ANTIMONY.

Properties of the metal—Alloys—Compounds—Chlorides, sulphides, oxides, hydride. Tartar emetic—solubility, composition, uses and occurrence—commercial, veterinary, medicinal. Doses and preparations—fatal dose, fatal period. Physiological effects—Antidotes—Separations and tests—(1) Reinsch’s—Presence of antimony; purity of the copper employed, how to be secured; different stains resulting from presence of arsenic, antimony, mercury, bismuth, tin, silver, gold, platinum, palladium, sulphur compounds—(2) Dr. Maclagan’s test in Pritchard’s trial—(3) Marsh’s test—Remarks on Pritchard’s trial—On Smethurst’s trial—Dr. Taylor and Mr. Herapath—Arsenic in bismuth—Antimony in grey powder.

ANTIMONY.

The metal antimony (symbol Sb, from its classical name Stibium) is heavier than arsenic (sp. gr. 6·8), less easily tarnished, more difficult to pulverize, and not nearly so volatile. It forms somewhat brittle masses, with a fern-like crystalline appearance on the surface. When broken the interior shows radiating (rhombohedral) crystals of a bluish-white, strongly metallic lustre (arsenicum is greyish, bismuth is pinkish, white), yielding a grey or black powder. Melting point, 425° C. Heated with the blowpipe on charcoal it gives white fumes of oxide, without odour (arsenic gives a garlic odour). The metal is insoluble in water and dilute acids, but soluble in aqua regia to form antimonious chloride; also soluble in sulphide of potassium or sodium. Hot concent. sulphuric acid converts it into sulphate. Nitric acid turns it into a white powder consisting chiefly of metantimonic acid, HSbO₃, of which a small quantity dissolves.[188] The powdered metal burns in chlorine, forming Sb Cl₃, or Sb Cl₅. Metallic antimony is obtained as a “mirror” in Marsh’s test: the distinctions between it and arsenic have been already given (p. 389).

The following is the percentage of metallic antimony in different alloys. English type metal, 20 to 25; German ditto, 15; Britannia metal, 10 to 16; pewter, 7; Argentine, 14½; Ashbury metal, 19½; white or anti-friction metal for engine-bearings, 10; Babbit’s metal, for similar purposes, 13; alloy for ships’ nails, 17 (Ure’s Dictionary, I., 169; Roscoe and Schorlemmer’s Chemistry, 1880, ii., 2, p. 307). There is also antimony in brass, metallic mirrors, bell-metal, &c. (Blyth). Antimony black, used for giving a steel-like lustre to plaster casts, is finely divided Sb, precipitated from the chloride by zinc.

Metallic antimony is not poisonous unless partially oxidized. Commercial samples usually contain a little arsenic, which enters into the salts.

Antimonious chloride, Sb Cl₃, when pure, forms colourless glistening deliquescent crystals. A solution in hydrochloric acid constitutes the commercial “butter of antimony” used for giving a dark bronzing to brass. It is a thick, powerfully acid liquid, coloured brown by the presence of iron, fuming in air, very corrosive, and of an irritating odour, distilling over at about 200° C. (pure Sb Cl₃ boils at 223° C.), decomposed by water into a white magma of oxychloride, Sb O Cl, “powder of Algaroth” (tartar emetic is not decomposed by water). It is a violent corrosive poison, blackening and destroying the surfaces like oil of vitriol. For cases, see Woodman and Tidy, p. 130.

Antimonic chloride, Sb Cl₅, is rarely met with. It resembles Sb Cl₃, but is liquid.

Antimonious sulphide, Sb₂ S₃, is found native as “stibnite,” “speiss-glas,” “grey antimony,” or “antimony glance,” sp. gr. 4·63, in lead-grey striated prisms, fibrous or massive, of a strong metallic lustre, fusing readily to a dark-brown glass —“vitrum antimonii”), giving before the blowpipe white fumes, and an odour of sulphur dioxide —“brimstone”). It is the principal ore, the source of all the preparations, and is itself used in fireworks. When powdered it is black, and in this state was used by the Roman ladies under the name of “stibium,” by the Orientals as “Kohl,” for darkening the eyelids. It is soluble in hot hydrochloric acid to form SbCl₃. The precipitated sulphide is orange, and will be noticed under the tests. Sb₂ S₃ would not be poisonous until oxidized.

Antimonious oxide, Sb₂ O₃, obtained by burning Sb in air, is a white powder, turned yellow on heating, soluble in hydrochloric acid to form Sb Cl₃, and in cream of tartar (acid potass. tartrate) to form tartar emetic. Unlike As₂ O₃, it does not easily volatilize in crystals. It is occasionally found native.

Antimonic oxide, Sb₂ O₅, is a pale yellow powder. There is also an intermediate oxide, Sb₂ O₄.

Antimonious and antimonic acids are hydrates of the above oxides. They exist in several modifications, and form metallic salts, one of which, sodium pyrantimonate, Na₂ H₂ Sb₂ O₇, 6 H₂ O, is the only known insoluble salt of sodium, and hence available as a test.

