PART IX.—INORGANIC POISONS.

I.—PRECIPITATED FROM A HYDROCHLORIC ACID SOLUTION BY HYDRIC SULPHIDE—PRECIPITATE YELLOW OR ORANGE.[700] Arsenic—Antimony—Cadmium.

1. ARSENIC.

§ 707. Metallic Arsenic, at. wt. 75, specific gravity of solid 5·62 to 5·96, sublimes without fusion in small quantities at 110° (230° F.) Guy. It occurs in commerce in whitish-grey, somewhat brittle, crystalline masses, and is obtained by subjecting arsenical pyrites to sublimation in earthen retorts, the arsenic being deposited in suitable receivers on sheet iron. Metallic arsenic is probably not poisonous, but may be changed by the animal fluids into soluble compounds, and then exert toxic effects—volatilised metallic arsenic is easily transformed in the presence of air into arsenious acid, and is therefore intensely poisonous.

§ 708. Arsenious Anhydride—Arsenious Acid—White Arsenic—Arsenic, As₂O₃ = 198; specific gravity of vapour, 13·85; specific gravity of opaque variety, 3·699; specific gravity of transparent variety, 3·7385. Composition in 100 parts, As 75·75, O 24·25; therefore one part of metallic arsenic equals 1·32 of As₂O₃. It is entirely volatilised at a temperature of 204·4°.

In analysis it is obtained in brilliant octahedral crystals as a sublimate on discs of glass, or within tubes, the result of heating a film of metallic arsenic with access of air. It is obtained in commerce on a very large scale from the roasting of arsenical pyrites. As thus derived, it is usually in the form of a white cake, the arsenious acid existing in two forms—an amorphous and a crystalline—the cake being generally opaque externally, whilst in the centre it is transparent. According to Kruger, this change from the crystalline to the amorphous condition is dependent upon the absorption of moisture, no alteration taking place in dry air. Both varieties of arsenious anhydride are acid to test-paper.

The solubility of arsenious acid is often a question involving chemical legal matters of great moment. Unfortunately, however, no precisely definite statement can be made on this point, the reason being that the two varieties of arsenic occur in very different proportions in different samples. Both the amorphous and crystalline varieties having very unequal solubilities, every experimenter in succession has given a different series of figures, the only agreement amid the general discrepancy being that arsenic is very sparingly soluble in water.

The statement of Taylor may, however, be accepted as very near the truth, viz., that an ounce of cold water dissolves from half a grain to a grain. According to M. L. A. Buchner,[701] one part of crystalline arsenious acid dissolves after twenty-four hours’ digestion in 355 parts of water at 15°; and the amorphous, under the same condition, in 108 of water. A boiling solution of the crystalline acid, left to stand for twenty-four hours, retains one part of acid in 46 of water; a similar solution of the amorphous retains one of arsenic in 30 parts of water, i.e., 100 parts of water dissolve from 2·01 to 3·3 parts of As₂O₃.

Boiling water poured on the powdered substance retains in cooling a grain and a quarter to the ounce; in other words, 100 parts of water retain ·10. Lastly, arsenious acid boiled in water for an hour is dissolved in the proportion of 12 grains to the ounce, i.e., 100 parts of water retain 2·5.

K. Chodomisky[702] has investigated the solubility of recrystallised arsenious acid in dilute acids, and his results are as follows:—100 c.c. of 1·32 per cent. hydrochloric acid dissolves 1·15 grm. As₂O₃ at 18·5°. 100 c.c. of 6 per cent. hydrochloric acid dissolves 1·27 grm. at 18·5°. 100 c.c. of pure hydrochloric acid of the ordinary commercial strength dissolves 1·45 grm. As₂O₃. 100 c.c. of dilute sulphuric acid at 18° dissolves about 0·54 grm.; at 18·5° from 0·65 to 0·72 grm.; and at 80° from 1·09 to 1·19 grm.

§ 709. Arsine—Arseniuretted Hydrogen, H₃As.—Mol. weight, 78; vol. weight, 39; specific gravity, 2·702; weight of a litre, 3·4944 grammes; percentage composition, 95·69 As, 4·31 H; volumetric composition, 2 vol. H₃As = half vol. As + 3 vol. H. A colourless inflammable gas, of a fœtid alliaceous odour, coercible into a limpid colourless liquid at a temperature of from -30° to -40°. The products of the combustion of arseniuretted hydrogen are water and arsenious acid; thus, 2H₃As + 6O = 3H₂O + As₂O₃. If supplied with air in insufficient quantity, if the flame itself be cooled by (for example) a cold porcelain plate, or if the gas pass through a tube any portion of which is heated to redness, the gas is decomposed and the metal separated. Such a decomposition may be compared to the deposit of carbon from ordinary flames, when made to play upon a cooled surface. It may also be decomposed by the electric spark,[703] e.g., if the gas is passed slowly through a narrow tube 0·7 to 0·8 mm. internal diameter, provided with wires 0·5 to 0·6 mm. apart, and a small induction coil used connected with two large Bunsen’s cells, then, under these conditions, arsenic as a metal is deposited in the neighbourhood of the sparks. For the decomposition to be complete, the gas should not be delivered at a greater speed than from 10 to 15 c.c. per minute. The gas burns with a blue-white flame, which is very characteristic, and was first observed by Wackenroder. It cannot, however, be properly seen by using the ordinary apparatus of Marsh, for the flame is always coloured from the glass; but if the gas is made to stream through a platinum jet, and then ignited, the characters mentioned are very noteworthy.

Oxygen or air, and arsine, make an explosive mixture. Chlorine decomposes the gas with great energy, combining with the hydrogen, and setting free arsenic as a brown cloud; any excess of chlorine combines with the arsenic as a chloride. Sulphur, submitted to arseniuretted hydrogen, forms sulphuretted hydrogen, whilst first arsenic and then sulphide of arsenic separate. Phosphorus acts in a similar way. Arseniuretted and sulphuretted hydrogen may be evolved at ordinary temperatures without decomposition; at the boiling-point of mercury (350°) they are decomposed, sulphide of arsenic and hydrogen being formed; thus, 3H₂S + 2AsH₃ = As₂S₃ + 6H₂, a reaction which is of some importance from a practical point of view. Many metals have also the property of decomposing the gas at high temperatures, and setting hydrogen free. Metallic oxides, again, in like manner combine with arsenic, and set water free, e.g., 3CuO + 2H₃As = Cu₃As₂ + 3H₂O.

Arsine acts on solutions of the noble metals like phosphuretted hydrogen, precipitating the metal and setting free arsenious acid; for example, nitrate of silver is decomposed thus—

12AgNO₃ + 2H₃As + 3H₂O = As₂O₃ + 12HNO₃ + 12Ag.

Vitali[704] thinks the reaction is in two stages, thus:—

(1) 2AsH₃ + 12AgNO₃ = 2(Ag₃As3AgNO₃) + 6HNO₃. (2) 2(Ag₃As,3AgNO₃) + 6H₂O = 6HNO₃ + 6Ag₂ + 2H₃AsO₃.

This reaction admits of valuable practical application to the estimation of arsenic; for the precipitated silver is perfectly arsenic-free; the excess of nitrate of silver is easily got rid of by a chloride of sodium solution, and the absorption and decomposition of the gas are complete.

In cases of poisoning by arsine, the blood, when examined by the spectroscope (a process the analyst should never omit where it is possible), is of a peculiar inky colour, and the bands between D and C are melted together, and have almost vanished. Such blood, exposed to oxygen remains unaltered.

§ 710. Arsine in the Arts, &c.—In the bronzing of brass, in the desilverising of lead by zinc, and subsequent treatment of the silver zinc with hydrochloric acid, in the tinning of sheet iron, and similar processes, either from the use of acids containing arsenic as an impurity, or from the application of arsenic itself, arsine is evolved.

§ 711. Effects on Animals and Man of Breathing Arsine.—The most general effect on mammals is to produce jaundice, bloody urine, and bile. In the course of numerous experiments on dogs, Stadelmann[705] found that by making them breathe a dose of arsine, which would not be immediately fatal, icterus was always produced under these circumstances, and could be always detected by the appearance of the tissues. The bile is remarkably thickened, and the theory is, that in such cases the jaundice is purely mechanical, the gall-duct being occluded by the inspissated bile. Rabbits experimented upon similarly showed increased biliary secretion, but no jaundice; while it was proved that cats are not so sensitive to arsine as either rabbits or dogs. There are not wanting instances of arsine having been breathed by man—the discoverer of the gas, Gehlen, was in fact the first victim on record. In order to discover a flaw in his apparatus he smelt strongly at the joints, and died in eight days from the effects of the inhalation.

Nine persons, workmen in a factory, were poisoned by arsine being evolved during the treatment by hydrochloric acid of silver-lead containing arsenic. Three of the nine died; their symptoms were briefly as follows:—

(1) H. K., 22 years old; his duty was to pour hydrochloric acid on the metal. Towards mid-day, after this operation, he complained of nausea, giddiness, and malaise. In the afternoon he felt an uncommon weight of the limbs, and an oppression in breathing. His fellow-workmen thought that he looked yellow. On going home he lay down and passed into a narcotic sleep. Next morning he went to his work as usual, but was not capable of doing anything; he passed bloody urine several times throughout the day, and fell into a deep sleep, from which he could scarcely be roused. On the third day after the accident, a physician called in found him in a deep sleep, with well-developed jaundice, the temperature moderately high, pulse 100. On the fifth day the jaundice diminished, but it was several months before he could resume his work.

(2) J. T., aged 19, suffered from similar symptoms after five and a half hours’ exposure to the gas. He went home, vomited, was jaundiced, and suffered from bloody urine; in six days became convalescent, but could not go to work for many months.

(3) C. E. was very little exposed, but was unwell for a few days.

(4) L. M., 37 years old, was exposed two days to the gas; he vomited, had bloody urine, passed into a narcotic sleep, and died in three days from the date of the first exposure.

(5) J. S., aged 40, was exposed for two days to the gas; the symptoms were similar to No. 4, there was suppression of urine, the catheter drawing blood only, and death in eight days.

(6) M. E., 36 years old; death in three days with similar symptoms.

(7), (8), and (9) suffered like Nos. 1 and 2, and recovered after several months.

