probably the sulphate of ammonia.[236] In like manner MM. Orfila and Lesueur found that when this acid was left some months in a mixture which contained putrefying azotized matter, it was gradually neutralized by ammonia.[237] It appears from Orfila’s latest researches,[238] that in most cases of acute poisoning with this substance some free acid will be found in the contents or tissues of the stomach, provided alkalis or earths were not given as antidotes, and the examination of the body be made before decay sets in.

The detection of sulphuric acid in complex organic mixtures, simple though it appears at first sight, is one of the most difficult problems in medico-legal chemistry. The difficulty arises from a variety of sources,—from the probable presence of neutral sulphates along with free hydrochloric, acetic, or some other acid,—the possible presence of a bisulphate,—the occasional neutralization of the sulphuric acid by antidotes given during life, or ammonia evolved during decay after death,—or its neutralization, together with the development of a different free acid, by its having displaced this acid from a salt existing in the mixture.

The subject was investigated in most of its relations in the last edition of the present work, and a process proposed which overcame some difficulties, but left others untouched. The inquiry has been since undertaken also by M. Devergie and Professor Orfila, but with most success in Germany by Dr. Simon.[239] The result of all these researches is, that a satisfactory process for detecting sulphuric acid in organic mixtures still remains to be discovered. Meanwhile the most eligible method appears to me to be the following.

a. _If the mixture be acid_, add distilled water, if necessary, boil, filter, and test a few drops of the fluid with nitrate of baryta, followed by nitric acid. If there be no precipitate, the search for sulphuric acid is at an end. If a precipitate form, distil the fluid from a muriate of lime or oil bath, at a temperature not above 240°, till the residuum acquire a thick syrupy consistence; and preserve apart the last sixth of the distilled liquor. In this liquor test for hydrochloric acid by litmus-paper and nitrate of silver, and for acetic acid by litmus-paper, and the odour and taste of the liquid. If these acids be not in the distilled fluid, they are not in the residuum. In a portion of this residuum search for nitric acid, and in another portion for oxalic acid, by the processes for these poisons in complex mixtures. If all these acids be thus proved to be absent, it is most unlikely that the acidity of the mixture is owing to any other but sulphuric acid, especially in the case of the contents or textures of the stomach.

Dilute now what remains of the syrupy extract, and add nitrate of baryta with nitric acid. If a precipitate arise, there is a strong presumption that the acidity of the mixture was owing either to a bisulphate or to free sulphuric acid. And between these the question may be almost settled, first by the probability or improbability of a bisulphate having come in the way, and secondly, by the symptoms and morbid appearances. The result however cannot justify more than a presumptive opinion.—But if hydrochloric, acetic or nitric acid be indicated in the subject of analysis, or an acid sulphate, the whole process is vitiated, and it is scarcely possible to arrive at any trustworthy conclusion.

The difficulties adverted to above have been made the ground-work of various processes; which however seem to me all imperfect.—It has been proposed to divide the mixture into two equal parts, to precipitate one directly by a barytic salt, to do the same with the other after drying and incinerating it, to compare the weight of the precipitates, and to infer the presence of free sulphuric acid if the former is more than double the latter. Various objections however may be brought against this check, not the least serious being its difficulty in ordinary hands, whenever the precipitates are none of them considerable.—Simon proposes to exhaust the residuum of evaporation with absolute alcohol, in the hope that free sulphuric acid will alone be taken up;[240] but he himself found that neutral sulphates are dissolved partially; and besides, alcohol removes sulphuric acid from bisulphates.—Orfila proposes to remove free sulphuric acid by agitating the concentrated liquor with sulphuric ether, and separating and evaporating off the ether; for he holds that all neutral and acid salts of sulphuric acid are insoluble in ether.[241] This proposal is unaccountable. Simon stated in his paper three years before, that ether does not remove sulphuric acid from watery fluids containing it. And Dr. Douglas Maclagan and I, on inquiring into the matter, found that we could not, by means of ether, separate a particle of sulphuric acid from an ounce of rice soup and mucilage to which ten drops of the acid had been added. The process of Orfila for establishing the absence of bases in a simple watery solution is applicable to organic mixtures also, after incineration. But if bases be present in material quantity, all the difficulties now in question remain in full force.

b. _When the mixture is neutral_, sulphuric acid may be detected in it by the first steps of the preceding process. But the inference, that it once existed free can only be drawn when the subject of examination is not in a state of decay, when the quantity of sulphate of baryta obtained is considerable, when the administration of an antidote is proved, and when the ashes after incineration contain the antacid base which is said to have been administered. Even then the inference is only presumptive.

SECTION II.—_Of the Mode of Action of Sulphuric Acid, and the Symptoms caused by it in Man._

It was formerly observed that the action of the strong mineral acids is independent of the function of absorption. They act by the conveyance along the nerves of an impression produced by the irritation or destruction of the part to which they are applied. There is very little difference between the three acids in the symptoms they excite or the action they exert.

When sulphuric acid is introduced directly into a vein it causes death by coagulating the blood. Thus, when Professor Orfila injected in the jugular vein of a dog half a drachm diluted with an equal weight of water, he observed that the animal at once struggled violently, stretched out its limbs, and expired; and on opening the chest immediately, he found the heart and great vessels filled with coagulated blood.[242]—Nitric acid and hydrochloric acid act in the same way.

If, on the other hand, they are introduced into the stomach, the blood as usual remains fluid for some time after death; the symptoms are referrible almost solely to the abdomen; and in the dead body the stomach is found extensively disorganised, and the other abdominal viscera sometimes inflamed. If the dose be large, and the animal fasting, death may take place in so short a time as three hours: but in general it lives much longer.[243]

When the strong mineral acids are applied outwardly, they irritate, inflame, or corrode the skin. The most rapid in producing these effects is the nitric, or rather the nitrous acid. The strong, fuming nitrous acid even causes effervescence when dropped on the skin.

Orfila has proved that sulphuric acid, as well as the two other mineral acids, is absorbed; for they may be detected in the urine, when they are introduced either into the stomach or through a wound.[244] He could not succeed, however, in detecting any of them in the liver or spleen; in which organs it will be seen, hereafter, that various other poisons may be discovered by chemical analysis. But Mr. Scoffern seems to have found sulphuric acid in the kidney, even although the individual survived the taking of the poison nearly two days.[245] It is also worthy of remark, that, as will be proved presently, these acids may pass through the coats of the stomach by transudation, and so be found on the surface of the other organs in the belly.

Toxicology is indebted to M. Tartra for the first methodic information published respecting the symptoms caused in man by sulphuric acid and the other mineral acids:[246] but many important additional facts have been made known by numberless cases of poisoning which have since appeared, chiefly in the periodic journals.

The symptoms caused by all the three acids are so nearly the same, that after a detailed account of those occasioned by sulphuric acid, it will not be necessary to add much on the subject under the head of nitric and muriatic acid.

