104

HYDROCHLORIC OR MURIATIC ACID.

organic liquids. The stains from this acid on black and blue cloth are of a yellow or brownish-yellow color and are indelible. When long exposed they become dry, but the cloth is easily torn. A simple method of detecting the acid is to boil at once a piece of the stained cloth with a fragment of gold-leaf and hydrochloric acid. If nitric acid is present in the stain, a portion of the gold will be dissolved.

In 1889, a man was convicted of the murder of a woman by pouring nitric acid down her throat whilst in bed (Reg. v. Lipski, C. C. C., July, 1888). In reality a mixture of acids, containing more sulphuric than nitric, was employed. Such a mixture does not char cellulose (wood and cotton) like sulphuric acid, but converts it into nitro-cellulose, which substance was found by the editor in the stains on the deceased woman's linen, and also in wood cut from the floor of the room in which the murder was committed.

HYDROCHLORIC ACID. MURIATIC ACID.

This acid, which is also called muriatic acid, and is popularly known under the name of spirit of salt, is often taken as a poison. In the cases which have hitherto been observed, the symptoms and appearances have been similar to those caused by nitric acid. A woman, æt. 63, swallowed half an ounce of concentrated hydrochloric acid. She was received into the hospital in three-quarters of an hour. The prominent symptoms were burning pain in the throat and stomach, feeble pulse, cold, clammy skin, retching, and vomiting of a brown matter streaked with blood and containing shreds of membrane. There was great exhaustion. The throat became swollen, the patient lost the power of swallowing, and died in eighteen hours. She retained her senses until the last. The appearances in the body were as follows: The mucous membrane of the mouth and throat was white, softened, and destroyed in many places by the corrosive action of the acid. The mucous membrane of the gullet was red and inflamed. The back part of the stomach near the pylorus was dark-colored, stripped of its mucous membrane (which was generally softened), and marked with black lines. It was not perforated (Lancet, 1859, ii. p. 59). In this case the smallest quantity of hydrochloric acid was taken which has as yet been known to prove fatal.

In 1885, a man, æt. 37, was admitted into Guy's Hospital after swallowing, for suicidal purposes, a fluidounce of strong hydrochloric acid, in which he had dissolved a dram of oxalic acid. The ordinary antidotes were employed, and he progressed favorably till the tenth day, when he died rather suddenly. On post-mortem examination the editor found a membranous exudation and minute ulcers at the back of the pharynx. The mucous membrane of the gullet was white, thickened, and interspersed with small extravasations of blood. The stomach contained remains of food of the ordinary acidity. The mucous membrane was white and mammillated. Towards the pyloric or intestinal end there were small ulcers with open blood vessels, from the mouths of which extended considerable extravasations of blood blackened by the action of the acids of the stomach. Between the ulcers the surface was raw and hemorrhagic. The hemorrhage extended into the duodenum, but not beyond.

Chemical Analysis.—In a concentrated state, hydrochloric acid evolves copious fumes. The pure acid is nearly colorless; the commercial acid is of a lemon-yellow color, and frequently contains iron, arsenic, common salt, and other impurities. When boiled with a small quantity of peroxide of manganese, chlorine is evolved. It does not dissolve gold-leaf until a

few drops of nitric acid. have been added to it, and the mixture is heated. In the diluted state, it may be recognized by the dense white precipitate which it gives when a solution of nitrate of silver is added to it. This precipitate is insoluble in nitric acid, but soluble in ammonia; it becomes purple when exposed to light; and when heated it melts without decom. position, forming a yellowish-colored solid in cooling. If the acid is contained in organic liquids in moderate quantity, it admits of separation by distillation to dryness. In this case any chlorides present are left in the retort. It may also be procured by dialysis in a pure enough state for testing (see p. 99, ante). In all cases the presence of a free mineral acid must be ascertained (see p. 99, ante).

Hydrochloric acid, in small quantity, as well as alkaline chlorides, is a natural constituent of the fluids of the stomach and bowels. The presence of local chemical changes in the throat and stomach would show whether the acid had been taken as a poison. If the acid is found only in minute quantity, no inference of poisoning can be drawn, unless there are distinct marks of its chemical action upon the throat and stomach. It darkens the blood like sulphuric acid, although it has not the same degree of carbonizing action on organic matter. The stains produced by this acid on black cloth are generally of a reddish color. As the acid is volatile, it may disappear from the stuff. If recent, the acid may be separated by boiling the stuff in water and applying the silver test, and the tests for a free mineral acid (see p. 99, ante). An unstained portion of cloth should be similarly tested for the sake of comparison.

[NITRO-HYDROCHLORIC ACID. (AQUA REGIA.)

The general symptoms, effects, and post-mortem appearances resemble those of the preceding acid. The test is its solvent power over gold. Its chlorine can be detected by the odor evolved and also by nitrate of silver; its nitric acid, by the action on copper in the cold. (Reese.)]

CHAPTER VIII.

OXALIC ACID.-SYMPTOMS AND APPEARANCES.-CHEMICAL ANALYSIS.-DIALYSIS OF ORGANIC LIQUIDS.-ACID oxalate OF POTASSIUM, OR SALT of sorrel.-VEGETABLE ACIDS.