The chief post-mortem appearance was a dirty green colour of the mucous membrane of the intestines, and congestion of the kidneys. Arsenic was detected in all parts of the body.[706]

Two cases are detailed by Dr. Valette in Tardieu’s Étude.[707] A mistake occurred in a laboratory, by which a solution of arsenic (instead of sulphuric acid) was poured on zinc to develop hydrogen. Of the two sufferers, the one recovered after an illness of about a week or ten days, the other died at the end of twenty-eight days. The main symptoms were yellowness of skin, vomiting, bloody urine, great depression, slight diarrhœa, headache, and in the fatal case a morbiliform eruption. In a case recorded in the British Medical Journal, November 4, 1876, there were none of the usual symptoms of gastric irritation, but loss of memory of recent acts, drowsiness, and giddiness.

§ 712. The Sulphides of Arsenic.—Of the sulphides of arsenic, two only, realgar and orpiment, are of any practical importance. Realgar, As₂S₂ = 214; specific gravity, 3·356; composition in 100 parts, As 70·01, S 29·91; average composition of commercial product, As 75, S 25. Realgar is found native in ruby-red crystals, and is also prepared artificially by heating together 9 parts of arsenic and 4 of sulphur, or 198 parts of arsenious anhydride with 112 parts of sulphur, 2As₂O₃ + 7S = 2As₂S₂ + 3SO₂. It is insoluble in water and in hydrochloric acid, but is readily dissolved by potassic disulphide, by nitric acid, and by aqua regia. It is decomposed by caustic potash, leaving undissolved a brown sediment (As₁₂S), which contains 96·5 per cent. of arsenic. The dissolved portion is readily converted into arsine by aluminium.

§ 713. Orpiment, or Arsenic Trisulphide.—As₂S₃ = 246; specific gravity, 3·48; composition in 100 parts, As 60·98, S 39·02; found native in crystals, presents itself in the laboratory usually as a brilliant yellow amorphous powder, on passing sulphuretted hydrogen through an acid solution of arsenious acid or an arsenite. It is very insoluble in water (about one in a million, Fresenius), scarcely soluble in boiling concentrated hydrochloric acid, and insoluble generally in dilute acids. Red fuming nitric acid dissolves it, converting it into arsenic and sulphuric acids; ammonia and other alkaline sulphides, the alkalies themselves, alkaline carbonates, bisulphide of potassium, and aqua regia, all dissolve it readily. In the arts it is used as King’s yellow (see p. 532). Tanners also formerly employed a mixture of 90 parts of orpiment and 10 of quicklime, under the name of Rusma, as a depilatory; but the alkaline sulphides from gas-works are replacing this to a great extent.

§ 714. Haloid Arsenical Compounds.—The Chloride of Arsenic, AsCl₃ = 181·5; specific gravity liquid, 0° 2·205; boiling-point 134° (273·2°F.), is a heavy, colourless, oily liquid, which has been used as an escharotic in cancerous affections (principally by quacks). In one process of detecting and estimating arsenic, the properties of this substance are utilised (see p. 575). It is immediately decomposed by water into arsenious and hydrochloric acids.

The Iodide of Arsenic (AsI₃) is used occasionally in skin diseases, but is of little interest to the analyst; it is commonly seen in the form of brick-red brilliant flakes.

§ 715. Arsenic in the Arts.—The metal is used in various alloys; for example, speculum metal is made of tin, copper, and a little arsenic; white copper is an alloy of copper and arsenic; shot is composed of 1000 parts of lead mixed with 3 of arsenic; the common Britannia metal used for tea-pots, spoons, &c., often contains arsenic; and brass is bronzed with a thin film of arsenic. It was formerly much employed in the manufacture of glass, but is being gradually superseded. It is also now used to some extent in the reduction of indigo blue, and in that of nitro-benzole in the manufacture of aniline.

In cases of suspected poisoning, therefore, and the finding of arsenic in the stomach, or elsewhere, it may be set up as a defence that the arsenic was derived from shot used in the cleansing of bottles, from the bottles themselves, or from metal vessels, such as tea-pots, &c.

The arsenic in all these alloys being extremely insoluble, any solution to a poisonous extent is in the highest degree improbable. It may, however, be necessary to treat the vessels with the fluid or fluids which have been supposed to exert this prejudicial action, and test them for arsenic. The treatment should, of course, be of a severe and exhaustive character, and the fluids should be allowed to stand cold in the vessels for twenty-four hours; then the effect of a gentle heat should be studied, and, lastly, that of boiling temperatures. The analysis of the alloy itself, or of the glass, it would seldom be of value to undertake, for the crushed and finely divided substance is in a condition very different from that of the article when entire, and inferences drawn from such analytical data would be fallacious.

Arsenious anhydride is also used for the preservation of wood, and is thrown occasionally into the holds of vessels in large quantities to prevent vegetable decomposition. In India, again, a solution of arsenic is applied to the walls as a wash, in order to prevent the attacks of insects.

§ 716. Pharmaceutical, Non-officinal, and other Preparations of Arsenic.—(1) Pharmaceutical Preparations.—The Liquor arsenicalis (Fowler’s solution), or solution of arsenic of the pharmacopœia, is composed of:—

Carbonate of Potash, 87 grains (5·64 grms.)

Arsenious Acid, 87 gra„ns(5·64 g„ms.)

Compound Tincture of Lavender, 5 drachms (17·72 c.c.)

dissolved in 1 pint (567·9 c.c.) of water; every ounce, therefore, contains 4·3 grains of arsenious acid (or 100 c.c. = ·9As₂O₃); the strength is therefore nearly 1 per cent.

Liquor Ammonii Arsenitis (not officinal) is made of the same strength, ammonium carbonate being substituted for potassic carbonate.

The hydrochloric solution of arsenic is simply arsenious acid dissolved in hydrochloric acid; its strength should be exactly the same as that of Fowler’s solution.

A solution of arseniate of soda[708] contains the anhydrous salt in the proportion of 4 grains to the ounce (·9 in 100 c.c.) of water.

Liquor Arsenii et Hydrargyri Iodidi (Donovan’s Solution of Arsenic).—This is not officinal, but is used to some extent in skin diseases; it is a solution of the iodides of mercury and arsenic; strength about 1 per cent. of each of the iodides.

Arseniate of Iron, Fe₃As₂O₈, is an amorphous green powder, used to some extent in medicine. It should contain 33·6 per cent. of metallic arsenic.

Clemen’s Solution.—A solution of the bromide and arseniate of potassium; strength equal to 1 per cent. arsenious acid. Officinal in U.S., France, and Norway.

Pilula Asiatica (not officinal) is composed of arsenious acid, extract of gentian, and black pepper. There is ¹⁄₁₂th of a grain (5·4 milligrams) of arsenious acid in each pill.

Dr. De Valanguis’ Solutio solventes mineralis is composed of 30 grains of As₂O₃ dissolved by 90 minims of HCl in 20 oz. of water; strength = 0·034 per cent. As₂O₃.

(2) Veterinary Arsenical Medicine.—Common veterinary preparations containing arsenic are:—A ball for worms, containing in parts—

Calomel, 1·3 per cent.

Arsenious Acid, 1·3 per „

Tin Filings, 77·9 per „

Venice Turpentine,[709] 19·5 per „

A common tonic ball:[710]—

Arsenious Acid, 5 to 10 grains (·324 to ·648 grm.)

Aniseed, ¹⁄₂ oz. ( 14 ·1744 grms. )

Opium, 30 grains ( 1 ·94 gr„ )

Treacle, q. s.

An arsenical ball, often given by grooms to horses for the purpose of improving their coats, contains in 100 parts:—

Arsenious Acid, 2 ·5 per cent.

Pimento, 19 ·2 „

Extract of Gentian, 78 ·3 „

Another ball in use is composed of arsenic and verdigris (acetate of copper), of each 8 grains (·518 grm.); cupric sulphate, 20 grains (1·3 grm.); q. s. of linseed meal and treacle.

(3) Rat and Fly Poisons, &c.—An arsenical paste sold for rats has the following composition:—

Arsenious Acid, 5 ·0 per cent.

Lampblack, ·6 „

Wheat Flour, 46 ·3 „

Suet, 46 ·3 „

Oil of Aniseed, a small quantity.

Another rat poison is composed as follows:—

White Arsenic, 46 ·8 per cent.

Carbonate of Baryta, 46 ·8 „

Rose-pink,[711] 5 ·8 „

Oil of Aniseed, ·2 „

Oil of Rhodium, ·2 „

Various arsenical preparations are used to kill flies; the active principle of the brown “papier moure” is arsenious acid. A dark grey powder, which used to be sold under the name of fly-powder, consisted of metallic arsenic that had been exposed some time to the air.

Fly-water is a strong solution of arsenious acid of uncertain strength, sweetened with sugar, treacle, or honey. Another fly-poison consists of a mixture of arsenious acid, tersulphide of arsenic, treacle, and honey.

(4) Quack and other Nostrums.—The analyst may meet with several quack preparations for external use in cancer. A celebrated arsenical paste for this purpose is composed of:—

Arsenious Acid, 8 per cent.

Cinnabar, 70 „

Dragon’s Blood, 22 „

Frères Come’s Cancer Paste is composed of arsenious acid, 1; charcoal, 1; red mercury sulphide, 4; water, q. s.

The tasteless “ague drops” used in the fen countries are simply a solution of arsenite of potash.

Davidson’s Cancer Remedy consists, according to Dr. Paris, of equal parts of arsenious acid and powdered hemlock.

In India, arsenic given as a medicine by native practitioners, or administered as a poison, may be found coloured and impure, from having been mixed either with cow’s urine, or with the juice of leaves, &c.[712]

Arsenious acid is used by dentists to destroy the nervous pulp of decayed and painful teeth, about the twenty-fifth of a grain (2·5 mgrms.) being placed in the cavity. A common formula is arsenious acid, 2; sulphate of morphine, 1; creasote, q. s. to make a stiff paste. There is no record of any accident having resulted from this practice hitherto; but since the dentist seldom weighs the arsenic, it is not altogether free from danger.

(5) Pigments, &c.—King’s yellow should be As₂S₃, the trisulphide of arsenic or orpiment. It is frequently adulterated with 80 to 90 per cent. of arsenious acid, and in such a case is, of course, more poisonous. King’s yellow, if pure, yields to water nothing which gives any arsenical reaction.

A blue pigment, termed mineral blue, consists of about equal parts of arsenite of copper and potash, and should contain 38·7 per cent. of metallic arsenic (= to 51·084 As₂O₃H) and 15·6 of copper.

Schweinfurt green (Syn. Emerald-green), (CuAs₂O₄)₃Cu(C₂H₃O₂)₂ is a cupric arsenite and acetate, and should contain 25 per cent. of copper and 58·4 per cent. of arsenious acid. In analysis, the copper in this compound is readily separated from the arsenic by first oxidising with nitric acid, and then adding to the nitric acid solution ammonia, until the blue colour remains undissolved. At this point ammonium oxalate is added in excess, the solution is first acidified by hydrochloric or nitric acid, and, on standing, the copper separates completely (or almost so) as Oxalate, the arsenic remaining in solution.