M. Tartra considers that four varieties may be observed in the effects of the mineral acids. 1. Speedy death from violent corrosion and inflammation; 2. Slow death from a peculiar organic disease of the stomach and intestines; 3. Imperfect recovery, the person remaining liable ever after to irritability of the stomach; 4. Perfect recovery.

1. The most ordinary symptoms are those of the first variety,—namely, all the symptoms that characterise the most violent gastritis, accompanied likewise with burning in the throat, which is increased by pressure, swallowing, or coughing;[247]—eructations proceeding from the gases evolved in the stomach by its chemical decomposition;—and an excruciating pain in the stomach, such as no natural inflammation can excite. The lips are commonly shrivelled, at first whitish, but afterwards brownish in the case of sulphuric acid. Occasionally there are also excoriations, more rarely little blisters. Similar marks appear on other parts of the skin with which the acid may have come in contact, such as the cheeks, neck, breast, or fingers; and these marks undergo the same change of colour as the marks on the lips. I had an opportunity of witnessing this in the case of the man who was disfigured by the Macmillans (p. 122) with sulphuric acid. He was cruelly burnt on the face as well as on the hands, which he had raised to protect his face; and the marks were at first white, but in sixteen hours became brownish. The inside of the mouth is also generally shrivelled, white, and often more or less corroded; and as the poisoning advances, the teeth become loose and yellowish-brown about the coronæ. The teeth sometimes become brown in so short a time as three hours.[248] Occasionally the tongue, gums, and inside of the cheeks are white, and as it were polished, like ivory.[249] There is almost always great difficulty, and sometimes complete impossibility, of swallowing. In the case of a child related by Dr. Sinclair, of Manchester, fluids taken by the mouth were returned by the nose; and the reason was obvious after death; for even then the pharynx was so much contracted as to admit a probe with difficulty.[250] On the same account substances taken by the mouth have been discharged by an opening in the larynx which had been made to relieve impending suffocation. The matter vomited, if no fluids be swallowed, is generally brownish or black, and at first causes effervescence, if it falls on a pavement containing any lime. Afterwards this matter is mixed with shreds of membrane, which resemble the coats of the stomach, and sometimes actually consists of the disorganised coats, but are generally nothing more than coagulated mucus. The bowels are obstinately costive, the urine scanty or suppressed; and the patient is frequently harassed by distressing tenesmus and desire to pass water. The pulse all along is very weak, sometimes intermitting, and towards the close imperceptible. It is not always frequent; on the contrary, it has been observed of natural frequency, small and feeble in a patient who survived fifteen days.[251] The countenance becomes at an early period glazed and ghastly, and the extremities cold and clammy. The breathing is often laborious, owing to the movements of the chest increasing the pain in the stomach,—or because pulmonary inflammation is also at times present,—or because the admission of air into the lungs is impeded by the injury done to the epiglottis and entrance of the larynx. To these symptoms are added occasional fits of suffocation from shreds of thick mucus sticking in the throat, and sometimes croupy respiration, with sense of impending choking.

Such is the ordinary train of symptoms in cases of the first variety. But sometimes, especially when a large dose has been swallowed, instead of these excruciating tortures, there is a deceitful tranquillity and absence of all uneasiness. Thus, in the case of a woman who was poisoned by her companions making her swallow while intoxicated aqua-fortis mixed with wine, although she had at first a good deal of pain and vomiting, there were subsequently none of the usual violent symptoms; and she died within twenty hours, complaining chiefly of tenesmus and excessive debility.[252] Occasionally eruptions break out over the body:[253] but their nature has not been described.

Death is seldom owing to the mere local mischief, more generally to sympathy of the circulation and nervous system with that injury. According to Bouchardat death arises from the acid entering the blood in sufficient quantity to cause coagulation.[254] But although this certainly happens sometimes to the blood in the vessels of the stomach and adjacent organs, as will be proved under the head of the morbid appearances, there is no evidence that the same takes place throughout the blood-vessels generally, or in the great veins and heart in particular. Bouchardat’s proofs of the detection of sulphuric acid in the blood are not satisfactory.

The duration of this variety of poisoning with the acids is commonly between twelve hours and three days. But sometimes life is prolonged for a week[255] or a fortnight;[256] and sometimes too death takes place in a very few hours. The shortest duration among the numerous cases of adults mentioned by Tartra is six hours;[257] but Dr. Sinclair, of Manchester, has related a case which lasted only four hours and a half;[258] a man lately died in the Edinburgh Infirmary within four hours; and Professor Remer of Breslau once met with a case fatal in two hours.[259]

The quantity required to produce these effects has not been ascertained, and must be liable to the same uncertainty here as in other kinds of poisoning. The smallest fatal dose of sulphuric acid I have hitherto found recorded was one drachm. It was taken with sugar by mistake for stomachic drops by a stout young man, and killed him in seven days.[260] An infant of twelve months has been killed in twenty-four hours by half a tea-spoonful, or about thirty minims.[261] A man has recovered after taking six drachms.[262]

2. The second variety of symptoms belong to a peculiar modification of disease, which is described by Tartra in rather strong language. It begins with the symptoms already noticed; but these gradually abate. The patient then becomes affected with general fever, dry skin, spasms and pains of the limbs, difficult breathing, tension of the belly, salivation, and occasional vomiting, particularly of food and drink. Afterwards membranous flakes are discharged by vomiting, and the salivation is accompanied with fœtor. These flakes are often very like the mucous membrane of the stomach and intestines; and such they have often been described to be. More probably, however, they are of adventitious formation; for the mere mucous coat of the alimentary canal cannot supply the vast quantity that is evacuated. There is no doubt, however, that the lining membrane of the alimentary canal is occasionally discharged. Dr. Wilson has mentioned an instance of the ejection by coughing of about nine inches of the cylindrical lining of the pharynx and gullet six days after sulphuric acid was taken.[263] Sometimes worms are discharged dead, and evidently corroded by the poison.[264] Digestion is at the same time deranged, the whole functions of the body are languid, and the patient falls into a state of marasmus, which reduces him to a mere skeleton, and in the end brings him to the grave. Death may take place in a fortnight, or not for months. In one of Tartra’s cases the patient lived eight months. The vomiting of membranous flakes continues to the last.

3. The third variety includes cases of imperfect recovery. These are characterized by nothing but the greater mildness of the primary symptoms, and by the patient continuing for life liable to attacks of pain in the stomach, vomiting of food and general disorder of the digestive function.

4. The last variety comprehends cases of perfect recovery, which are sufficiently numerous even under unpromising appearances. From the average of 55 cases recorded by Tartra it appears that the chances of death and recovery are nearly equal. Twenty-six died, 19 of the primary, 7 of the secondary disorder. Twenty-nine recovered, and of these twenty-one perfectly. Suicidal are for obvious reasons more frequently fatal than accidental cases.