Antimonious hydride, Stibine, or “antimoniuretted hydrogen,” Sb H₃, has never been obtained pure. In admixture with hydrogen, as given by Marsh’s test, it is a colourless gas, almost or quite inodorous (distinction from As H₃ which smells like garlic), decomposed by heat into hydrogen and a “mirror” of Sb. Its poisonous properties have been doubted, but it is probably more dangerous than As H₃, on account of the absence of the warning odour. It burns with a bluish-green flame, giving white clouds of Sb₂ O₃, and a spot of Sb, duller and greyer than As, when a cold porcelain surface is depressed into the flame. Passed into silver nitrate solution, the Sb is precipitated along with metallic silver as silver antimonide, Ag₃ Sb, whereas arsenic under the same circumstances would remain in solution as As₂ O₃.

TARTAR EMETIC.

Potassio-antimonyl tartrate, tartrate of antimony and potash, “antimonium tartarizatum,” “tartarized antimony,” “stibiated tartar,” symbol K (Sb O) C₄ H₄ O₆, ½ H₂ O, occurs in colourless rhombic octahedral crystals, transparent at first, but becoming opaque by efflorescence, or as a white powder, inodorous, and with a strong metallic taste. The aqueous solution is faintly acid to test-paper, and becomes mouldy on keeping. When evaporated on a glass slide, it leaves a crystalline residue of tetrahedra, cubes and branching forms. (See figure in Guy and Ferrier’s For. Med., p. 469.) Heated on platinum, tartar emetic blackens and swells up with an odour of burnt sugar (due to the tartaric acid), gives a bluish-green tint to the flame, and quickly fuses and makes a hole in the platinum, from the formation of a fusible alloy. Heated in a closed tube, it gives charcoal, potass. carbonate, and metallic antimony, which does not sublime at a moderate temperature, is inodorous, and may be separated in metallic globules by washing (differences from arsenic; see p. 389). Sulph. hydrogen of course gives the orange-red sulphide.

Solubility.—Tartar emetic is almost insoluble in alcohol, and still less soluble in ether, chloroform, &c. Spirits and water, such as are mixed for drinking, dissolve nearly as much as cold water, and more if warm. The solubility in cold water is given very variously in the text-books, from 1 part in 21·8 —“20 grains per fluid ounce,” British Pharmacopoeia), 1 in 20 (Garrod and Blyth), 1 in 15 (Brande’s and Gmelin’s Chemistry), to 1 in 14 (Graham and Taylor). To clear up this difficulty I prepared for Dr. Bernays in 1879 a very pure sample of the salt: he found that 100 cubic centimetres of water at 58° F. dissolved 6·67 grammes, equal to one part in fifteen. The solubility rises rapidly with the temperature, till it reaches one part in two at the boiling point. The discrepancies are accounted for by the facts that, (1), the textbooks do not mention the temperature; (2), the salt readily effloresces in air, losing water and becoming less soluble; (3), impurities are often present.

Composition.—Commercial tartar emetic is generally very pure. It sometimes contains a trace of sand and dirt, occasionally an excess of cream of tartar (potass. hydrogen tartrate) from careless preparation, but I have never found arsenic. The theoretical percentage of Sb is 36·53: in good commercial samples Bernays found 36·03 to 36·32 per cent.; in an over-dried specimen, 37·4 per cent. One sample contained 23 per cent. of cream of tartar and only 28·13 of Sb; another, 10 per cent. tartar and 32·7 of Sb.

USES AND OCCURRENCE.

The alloys and pyrotechnic uses have been already mentioned. The impure fused sulphide (vitrum antimonii) is employed to give a yellow tint to glass and porcelain. The oxides are used in glazing earthenware, and in glass and china painting. The following are antimonial pigments: “Antimony cinnabar,” and “crocus,” or “saffron of antimony,” are oxysulphides: “Naples,” “Cassell,” and “antimony yellows,” are chiefly antimoniates of lead. Small quantities of antimony occur in iron ores, ferruginous waters, the coal formation, and in river sand (Roscoe).

In veterinary practice, large doses of antimonials are given to animals, as much as 90 grains of tartar emetic being often administered to a horse in his gruel three times a day. Other preparations are used (see Blyth’s Pract. Chem. 1879, p. 404). They are supposed to cause fattening.

Medicinally it is employed in typhus, delirium tremens, small doses in croup and the broncho-pneumonia of children, as a general expectorant in asthma and bronchitis, in whooping-cough, by some recommended also in scaly skin affections. In acute inflammations and pneumonia, it has lost favour, as too depressing (Farquharson’s Therapeutics). In times before chloroform, tartar emetic was even used to lower the muscular tension previous to reducing dislocations.

DOSES AND PREPARATIONS.

Pulvis antimonialis, 3 to 10 grains. This is the Pharmacopoeial equivalent of “James’s Powder,” a secret remedy once highly popular. It contains one part of Sb₂ O₃ to two of phosphate of lime.

Vinum antimoniale, antimonial wine, is a solution of 10 grains of tartar emetic to each ounce of sherry: dose, 5 minims to 1 fluid drachm.