Another method is to pass SH₂ to saturation, collect the sulphides on a filter, and, after washing and drying the mixed sulphides, oxidise with fuming nitric acid, evaporate to dryness, and again treat with nitric acid. The residue is fused with soda and potassic nitrate, the fused mass is dissolved in water, acidulated with nitric acid, and the copper is precipitated by potash; the solution is filtered, and in the filtrate the arsenic is precipitated as ammonio-magnesian arseniate or as trisulphide.[713]

Scheele’s green (CuHAsO₃) is a hydrocupric arsenite, and contains 52·8 per cent. of arsenious anhydride and 33·8 per cent. of copper.

(6) External Application of Arsenic for Sheep, &c.—Many of these are simply solutions of arsenic, the solution being made by the farmer. Most of the yellow sheep-dipping compounds of commerce are made up either of impure carbonate of potash, or of soda ash, arsenic, soft soap, and sulphur. The French bain de Tessier is composed of:—

Arsenious Acid, 1·00 kgrm.

Ferrous Sulphate, 10·00 „

Peroxide of Iron, 0·40 „

Gentian Powder, 0·20 „

This is to be added to 100 kgrms. of water. Another common application consists of alum and arsenic (10 or 12 to 1), dissolved in two or three hundred parts of water.

(7) Arsenical Soaps, &c.—Arsenic is used in preserving the skins of animals. One of the compounds for this purpose, known under the name of Bécoeur’s arsenical soap, has the following composition:—

Camphor, 3·4 per cent.

Arsenic, 20·2 „

Carbonate of Potash, 56·2 „

Lime,[714] 20·2 „

(8) Arsenical compounds used in pyrotechny:—

Parts.

Blue fires—(1) Realgar, 2

Charcoal, 3

Potassic Chlorate, 5

Sulphur, 13

Nitrate of Baryta, 77

——

(2) Sulphur, 40 ·9

Nitre, 36 ·8

Sulphide of Antimony, 12 ·3

Sulp„ide of Arsenic, 5

Charcoal, 5

——

Green fires— Metallic Arsenic, 2

Charcoal, 3

Chlorate of Potash, 5

Sulphur, 13

Nitrate of Baryta, 7

——

Light green fire— Charcoal, 1 ·75

Sulphide of Arsenic, 1 ·75

Sulphur, 10 ·50

Chlorate of Potash, 23 ·25

Nitrate of Baryta, 62 ·50

——

White fire—(1) Arsenious Acid, ·76

Charcoal, 1 ·63

Sulphide of Antimony, 12 ·27

Nitrate of Potash, 36 ·59

Sulphur, 48 ·75

——

(2) Realgar, 6 ·1

Sulphur, 21 ·2

Nitrate of Potash, 72 ·7

§ 717. Statistics.—During the ten years 1883-92 there were registered in England and Wales 113 deaths from arsenic; of these 57, or about half, were suicidal deaths, and 5 were classed under the head of “murder”; the rest were due to accident. The age and sex distribution of persons dying from accidental or suicidal arsenical poisoning are detailed in the following table:—

DEATHS FROM ARSENIC DURING THE TEN YEARS 1883-1892.

Accident or Negligence.

Ages, 1-5 5-15 15-25 25-65 65 and above Total

Males, 1 4 3 23 6 37

Females, 4 ... 3 4 3 14

Total, 5 4 6 27 9 51

Suicide.

Ages, 15-25 25-65 65 and above Total

Males, 3 32 2 37

Females, 5 12 3 20

Total, 8 44 5 57

§ 718. Law Relative to the Sale of Arsenic.—By the 14th of Vict. c. 12, every person selling arsenic is bound to keep a written record of every particular relative to each transaction, such as the name, abode, and calling of the purchaser, the purpose for which the poison is required, and the quantity sold, &c. These particulars are to be signed also by the purchaser. No person (sec. 2) is allowed to sell arsenic to any one unknown to the seller, unless in the presence of a witness whom the seller is acquainted with. The arsenic sold (sec. 3) is to be mixed with soot or indigo in the proportion of half an ounce of indigo to a pound of arsenic. It, therefore, follows that the coloured substance should not contain more than 70 per cent. of arsenious acid. The Act applies to all the colourless preparations of arsenic: but it is not to affect chemists in making up prescriptions for medical men, or in supplying medical men; nor is it to affect the wholesale dealers in supplying arsenic to retail shops, &c. The penalty for conviction is £20, or less.[715]

§ 719. Dose.—The smallest dose of arsenic known to have proved fatal to a human being is ·16 grm. (2¹⁄₂ grains). Farriers and grooms are in the habit of giving as much as l·3 grm. (20 grains) a day to a horse, so that the poisonous dose for this animal must be very large.

The maximum dose for the horned cattle appears to be from ·32 to ·38 grm. (5 to 6 grains); that for a dog is 16 mgrms. (¹⁄₄ grain), and even this may, in the smaller kinds, cause illness.

The following may be considered as dangerous doses of arsenic:—·13 grm. (2 grains) for an adult; 1·9 grm. (30 grains) for a horse; ·64 grm. (10 grains) for a cow; and 32 to 64 mgrms. (¹⁄₂ to 1 grain) for a dog.

§ 720. Effects of Arsenious Acid on Plants.—If the root or stem of a plant is immersed in a solution of arsenious acid, the hue of the leaves soon alters in appearance, the green colour becomes of a whitish or brownish hue, and the plant withers; the effect being very similar to that produced by hot water. The toxic action may be traced from below upwards, and analysis will detect minute quantities of arsenic in all portions of the plant.

It has, however, been shown by Gorup-Besanez,[716] that if arsenious acid be mixed with earth, and plants grown in such earth, they only take up infinitesimal quantities of arsenic. Hence, in cases of cattle poisoning, any defence based upon the alleged presence of arsenic in the pasture will be more ingenious than just.

The influence of arsenical fumes as evolved from manufactories upon shrubs and trees is in general insignificant. Pines and firs, five to six years old, have been known to suffer from a disease in which there is a shedding of the leaves, the more tender herbage being at the same time affected. Whatever dangers the practice of steeping corn intended for seed in a solution of arsenious acid, as a preventive of “smut,” may possess, it does not appear to influence deleteriously the growth of the future plant.

Superphosphate of manure is frequently rich in arsenic. Dr. Edmund Davy asserts that plants to which such manure is applied take up arsenic in their tissues, and M. Andonard has made a similar statement. Tuson[717] has also undertaken some experiments, which confirm Andonard and Davy’s researches. The bearing of this with relation to the detection of arsenic in the stomachs of the herbivora needs no comment.

§ 721. Effects on Animal Life—Animalcules.—All infusoria and forms of animalcule-life hitherto observed perish rapidly if a minute quantity of arsenious acid is dissolved in the water in which they exist.

Insects.—The common arsenical fly-papers afford numerous opportunities for observing the action of arsenic on ordinary flies; within a few minutes (five to ten after taking the poison into their digestive organs) they fall, apparently from paralysis of the wings, and die. Spiders and all insects into which the poison has been introduced exhibit a similar sudden death. It is said that in the neighbourhood of arsenical manufactories there is much destruction among bees and other forms of insect life.

Annelids.—If arsenious acid is applied to the external surface of worms or leeches, the part which it touches perishes first, and life is extinguished successively in the others. If a wound is made first, and the arsenious acid then applied to it, the effects are only intensified and hastened. There is always noticed an augmentation of the excretions; the vermicular movements are at first made more lively, they then become languid, and death is very gradual.

Birds.—The symptoms with birds are somewhat different, and vary according to the form in which the poison is administered, viz., whether as a vapour or in solution. In several experiments made by Eulenberg on pigeons, the birds were secured under glass shades, and exposed to the vapour of metallic arsenic vaporised by heat. It is scarcely necessary to remark that in operating in this way, the poisoning was not by metallic arsenic vapour, but by that of arsenious acid. One of these experiments may be cited:—A pigeon was made to breathe an atmosphere charged with vapour from the volatilisation of metallic arsenic. The bird was immediately restless; in thirty minutes it vomited repeatedly, and the nasal apertures were noticed to be moist; after a little while, the bird, still breathing the arsenious acid atmosphere, was much distressed, shook its head repeatedly, and yawned; in fifty minutes the respiration was laboured, and in fifty-nine minutes there was much vomiting. On removing the bird, after it had been exposed an hour to the vapour (·16 grm. of metallic arsenic having been evaporated in all), it rapidly recovered.

Six days after, the pigeon was again exposed in the same way to the vapour, but this time ·56 grm. of metallic arsenic was volatilised. In fifteen minutes there was retching, followed by vomiting. On taking it out after an hour it remained very quiet, ate nothing, and often puffed itself out; the breathing was normal, movements free, but it had unusual thirst. On the second and third day the excretions were frequent and fluid; the cardiac pulsations were slowed, and the bird was disinclined to move. On the fourth day it continued in one place, puffing itself out; towards evening the respirations slowed, the beak gaping at every inspiration. On attempting flight, the wings fluttered and the bird fell on its head. After this it lay on its side, with slow, laboured respiration, the heart-beats scarcely to be felt, and death took place without convulsions, and very quietly. On examining the organs after death, the brain and spinal cord were very bloodless; there were ecchymoses in the lungs; but little else characteristic. The experiment quoted has a direct bearing upon the breathing of arsenical dust; as, for example, that which floats in the air of a room papered with an easily detached arsenical pigment. Other experiments on birds generally have shown that the symptoms produced by arsenious acid in solution, or in the solid form, in a dose insufficient to destroy life, are languor, loss of appetite, and the voidance of large quantities of liquid excreta like verdigris. With fatal doses, the bird remains quiet; there are fluid, sometimes bloody, excretions; spasmodic movements of the pharynx, anti-peristaltic contraction of the œsophagus, vomiting, general trembling of the body, thirst, erection of the feathers, and laboured respiration. The bird becomes very feeble, and the scene mostly closes with insensibility and convulsions.

Mammals, such as cats, dogs, &c., suffer from symptoms fairly identical with those observed in man; but the nervous symptoms (according to P. Hugo) do not predominate, while with rabbits and guinea-pigs, nervous symptoms are more marked and constant.[718] There are vomiting, purging, and often convulsions and paralysis before death. It has been noticed that the muscles after death are in a great state of contraction. The slow poisoning of a dog, according to Lolliot,[719] produced an erythematous eruption in the vicinity of the joints, ears, and other parts of the body; there were conjunctivitis, increased lachrymal secretion, and photophobia; the hair fell off.