OXALIC ACID.

Symptoms. If this poison is taken in a large dose, i.e. from half an ounce to an ounce of the crystals, dissolved in water, a hot, burning, acid taste is experienced during the act of swallowing the poison. This is accompanied by a similar sensation extending down the gullet to the stomach. There is sometimes a sense of constriction or suffocation: the countenance is livid, and the surface of the skin soon becomes cold and clammy. Vomiting occurs either immediately or within a few minutes. Should the poison be much diluted, there is merely a sensation of strong acidity, and vomiting may not occur until after a quarter of an hour or twenty minutes. In some cases there has been little or no vomiting, while in others this symptom has been incessant until death. In one case, in which an ounce

106

APPEARANCES AFTER DEATH.

of the acid was swallowed, the vomiting and pain in the stomach continued until the fifth day, when the man died suddenly (Lancet, 1860, ii. p. 509); but in another, in which the poison was much diluted, vomiting did not occur for seven hours. (Christison.) The vomited matters are highly acid, have a greenish-brown or almost black color, and consist chiefly of mucus and altered blood. The patient complains of great pain and tenderness in the abdomen, with a burning sensation in the stomach. There may be convulsions. There is in general an entire prostration of strength, so that if the person is in the errect position he falls; there is likewise unconsciousness of surrounding objects, and a kind of stupor, from which, however, the patient may be without difficulty roused. Owing to the severity of the pain, the legs are sometimes drawn up towards the abdomen, or the patient rolls about on the floor or bed. The pulse is small, irregular, and scarcely perceptible; the skin cold and clammy; and there is a sensation of numbness in the limbs. The breathing is spasmodic, the inspirations being deep, and a long interval elapses between them. Should the patient survive the first effects of the poison, the following symptoms may appear: soreness of the mouth, constriction and burning pain in the throat, pain in swallowing, tenderness in the abdomen, and irritability of the stomach, so that there is frequent vomiting, accompanied by purging. The tongue is swollen, and there is great thirst. Sometimes there is aphonia, or the patient speaks in a feeble punchinello voice. The following case is exceptional, from the fact that the symptoms throughout were chiefly referable to the brain. A man took what was supposed to be a black draught, but it contained oxalic acid instead of Epsom salts. Two hours afterwards he was found in a state of complete coma, but the symptoms set in a quarter of an hour after he had taken the draught. The man died in five hours, without recovering his consciousness. The only marked appearance on inspection was intense congestion of the brain (Lancet, 1872, ii. p. 41.) Oxalic acid injected into the circulation of animals acts as a cardiac poison; and this is in accordance with its well-known rapidly-fatal effects on man. Christison says: "If a person, immediately after swallowing a solution of a crystalline salt, which tasted purely and strongly acid, is attacked with burning in the throat, then with burning in the stomach, vomiting, particularly of bloody matter, imperceptible pulse, and excessive languor, and dies in half an hour, or, still more, in twenty, fifteen, or ten minutes, I do not know any fallacy which can interfere with the conclusion that oxalic acid was the cause of death. No parallel disease begins so abruptly and terminates so soon; and no other crystalline poison has the same effect." Ringer asserts that soluble oxalates precipitate calcium from the blood as insoluble oxalate of calcium; and as soluble calcium salts in the blood are requisite for the maintenance of the muscular contractility, oxalates may kill by destroying the cardiac muscular contractility. (Practitioner, 1885, xxxiv. p. 81.)

Appearances after Death.-The mucous membrane of the tongue, mouth, throat, and gullet is softened, and commonly white as if bleached; but it is sometimes coated with a portion of the brown mucous matter discharged from the stomach. This latter organ contains a dark brown mucous liquid, often acid, and having an almost gelatinous consistency. On removing the contents, the mucous membrane will be seen pale and softened, without always presenting marks of inflammation or abrasion, if death has taken place rapidly. The mucous membrane is soft and brittle, easily raised by the scalpel, and presents the appearance which we might suppose it would assume after having been for some time boiled in

water. The small vessels are seen ramifying over the surface, and filled with dark-colored blood apparently solidified within them. The lining membrane of the gullet presents the same characters, and has often a worm-eaten appearance. It is pale, and appears as if it had been boiled in water, or digested in alcohol; it has been found s rongly raised in longitudinal folds, interrupted by patches where the membrane has become abraded. In a case which was fatal in eight hours, the tongue was covered with white specks; the gullet was not inflamed, but the stomach was extensively destroyed and had a gangrenous appearance. Portions of the mucous membrane were detached, exposing the muscular coat. With respect to the intestines, the upper portion may be found inflamed; but, unless the case is protracted, the appearances in the bowels are not strongly marked.