Antimonii oxidum, Sb₂ O₃, is often very impure. It may contain, (1), higher oxides of Sb, when it is not completely soluble on boiling with water and cream of tartar; (2), carbonate of lime, when it effervesces with acids and contains less Sb; (3), traces of arsenic, when it gives a garlic odour before the blowpipe on charcoal. Percentage of Sb, 83·56: dose, 1 to 4 grains.

Antimonium sulphuratum, or oxysulphuretum, is precipitated Sb₂ S₃ with a small amount of Sb₂ O₃. It contains about 62 to 65 per cent. Sb (pure Sb₂ S₃ has 70·2 per cent.). Dose, 1 to 5 grains, but rarely prescribed, except in “compound calomel pill,” pil. hydrarg. subchlorid. co., which contains 20 per cent. of Sb₂ S₃.

Antimonii chloridi liquor, a solution of Sb Cl₃ in hydrochloric acid, is sometimes used as a caustic, never internally.

Antimonium tartaratum, tartar emetic: dose, as a diaphoretic, ¹/₁₆ to ? grain; as a depressant, ? to 1 grain; as an emetic, 1 to 2 grains (to 3 grains, Farquharson). It should never be used as an emetic in suspected poisoning, as its presence would confuse the investigation.

Unguentum antimonii tartarati, antimonial ointment, contains 20 per cent. of tartar emetic.

The following proprietary pills contain tartar emetic in the annexed proportion per pill weighing about 3 grains:—Dr. J. Johnson’s, 0·04 grain; Mitchell’s, 0·05 grain: Dixon’s, 0·06 grain (Blyth).

It has been stated that the liqueur absinthe owes its deleterious effects to antimony. I have tested several specimens, but never found antimony, though traces of lead or copper were occasionally present.

Fatal dose.—About this, nothing can be exactly stated. The smallest was, in a child, ¾ grain; in an adult, 2 grains; but in this instance there were circumstances which favoured the fatal operation (Taylor, Med. Jur. i., 310).

If vomiting and purging happen, the poison is for the most part expelled: except for the effects of exhaustion, there may then be hardly a limit to the amount which may pass in and pass out. Taylor records recoveries from 120 grains, 200 grains, and even half an ounce of tartar emetic. In pneumonia it has been given in repeated doses of 2 grains without ill effects. It must be remembered that, in the hands of the poisoner, its perverted use is, not to kill, but to so weaken the vital powers that a small and not suspicious dose of some other poison may complete the death.

Fatal period.—Shortest, seven hours in an adult female (Wormley); eight hours in a boy after 10 grains tartar emetic (Lancet, 1846, p. 460). Usually much longer: four days after 40 grains (Orfila, i., 480); up to one year from after effects (Guy and Ferrier).

PHYSIOLOGICAL EFFECTS.

The unpleasant metallic taste, the heat in the throat, and burning in the stomach, have been described in the previously reported trials, and in other cases. Afterwards there is nausea, severe vomiting, profuse watery purging, often convulsions which are sometimes tetanic in character; the skin is generally cold and clammy with perspiration; there is collapse from exhaustion, and occasionally delirium and insensibility. Death may happen either during the convulsions, or during the collapse. The heat and constriction in the throat is not invariably present.

After death there is generally found inflammation of the stomach and intestines, especially the cÆcum: the brain is sometimes congested, the throat rarely affected. The stomach-contents are usually tinged with blood, as with most irritant poisons.

In smaller doses it acts at first as a sedative on the brain; the action of the heart becomes slower, weaker, and finally irregular, the pulse is soft, the breathing slower; there is an increased bronchial secretion, and general muscular relaxation. As an emetic it is sluggish and depressing, and is often followed by diarrhoea. It powerfully promotes perspiration, and is therefore used in influenza, &c. Poisonous doses may cause paralysis, prostration, degeneration of the liver and other organs (see Taylor’s remark about the geese at Strasburg, p. 464), inflammation and even ulceration of the intestines (Farquharson and others).

ANTIDOTES.

Sometimes vomiting does not occur: in this case it should be promoted by tickling the throat, and by draughts of warm water. Tannin precipitates compounds of antimonious oxide (Sb₂ O₃), but not those of antimonic oxide (Sb₂ O₅): as the former are the ones almost invariably used, astringent preparations, such as strong tea, coffee, decoction of oak bark, galls, tincture of catechu or kino, should be given. Tannin, or tannic acid, is commonly kept by photographers. Failing this, sodium carbonate (washing soda), in not too strong solution, may do good. Opium to allay the irritation, and brandy to overcome the depression, should then be tried.

SEPARATION AND TESTS.

During life, antimony may be found in the urine and fÆces: after death, if its administration has been long continued, it will be found in all parts of the body, but especially in the liver and spleen. If the doses have been discontinued some time before death, none may be left in the stomach and intestines.

The enquiry divides itself into three parts: 1st, the presence of antimony; 2nd, the preparation used; 3rd, the quantity.

I. Presence of Antimony.

Marsh’s and Reinsch’s tests have been mentioned under arsenic. It, however, will be necessary to add a few observations on their special use for Sb.