§ 722. Effects of Arsenious Acid on Man.—The symptoms produced by arsenious acid vary according to the form of the poison—whether solid, vaporous, or soluble—according to the condition of bodily health of the person taking it, and according to the manner in which it is introduced into the animal economy, while they are also in no small degree modified by individual peculiarities of organisation and by habit, as, for instance, in the arsenic-eaters.

Arsenic-Eaters.—In all European countries grooms and horse-dealers are acquainted with the fact that a little arsenic given daily in the corn improves the coat, increases, probably, the assimilation of the food, and renders the horse plump and fat. On the Continent grooms have been known to put a piece of arsenic, the size of a pea, in a little oatmeal, make it into a ball, tie it up in a linen rag, and attach it to the bit; the saliva dissolves, little by little, the poison, while both the gentle irritation and physiological action excite a certain amount of salivation, and the white foam at the mouth, and the champing of the horse, are thought vastly to improve the appearance. Shot, which contains a small quantity of arsenic, have been used for the same purpose, and from half a pound to a pound of small shot has been given to horses. When a horse has been for a long time dosed with arsenic, it seems necessary to continue the practice; if this is not done, the animal rapidly loses his condition. The explanation probably is, that the arsenic stimulates the various cells and glands of the intestinal tract to a superaction, the natural termination of which is an enfeeblement of their secreting power—this especially in the absence of the stimulus. Turning from equine involuntary arsenic-eaters, we find the strange custom of arsenic-eating voluntarily pursued by the races of lower Austria and Styria, especially by those dwelling on the mountains separating Styria from Hungary. In India also (and especially in the Punjaub) the same practice prevails, and here it is often taken as an aphrodisiac. The mountaineers imagine that it increases the respiratory power, nor is there wanting some evidence to show that this is actually the fact, and medicinal doses of arsenic have been in use for some time in cases of asthma and other diseases of the chest. The arsenic-eaters begin with a very small dose, which is continued for several weeks or months, until the system gets accustomed to it. The amount is then slightly augmented until relatively large doses are taken with impunity. In one case[720] it appears that a countryman, in good health, and sixty years of age, took daily 4 grains of arsenious acid, a habit which he had inherited from his father, and which he in turn bequeathed to his son.

The existence of such a custom as arsenic-eating, in its literal sense, has more than once been doubted, but all who have travelled over Styria and other places where the habit prevails have convinced themselves that the facts have not been overstated. For example, Dr. Maclagan, in company with Dr. J. T. Rutter,[721] visited Styria in 1865, and having carefully weighed 5 or 6 grains of arsenic, saw these doses actually swallowed by two men. On collecting their urine, about two hours afterwards, abundant quantitative evidence of its presence was found; but in neither of the men were there the slightest symptoms of poisoning. It is obvious that the existence of such a habit might seriously complicate any inquiry into arsenical poisoning in these regions.

§ 723. Manner of Introduction of Arsenic.—Arsenious acid exerts a poisonous action, whether it is taken by the stomach, or introduced into the system by any other channel whatever. The differences in the symptoms produced by external application (as through a wound), and by swallowing arsenious acid in substance or in solution, are not so marked as might be expected. It was probably Hunter who first distinctly recognised the fact that arsenic, even when introduced outwardly by application to an abraded surface, exerts a specific effect on the mucous membrane of the stomach. Brodie[722] states, “Mr. Home informed me that in an experiment made by Mr. Hunter himself, in which arsenic was applied to a wound in a dog, the animal died in twenty-four hours, and the stomach was found to be considerably inflamed. I repeated this experiment several times, taking the precaution of always applying a bandage to prevent the animal licking the wound. The result was that the inflammation of the stomach was commonly more violent and more immediate than when the poison was administered internally, and that it preceded in appearance the inflammation of the wound.”

§ 724. Cases of Poisoning by the External Application of Arsenic.—A mass-poisoning by the external use of arsenical violet powder to infants occurred in England some years ago. Two deaths from this cause were established by coroners’ inquests.[723] Dr. Tidy found the violet powders used in the two cases to have the following composition:—

1. Per cent. 2. Per cent.

Arsenious Acid, 38·5 38·3

Starch (Potato), 54·8 55·4

Magnesia, &c. 6·7 6·3[724]

Although the children were poisoned by absorption through the skin (unless it is allowed that some may have found its way in the form of arsenical dust into the throat, or, what is still more probable, that the infants may from time to time have seized the puff-ball and sucked it), the large quantity of ·421 grm. (6·5 grains) of arsenious acid was separated in the one case, and ·194 grm. (3 grains) in the other. In these cases arose the question which is sure to recur in legal inquiries into poisoning by absorption, viz., whether the poison lying on the surface and folds of the skin could not have been mixed during the post-mortem examination with the organs of the body? In these particular cases special care appears to have been taken, and the answer was satisfactory. It is not amiss, however, to call attention to the extreme precaution which such instances necessitate.

A woman, aged 51, had used a solution of arsenious acid to cure the itch; erysipelas of the body, however, followed, and she died after a long illness—one of the symptoms noted being trembling and paresis of the limbs.[725] In a case recorded by Desgranges,[726] a young chambermaid had applied to the unwounded scalp an arsenical ointment for the purpose of destroying vermin. She also suffered from a severe erysipelas, and the hair fell off. Quacks have frequently applied various arsenical pastes to ulcers and cancerous breasts with a fatal result. Instances of this abound; in one, a charlatan applied to a chronic ulcer of the leg an arsenical caustic; the patient showed symptoms of violent poisoning, and died on the sixth day.[727] In another, a lady suffering from some form of tumour of the breast, applied to an unqualified practitioner, who made from fifteen to twenty punctures with a lancet in the swelling, covered a piece of bread with an arsenical compound, and applied the bread thus prepared to the breast. Twelve hours afterwards symptoms of violent gastric irritation commenced; and vomiting and a sanguinolent diarrhœa followed, with death on the fifth day. Arsenic was found in all the organs.[728] Such examples might be multiplied. Arsenic has been in more than one case introduced criminally into the vagina with a fatal result.[729] Foderé, e.g., has recorded the case of a maid-servant who poisoned her mistress by intentionally administering several arsenical enemata.[730] Arsenious acid again has been respired in the form of vapour. One of the best instances of this is recorded by Taylor, and was the subject of a trial at the York Lent Assizes, 1864. The prisoner placed some burning pyrites at the doorway of a small room, in which there were eight children, including an infant in the cradle. The other children were removed speedily, but the infant was exposed to the vapour for an hour; it suffered from vomiting and diarrhœa, and died in twenty-four hours. There was slight inflammation of the stomach and intestines, the brain and lungs were congested, and the lining membrane of the trachea of a bright red colour. Arsenic was detected in the stomach, in the lungs, and spleen. The pyrites contained arsenic, and the fatal fumes were in effect composed of sulphurous and arsenious acids.

§ 725. Arsenic in Wall-Papers.—It is now an accepted fact that arsenical colours on wall-papers cause illness. The symptoms are those of chronic poisoning, and present nothing distinctive from the effects produced from small doses of arsenic.

Kirschgasser[731] has described the symptoms in detail of twenty-six cases. That arsenic is actually present in patients suffering is often susceptible of proof, by examining skilfully and carefully a considerable volume (from one to two days’ collection) of the urine; in most of the cases thus examined arsenic has been discovered. This poisoning is produced, sometimes from the dust, at others from a volatile compound of arsenic, which has the following properties:—It is very volatile (perhaps a gas), it has a strong alliaceous odour, it is not entirely decomposed by a solution of silver nitrate, but is apparently decomposed by a boiling acid solution of potassic permanganate. The author suggests that it may be a compound of CO and As, but this is only a supposition. The existence of this volatile substance has been settled beyond all question by the experiments of Gosio,[732] confirmed by those of Charles Robert Sanger.[733]

This substance appears to be readily enough produced by the action of the common moulds upon organic matter in the presence of small amounts of arsenic; the moulds vary in this property: Mucor, Mucedo, and Aspergillum glaucum react well; on the contrary, Penicillium glaucum, Mucor ramosus, and several others have either no action, or the action is but slight. One mould, the Penicillium brevicaule, has quite a special endowment in forming this peculiar arsenical compound; so much so, that Gosio has proposed its use as a reagent for arsenic, the garlic odour being perceived when the fungus is made to grow in solutions containing organic matter and only traces of arsenic.

§ 726. Forms of Arsenical Poisoning.—There are at least four distinct forms of arsenical poisoning, viz., an acute, subacute, a nervous, and a chronic form.

Acute Form.—All those cases in which the inflammatory symptoms are severe from the commencement, and in which the sufferer dies within twenty-four hours, may be called acute. The commencement of the symptoms in these cases is always within the hour; they have been known, indeed, to occur within eight minutes, but the most usual time is from twenty minutes to half an hour. There is an acrid feeling in the throat, with nausea; vomiting soon sets in, the ejected matters being at first composed of the substances eaten; later they may be bilious or even bloody, or composed of a whitish liquid. Diarrhœa follows and accompanies the vomiting, the motions are sometimes like those met with in ordinary diarrhœa and English cholera, and sometimes bloody. There is coldness of the extremities, with great feebleness, and the pulse is small and difficult to feel. The face, at first very pale, takes a bluish tint, the temperature falls still lower; the patient sinks in collapse, and death takes place in from five to twenty hours after the taking of the poison.

There can scarcely be said to be any clinical feature which distinguishes the above description from that of cholera; and supposing that cholera were epidemic, and no suspicious circumstance apparently present, there can be little doubt that a most experienced physician might mistake the cause of the malady, unless surrounding circumstances give some hint or clue to it. In the acute form diarrhœa may be absent, and the patient die, as it were, from “shock.” This was probably the cause of death in a case related by Casper,[734] that of Julius Bolle, poisoned by his wife. He took an unknown quantity of arsenic in solution at seven in the morning, and in about three-quarters of an hour afterwards suffered from pain and vomiting, and died in little more than three hours. There were no signs of inflammation in the stomach and intestines, but from the contents of the stomach were separated ·0132 grm. of arsenious acid, and ·00513 grm. from pieces of the liver, spleen, kidneys, lung, and blood. The dose actually taken is supposed not to have been less than ·388 grm. (6 grains).