Tartra has not taken notice in his treatise of another form of poisoning with the strong acids,—in which the injury is confined to the gullet and neighbouring parts. In Corvisart’s Journal there is the case of a man, who began to drink sulphuric acid for water while intoxicated, but suddenly found out his error before he had swallowed above a few drops; and consequently the chief symptoms were confined to the throat. After his physician saw him he was able to take one dose of a chalk mixture; but from that time he was unable to swallow at all for a fortnight.[265] Martini likewise met with a similar instance of complete dysphagia from stricture in the gullet caused by sulphuric acid.[266] His patient recovered.

It also appears exceedingly probable, that the strong acids may cause death, without reaching the stomach or even the gullet, by exciting inflammation and spasm of the glottis and larynx. Such an effect may very well be anticipated from an attempt to commit murder with these poisons; as the person, if he retains consciousness at the time, may become aware of their nature before he has swallowed enough to injure the stomach.

Thus, Dr. A. T. Thomson says in 1837, that he once met with the case of a child, who, while attempting to swallow strong sulphuric acid by mistake for water, died almost immediately, to all appearance from suffocation caused by contraction of the glottis; and it was ascertained after death that none of the poison had reached the stomach.[267] Professor Quain describes a similar case, occurring also in a child, where impending death was prevented by artificial respiration, and acute bronchitis ensued, which proved fatal in three days. In this instance thickening of the epiglottis and great contraction of the upper opening of the larynx showed the violent local injury inflicted there, inflammation could be traced down the trachea into the bronchial tubes, but no trace of injury could be detected in the gullet and stomach.[268] In a very interesting and carefully detailed case by Mr. Arnott, where the poison taken was the nitric acid, the injury was confined in a great measure to the gullet and larynx,—the stomach, which was distended with food at the time, being very little affected. The chief symptoms at first, besides great general depression, were croupy respiration and much dyspnœa, which became so urgent, that laryngotomy was performed, and with complete relief to the breathing. But the patient nevertheless rapidly sunk under the symptoms of general exhaustion, and died in thirty-six hours without presenting any particular signs of the operation of the poison on the stomach; and the traces of action found there after death were trifling.[269]

The importance of the fact established by these cases will appear from the following medico-legal inquiries. A Prussian medical college was consulted in the case of a new-born child, in which the stomach and intestines were healthy, and did not contain poison, but in which the cuticle of the lips was easily scraped off, the gums, tongue, and mouth yellowish-green, as if burnt, the velum and uvula in the same state, the rima glottidis contracted, and the epiglottis, larynx, and fauces violently inflamed. The College declared, that a concentrated acid had been given, and that death had been occasioned by suffocation. Sulphuric acid was found in the house; and the mother subsequently confessed the crime.[270] A case was formerly quoted (p. 75), where MM. Ollivier and Chevallier found traces of the action of nitric acid on the lips, mouth, throat and upper fourth of the gullet, but not lower. In this instance the reporters came to the opinion from the absence of injury in the more important parts of the alimentary canal, as well as from the marks of nail scratches on the neck, and the gorged state of the lungs, that death had been produced by strangling, after an unsuccessful attempt by the forcible administration of nitric acid. It is quite possible, however, that death might quickly ensue from the effects of the poison on the throat and gullet. In the course of the judicial inquiries M. Alibert stated that he had known repeated instances of death from swallowing nitric acid, although none of it reached lower down than the pharynx. Ollivier in his paper doubts the accuracy of this statement; but the cases quoted above show clearly that such injury may be done to the glottis as will be adequate of itself to occasion death.[271]

It seems farther not improbable that, among the terminations of poisoning with the strong mineral acids, scirrhous pylorus must also be enumerated. This is a very rare effect of the action of corrosive poisons. But M. Bouillaud has related an instance of death from scirrhous pylorus in its most aggravated shape, which supervened on the chronic form of the effects of nitric acid, and which proved fatal in three months.[272]

In some circumstances the stomach seems to acquire a degree of insensibility to the action of the strong acids. Tartra, in alluding to what is said of certain whisky-drinkers acquiring the power of swallowing with impunity small quantities of the concentrated acids, has related the case of a woman at Paris, who, after passing successively from wine to brandy and from that to alcohol, at last found nothing could titillate her stomach except aqua-fortis, of which she was seen to partake by several druggists of veracity.[273] The fire-eating mountebanks too are said to acquire the same power of endurance; but much of their apparent capability is really legerdemain. On the other hand, a very extraordinary sensibility to the action of the diluted mineral acids has been supposed to exist in the case of infants at the breast,—so great a sensibility, that serious symptoms and even death itself have been ascribed to the nurse’s milk becoming impregnated with sulphuric acid, in consequence of her having taken it in medicinal doses. By two writers in the London Medical Repository griping pains, tremors and spasms have been imputed to this cause;[274] and a writer in the Medical Gazette says he has seen continued griping, green diarrhœa and fatal marasmus ensue,—apparently, he thinks, from ulceration of the gastro-intestinal mucous membrane.[275] Without questioning the great delicacy and tenderness of that membrane in infants, I must nevertheless express my doubts whether so small a quantity taken by a nurse, amounting in the cases in question only to four or six drops a day, could really produce fatal or even severe effects on her child.

Sulphuric acid is not less deadly when admitted into the body through other channels besides the mouth. Thus, it may prove fatal when introduced into the rectum. A woman at Bruges in Belgium had an injection administered, in which, being prepared hastily in the middle of the night, sulphuric acid had been substituted by mistake for linseed-oil. The patient immediately uttered piercing cries, and passed the remainder of the night in excessive torture. In the morning the bed-clothes were found corroded, and a portion of intestine had apparently come away; and she expired not long afterwards.[276]

Death may also be occasioned by the introduction of this acid into the ear. Dr. Morrison relates a case of the kind, where nitric acid, which is analogous in action, was poured by a man into his wife’s ear, while she lay insensible from intoxication. She awoke in great pain, which continued for two or three days. In six days an eschar detached itself from the external passage of the ear; and this was followed by profuse hemorrhage, which recurred daily more or less for a month. On the day after the eschar came away, and without any precursory symptom referrible to the head, she was attacked with complete palsy of the right arm, and in eight days more with tremors and incomplete palsy of the rest of that side of the body. These symptoms subsequently abated; but they again increased after an imprudent exertion, and she died in a state of exhaustion seven weeks after the injury. The whole petrous portion of the temporal bone was found carious, but without any distinct disease of the brain or its membranes.[277]

Sulphuric acid and the other mineral acids are equally poisonous when inhaled in the form of gas or vapour; and they then act chiefly by irritating or inflaming the mucous membrane of the air-passages and lungs. For some observations on their effects in this form both on plants and animals the reader may refer to the Chapter on Poisonous Gases.