A fractional part, say one-fourth, of the suspected matter, after mincing or pounding, is digested with hot distilled water containing 5 per cent. of pure hydrochloric, and a little tartaric, acids, well shaken or stirred in a covered or closed vessel, and after some hours filtered. To a portion of the filtrate is added a little more hydrochloric and a little sulphuric acid (to reduce the higher oxides of As and Sb), and the whole is boiled for ten minutes. A portion of the filtrate is now subjected to

Reinsch’s Test.—First it is absolutely necessary to have pure copper; so pure, in fact, that a quantity, larger than would be used in testing, will not, if totally dissolved up, yield any As or Sb to another piece of copper boiled in the solution.

Dr. Taylor’s mistake in the case of Smethurst, more fully treated of hereafter, was a very natural one. The trace of arsenic in his copper would not have affected the conclusion in ordinary cases: but it would be better not to test at all than to use materials which are not proved beforehand to be free from the poison we are seeking. Pure “electrotype” copper can now be purchased; or it can be made pure by either of the following methods.

(a) “Pure” commercial sulphate of copper is boiled with a slight excess of chlorine water, then treated with dilute ammonia till a slight permanent precipitate forms: after standing twelve hours it is filtered (the precipitate containing iron and arsenic), acidulated with pure sulphuric acid, and subjected to the current from two Daniell cells, the terminals being two plates of hard wax well coated with purified graphite: the coating must communicate with the copperwire from the battery, and the wire must not dip into the solution. The distance between the terminals should be so regulated that the copper may be deposited slowly and in a tough layer on the negative pole: the thin plate so obtained may afterwards be easily detached, hammered or rolled, and cut into suitable pieces: it is absolutely free from arsenic.

(b) Pure crystallized chloride of copper is mixed with pure carbonate of soda in excess, the mixture dried with constant stirring, heated to near redness, powdered, mixed with an equal volume of lamp-black, and introduced into a “plumbago” crucible lined with a paste of purified graphite and oil. The crucible is covered, and gradually heated in a Fletcher’s or Griffin’s gas furnace (not with coal or coke), and finally kept at a very high temperature till the copper is reduced. The fumes contain chlorides of copper, sodium, &c., and are poisonous. The copper, after separation from the slag, may be cast, hammered, or rolled, and is free from As or Sb.

I suggest these processes more for manufacturers than for chemists, but expense and trouble should really be subordinate considerations where life is concerned.

Now for the application. Two flasks containing pure diluted (25 per cent.) hydrochloric acid are placed on a sandbath, and nearly closed by small glass funnels. About a square inch of pure copper, cleaned by sand-paper, is placed in each: to one is added the suspected liquid, to the other an equal bulk of 5 per cent. hydrochloric acid. Both are boiled, with occasional inspection. If the following are present, the copper will be darkened:—

Arsenic.—Stain steel-grey: dried and heated in closed tube it gives easily a sublimate of octahedral crystals of As₂ O₃. (See Arsenic, ante.)

Antimony.—Stain black, or in small quantity, violet: in the closed tube it gives with difficulty an amorphous white sublimate of Sb₂ O₃, soluble in H Cl, and then precipitated orange by H₂ S.

Mercury.—Stain silvery: in closed tube gives a sublimate of metallic globules, made more visible by rubbing them together with a splinter of wood.

Bismuth, tin, silver, gold, platinum, palladium, &c., give black, grey or silvery deposits, but no sublimate in the tube. Gold gives a stain which is yellow on burnishing, and yields no sublimate.

Sulphur compounds in the organic matter may give a dull stain, which may even yield a kind of sublimate in the tube, but this sublimate will not conform to the tests for As or Sb.

If there is much As or Sb, the deposit sometimes peels off if boiled too long.

The process used by Prof. Maclagan in the Pritchard trial is also a good means of verification. Boil the stained foil in a solution of caustic potash, exposing it occasionally to the air (or boil with a weak, slightly alkaline solution of potass, permanganate, and filter—Odling). The Sb will be oxidized and dissolved. Add HCl and pass H₂ S: an orange precipitate of Sb₂ S₃ will prove the presence of antimony.

If Sb has been found, remove the first piece of copper, and boil with another piece, and so on till the Sb is all removed. The coated slips, the sublimate, the Sb₂ S₃, and the copper in the second flask which has still remained bright, should be sealed up to be shown in court.

The previous treatment with sulphurous acid prevents any interference by oxidizing agents such as chlorate of potash, nitrates, iodine, &c.

Marsh’s Test is more delicate, but more liable to error, than Reinsch’s.

Two methods of applying Marsh’s test to antimony may be used.

A. By Edmund Davy’s process with sodium amalgam (see Arsenic, p. 388), only As H₃ passes off, the Sb remaining behind. Hence, when the arsenic has finished coming over, if the remaining solution be acidulated with pure sulphuric acid,[189] pure zinc put in, and one or two drops of pure platinic chloride added to facilitate the evolution of hydrogen, the antimony will then come over as Sb H₃.

B. Or the original substance may be placed in the flask, treated at once with the zinc and dilute acid, and the As H₃ and Sb H₃ passed together into silver nitrate solution, and separated by filtration as directed under arsenic. See p. 389, also as to the distinctions between the stains of Sb and As. To these add, that metallic spots of both As and Sb are soluble in yellow ammonium sulphide: the solutions on evaporation to dryness on the water-bath give:

(a). With arsenic a yellow stain, soluble in ammonia, insoluble in hydrochloric acid;

(b). With antimony an orange stain, insoluble in ammonia, soluble in hydrochloric acid.