§ 727. The Subacute Form.—The subacute form is that which is most common; it exhibits some variety of phenomena, and individual cases vary much in the matter of time. The commencement of symptoms is, as in the most acute form, usually within the hour, but exceptions to this rule occur. In a case quoted by Taylor,[735] and recorded by M. Tonnelier, the poison did not cause any marked illness for eight hours; it was found, on post-mortem examination, that a cyst had been formed in the stomach which sheathed the arsenic over, and in some degree explained this delay. In another case, again, ten hours elapsed, and this is considered to be the maximum period yet observed. As with the acute form, there is a feeling of nausea, followed by vomiting, which continues although the stomach is quite empty; at first the ejected matter is a watery fluid, but later it may be streaked with blood. The tongue is thickly coated; there is great thirst, but the drinking of any liquid (even of ice-cold water) increases the vomiting. Nearly always pain is felt in the epigastrium, spreading all over the abdomen, and extending to the loin (which is tense and tender on pressure). Deglutition is often painful, and is accompanied by a sort of spasmodic constriction of the pharyngeal muscles. Diarrhœa follows the vomiting, and has the same characters as that previously described; occasionally, however, this feature is absent. In the case recorded by Martineau,[736] a man, aged 25, was seized at 10 A.M. suddenly with vomiting, which persisted all that day and the next, during which time the bowels were obstinately confined. On the second day a purgative was administered, whereupon diarrhœa set in, and continued until his death, which occurred in about two days and sixteen hours from the commencement of the symptoms. This case is also remarkable from the absence of pain or tenderness of the abdomen.

In subacute cases the urine has several times been suppressed, and it is generally scanty and red in colour. Irregularity of the heart’s action and feebleness are tolerably constant phenomena. As the end approaches, there is excessive muscular weakness, the face is pale, the eyes hollow; the mucous membranes first, and then the skin, take a bluish tint; the skin itself is covered with perspiration, and there has been noticed a peculiar odour, which has been likened to arsine (arseniuretted hydrogen). The respiration is troubled, convulsive movements of the limbs have been observed, and cramps in the calves of the legs; death follows in a variable time—from twenty-four hours to several days. In certain cases there is a curious remission after violent symptoms, the patient rallies and seems to have recovered; but the appearance is deceptive, for the symptoms recur, and death follows. Recovery may also take place partially from the primary effects, and then inflammatory changes in the stomach, &c., set in, with fever and the ordinary symptoms which are common in all internal inflammation.

A single dose of arsenious acid may cause a prolonged and fatal illness, one of the best known examples being that of the suicide of the Duc de Praslin,[737] who took, with suicidal intent, on Wednesday, August 18, 1847, a dose of arsenious acid. The exact time of the act could not be ascertained, but the first effects appeared at 10 P.M.; there were the usual signs of vomiting, followed on the next day by diarrhœa, fainting, and extreme feebleness of the pulse. On Friday there was a remission of the symptoms, but great coldness of the limbs, intermittency and feebleness of the heart’s action, and depression. On Saturday there was slight fever, but no pain or tenderness in the abdomen, vomiting, or diarrhœa; on this day no urine was passed. On the Sunday he complained of a severe constriction of the throat, and deglutition was extremely painful; thirst was extreme, the tongue intensely red, as well as the mucous membrane of the mouth and pharynx, and the patient had a sensation of burning from the mouth to the anus. The abdomen was painful and distended, the heat of the skin was pronounced, the pulse frequent and irregular,—sometimes strong, at others feeble,—the bowels had to be relieved by injections, the urine was in very small quantity; during the night there was no sleep. The duke died at 4.35 A.M. on Tuesday the 24th, the sixth day; intelligence was retained to the last. As the end approached, the respiration became embarrassed, the body extremely cold, and the pulse very frequent.

§ 728. In the nervous form the ordinary vomiting and purging are either entirely suppressed, or present in but feeble degree; and under this heading are classed the rare cases in which, in place of the ordinary symptoms, affections of the nervous system predominate. Narcotism, paresis, deepening into paralysis, delirium, and even acute mania, as well as epileptiform convulsions, have all been recorded. In short, the symptoms show so much variety, that an idea of the malady produced in this very rare form can only be obtained by studying the clinical history of cases which have presented this aspect. In a case recorded by Guilbert,[738] a man, thirty-five years of age, had swallowed a solution of arsenic, half of which was immediately rejected by vomiting. A little while afterwards his respiration became laborious; the eyes were bathed with tears, which were so acrid as to inflame the eyelids and the cheeks; the muscles of the face were from time to time convulsed; he perspired much, and the perspiration had a fœtid odour; there was some diarrhœa, the urine was suppressed, and from time to time he was delirious. Afterwards the convulsions became general, and the symptoms continued with more or less severity for five days. On the sixth a copious miliary eruption broke out, and the symptoms became less severe. The eruption during fifteen days every now and again reappeared, and at the end of that time the patient was convalescent, but weak, liable to ophthalmia, and had a universal trembling of the limbs.

In one of Brodie’s[739] experiments on rabbits, 7 grains of arsenious acid were inserted in a wound in the back; the effect of which was to paralyse the hind legs. In other experiments on animals, paralysis of the hind legs has been frequently noticed, but paralysis certainly is rare in man; in the case, however, recorded by Barrier,[740] of the five men who took by mistake a solution of arsenious acid, one of them was found stretched on the ground with the inferior extremities paralysed.

In a case of “mass” poisoning reported by Dr. Coqueret,[741] three persons ate by mistake an unknown quantity of arsenious acid—two of them only suffered slightly, but the third severely, vomiting occurring almost immediately, and continuing with frequency until the end of the fourth day. Two hours after swallowing the poison, the patient took the hydrated oxide of iron as an antidote. On the sixth day there was stupor and a semi-delirious state, with an eruption of a pustular character compared to that of the small-pox. These symptoms continued more or less until the fifteenth day, when they diminished, and ultimately the patient recovered. In a case related by Tardieu,[742] in which a person died on the eleventh day from the effects of the poison, towards the end, as a specially marked symptom, there was noted hyperæsthesia of the inferior extremities, so that the least touch was painful.

§ 729. Absence of Symptoms.—In a few cases there have been a remarkable absence of symptoms, and this both in man and animals. Seven horses were fed with oats accidentally mixed with arseniate of soda. The first succumbed three hours after taking the poison, without having presented any symptom whatever; he fell suddenly, and in a short time expired.[743] It is related by Orfila,[744] that a woman, aged 27, expired in about twelve hours from a large dose of arsenious acid; there were the usual post-mortem appearances, but in life no sign of pain, no vomiting, and but little thirst.

§ 730. Slow Poisoning.—Slow poisoning has been caused accidentally by arsenical wall-paper, in the manufacture of arsenical pigments, by the admixture of small quantities of arsenic with salt or other condiments, and repeated small doses have been used for criminally producing a fatal illness intended to simulate disease from natural causes. The illness produced by small intermittent doses may closely resemble in miniature, as it were, those produced by large amounts; but, on the other hand, they may be different and scarcely to be described otherwise than as a general condition of ill-health and malaise. In such cases there is loss of appetite, feebleness, and not unfrequently a slight yellowness of the skin. A fairly constant effect seen, when a solution of arsenious acid is given continuously for a long time, is an inflammation of the conjunctivæ, as well as of the nasal mucous membrane—the patient complains of “always having a cold.” This inflammatory action also affects the pharynx, and may extend to the air-passages, and even to the lung-tissue. At the same time there is often seen an exanthem, which has received a specific name—“eczema arsenicale.” Salivation is present, the gums are sore, at times lacerated. In chronic poisoning by arsenic, nervous symptoms are almost constant, and exhibit great variety; there may be numbness, or the opposite condition, hyperæsthesia, in the extremities. In certain cases fainting, paresis, paralysis, and sometimes convulsions occur; towards the end a sort of hectic fever supervenes, and the patient dies of exhaustion.

§ 731. The Maybrick Case.[745]—The Maybrick case may be considered an example of poisoning extending over a considerable period of time:—Mr. James Maybrick, a Liverpool cotton-broker, aged 49, married Florence Elizabeth, an American lady, aged 21. They had two children. The marriage proved an unhappy one. Some two years before his death in May 1889 they had occupied two separate rooms. Seven weeks before the husband’s death, Mrs. Maybrick went to London on a false pretext, and lived for some days at an hotel, ostensibly the wife of another man. Two days after her return, Mr. and Mrs. Maybrick attended the Grand National race meeting, and there a serious quarrel arose between them respecting the man with whom she had cohabited in London; they returned from the race, each separately, and she slept apart. Next day an apparent reconciliation took place through the intervention of Dr. Fuller, the family medical attendant.

On or about April 12-19th, 1889, Mrs. Maybrick purchased arsenical fly-papers. On April 13-20th Mr. Maybrick visited London, and consulted Dr. Fuller for dyspepsia, who prescribed nux vomica, acids, and mild remedies (but no arsenic); in one bottle of medicine, ostensibly made according to Dr. Fuller’s prescription, arsenic was subsequently found.

Up to Saturday, April 27th, Mr. Maybrick was in his usual health; he was then sick, numbed, and in pain, and had cramps; he told his clerk he had been an hour in the water-closet, but whether for diarrhœa or constipation does not appear; he ascribed the symptoms to an overdose of Fuller’s medicine. About this date fly-papers were found by the servants soaking in Mrs. Maybrick’s bedroom in a sponge-basin, carefully covered up. On the 29th she again purchased two dozen fly-papers from another chemist. On April 28th Mr. Maybrick was sick and ill; at 11 A.M. Dr. R. Humphreys was called in; Mr. Maybrick complained of a peculiar sensation about his heart, and said he was in dread of paralysis. He attributed his illness to a strong cup of tea taken before breakfast. On the following day he was better, and on the 30th still improving. On May 1st and 2nd Mr. Maybrick went to his office and lunched, both days, off revalenta food, prepared at home and warmed at his office in a new saucepan purchased for the occasion; on one of these days the lunch was forgotten, and was sent to Mr. Maybrick by his wife; and on one of the two days, it is not clear which, Mr. Maybrick complained that his lunch did not agree with him, and he attributed it to inferior sherry put into his food.

In a jug found at the office, and in which food had been taken there, a trace of the food still remained after Mr. Maybrick’s death, and arsenic was found therein.

On May 3rd the last fatal illness set in. It is uncertain what food he had after breakfast; he went to the office, and returned home between 5 and 6 P.M. He had been seen by Dr. Humphreys in the morning, and appeared then not quite so well; he found him at midnight suffering from what he thought was severe sciatica; the patient said he had been sick from revalenta. On May 4th he was continually sick, nothing could be retained on the stomach, but the sciatic pain was gone; on May 5th the vomiting continued, the patient complained of the sensation of a hair sticking in the throat, and of a filthy taste in the mouth. The throat and fauces were only slightly reddened, the tongue was furred.