Sulphuric acid belongs to the poisons alluded to under the head of General Poisoning,—of whose operation satisfactory evidence may be occasionally drawn from symptoms only. If immediately after swallowing a liquid which causes a sense of burning in the throat, gullet, and stomach, violent vomiting ensues, particularly if the vomited matter is mixed with blood; if the mouth becomes white, and stripped of its lining membrane, and the cheeks, neck, or neighbouring parts show vesications, or white, and subsequently brown excoriated spots;—if the clothes show red spots and are moist and disintegrated there,—I cannot see any objection to the inference, that either sulphuric or muriatic acid has been taken. In this opinion I am supported by a good authority, Dr. Mertzdorff, late medical inspector at Berlin.[278]

SECTION III.—_Of the Morbid Appearances caused by Sulphuric Acid._

The outward appearance of the body in cases of Tartra’s first variety in the action of the acids is remarkably healthy; every limb is round, firm, and fresh-looking.

On the lips, fingers, or other parts of the skin, spots and streaks are found where sulphuric acid has disorganized the cuticle. These marks are brownish or yellowish-brown, and present after death the appearance of old parchment or of a burn; sometimes there are little blisters.[279]

The lining membrane of the mouth is more or less disorganized, generally hardened, and whitish or slightly yellowish. The pharynx is either in the same state, or very red or even swelled. The rima glottidis, as in the case described by Dr. Sinclair and in that of Mr. Arnott, is sometimes contracted, the epiglottis swelled, or on the contrary shrivelled, and the commencement of the larynx inflamed.[280] The gullet is often lined with a dense membrane, adhering firmly, resembling the inner coat, but probably in general a morbid formation; and the subjacent tissue is brown or red. Sometimes, however, the inner coat or epithelian of the gullet loses its vitality, and is detached in part or altogether. In Mr. Arnott’s case the pharynx and upper gullet were lined by a pale lemon-coloured membrane, which in the lower two-thirds of the canal was completely detached and was plainly the œsophageal membrane; in the case related by Mertzdorff, the whole inner coat of the gullet, as well as that of the throat, epiglottis, and mouth, was stripped from the muscular coat;[281] and in Dr. Wilson’s case (p. 131), which proved fatal in ten months, the upper third of the gullet shone like an old cicatrix, and the lower two-thirds were narrowed, vascular, and softened on the surface.[282] In a few rare cases of chronic poisoning with the mineral acids the gullet is found perforated by an ulcerative process;[283] but it is never perforated by their corrosive action in quickly fatal cases. Occasionally the gullet is not affected at all, though both the mouth and the stomach are severely injured; and an instance has even been published where the acid, in this instance the nitric, left no trace of its passage downwards till near the pylorus.[284]

The outer surface of the abdominal viscera is commonly either very vascular or livid, or bears even more unequivocal signs of inflammation, namely, effusion of fibrin and adhesions among the different turns of intestine; and these appearances may take place although the stomach is not perforated.[285] The cause of this appearance, which is seldom observed in poisoning with other irritants, more especially with the metallic irritants, is that the acid passes through the membranes of the stomach by transudation during life,—as will be proved immediately. It must be observed, that the peritonæum is sometimes quite natural after death from sulphuric acid, even although the stomach was perforated. I have seen this in a case which proved fatal in twelve hours. An important appearance in the abdomen, to which less attention has been hitherto paid than it deserves, is gorging of the vessels beneath the peritonæal membrane of the stomach and adjoining organs with dark, firmly coagulated blood, arising from the acid having transuded through the membranes and acted on the blood chemically. My attention was first turned to this appearance by an interesting case, which I saw in 1840 in the Royal Infirmary of this city, and of which an able account has been published by Dr. Craigie.[286] The whole vessels of the stomach were seen externally to be most minutely injected and gorged, and the blood in them was coagulated into firmly-cohering cylindrical masses, as if the vessels had been successfully filled with the matter of an anatomical injection. This appearance was also observed in the superior mesenteric arteries, in the omental vessels, and over the greater part of the mesentery. It was occasioned by the chemical action of the acid coagulating the colouring matter and albumen; for the clotted blood was strongly acid to litmus-paper. So too was the peritoneal surface of the stomach, omentum and intestines. And the acid had transuded through the stomach and into the omentum and tissues of the intestines during life; for in the first place, there was no perforation of the stomach, and secondly, I ascertained that there was no free acid either in the matter discharged from the stomach before death after the free administration of antacids, or in the contents of the stomach obtained at the examination of the dead body.

The stomach, if not perforated, is commonly distended with gases. It contains a quantity of yellowish-brown or black matter, and is sometimes lined with a thick paste composed of disorganized tissue, blood and mucus. The pylorus is contracted.

The mucous membrane is not always corroded. If the acid was taken diluted, the coats may escape corrosion; but there is excessive injection, gorging, and blackness of the vessels, general blackness of the membrane, sometimes even without softening, as in a case related by Pyl of a woman who first took aqua-fortis and then stabbed herself.[287] More commonly, however, along with the blackness there is softening of the rugæ or actual removal of the villous coat, and occasionally regular granulated ulceration with puriform matter on it.[288] The stomach is not always perforated. But if it is, the holes are commonly roundish, and the coats thin at the margin, coloured, disintegrated, and surrounded by vascularity and black extravasation. In some rare cases there is no mark of vital reaction except in the neighbourhood of the aperture. A case of this kind is related by Mertzdorff: The margin of the hole was surrounded to the distance of half an inch with apparent charring of the coats, and this areola was surrounded by redness; but the rest of the stomach was grayish-white.[289] I examined with the late Dr. Latta of Leith a similar case, where the limitation of the injury was evidently owing to the stomach having been at the time filled with porridge. The patient, a child two years old, died in twelve hours; and on the posterior surface of the fundus of the stomach, towards the pylorus, there was a hole as big as a half-crown, which was surrounded to the distance of an inch with a black mass formed of the disorganized coats, and of incorporated charred blood. But the rest of the stomach was quite healthy. The most remarkable instance of chemical destruction of the coats yet known to me is a case mentioned by Mr. Watson of this city, where suicide was effected by cutting the throat about half an hour after two ounces of sulphuric acid had been swallowed. The individual was at first thought to have died simply of the wound of the throat. But on dissection the usual signs of acid poisoning were found; and among other effects, it was observed that nearly three-fourths of the stomach had been entirely destroyed.[290] The perforation, if the patient lives long enough, is generally accompanied with a copious effusion into the belly of the usual muddy liquor of peritonitis; and the outer surface of the viscera feels unctuous, as if from a slight chemical action of the acid on them. The acid has actually been found in the contents poured out from the stomach into the sac of the peritonæum.[291]

One would expect to find the acid always in the stomach when it is perforated. Nevertheless it is sometimes almost all discharged. In Mertzdorff’s case, that of an infant who was killed in twelve hours, a hole was found in the stomach ¾ths of an inch in diameter, and the contents of the stomach were effused into the belly: yet by a careful analysis the whole acid he could procure from the contents and tissues together was only 4½ grains. Sometimes of course the disappearance of the acid may be owing, as in Dr. Craigie’s case, to the effectual administration of antacids during life.