Metallic antimony can be precipitated as a black powder from its solutions by acidulating with hydrochloric acid and treating with a slip of pure tin, which does not precipitate arsenic. Zinc or electrolysis also precipitate Sb, along with copper and many other metals. Hence this method is not available in mixtures.

Sulphuretted hydrogen gives with antimonial solutions slightly acidulated an orange-red precipitate of sulphide, insoluble in ammonia or ammonium carbonate, soluble in ammonium sulphide, soluble in hot strong hydrochloric acid by conversion into antimonious chloride, and sulphuretted hydrogen: the former then gives a white precipitate with water, the latter gives the characteristic odour and blackens lead paper.

The reactions with sodium hydrate and sodium carbonate, are not so clear or decisive. Potass. ferrocyanide gives no precipitate. Tannin and tincture of galls give a yellowish white precipitate. Before the blowpipe with sodium carbonate on charcoal, solid Sb compounds give a grey brittle globule of the metal and a white incrustation. But there is rarely sufficient for such a test to be of use in toxicological work, there is also a risk of loss, and other metals give a similar reaction.

N.B.—Among other substances, sulphide of antimony is frequently added to caoutchouc in the process of vulcanising india-rubber: in all toxicological experiments involving tests for antimony (and arsenic), great danger of a mistake is thus attendant on the use of ordinary vulcanised india-rubber tubing. Black unvulcanised tubing should alone be employed.

II. Preparation Used.

The insoluble compounds would act very slowly as poisons and would require very large doses, hence would be found in the solid form in the stomach, and could be identified by appearance, by the microscope, and by the tests, after washing and settling down.

To ascertain whether antimony was in solution, the liquid contents of the stomach, after dilution with water if necessary, should be allowed to settle, the nearly clear top layer decanted and filtered, and the filtrate examined. The soluble compounds are:—

1. Tartar emetic. Solution slightly acid, taste metallic. On evaporation on a glass slide tetrahedral crystals are obtained. If the solution is moderately strong, it gives a white precipitate with a little hydrochloric acid, soluble in excess: with water it gives no precipitate. Stomach generally inflamed but not corroded.

2. Antimonious chloride, Sb Cl₃. Solution strongly acid, effervescing and giving a white precipitate with sodium carbonate. Taste corrosive and powerfully metallic. On evaporation, no tetrahedra. No precipitate with hydrochloric acid: with water a white precipitate, re-dissolved by tartaric acid.[190] By analysis a large quantity of chlorine will be found. The stomach is corroded and often blackened or charred.

3. Antimonates, antimonites, sulphantimonites, and -ates (such as “Schlippe’s salt”), are rare and improbable. Antimonates are alkaline, give a white precipitate with acids, and a white crystalline one with sodium salts. Schlippe’s salt is strongly alkaline, and gives with hydrochloric acid an orange-red precipitate of sulphide.

III. Quantity.

To ascertain the amount of Sb is absolutely necessary. Marsh’s test is not available, since a large part of the antimony is thrown down on the zinc and remains in the generating flask. It has been proposed to wash this off and weigh it, but other metals and impurities are present, so that this is not practicable. Reinsch’s test has been applied quantitatively by weighing the copper before and after the test: the difference of weight was supposed to be the As or Sb. But the copper may dissolve or oxidise, sulphur and other things deposit on it; so that this method is not correct.

If antimony only is present, acidulate with hydrochloric acid, pass sulph. hydrogen in excess, warm, filter, wash the orange hydrated antimonious sulphide into a porcelain capsule, remove most of the water, dry on the water bath, finally at 200°C. and weigh. 100 grains of Sb₂ S₃ correspond to 85·88 of Sb₂ O₃, to 196·47 of tartar emetic, to 71·76 of Sb, to 134·41 of Sb Cl₃.

But in the stomach any other metal may be present, hence a process of separation must be used. It is not generally necessary to destroy the organic matter: if this be desired, Fresenius and v. Babo’s process, of heating with H Cl and potass. chlorate (previously proved pure) may be used without much danger of loss, as Sb Cl₃ is not so volatile as As Cl₃. Otherwise the solution made by pure hydrochloric and a little tartaric acids is treated with sulphuretted hydrogen. The precipitated sulphide may be of uncertain, though suspicious colour. After collection on a filter and washing, it should be extracted with dilute ammon. carbonate solution (10 per cent.): arsenic only will dissolve and will be reprecipitated as sulphide on adding an acid. The remainder on the filter must be treated with freshly prepared ammon. sulphide: antimony and tin will dissolve. If any black residue remains on the filter, it will consist of mercury, lead, bismuth, or copper: it should be treated with hot 25 per cent. nitric acid, when all will dissolve except mercuric sulphide. We shall then have three portions:—

1st. The mercuric sulphide. Wash, dry, and weigh. Then heat in a sealed tube with dry sodium carbonate, collect the sublimate of metallic mercury, weigh it, and preserve in a sealed tube.