On May 6th there was less vomiting, but otherwise the condition was the same, and Fowler’s solution ordered, but only a quantity equal to ¹⁄₃₀₀ grain was actually taken.

May 7th the condition was improved, but there was no increase of power. Dr. W. Carter was called in consultation. The vomiting was passing away, and diarrhœa commencing. The throat was red, dry, and glazed; there were incessant attempts to cough up an imaginary hair. No cramps, no pain in the stomach or intestines, nor conjunctivitis. On this day the first direct evidence of diarrhœa is recorded, the medical men actually seeing a loose motion. The result of the consultation was that Mr. Maybrick must have taken some irritant in his food or drink.

On the 8th a professional nurse took charge. During the 8th and 9th severe tenesmus set in with diarrhœa, and blood was observed in the fæces. Now arsenic was suspected, the urine was examined by Dr. Humphreys, and a rough analysis was made of some Neaves’ food which the patient had been taking.

The patient died on the 10th, at 8.30 P.M.

The post-mortem appearances were as follows:—

The tongue was dark, the top of the gullet slightly red, but otherwise healthy, save at the lower end, where the mucous membrane was gelatinous, and was dotted over with black dots, like frogs’ spawn.

There was a small shallow ulcer in the mucous membrane of the larynx at the back of the epiglottis. The free margin of the epiglottis was rough and eroded; and on the posterior aspect of the ericoid cartilage there were two small red patches. In the stomach were from 5-6 ozs. of brownish fluid. At the cardiac end there was a large vermilion-red patch, interspersed here and there with small dark ecchymoses (spoken of by Dr. Humphreys as a flea-bitten appearance); to this followed a non-inflamed space, and near the pyloric orifice, and extending 2 inches from it, was another red inflamed portion of mucous membrane. In the small intestine the mucous membrane was red and inflamed, from 3 inches below the pylorus to about 3 feet downwards. About 18 or 20 feet lower down, i.e., a little below the ileo-cæcal valve, the mucous membrane was again inflamed to a lesser extent over a space of about 2 feet; the lower end of the rectum was also red and inflamed. No arsenic was found in the stomach or its contents, or in the spleen. Arsenic was present in the liver, in the intestines, and in the kidneys. The quantity separated altogether amounted to over 0·1 grain. The liver weighed 48 ozs., and from 12 ozs. of the liver 0·076 grain of arsenic, reckoned as As₂O₃, was separated.

The whole course of the symptoms and the post-mortem examination showed that the deceased died from an irritant poison; and from the fact of a small quantity of arsenic having been found in the body, there can be little doubt but that the poison was arsenic. The symptoms were somewhat anomalous, but not more so than in other recorded cases of undoubted arsenical poisoning. The facts that tended to connect the accused with the death were as follows:—On the night of either May 9th or the 10th Mrs. Maybrick was observed to remove from the table an opened bottle of Valentine’s meat juice, and take it into an inner dressing-room, and then replace it—the acts being surreptitious. In replacing it, she was observed to take it either from the pocket of her dressing-gown or from an inner pocket. The lining of this pocket was found to be impregnated with As₂O₃. The juice was found to contain 0·5 grain As₂O₃, and the liquid was of lower gravity than commercial juice; it had probably, therefore, been diluted.

The following is a list of things containing arsenic:—

Mrs. Maybrick’s dressing-gown.

Mrs. Ma„brick’s apron.

A handkerchief wrapped around a bottle.

Packet of arsenic “for cats.” (Arsenious acid mixed with charcoal.) Tumbler containing milk, with handkerchief soaking in it; at least 20 grains of As₂O₃ in the tumbler mixed with charcoal.

A portion of a handkerchief.

A bottle containing a strong solution of arsenious acid and several grains of undissolved arsenious acid.

A bottle containing from 15-20 grains of solid arsenic and a few drops of solution.

A saturated solution of arsenious acid and some solid arsenious acid.

Valentine’s meat juice.

Price’s glycerin; ²⁄₃ grain in the whole bottle.

A bottle containing 0·1 grain of arsenious acid.

A bottle from Mr. Maybrick’s office containing a few drops of medicine prescribed by Dr. Fuller (decidedly arsenical).

Jug from the office with remains of food.

Sediment from trap of w.c. and lavatory drain containing As₂O₃.

Mrs. Maybrick was convicted, but afterwards the sentence was commuted to penal servitude for life.

§ 732. Post-mortem Appearances in Animals.—P. Hugo[746] has made some minute researches as to the pathological appearances met with in animals. His experiments were made on seven dogs, eight guinea-pigs, five rabbits, two pigeons, and five cats—all poisoned by arsenious acid. According to Hugo, so far as these animals were concerned, changes were more constant in the intestine than in the stomach.

Stomach.—Changes in the mucous membrane were especially noticed in the great curvature and towards the pylorus; the pylorus itself, and a part of the cardiac portion, remained unchanged. The mucous membrane in dogs and cats was red, with a tinge of blue—in many cases the redness was in streaks, with injection of the capillaries. The stomach of plant-eaters was less altered, and a microscopical examination of the mucous tissues did not show any fatty change.

The Intestines.—In dogs and cats changes were evident; in rabbits and guinea-pigs they were not so marked, but the intestines of the last were extremely tender and brittle, very moist, and filled with a slimy, serous, grey-white fluid; nevertheless, the changes in all these animals appear to be of essentially the same nature. The most striking effect is the shedding of a pseudo-membrane; in quite recent cases there is a layer of from 1 to 1¹⁄₂ mm. wide of a transparent, frog-spawn-like jelly streaking the intestine. In later stages it becomes thicker, while occasionally it resembles a diphtheritic exudation. The mucous membrane itself is deep purple-red, showing up by the side of the pseudo-membrane. With regard to the villi, the epithelial layer is detached, and the capillary network filled with blood and enlarged.

The Liver.—Hugo met only occasionally with fatty degeneration of the liver, but there was marked steatosis of the epithelium of the gall-bladder of dogs. A fact not prominently noticed before, is (at all events, in dogs) a serous transudation into the pleural sac and acute œdema of the lungs; the exudation may be excessive, so that more than 100 c.c. of serous fluid can be obtained from the thorax; there is also usually much fluid in the pericardium. In two of Hugo’s experiments there was fluid in the cerebral ventricles; and in all there was increased moisture of the brain substance with injection of the capillary vessels, especially of the pia.

§ 733. Post-mortem Appearances.—A remarkable preservation of the body is commonly, but not constantly, observed. When it does occur it may have great significance, particularly when the body is placed under conditions in which it might be expected to decompose rapidly. In the celebrated Continental case of the apothecary Speichert (1876), Speichert’s wife was exhumed eleven months after death. The coffin stood partly in water, the corpse was mummified. The organs contained arsenic, the churchyard earth no arsenic. R. Koch was unable to explain the preservation of the body, under these conditions, in no other way than from the effect of arsenic; and this circumstance, with others, was an important element which led to the conviction of Speichert.

When arsenious acid is swallowed in substance or solution, the most marked change is that in the mucous membrane of the stomach and intestines; and, even when the poison has been absorbed by the skin, or taken in any other way, there may be a very pronounced inflammatory action. On the other hand, this is occasionally absent. Orfila[747] relates a case in which a man died in thirteen hours after having taken 12 grms. of arsenious acid:—“The mucous membrane of the stomach presented in its whole extent no trace of inflammation, no redness, and no alteration of texture.” Many other similar cases are on record; and, according to Harvey’s statistics, in 197 cases, 36 (about 18·2 per cent.) presented no lesion of the stomach.

The usual changes produced by arsenious acid may be studied in the museums of the London hospitals. In Guy’s Hospital Museum there are three preparations. In preparation 1798³² is seen a large stomach with the mucous membrane at certain points abraded, and at the great curvature the whole coats are thinned; it is also somewhat congested. In preparation 1798⁶⁴ is a portion of coagulated lymph, from the stomach of a lad, aged 14, who had taken accidentally a piece of cheese charged with arsenious acid, prepared for the purpose of destroying rats. He lived twenty-eight hours, and presented the ordinary symptoms. The lymph has a membranous appearance, and the rugæ of the stomach are impressed upon it. It is said when recent to have presented numerous bright bloody spots, although there was no visible breach of substance on the surface of the stomach. The mucous membrane of the stomach is stated to have been injected, and there was also diffuse injection of the duodenum. Preparation 1798⁸⁰ is the stomach of a person who survived thirteen hours after taking a fatal dose of arsenious acid; and in the same museum there is a wax model of the appearances which the fresh preparation exhibited, showing a large oval patch coated with mucus and the poison. The stomach was intensely inflamed, the cæcum injected. The rest of the intestine was healthy.

In the museum of University College there are two preparations, one[748] exhibiting intense swelling and congestion of the gastric mucous membrane, which is of a perfectly vermilion colour. Another preparation (No. 2868) shows the effect of a small dose of arsenic on the stomach; there are spots of arborescent extravasation, and slight congestion of the summits of the rugæ, but in other respects it is normal. There is also a cast of Peyer’s patches from the same case, showing great prominence of the glands, with some injection of the intestinal mucous membrane.

In St. Thomas’ Hospital there is an interesting preparation (No. 8) showing the gastric mucous membrane dotted all over with minute ulcers, none of which have an inflammatory zone.[749] I have not, however, seen in any museum a preparation of the curious emphysematous condition of the mucous membrane, which has more than once been met with. For example, in a case related by Tardieu,[750] Schwann, a labourer, died from the effects of arsenic in thirty-six hours. The autopsy showed that the mucous membrane of the stomach and small intestine was covered with a pasty coating, and was elevated in nearly its whole extent by bullæ filled with gas, forming true emphysematous swellings which encroached upon the diameter of the intestine. There was neither redness nor ulceration, but the mucous membrane was softened.

The author saw, many years ago, at Barnard Castle, an autopsy made on a gentleman who died from arsenic. In this case the mucous membrane of the stomach presented a peculiar appearance, being raised here and there by little blebs, and very slightly reddened.

§ 734. The inflammatory and other changes rarely affect the gullet. Brodie[751] never observed inflammation of the œsophagus as an effect of arsenic; but, when arsenic is swallowed in the solid state, as in the suicide of Soufflard, graphically described by Orfila,[752] it may be affected. In Soufflard’s case there was a vivid injection of the pharynx and gullet.