In a well-marked instance of poisoning by this acid, recorded by Hildebrand, the mucous membrane of the stomach and duodenum was much reddened, although the patient, a girl of eighteen, died in threequarters of an hour after taking one ounce of the acid, by mistake for Epsom salts. (Casper's Vierteljahrsschr., 1853, p. 256.) In a case of poisoning, in which two ounces of the acid had been taken, and death was rapid, the coats of the stomach presented the almost black appearance produced by sulphuric acid, owing to the color of the altered blood spread over them. In protracted cases, the gullet, stomach, and intestines have been found more or less congested or inflamed. In the case already cited, in which an ounce was swallowed, and death occurred on the fifth day, the stomach was slightly congested, and contained a bloody fluid, but the mucous membrane was entire. (Lancet, 1860, ii. p. 509.)

The glairy contents of the stomach do not always indicate strong acidity until after they have been boiled in water. Oxalic acid does not appear to have so strongly corrosive an action on the stomach as that possessed by the mineral acids. It is, therefore, rare to hear of the coats of the organ being perforated by it; but the acid, when in a concentrated state, renders the mucous coat soft and brittle, and perforation of the coats may occasionally occur either during life or after death, as a result of its chemical action. Wood has recorded the case of a woman, æt. 27, found dead, whose death had been obviously caused by oxalic acid; but the quantity taken, and the duration of the case, were unknown. The stomach presented, at its upper and fore part near the cardiac opening, an irregular aperture of a size to admit the point of the finger.

Fatal Dose. The smallest quantity of this poison which has been known to destroy life is 60 grains. A boy, æt. 16, took that quantity, as he said, of the poison in a solid form, and was found in about an hour insensible, pulseless, and his jaws spasmodically closed. He had vomited some bloody matter; his tongue and lips were unusually pale, but there was no excoriation. He died in eight hours. (Lancet, 1855, ii. p. 521.) Tardieu (L'Empoisonnement, p. 253) speaks of a fatal case in a young man, æt. 16, from a dose of 30 grains (2 grammes), but it is doubtful, since he gives no details, whether this is not the English case just now mentioned. Two cases occurred at Guy's Hospital, in each of which half an ounce of oxalic acid had been swallowed. Active treatment was adopted, and both patients recovered. When the dose of oxalic acid is half an ounce and upwards, death commonly takes place within an hour; but there are numerous exceptions to this rapidity of action. Christison mentions an instance in which an ounce of oxalic acid killed a girl in thirty minutes; and another in which the same quantity destroyed life

108

CHEMICAL ANALYSIS-TESTS.

in ten minutes; but in a third case death did not occur until the fifth day. The editor has met with cases of death in fifteen and twenty minutes respectively. Ogilvy has reported a case of poisoning by oxalic acid in which it is probable that death took place within three minutes after the poison had been swallowed. The quantity of the acid taken could not be determined.

Chemical Analysis. In the simple state. This acid may be met with, either as a solid or in solution in water. Solid oxalic acid crystallizes in long slender prisms, which, when perfect, are four-sided (Fig. 2). In this respect it differs from other common acids, mineral and vegetable. The crystals are unchangeable in air, and to the eye are precisely like those of Epsom salts and white vitriol; they are soluble in water and alcohol, forming strongly acid solutions. When heated on

Fig. 2.

000000

Crystals of Oxalic Acid, magnified 30 diameters.

platinum-foil they melt, and are entirely dissipated without blackening. Heated in a close tube they melt, and a white crystalline sublimate forms in the cold part of the tube. There should be no residue whatever if the acid is pure, but the commercial acid generally leaves a slight residue of fixed impurity. By this effect of heat, oxalic acid is easily distinguished from those crystalline salts for which it has been sometimes fatally mistaken, namely, the sulphates of magnesium and zinc: these leave white residues. A teaspoonful of oxalic acid in small crystals weighs seventy-six grains, and half an ounce of the crystals is equivalent to three teaspoonfuls.

Tests.--1. Nitrate of silver.-When added to a solution of oxalic acid, it produces an abundant white precipitate of oxalate of silver. A solution containing so small a quantity of oxalic acid as not to redden litmus-paper, is affected by this test; but when the quantity of poison is small, it is advisable to concentrate the liquid by evaporation before applying the test. The oxalate of silver is identified by the following properties: It is completely dissolved by cold nitric acid. If collected on a filter, thoroughly dried, and heated on platinum-foil, it is dissipated in a white vapor with a slight detonation, and a residue of silver is left. When the oxalate is in small quantity, this detonation may be observed in detached particles on burning the filter previously well dried. 2. Sulphate of calcium. A solution of oxalic acid is precipitated white by lime-water and all the salts of calcium. Lime-water is itself objectionable as a test, because it is precipitated white by several other acids. The salt of calcium, which, as a test, is open to the least objection, is the sulphate. As this is not a very soluble salt, its solution must be added in rather large quantity to the suspected acid poisonous liquid previously concentrated. A white precipitate of oxalate of calcium is slowly formed. This precipitate should possess the following properties: 1. It ought to be immediately dissolved by nitric or hydrochloric acid. 2. It ought not to be dissolved by acetic or any other vegetable acid, or by ammonia.

In organic liquids. The process is the same, whether it is applied to liquids in which the poison is administered, or to the matters vomited, or, lastly, to the contents of the stomach. Should the liquid be very acid, we must filter it to separate any insoluble matters; should it not be strongly acid, the whole may be boiled if necessary with distilled water,