The inner coat of the duodenum often presents appearances closely resembling those of the stomach. Sometimes, however, as in the case just related from Mertzdorff, and in the infant I examined, the inner coat of the small intestines is not affected at all, probably because in such rapid cases the pylorus retains a state of spasmodic contraction till death or even after it.

The urinary bladder is commonly empty. The thoracic surface of the diaphragm is sometimes lined with lymph, indicating inflammation of the chest. In the case which was fatal in two hours [p. 131], Professor Remer found the surface of the lungs, as well as that of the liver and spleen, brown and of a leathern consistence, and the tissue beneath scarlet;—appearances which he thinks arose from the acid penetrating in vapour and acting chemically. I have not found this appearance mentioned by any other writer; but I have seen it in animals poisoned with oxalic acid. The blood in the heart and great vessels has been several times seen forming a firm black clot. Kerkring[292] relates an instance of the kind; in Dr. Latta’s case the appearance was very distinct; and it is dwelt on strongly in a recent paper by M. Bouchardat.[293] Bouchardat thinks this state of the blood is simply the effect of the absorbed acid; but coagulation of the blood in the heart and great vessels,—a striking appearance in contradiction to what is observed after death from most other poisons,—is more probably the healthy state of the blood, and not the effect of the particular poison.

The general appearance of the body of those who have died of the second or chronic variety of poisoning with the acids, is that of extreme emaciation. The stomach and intestines are excessively contracted: The former has been found so small as to measure only two inches and a half from the cardia to the pylorus, and two inches from the lesser to the greater curvature.[294] Tartra says the intestines are sometimes no thicker than a writing quill. They are in other respects sound outwardly, except that they sometimes adhere together.

Internally the pylorus is contracted. In a case of slow poisoning, fatal in three months, which has been described by Dr. Braun of Fürth, the chief appearance besides excessive emaciation was a thickening of the coats round and behind the pylorus to such a degree that the opening of the pylorus was formed of an almost cartilaginous ring several lines broad, and only wide enough to pass a quill.[295] There are spots over the stomach apparently of regenerated villous tissue, smoother and redder than the natural membrane. At the points where the stomach adheres to the neighbouring organs, its coats are sometimes wanting altogether, so that when its connections are torn away, perforations are produced. The other parts of the body are natural.

It may in some circumstances be necessary to determine from the appearances in the dead body whether sulphuric acid has been the occasion of death or has been introduced into the body after death. This may always be easily done. If a few drachms of sulphuric acid be injected into the anus immediately after death, and the parts be examined in twenty-four hours, it will be found, that wherever the acid touches the gut, its mucous coat is yellowish and brittle, its muscular and peritonæal coats white, as if blanched, and the blood in the vessels charred; the injury is confined strictly to the parts actually touched, is surrounded by an abrupt line of demarcation, and shows no sign of inflammatory redness. Nitric acid produces nearly the same effects. The whole tunics are yellow, and the disorganization is greater. For these facts we are indebted to Orfila.[296]

In closing this account of the morbid appearances, some observations will be required on the force of evidence derived from them; because circumstances may exclude all other branches of medical proof. In many instances both of acute and of chronic poisoning with the strong acids, I conceive, contrary to the general statements of most systematic writers on modern medical jurisprudence, that distinct evidence might be derived from morbid appearances only. Thus, what fallacy can intervene to render the following opinion doubtful? In a case several times alluded to as described by Mertzdorff, there were vesicles and brown streaks on the lips, neck, and shoulders, similar to the effects of burning,—almost total separation of the lining membrane of the mouth, throat, epiglottis, and gullet,—perforation of the stomach, with a margin half an inch wide, which was extensively charred, and surrounded by a red areola. From the appearances alone Mertzdorff declared that the child must have been poisoned with sulphuric acid. Perhaps he should have said sulphuric or muriatic acid.

Or take the case of Richard Overfield, who was condemned at Shrewsbury Assizes in 1824 for murdering his own child, a babe three months old, by pouring sulphuric acid down its throat. In the dead body the following appearances were found: The lips were blistered internally and of a dark colour externally; the gullet was contracted and its inner coat corroded; the lining membrane of the mouth and tongue of a dull white colour; the great curvature of the stomach corroded and converted into a substance like wet brown paper; the stomach perforated and a bloody-coloured fluid in the sac of the peritonæum.[297] If to these appearances be added the fact that the child’s dress was reddened, what is there to prevent the medical jurist from declaring, without reference to chemical evidence, that this case must have been one of poisoning by sulphuric acid or some other mineral acids?

In like manner in the case of Mrs. Humphrey, who was condemned at Aberdeen in 1830 for murdering her husband by pouring sulphuric acid down his throat while he was asleep, there was found, on examining the dead body, two brown spots on the outside of the lips,—whiteness of the inside of the lips and of the gums,—glazing of the palate,—redness, with here and there ash-coloured discoloration, of the uvula, posterior part of the throat, pharynx and epiglottis,—abrasion of most of the inner coat of the gullet,—erosion and dark-red ulceration of the inner coat of the stomach in winding furrows. When to these appearances it is added, that the man was in good health only forty-seven hours before death, and was taken ill instantaneously and violently with burning pain in the throat and stomach,[298] it is not easy to see what other opinion could be formed of the case, unless that he died of poisoning with a mineral acid, and probably with sulphuric acid.

Among the appearances justifying an opinion where chemical evidence happens to be wanting, not the least important seems to me to be the peculiar turgescence and induration of vessels under the peritonæum of the stomach and neighbouring organs, occasioned by the chemical coagulation of blood in them. It is an appearance, which, when once seen, cannot be confounded with any natural morbid phenomenon I have ever witnessed.

I am far from desiring to encourage rashness of decision, or to revive the loose criterions of poisoning relied on in former times. But there cannot, in my opinion, be a rational doubt that in the instance of sulphuric acid there may often be distinct exceptions to the general law regarding the feebleness of the evidence from morbid appearances; and that a witness would certainly be guilty of thwarting the administration of justice, if, relying on general rules, he refused to admit such exceptions. What natural disease could produce appearances like those described above? Assuredly no form of spontaneous perforation bears any resemblance to that caused in most cases of death from sulphuric acid; nor is it easy to mention any combination of natural diseases which could produce the peculiar conjunction of appearances remarked in the case of the man Humphrey.