In many instances, when the arsenic has been taken in the solid form, the crystals with mucus and other matters adhere to the lining membrane. I have seen in the stomach of a horse, poisoned by an ounce of arsenic, an exquisite example of this. The inflammatory changes may be recognised many months after death owing to the antiseptic properties of arsenic; nevertheless, great caution is necessary in giving an opinion, for there is often a remarkable redness induced by putrefactive changes in healthy stomachs. Casper,[753] on this point, very justly observes:—“If Orfila quotes a case from Lepelletier, in which the inflammatory redness of the mucous membrane of the stomach was to be recognised after nine months’ interment, and if Taylor cites two cases in which it was observed nineteen and twenty-one months after death respectively, this is in contradiction of all that I, on my part, have seen in the very numerous exhumed corpses examined by me in relation to the gradual progress of putrefaction and of saponification, and I cannot help here suspecting a confusion with the putrefactive imbibition redness of the mucous membrane.”

If examined microscopically, the liver and kidneys show no change, save a fatty degeneration and infiltration of the epithelial cells. In the muscular substance of the heart, under the endocardium, there is almost constantly noticed ecchymosis. In the most acute cases, in which a cholera-like diarrhœa has exhausted the sufferer, the blood may be thickened from loss of its aqueous constituents, and the whole of the organs will present that singularly dry appearance found in all cases in which there has been a copious draining away of the body fluids. In the narcotic form of arsenical poisoning, the vessels of the brain have been noted as congested, but this congestion is neither marked nor pathognomonic. Among the rare pathological changes may be classed glossitis, in which the whole tongue has swollen, and is found so large as almost to fill the mouth. This has been explained, in one case, as caused by solid arsenious acid having been left a little time in the mouth before swallowing it. On the other hand, it has also been observed when the poison has been absorbed from a cutaneous application. When arsenic has been introduced into the vagina, the ordinary traces of inflammatory action have been seen, and, even without direct contact, an inflammation of the male and female sexual organs has been recorded, extending so far as gangrene. As a rule, putrefaction is remarkably retarded, and is especially slow in those organs which contain arsenic; so that, if the poison has been swallowed, the stomach will retain its form, and, even to a certain extent, its natural appearance, for an indefinite period. In corpses long buried of persons dying from arsenical poisoning, the ordinary process of decay gives place to a saponification, and such bodies present a striking contrast to others buried in the same graveyard. This retardation of putrefaction is what might, à priori, be expected, for arsenic has been long in use as a preservative of organic tissues.

§ 735. Physiological Action of Arsenic.—The older view with regard to the essential action of arsenic was, without doubt, that the effects were mainly local, and that death ensued from the corrosive action on the stomach and other tissues—a view which is in its entirety no longer accepted; nevertheless, it is perfectly true that arsenic has a corrosive local action; it will raise blisters on the skin, will inflame the tongue or mucous membranes with which it comes in contact; and, in those rapid cases in which extensive lesions have been found in the alimentary canal, it can hardly be denied that instances of death have occurred more from the local than the constitutional action. In the vast majority of cases, however, there is certainly insufficient local action to account for death, and we must refer the lethal result to a more profound and intimate effect on the nervous centres. The curious fact, that, when arsenic is absorbed from a cutaneous surface or from a wound, the mucous membrane of the stomach inflames, is explained by the absorption of the arsenic into the blood and its separation by the mucous membrane, in its passage exerting an irritant action. The diarrhœa and hyperæmia of the internal abdominal organs have been referred to a paralysis of the splanchnic nerves, but Esser considers them due to an irritation of the ganglia in the intestinal walls. Binz has advanced a new and original theory as to the action of arsenious acid; he considers that the protoplasm of the cells of many tissues possess the power of oxidising arsenious acid to arsenic acid, and this arsenic acid is again, by the same agency, reduced to arsenious acid, in this way, by the alternate oxidation and reduction of the arsenious acid, the cells are decomposed, and a fatty degeneration takes place. Thus arsenic causes fatty changes in the liver, kidney, and other cells by a process analogous to the action of phosphorus. T. Araki[754] also considers that both arsenic and phosphorus lessen oxidation, and points out that lactic acid appears in the urine when either of these poisons are taken, such acid being the result of insufficient oxidation. A notable diminution of arterial pressure has been observed. In an experiment by Hugo[755] ·03 grm. of As₂O₃ was injected intravenously, the normal arterial pressure being 178 mm. Ten minutes after injection the pressure sank to 47 mm.; in sixteen minutes it again rose to 127 mm. Accumulative action of arsenic does not occur. Hebra has given, in skin diseases, during many months, a total quantity of 12 grms. without evil result.

§ 736. Elimination of Arsenic.—Arsenic is separated especially by the urine,[756] then through the bile, and by the perspiration. The eruption often observed on the skin has been referred to the local action of small quantities of arsenic in this way eliminated. It is found in the urine first after from five to six hours, but the elimination from a single dose is not finished till a period of from five to eight days; it has often been looked for twelve days after taking it, but very seldom found. According to Vitali, the arsenic in the urine is not free, but probably displaces phosphorus in phospho-glyceric acid; possibly it may also replace phosphorus in lecithin.

§ 737. Antidote and Treatment.—In any case in which there is opportunity for immediate treatment, ferric hydrate should be administered as an antidote. Ferric hydrate converts the soluble arsenious acid into the insoluble ferric arseniate, the ferric oxide being reduced to ferrous oxide. It is necessary to use ferric hydrate recently prepared, for if dried it changes into an oxyhydrate, or even if kept under water the same change occurs, so that (according to the experiments of Messrs. T. & H. Smith) after four months the power of the moist mass is reduced to one-half, and after five months to one-fourth.

It is obvious that ferric hydrate is not in the true sense of the word an antidote, for it will only act when it comes in contact with the arsenious acid; and, when once the poison has been removed from the stomach by absorption into the tissues, the administration of the hydrate is absolutely useless. Ferric hydrate may be readily prepared by adding strong ammonia to the solution or tincture of ferric chloride, found in every medical man’s surgery and in every chemist’s shop, care being taken to add no caustic excess of ammonia; the liquid need not be filtered, but should be at once administered. With regard to other methods of medical treatment, they are simply those suggested by the symptoms and well-known effects of the poison. When absorbed, the drinking of water in excess cannot but assist its elimination by the kidneys.

§ 738. Detection of Arsenic.—The analyst may have to identify arsenic in substance, in solution, in alloys, in wall-papers, in earth, and in various animal, fatty, resinous, or other organic matters.

Arsenious Acid in Substance.—The general characters of arsenious acid have been already described, and are themselves so marked as to be unmistakable. The following are the most conclusive tests:—

(1) A small fragment placed in the subliming cell (p. 258), and heated to about the temperature of 137·7° (286° F.), at once sublimes in the form of an amorphous powder, if the upper glass disc is cool; but if heated (as it should be) to nearly the same temperature as the lower, characteristic crystals are obtained, remarkable for their brilliancy and permanency, and almost always distinct and separate. The prevailing form is the regular octahedron, but the rhombic dodecahedron, the rectangular prism, superimposed crystals, half crystals, deep triangular plates like tetrahedra, and irregular and confused forms, all occasionally occur.

(2) A beautiful and well-known test is that of Berzelius:—A small hard-glass tube is taken, and the closed end drawn out to the size of a knitting needle. Within the extreme point of this fine part is placed the fragment (which may be no more than a milligramme) and a splinter of charcoal, fine enough to enter freely the narrow part, as shown in the figure. The portion of the tube containing the charcoal (e) is first heated until it glows, and then the extreme end; if arsenic is present, a mirror-like coating is easily obtained in the broader portion of the tube (d). That this coating is really arsenical can be established by the behaviour of metallic crusts of arsenic towards solvents (as given at p. 557). The portion of the tube containing the crust may also be broken up, put in a very short, wide test-tube (the mouth of which is occupied by a circle of thin microscopic glass) and heated, when the arsenic will sublime on to the glass disc, partly as a metal and partly as crystalline arsenious acid.

(3) Arsenious acid, itself inodorous, when heated on coal, after mixing it with moist oxalate of potash, evolves a peculiar garlic-like odour. To this test oxide of antimony adulterated with arsenic will respond, if there is only a thousandth part present. Simply projecting arsenious acid on either red-hot charcoal or iron produces the same odour.

(4) A little bit of arsenious acid, heated in a matrass with two or three times its weight of acetate of potash, evolves the unsupportable odour of kakodyl.

Arsenites and Arseniates, mixed with oxalate of soda and heated in a matrass, afford distinct mirrors, especially the arsenites of the earths and silver; those of copper and iron are rather less distinct.

Sulphides of Arsenic are reduced by any of the processes described on p. 573 et seq.

In Solution.—An acid solution of arsenious acid gives, when treated with SH₂, a canary-yellow precipitate, soluble in ammonia, carbonate of ammonia, and bisulphite of potash, and also a metallic sublimate when heated in a tube with the reducing agents in the manner described at p. 575. By these properties the sulphide is distinguished and, indeed, separated from antimony, tin, and cadmium.

The sulphides of tin and cadmium are certainly also yellow, but the latter is quite insoluble in ammonia, while the former gives no metallic sublimate when heated with reducing substances.

The sulphide of antimony, again, is orange, and quite insoluble in potassic bisulphite, and scarcely dissolves in ammonia.

A small piece of sodium amalgam placed in a test-tube or flask containing an arsenic-holding liquid, or the liquid made alkaline with soda or potash and a little bit of aluminium added, produces in a short time arsine, which will blacken a piece of paper, soaked in nitrate of silver, and inserted in the mouth of the flask. This is certainly the most convenient test for arsenic. No antimoniuretted hydrogen (stibine) is given off from an alkaline solution and no SH₂.

Marsh’s Original Test for Arsenic consisted in evolving nascent hydrogen by zinc and sulphuric acid, and then adding the liquid to be tested. The apparatus for Marsh’s test, in its simplest form, consists of a flask provided with a cork conveying two tubes, one a funnel reaching nearly to the bottom of the flask; the other, a delivery tube, which is of some length, is provided with a chloride of calcium bulb,[757] and towards the end is turned up at right angles, the end being narrowed. By evolving hydrogen from zinc and sulphuric acid, and then adding portions of the liquid through the funnel, arseniuretted hydrogen in a dry state is driven along the leading tube, can be ignited on its issue, and on depressing a piece of cold porcelain, a dark metallic spot of arsenic is obtained.[758] Or, if any portion of the tube be made red-hot, the metal is deposited in the same way as a ring. The apparatus admits of much complication and variety. One of the most useful additions is, perhaps, the interposition of a small gasometer. This consists of a cylindrical glass vessel with entrance and exit tubes, open at the bottom, immersed in water in a larger vessel, and counterpoised by weights and rollers, exactly like the large gasometers used at gasworks; the exit tube must have a stop-cock, and the gas must pass over calcic chloride in order to dry it thoroughly.