2nd. The nitric acid solution containing lead, bismuth, and copper. Evaporate nearly to dryness, dilute, add dilute sulphuric acid, and a little alcohol, after standing collect and weigh the precipitated sulphate of lead. Precipitate the bismuth by ammon. carbonate in excess, and the copper from the filtrate by zinc or by sulph. hydrogen. (See Fresenius’ Quant. Anal. p. 411).

3rd. The ammon. sulphide solution of the antimony and tin. Evaporate to dryness, dissolve in hot strong hydrochloric acid, dilute, divide into two equal portions: in one throw down both metals by a rod of zinc: in the other throw down only Sb by a slip of tin. Wash off both precipitates, dry and weigh. The first is antimony and tin together, the second is antimony alone (Gay Lussac). The difference is the tin.

Usually only some of these metals will be present. Tin has derived more importance lately since Hehner has proved its almost constant presence in canned provisions.

As to the delicacy of the precipitation of antimony by zinc or galvanism, Mohr (Toxicologie, 1876) states that a solution containing ·00005 gramme of Sb in one cub. centimetre gives a distinct reaction in fifteen minutes. Such a solution gives with H₂S only a colouration, and after a long time a faint precipitate. ¹/₃₀₀₀₀ part gives with zinc a clear reaction in one half-hour: with H₂ S, only a colour, no precipitate, in twelve hours. ¹/₄₀₀₀₀, doubtful: ¹/₅₀₀₀₀, imperceptible with zinc: of course, nothing with H₂ S. The reaction is only decisive if other metals are excluded.

From the solution of Sb Cl₃, or tartar emetic in H Cl, gallic acid throws down Sb, and not As or tin. The precipitate after washing and drying contains 40·85 per cent. of Sb. (Chem. News, XXIV. 207, 251.)

To sum up, the decisive characters of antimony are:—

1. An orange red precip. by H₂ S in slightly acid solutions.

2. The insolubility of this precip. in ammon. carbonate.

3. Its solubility in ammonium sulphide.

4. Its solubility in hot H Cl, with evolution of H₂ S, and formation of a solution of Sb Cl₃, which is precipitated by water and cleared up again by tartaric acid.

Remarks.
DR. PRITCHARD’S CASE.

In connection with the supposed administration of tartar emetic on a piece of cheese, in Dr. Pritchard’s trial (see Mr. Clark’s review of McCleod’s evidence, p. 438), the following considerations are of interest.

1. An exceedingly small (weighed) quantity of dry powdered tartar emetic was sprinkled on the surface of a little piece of cheese: although the amount of tartar emetic used was far less than that required to induce vomiting, &c., the powder was found to be plainly visible, and the appearance of the cheese so treated would certainly have excited suspicion in the mind of any ordinarily observant person. Hence it is impossible that enough tartar emetic to produce the recorded effects should have been sprinkled externally on the very small amounts of cheese described —“not larger than a bean”—M. McCleod: “size of a good large pea”—M. Patterson).[191]

2. With reference to the Lord Justice Clerk’s observation, p. 439, note, tartar emetic is not easily dissolved, a cold saturated aqueous solution containing only 5 per cent. of the salt (according to the B. P., 20 grains dissolve without residue in 1 ounce of water). A piece of cheese, the size of a bean, would weigh about ? ounce. I have found by experiment that 1 ounce cheese took up by soaking not more than ¼ ounce water, which, from the above, could contain in solution 5 grains of tartar emetic. Hence a piece of cheese, the size of a bean, = ¼ × ? = ¹/₃₂ ounce water = ? grain of tartar emetic. This amount could not cause the symptoms described.

3. If put on in powder the poisonous salt could only be concealed by being rubbed over with butter or oil: if soaked in a solution of tartar emetic, the cheese, in order to avert suspicion, must be wiped or dried—operations practically impossible at the table with so many present.

Two possibilities remain: (a) Cheese is often eaten with salt. Dr. Pritchard may have had a little salt-cellar by his side, professedly for his own use, containing tartar emetic, either alone or mixed with salt. He may have placed a spoonful of this on the plate with the cheese: the latter may have been either dipped into the salt or got into it accidentally. No question was asked at the trial about such a likely fact, which would account for one person suffering, and not another, according as they got the salt or not. The strong taste of salt would avert suspicion from that of tartar emetic. (b) McCleod said that it was “new cheese—they had it in the house—it was soft—it tasted hot like pepper.” It is possible, but not easy, by warming and pounding in a mortar, to mix cheese with a considerable amount of a powder: it would then look soft and rather unnatural, but might, as “new cheese,” escape suspicion. This theory is less probable than the other.

Tapioca.—Mr. Clark’s remark, p. 438, “Now the suggestion of the Crown is that the prisoner put antimony in this tapioca, so nicely adjusted as to produce sickness leading to death, but not so as to produce death itself,” is inconclusive, as it requires a considerable amount to produce death. A large quantity of tartar emetic could be mixed with tapioca without suspicion, and would not betray itself by any peculiar appearance on cooking. The same remark applies to the sago in Winslow’s case.