SECTION IV.—_Of the Treatment of Poisoning with Sulphuric Acid._

Since this acid and the other mineral acids act entirely as local irritants, it may be inferred that their poisonous action will be prevented by neutralizing them. But in applying that principle to the treatment it is necessary to bear in mind their extremely rapid operation; for if much time is lost in seeking for an antidote, irreparable mischief may be caused before the remedy is taken. Should it be possible then to administer chalk or magnesia without delay, these are the antidotes which ought to be preferred; but it may be well for the physician to remember, that in the absence of both he may at once procure a substitute in the plaster of the apartment beat down and made into thin paste with water. M. Chevallier, in a paper on the antidotes for the mineral acids, quotes five cases of poisoning with sulphuric acid and two with nitric acid, where life seems to have been saved by the speedy and free administration of magnesia, although in some cases so large a quantity as two ounces of the poison had been swallowed.[299]—A solution of soap is another antidote of no small value. While the antidote is in preparation, the acid should be diluted by the free use of any mild fluid, such as milk or oleaginous matters.—The alkaline bicarbonates are also excellent antidotes; but their carbonates are ineligible, being themselves possessed of corrosive properties. In a paper on poisoning with the mineral acids by Dr. Lunding of Copenhagen, the author is disposed to ascribe the large proportion of deaths in his practice to the system pursued in the Copenhagen hospital of administering carbonate of potass as an antidote daily for weeks together.[300] On the other hand however it may be mentioned, that in a late memoir, on this description of poisoning Dr. Ebers of Breslau endeavours to show, that there is no reason to dread the administration of the alkaline carbonates, even the carbonate of potash, provided they be given with mucilaginous fluids and syrup in a rather concentrated form; and he gives three cases illustrative of the good effects of this mode of treatment, which he maintains to be free of all danger, and preferable to every other antidotal method, because the remedy may be administered in small volume,—an advantage possessed by it especially over chalk or magnesia.[301]

After the proper antidote has been given to a sufficient extent, the use of diluents ought to be continued, as they render the vomiting more easy.—Some have recommended the stomach-pump for administering antidotes and diluents; but this is unnecessary. When it is wished to evacuate the stomach, there is an advantage in allowing it to do so by its own efforts, if possible; because the evacuation is accomplished in this way more completely than by the stomach-pump. Besides, if the patient cannot swallow fluids, still less can he suffer the tube of the stomach-pump to be introduced. On several occasions, indeed, it has been found impracticable to introduce it.[302]

The treatment of the surpervening inflammation does not differ from that of inflammation of the stomach. Where there is great difficulty of breathing, evidently from obstruction of the larynx, and where the absence of abdominal pain, tension or vomiting affords a presumption that little injury has been done to the stomach, laryngotomy appears an advisable remedy, and has been known to give very great relief.[303] But the patient may nevertheless die soon of the sympathetic disorder of the circulation.

II.—OF POISONING WITH NITRIC ACID.

Nitric acid is more frequently used as a poison abroad than in this country. But even in Britain it is not an uncommon cause of severe accidents and death.

_Of the Tests for Nitric Acid._

1. _When concentrated_, nitric acid is easily known by the odour of its vapour, which is peculiar. When pure, the acid as well as its vapour is colourless; when mixed with nitrous acid it is of various tints, and generally yellow. The acid of commerce is at times rendered impure by sulphuric acid, a circumstance which must be attended to in applying the subsequent tests.—The simplest test for nitric or nitrous acid is the action of copper, lead, or tin. If any of these metals in small fragments, or powder, be thrown into either acid previously diluted with an equal volume of water, an effervescence takes place, which in the case of lead or copper is much accelerated by heat; nitric oxide gas is disengaged; and ruddy fumes of nitrous acid gas are formed when the gas comes in contact with the oxygen of the air. Another characteristic test, which has the advantage of being applicable on an extremely small scale, is morphia, the alkaloid of opium. This substance is turned in a few seconds to a beautiful orange-red colour by nitric acid, and after longer contact forms with it a bright yellow solution. No other acid has this effect. Muriatic acid, as Dr. O’Shaughnessey has remarked,[304] does not act at all on morphia, and sulphuric acid chars and blackens it. When nitric acid is added to a solution of narcotin in sulphuric acid, the colour of the solution is changed from yellow to blood-red.[305] When it is added to a solution of proto-sulphate of iron, the solution becomes brown, and the addition of sulphuric acid then alters the colour to violet.[306] When it is added even in the most minute proportion to sulphuric acid, the addition of a few particles of the alkaloid brucia will render the whole fluid red, passing gradually to yellow.[307]—Many other characteristic tests might be mentioned; but those now specified are more than enough.

2. _In a diluted state_ this acid is not so easily recognised as the other mineral acids, for it does not form any insoluble salt or precipitate with bases.

The most convenient process consists in first ascertaining the acidity of the fluid, then neutralizing it with potass, evaporating to dryness, and heating the residue in a tube with sulphuric acid. The vapour disengaged, if abundant, may be known by its orange colour in the tube and its odour. But if small in quantity it is best to distil over the vapour in a proper apparatus, and to subject the condensed product to the tests of morphia, narcotin dissolved in sulphuric acid, and proto-sulphate of iron dissolved in water. A convenient tube for the purpose is that represented in Fig. 3; into which the materials are introduced by the funnel, Fig. 4. The wide part of the tube may then be drawn out in the spirit-lamp flame to any length or fineness that may be necessary, so as to conduct the vapour into another tube as a condenser, or directly into the substances to be used as tests.

3. _When in a state of compound mixture_, nitric acid, like sulphuric acid in similar circumstances, may be after a time partly decomposed and partly neutralized; and when the matter with which it is mixed belongs to either of the organic kingdoms, more particularly to the animal world, its decomposition is more rapid than that of sulphuric acid. Still it is an important fact, that some of the acid may be discovered after a considerable interval. M. Ollivier detected it in various stains on the skin at least a day after it had been applied;[308] Dr. O’Shaughnessey detected it in a stain on cloth sent to him from Ireland to Edinburgh;[309] and I have found it in stains made on broad-cloth with detached drops seven weeks before.

_Process for Stains._ Nitric acid produces on the skin a yellow stain, which gradually becomes dirty orange, and finally of a dirty yellowish-brown; but in all of these states it is at once rendered for a time lively yellow by the action of ammonia. I am not aware that any other yellow stain is similarly affected. Stains on cloth are generally yellow, reddish-yellow, or brownish-yellow, and are attended with more or less disintegration of the texture of the cloth. The method of analyzing all these stains is as follows:—The stained parts is to be boiled in a few drachms of pure water several times in succession; and the liquid is then filtered, and may be subjected to litmus-paper for the purpose of ascertaining its acidity. It is then to be rendered neutral, or for the sake of greater facility, feebly alkaline, by adding a few drops of a diluted solution of caustic potass, after which the whole is evaporated to dryness, and in a vapour-bath, if practicable. The residuum is then to be decomposed by sulphuric acid in the same way as recommended above for the simple diluted acid.—Orfila thinks it advantageous to let the stains macerate for some hours in a solution of bicarbonate of soda rather than to boil them in water. In that case, however, it is necessary to ascertain the acidity of the stains with litmus-paper before proceeding to macerate them.