M. Blondlot has observed[759] that if pure zinc, a weak solution of arsenious acid, and a sulphuric acid containing nitric acid or nitrous compounds, be mixed together, the arsenic passes into a solid hydrate, which is deposited on the surface of the zinc; this is, however, prevented by the addition of a little stannous chloride dissolved in hydrochloric acid.

The precautions to be observed in Marsh’s test are:—

(1) Absolute freedom of the reagents used from arsenic, antimony,[760] and other impurities.

(2) The sulphuric acid should be diluted with five times its weight of water, and if freshly prepared should be cooled before use. Strong acid must not be employed.[761]

(3) The fluid to be tested should be poured in little by little.

(4) Nitrous compounds, nitric acid, hydrochloric acid, chlorides, are all more or less prejudicial.

(5) The gas should come off regularly in not too strong a stream, nor out of too small an opening.

(6) The gas should pass through the red-hot tube at least one hour, if no stain is at once detected.

(7) Towards the end of the operation, a solution of stannous chloride in hydrochloric acid is to be added to the contents of the flask. This addition precipitates any arsenic present in a finely divided state, in which it is readily attacked by nascent hydrogen.[762]

The characteristics of the metallic stains which may occur either on glass or porcelain in the use of Marsh’s test, may be noted as under:—

Mirror or Crust of Arsenic Mirror or Crust of Antimony

Is deposited at a little distance from the flame. Is deposited close to the flame, and on both sides of it, and is therefore notched.

An arsenical stain is in two portions, the one brownish, the other a glittering black. The stain is tolerably homogeneous, and usually has a tin-like lustre.

On heating, it is rapidly volatilised as arsenious acid. Volatilisation very slow; no crystalline sublimate obtainable.

On transmission of a stream of SH₂, whilst immediately behind the stain a gentle heat is applied, the arsenic is changed to yellow sulphide;[763] if dry ClH is now transmitted, the arsenical sulphide is unchanged. The same process applied in the case of antimony produces the orange or black sulphide; and on passing dry ClH, chloride of antimony volatilises without the application of heat.

Chloride of lime dissolves the arsenic completely. Antimony not affected.

Protochloride of tin has no action on metallic arsenic. Dissolves slowly but completely the antimony stain.

The arsenic stain, dissolved in aqua regia, or ClH and chlorate of potash, and then treated with tartaric acid, ammonia, and magnesia mixture, gives a precipitate of ammonia magnesian arseniate.[764] No precipitate with antimony.

The mirror or crust of arsenic is usually described and weighed as being composed of the pure metal, but J. W. Rettgers has investigated the matter, and the following is an abstract of his results:—

There is no amorphous form of arsenic, the variety generally thus called being crystalline. Two modifications can be distinguished: the one being a hexagonal silver-white variety possessed of metallic lustre, specifically heavier and less volatile than the second kind, which is black in colour, crystallises apparently in the regular system, and constitutes the true arsenic mirror. The former modification corresponds to red hexagonal phosphorus (red phosphorus having been recently proved by the author to be crystalline), and the latter to yellow phosphorus, which crystallises in the regular system. Both modifications of arsenic are perfectly opaque; deposits which are yellow or brown, and more or less transparent, consist of the suboxide and hydride, As₂O and AsH. The brown spot on porcelain produced by contact with a flame of arseniuretted hydrogen is not a thin film of As, but one of the brown solid hydride AsH, formed by the decomposition of AsH₃. This view is confirmed by the fact that arsenic sublimed in an indifferent gas (e.g., CO₂) is deposited in one or other of the modifications described above, the brown transparent product being obtained only in the presence of H or O. Moreover, pure arsenic is insoluble in all solvents, whereas the film on porcelain (AsH) is soluble in many solvents, including hydrocarbons of the benzene series (e.g., xylene), warm methylene iodide, and hot caustic potash.

Hence quantitative results from weighing arsenical mirrors can never be accurate, because the mirrors consist of mixtures of hydride and suboxide.

Reinsch’s Test.—A piece of bright copper foil, boiled in an acid liquid containing either arsenic or antimony, or both, becomes coated with a dark deposit of antimony or arsenic, as the case may be. The arsenical stain, according to Lippert, is a true alloy, consisting of 1 arsenic to 5 copper.[765] Properly applied, the copper will withdraw every trace of arsenic or antimony from a solution. Dr. John Clark[766] has lately introduced some improvements in Reinsch’s process. His experiments have been directed to the means of proving the presence of arsenic or antimony in the stain on the copper with greater certainty, and at the same time estimating the amount when they occur together.

The material to be tested is boiled gently in a porcelain vessel with dilute hydrochloric acid and a small strip of copper about 1 inch long by ¹⁄₄ inch broad, till the absence of arsenic or antimony has been ascertained, or a coating has been produced. When the coating is decided, the piece of copper is taken out, washed first with water, then with a little alcohol to get rid of fatty matter, and finally with water. It is then placed in a mixture of dilute caustic potash and peroxide of hydrogen, and allowed to digest in the cold. At the same time a second piece of copper is introduced into the material which has given a deposit on the first piece, the washings of the first piece being added, and the boiling continued.

The treatment of the first piece of copper by caustic potash and peroxide of hydrogen dissolves any antimony or arsenic and restores the copper to its original brightness; when this is accomplished, the second piece of copper is taken out and replaced by the first, and this second piece, if stained, is digested with potash, peroxide of hydrogen, and washed as in the former case. The process is repeated until the slips of copper cease to be stained in the slightest degree—until, in short, the whole arsenic or antimony has been withdrawn.

The alkaline liquid contains the arsenic, as arsenate of potassium; the antimony, if present, as antimonate; and the solution is also contaminated by a little hydrated copper oxide; this latter separates on boiling, and can be filtered off, and the filtrate is boiled down to a small bulk. The liquid is washed into a small distillation-flask with strong hydrochloric acid, ferrous chloride is added, the flask, fitted with a safety tube, is connected with a condenser, and the arsenic distilled into water. To obtain the last traces of arsenic it may be necessary to distil it twice in this way, adding, each time, fresh strong acid and distilling to dryness. The distillate is then tested for arsenic by adding an equal bulk of saturated SH₂ water. The sulphide of arsenic may be dealt with as described (p. 573).

The residue in the flask is now tested for antimony by saturating with SH₂; should antimony be present, the precipitate by SH₂ will probably be dark coloured, because of a small quantity of copper. The precipitate is collected, dissolved in dilute caustic soda, boiled, filtered to remove copper sulphide, the filtrate acidified by hydrochloric acid, and sulphuretted hydrogen water added. If antimony was present, this time the precipitate will be of an orange colour, and may be dealt with as described (p. 589).

The test experiments with regard to this combined process appear satisfactory.

§ 739. Arsenic in Glycerin.—Arsenic has been frequently found in commercial glycerin, the quantity varying from 0·1 to 1 mgrm. in 100 c.c. The best method to detect the presence of arsenic in glycerin is as follows:—A mixture of 5 c.c. of hydrochloric acid (1 : 7) and 1 grm. of pure zinc is placed in a long test-tube, the mouth of which is covered with a disc of filter-paper previously moistened with one or two drops of mercuric chloride solution, and dried. If arsenic is present, a yellow stain is produced upon the filter-paper within fifteen minutes, and it subsequently becomes darker.[767]

§ 740. Arsenic in Organic Matters.—Orfila and the older school of chemists took the greatest care, in searching for arsenic, to destroy the last trace of organic matter. Orfila’s practice was to chop up the substance and make it into a paste with 400 to 700 grms. of water; to this ·010 grm. KHO in alcohol was added, and ·020 grm. of potassic nitrate. The substances were heated up to from 80° to 90° for some time, until they were pretty well dissolved; the organic matter was then burnt off in a Hessian crucible heated to redness, on which small quantities of the matters were placed at a time. When the whole had thus been submitted to red heat, the melted mass was run into an almost red-hot porcelain basin, and allowed to cool. Afterwards, it was again heated with concentrated sulphuric acid, until all nitric and nitrous fumes were dissipated; on dissolving and filtering in water, the liquid was introduced into a Marsh’s apparatus. Orfila never seems to have failed in detecting arsenic by this process. For an organ like the liver, he considered that 100 grms. of potash and 86 of strong sulphuric acid were necessary in order to destroy the organic matters.

The liability of the various reagents used to impurity, and the probability of loss in these operations, have tended to discredit destruction of the organic matter by a red heat, and chemists generally have preferred to oxidise animal matters by a moist process. The organic substance is divided finely and digested with dilute hydrochloric acid, and from time to time crystals of potassic chlorate are thrown in until all the fluid is very thin and capable of passing through a filter. The filtrate must now be submitted to the prolonged action of sulphuretted hydrogen,[768] and the sulphide of arsenic separated from free sulphur by dissolving in sodic sulphide. After filtering, the arsenic sulphide may be again thrown down by the addition of hydrochloric acid, collected on a filter, and still further purified by solution in ammonic carbonate; once more precipitated by hydrochloric acid, and lastly identified by conversion into magnesia pyro-arseniate (see p. 572). The above process is a general and safe way of detecting arsenic in almost any organic tissue, but the author prefers the distillation process described p. 575 et seq.

From ordinary pills, quack extracts, and similar preparations, drying, powdering, and exhaustion with boiling dilute HCl, will remove the whole of the arsenic, if in a soluble state.

Oils and matters consisting almost entirely of fat, suspected of containing arsenic, are gently heated, and allowed to deposit any insoluble matter they may contain; the oil is then decanted, and, if necessary, filtered from any deposit; saponified by alcoholic potash, the soap decomposed by HCl, the fatty acids separated, and the arsenic looked for both in the first deposit and in the solution, now fairly free from fat, and easy to treat.

In searching for arsenic in the fluids or tissues of the body, the analyst is generally at the mercy of the pathologist, and sometimes the work of the chemist leads to a negative result, solely from not having the proper organ sent to him.[769]

Brodie long ago stated that when arsenious acid had been given in solution to any animal capable of vomiting, no arsenic could be detected in the stomach; this statement is too absolute, but in the majority of cases true.

In all cases the chemist should have portions of the brain, spinal cord, liver, kidneys, lungs, and muscular tissue, as well as the stomach and its contents.

According to the experiments of Scolosuboff,[770] arsenic is generally greatest in the marrow, then in the brain, next in the liver, and least in the muscles, and the following may be taken as a fairly accurate statement of the relative proportion in which arsenic is likely to be found in the body, 100 grms. being taken of each:—