Egg-flip.—“The amount of antimony introduced on the sugar into the egg-flip must have been a very powerful dose, because Patterson took only a teaspoonful and lay vomiting and suffering all night.” The total amount was a tumblerful (= 10 fluid ounces). Mrs. Pritchard took a wine-glassful (= 2 fluid ounces); was sick very soon and all night. Mary Patterson took a teaspoonful, was sick immediately, and vomited frequently throughout the night. Her dose must have been at least 1 grain. This would make 60 grains in the whole. Such a quantity of tartar emetic would be about a teaspoonful, and obviously could not be introduced on two lumps of loaf sugar, as the following experiment shows:—Two rather large pieces of loaf sugar weighing together 204 grains were gently shaken with powdered tartar emetic, and the loose part shaken off. The lumps now looked rather powdery, but nothing very noticeable. The amount of tartar emetic they had taken up was nearly 3 grains (2·96), not nearly a teaspoonful, though amply sufficient to cause vomiting. It is not the porosity, but the roughness of surface, that enables a powder to adhere to the sugar. The tartar emetic might have been slipped into the egg-flip, out of the hand, at the same time that the sugar was added, the mixture being afterwards stirred up.

DR. SMETHURST’S CASE.
Dr. Taylor and Mr. Herapath.

In his evidence before the committing magistrates, on the 20th of May, Dr. Taylor said:—

“I found no arsenic or antimony in any of the bottles delivered to me by Inspector McIntyre on the 5th and 7th of May, except one, and the homoeopathic medicine: that one was bottle 21.[192] When I received this bottle it was about half full of thin, watery-looking mixture, and I tested it. It had a cooling, pleasant saline taste, not repugnant, no smell. I detected nothing wrong with the taste. I evaporated some in a glass, and examined it by the microscope, and then found it was not tartar emetic, as I thought. I then applied the tests for arsenic, and every test I tried was destroyed, and failed to show the existence of arsenic, owing, as I supposed, to there being in it, and my tests convinced me that there was, something very peculiar about it that I had not met before. I tried Reinsch’s process, but I found that it dissolved the copper-gauze as soon as I put it into the liquid. I then determined to extract this noxious agent, and continued to put in copper-gauze until it no longer possessed the power to dissolve it. I then put in a piece of copper, which at once received the arsenic. I was able to decide by these tests that the mixture was chlorate of potash. I found there was of chlorate of potash 7 grains to the ounce, or 1 and ⁶/_10ths per cent., and there was a grain of arsenic to every ounce. I found that the taste of the liquid in this bottle was such that no one would be likely to suspect that it contained arsenic, more particularly as the quantity of arsenic was so small that the liquid could be mixed with any kind of food and swallowed without the person being aware of it.[193] In the bottles brought to me by Dr. Berry[194] I found arsenic—that was white arsenic. I could not give an opinion on that in the evacuation (No. 2), as that was mixed with blood and mucus. In No. 1 there was biliary matter without any metallic substance.”

Subsequently to the conviction of Smethurst, Mr. Herapath wrote the letter to the Times, on the 27th of August, before referred to in the Lord Chief Baron’s communication to the Home Secretary, in which, after a wordy and personal attack on Dr. Taylor, with special reference to his having used for twenty years untested copper, he said:—

“But was the arsenic said to have been found in bottle 21 really in the copper used to prove its presence? Could the copper wire-gauze dissolved by 7 grains of chlorate of potash and its associated hydrochloric acid deposit one grain of arsenic? In the face of all England, I say it could not. The 100th part of a grain of arsenic in that quantity of copper would render it so brittle that it could not be drawn into wire at all, much less into fine wire fit for gauze. The fact is the whole set of operations were a bungle. Reinsch’s process is inapplicable where nitrates or chlorates are present. Taylor must have known this: it was well known then that chlorates, nitrates, arsenates, and other oxidizing agents, interfered with Reinsch’s process. When Taylor found the copper dissolved—he knew that one of these oxidizing agents was present—he ought then to have either used Marsh’s test instead of Reinsch’s, or should have prepared the solution by sulphurous acid first. The method he did use was as dangerous as could be.”

Whether Mr. Herapath communicated this opinion to the friends of Smethurst before the trial, as he ought to have done, does not appear. At any rate he was not called for the defence, and his opinion was apparently only made public after the conviction. It stands, therefore, like all the other communications laid before the Home Secretary, untested by cross-examination. How far was he correct?

Taylor does not state how much of the liquid in bottle 21 he took for analysis. Assuming that he took 1 ounce, 7 grains of chlorate would dissolve, at the most, 22 grains of copper. If this yielded 1 grain of arsenic, the copper must have contained 4½ per cent. of that poison—an impossible quantity. Less than ½ per cent. of arsenic renders copper brittle. So far Herapath was right.[195]

(2.) If Taylor was right that what he got was white arsenic, that could not have come from the copper, which can only contain arsenicum—metallic arsenic. Therefore if Taylor’s analysis was not altogether wrong, in bottle 21 there really was arsenic, and the prisoner was proved to have had the materials for poisoning in his possession.

Taylor’s procedure in dissolving up piece after piece of copper, which had not been previously proved, by the same process, not to contain arsenic, was highly blameable, and his assertion that he had previously tried his tests and found them pure, was not strictly true. Altogether, his tests both for arsenic and antimony were not reliable.