_Process for Mixtures._ The detection of nitric acid in compound mixtures, such as the contents of the stomach, is not so easy a matter as its detection in stains; and indeed a sure and delicate process is still a desideratum in medico-legal chemistry. The process varies, as in the case of sulphuric acid, according as the subject of analysis is acid or neutral.

a. _If the mixture be acid_, and the proportion of the acid considerable, it maybe detected without difficulty. It is merely necessary to ascertain the acidity of the mixture by litmus-paper, to neutralize with potass, water being added if necessary, and then to filter and evaporate to a convenient degree of concentration. Crystals will form on cooling, which may be decomposed by sulphuric acid in the usual way. But the medical jurist ought not to flatter himself with the expectation of meeting often with a proportion large enough to admit of being discovered by so coarse a method of analysis. In general the crystallization of the nitrate of potass is prevented by co-existing animal or vegetable matter. When the proportion appears inconsiderable, therefore, a different process must be pursued. In preparing the former edition of this work, the present topic was investigated with some care, and a method suggested which appeared to me at that time more effectual, delicate, and conclusive than any previously made public. Since then Professor Orfila has also investigated the subject attentively, and after trying various methods, has ended in adopting one which is substantially the same as that now referred to, but without a precaution, which seems to me essential for success in certain probable enough circumstances.[310] I am therefore disposed to retain my former process, with some variations and additions in the details.

Macerate the subject of analysis for a few hours in distilled water, if it be not already liquid enough; and then boil for a few minutes, and filter it. Ascertain now whether the fluid be acid to litmus; and if it be so, neutralize it with solution of potash, or as Orfila suggests, with a solution of the purer salt, the bicarbonate of soda. Evaporate gently, to obtain crystals if possible; and if these do not tend to the cubical form, distil them with sulphuric acid, and proceed as directed for nitric acid simply diluted. If crystals do not appear, or their form tend to the cube,—in which case chloride of sodium is present,—redissolve the whole residue of evaporation in distilled water; add a slight excess of a warm solution of acetate of silver, to throw down organic matter and the chlorine of any chlorides that may be present; filter and evaporate to dryness, and distil the residuum with sulphuric acid, applying as usual to the vapour the tests of litmus-paper and morphia,—also, as Orfila proposes, the solution of narcotin in sulphuric acid, and proto-sulphate of iron in water,—and if the quantity of vapour be great enough, the sense of smell and the action of copper with the condensed vapour.

b. _If the mixture be neutral_, proceed exactly as above, except that it becomes unnecessary to neutralize the liquid with potash or bicarbonate of soda. This variety in the process will be principally required, where earths or alkalis have been administered as antidotes.

The process now detailed requires a word or two of commentary.—Organic matter is inconvenient because it prevents the nitrate of potash or soda in the mixture from crystallizing. But it will not prevent the evolution of nitric acid vapour by distillation with sulphuric acid, even although the material be a simple extract without crystals. At the same time it is better to get rid of as much organic matter as possible, if distinct crystals be not obtained by evaporation. A more serious difficulty, however, to which Orfila does not advert, arises from the co-existence of a chloride. For, in that case, distillation with sulphuric acid may disengage not nitric acid, but chlorine, in consequence of the reaction which takes place between the nitric and hydrochloric acids in the act of being liberated. This is a more important reason for purifying the liquid by acetate of silver before subjecting it to concentration; but in addition, by removing organic matter, this precaution increases the chance of crystals of nitrate of potash or soda being obtained. Its necessity, where a chloride co-exists, will appear from the following experiment. Four drops of nitric acid neutralized with potass were mixed with six ounces of strong barley-broth; from which half an ounce of limpid fluid was procured by filtration. One-half of this evaporated to dryness gave a crystalline residue, which, heated with sulphuric acid in a tube, emitted a strong odour of chlorine; and the moisture which bedewed the tube scarcely affected morphia. The residuum of the other half of the filtered fluid was redissolved, treated with acetate of silver, again filtered, and evaporated to dryness; and the residue was gently heated in a tube with sulphuric acid. An odour of nitric acid was now disengaged, and the moisture on the tube close to the mixture turned a fragment of morphia to bright orange-red.

Acetate of silver is prepared by mixing strong solutions of acetate of potass and nitrate of silver, draining and compressing between folds of bibulous paper the crystalline precipitate which forms, dissolving this precipitate by agitating it in boiling water, and finally crystallizing the salt again by refrigeration. The crystals, which are sparingly soluble in cold water, should be then separated, slightly washed with a little water, and again dried by compression. When put to use, a solution should be made by agitating the salt in boiling water, because at low temperatures water retains very little of the salt; but actual ebullition should be avoided, because acetate of silver is thus quickly decomposed.

In all medico-legal analyses for nitric acid, care must be taken that the different reagents used are free of this acid, and also of nitrates. Sulphuric acid often contains a little nitric, or rather nitrous acid; which may be discovered by the sulphuric acid becoming brown or dark-red when a solution of proto-sulphate of iron is gently poured over it in a test-tube; and which may be removed either by boiling the acid with a few grains of sugar, according to the formula of the Edinburgh Pharmacopœia, or, as Orfila directs, by boiling it with sulphate of ammonia.

SECTIONS II. III. IV.—_Of the Action, Symptoms, Morbid Appearances, and Treatment of Poisoning with Nitric Acid._

All the observations made on these topics under the head of sulphuric acid apply, with few exceptions, to the nitric acid also. A few statements therefore on the peculiarities ascertained to exist in the latter case are all that will be required in the present sections.

Nitric acid is not less powerful as a corrosive and irritant than sulphuric acid. It will act with energy as an irritant even when considerably diluted, for example with six or eight parts of water or even more.—The lips which are rendered at first whitish by all the acids, and eventually brownish by sulphuric acid, becomes soon yellow with nitric acid. The tongue too sometimes acquires a yellow colour instead of a white glazed appearance; but this character is not invariable.—All spots caused by it on the skin become speedily yellow, and long retain this hue; or if the tint become dull, which generally happens in a few days, it is enlivened and the yellow colour restored for a time, by ammonia, potash, soda, or soap.—An important fact, for which toxicology is indebted to Professor Orfila, is that the acid may be often found in the urine, both when it had been swallowed, and when it had been introduced through the medium of the cellular tissue.[311] It is to be discovered by the process for compound mixtures. Orfila adds that he has hitherto been unable to find it in the liver or spleen.

A difference of tint in the lining membrane of the mouth and gullet is the only difference observed in the morbid appearances caused by nitric and sulphuric acid. The former sometimes renders these parts yellow; but this appearance is far from being invariable.

The treatment in both instances is the same in every respect.

III.—OF POISONING WITH HYDROCHLORIC ACID.

This acid occurs more rarely than any of the other mineral acids in medico-legal cases; a fact which appears singular enough on considering, that it is a powerful corrosive, and more perhaps in the hands of the working-classes than any other.

SECTION I.—_Of the Tests for Hydrochloric Acid._

Like the other acids, hydrochloric acid occurs in the concentrated shape, in a state of simple dilution, and mixed with various matters, especially from organic kingdoms.

1. Hydrochloric acid, _in its concentrated state_, is colourless, if pure, but yellowish as usually sold; and it is easily known by the peculiar appearance and odour of its fumes. A convenient additional test, which, however, is not absolutely distinctive, is the formation of white vapour when a rod dipped in it is brought near another dipped in ammonia. If any farther evidence be desired, the strong acid must be diluted with water, and examined by the tests for it in a diluted state.

2. _When diluted_, it is recognised with facility, first by litmus-paper, and then by the nitrate of silver, which forms with it a dense, white precipitate, the chloride of silver. This is soluble in ammonia, reappears on neutralizing the ammonia by nitric acid, and is not redissolved by a large excess of nitric acid, even aided by heat. Its permanence under an excess of nitric acid distinguishes it from every other silver salt, but the cyanide; which again is known by disappearing when boiled with a large excess of the acid.

3. In the last edition of this work I proposed for the detection of hydrochloric acid in _compound organic mixtures_ a process, to which Professor Orfila has since made an important addition,[312] and which the investigations of that toxicologist, as well as my own, lead me to suppose superior to any other yet suggested, although it is not entirely free from objection. This process divides itself into two, according as the subject of analysis is acid or neutral; but in the latter case its indications are of dubious import.

a. If the matter to be examined be acid, boil it with water if necessary, filter, and distil it with a gentle heat till the residue acquire the consistence of a very thin syrup. Subject the distilled liquor to the tests for diluted hydrochloric acid. It will seldom be found there, however, because it is apt to be retained by the co-existence of organic matter. If it be not found, add to the thin extract in the retort a slight excess of a strong solution of tannin, filter, and distil the filtered liquid by means of a hot bath of solution of hydrochlorate of lime (consisting of two parts of crystallized salt and one of water,)—taking care that the temperature of the bath never exceeds 240°; and stop the distillation just before the residuum becomes dry. Examine now the distilled liquor with the tests for diluted hydrochloric acid.

Hydrochloric acid has a tendency to adhere with obstinacy to organic matters, especially when these are abundant; and therefore Orfila properly proposes to remove organic principles as far as possible by precipitating them with solution of tannin. I have found, as he did, that the acid may be obtained by distillation after this measure, when it could not be obtained previously.—Orfila objects to the process however that hydrochlorate of ammonia will pass over in the distillation. But I have not found this to be the fact, when the temperature did not rise above 240°; which in his experiments seem to have been considerably exceeded.—A more important fallacy is, that hydrochloric acid will be indicated by the process in a mixture which contains both a neutral chloride, such as common salt, and sulphuric acid. This fallacy can only be obviated by ascertaining that sulphuric acid is not present.—But the most important fallacy of all is, that free hydrochloric acid constitutes an essential part of the gastric juice, and an ingredient of the secretions of the stomach in various states of disordered digestion.[313] It is not easy to see how this fallacy can be obviated, unless the acid be obtained in large quantity; nor am I prepared to say what quantity would justify the conclusion, that the acid had been derived from an external source. Dr. Prout once found between four and five grains of pure acid in sixteen ounces of the fluid of water-brash.[314] The quantity of hydrochloric acid is to be known by drying, heating and weighing the chloride of silver thrown down in the distilled fluid by nitrate of silver, and allowing 100 parts of concentrated commercial acid for 145 of chloride.

b. When the mixture is neutral, hydrochloric acid can be no longer detected in it without the aid of sulphuric acid to decompose the chloride that has been formed. This should be added to the filtered fluid obtained after organic matter has been separated by solution of tannin. Hydrochloric acid will then distil over.—It is seldom however that the discovery of the acid in this way will warrant the conclusion, that it had ever existed free in the mixture whence it is obtained. For it may have proceeded from chlorides contained in the subject of analysis from the first, more especially chloride of sodium, which exists in small quantity in all animal fluids and solids, and more largely in many articles of food and drink. The only circumstance indeed in which the detection of hydrochloric acid by decomposition with sulphuric acid will yield any evidence,—and even then the evidence will only be presumptive,—is when it is known that an earth or alkali was given as an antidote, and when the alkali or earth which was used is found in the suspected substance.

SECTION II.—_Of the Action and Symptoms produced by Hydrochloric Acid._

Hydrochloric acid has been found by Professor Orfila to exert the same action as sulphuric and nitric acids; but it is a less powerful corrosive and irritant.—In the gaseous state, it is a most destructive poison to vegetables, as will be shown in the article on the Poisonous Gases.

The symptoms it occasions in man are very like those produced by sulphuric acid. As few cases however of poisoning with this substance have yet been published, its effects are not so well known as those of the other powerful acids; and it may therefore be right to mention the leading particulars of some of the cases which are met with in authors.—Mr. Quekett has related the case of a man, who, on arriving at home one day, told the woman he lodged with that he had poisoned himself with spirit of salt, but presented at the moment so little sign of uneasiness, that she at first scarcely believed him. In a short time however he suddenly became faint and fell down. On being removed to the London Hospital, magnesia and milk were given, about three hours after the acid had been taken; but no relief was experienced. He suffered intense thirst, complained of excessive pain in the stomach and throat, and expired in about fifteen hours.[315]—Mr. J. F. Crawfurd of Newcastle has related a still more rapid case which was occasioned by two ounces of an equal mixture of hydrochloric acid and “tincture of steel,” probably the tincture of chloride of iron. Vomiting occurred soon afterwards, but subsequently ceased; there was no complaint made either of pain or heat anywhere, or of thirst; and questions were answered intelligently. But the pulse was imperceptible, and the muscles of the extremities contracted; and death took place in five hours and a half.[316]—Orfila mentions that an hospital patient, affected with inflammation of the brain after a fall on the head, having got by mistake from his nurse 45 grammes, or two fluid ounces, of hydrochloric acid, was attacked with acute pain in the stomach, efforts to vomit, hiccup, extreme restlessness, a small pulse, a fiery red tongue, blackness of the lips, and a burning skin; and next day he died in a state of constant delirium, and covered with a cold clammy sweat.[317]

These cases present nearly the same violence and variety of action with that which results from the two other acids.

SECTION III.—_Of the Morbid Appearances caused by Hydrochloric Acid._

The morbid appearances are on the whole similar to what are caused by sulphuric acid. In Mr. Quekett’s case the stomach outwardly was leaden-coloured and its vessels gorged with black blood; the intestinal peritonæum injected and speckled with fibrinous effusion; the villous coat of the stomach lined with yellow, curdled milk, and itself irregularly black here and there, as if charred, and in some places softened and corroded, so that a rent was made in handling it; the inner membrane of the duodenum similarly affected, and also even the jejunum, though more irregularly. The contents of the stomach were not acid, and did not contain any chloride.—In Mr. Crawfurd’s case the villous coat presented black elevated ridges, as if charred, and the furrows between were scarlet-red; black granular extravasation had taken place at many points into the submucous tissue; similar appearances were seen in the duodenum and jejunum; and the lower part of the gullet looked as if it had been cauterized.—In the case related by Orfila the gullet and pharynx were red, and at one or two places excoriated; the stomach inflamed externally, and its inner membrane spotted with gangrenous (?) patches, and very brittle; the duodenum thickened, and the jejunum perforated by a round worm.