ADDENDA.

The “bismuth” frequently referred to in the report of Smethurst’s trial is the Bismuthi Subnitras, B. P., also known by the various names of “Bismuthum Album,” “White Bismuth,” “Trisnitrate of Bismuth,” “Subnitrate of Bismuth,” “Magistery of Bismuth,” “Pearl White,” &c. This compound is a basic nitrate of bismuth, Bi N 0₄, H₂ 0: it is insoluble in water, and is a heavy, white, minutely-crystalline powder, much used in medicine, and also as a cosmetic. The name “bismuth” is misleading as applied to this drug, which is not bismuth, but a salt of that metal.

Ordinary subnitrate of bismuth frequently contains various adulterations and impurities. The most usual adulterants are carbonate of lead, carbonate of lime and phosphate of lime (Royle’s Materia Medica, 1876): among the impurities which have been found are ammonia (Piper, Pharm. Journ., Ap. 21, 1877), arsenic, lead, iron, chlorine, and sodium salts. Some specimens of bismuth subnitrate analysed by Herapath contained 1 grain of arsenic in 1000: others contained as much as 1 grain in 433. Taylor, also, found arsenic in three samples out of five examined by him. Riche (J. Pharm. et Chim., 5, 384) states that the majority of commercial samples of bismuth subnitrate contain lead and arsenic, the former to the extent of ·03-·04 per cent. (as sulphate), and the latter (as arsenious acid) to ·002-·01 per cent., while Chas. Ekin (Pharm Journ., 3, III., 381) remarks that this preparation of bismuth is often very impure, containing much subchloride, copper, and occasionally lead. On the other hand, three specimens of subnitrate of bismuth, analysed by Bernays, contained no arsenic, lead, or carbonic acid, while the percentage of bismuth oxide present closely approximated to the theoretical amount. Moreover, in the Practitioner, Mar. 1871, p. 191, the results of the examination of six samples of bismuth subnitrate are given, the only impurities found being traces of chlorine and sulphuric acid: there was no arsenic. Hence it is evident that subnitrate of bismuth does not always contain arsenic: and the quantity of this impurity, when present, is so minute as (having regard to the small doses in which the drug is usually prescribed in medicine) to be insufficient to produce the graver symptoms of arsenical poisoning.[196]

The presence of arsenic in bismuth subnitrate may easily be detected by Marsh’s test.

Subnitrate of bismuth nearly always contains arsenic and other impurities, when it has been prepared from commercial bismuth. The British Pharmacopoeia, therefore; very properly directs that purified bismuth (Bismuthum Purificatum, B. P.) should be used in the preparation of this drug: the B. P. method of purifying the metal is as follows. 10 ounces of bismuth and 1 ounce of nitrate of potash are fused together in a crucible, heated and stirred, until the salt has solidified into a slag over the metal: the salt is now removed, another ounce of nitrate of potash is added, and the remainder of the process is repeated. The fused bismuth is now poured into a mould, and allowed to cool.

Herapath states that the arsenic is not all removed by this process, and he proposes to boil the nitrate in solution of a caustic alkali, which removes the arsenic and converts the bismuth into oxide, from which the salts can be prepared (Royle).

From the purified metal subnitrate of bismuth can be prepared by the following process, which is that given in the British Pharmacopoeia. 2 ounces of purified bismuth are gradually added to a mixture of 4 fluid ounces nitric acid with three ounces distilled water: when effervescence has ceased, heat is applied for a few minutes, and the solution is decanted from any insoluble residue. The liquid is concentrated by evaporation to 2 fluid ounces, and poured into half a gallon of distilled water. The precipitate formed (Bi N 0₄, H₂ 0) is well washed by decantation, filtered, and finally dried at a temperature not exceeding 150° F.

In the event of the bismuth used not having been thoroughly purified, and being therefore still likely to contain a trace of arsenic, a modification of the above process, recommended by R. Schneider (Journ. Prakt. Chem., 1879, 418), may be employed. It consists in heating the acid before the bismuth is added, and continuing the heating until the metal is dissolved. If arsenic be present, the solution will contain in suspension a white precipitate of bismuth arsenate, which is nearly insoluble in nitric acid, and can be removed by filtration through asbestos, before the solution is diluted. Cold nitric acid would convert any arsenic present into bismuth arsenite, which is readily soluble in nitric acid, and could not, therefore, be separated by filtration.

“Grey powder” is Hydrargyrum cum Creta, B. P., and consists of one part of metallic mercury in a very finely divided state, mixed with two parts of chalk. It is made by rubbing mercury and prepared chalk together until metallic globules are no longer visible. The mercury in this preparation always becomes in course of time more or less oxidised, the amount of oxide formed varying according to the length of time the mixture has been kept, and the extent of its exposure to the air.

Iron, silica, and phosphoric acid, might be present in very small quantities as impurities, in many samples of grey powder: caustic lime could not possibly occur, unless the specimen had been subjected to a red heat, which would drive off the mercury and so spoil the preparation. Antimony and arsenic would rarely be met with as impurities in grey powder, and if present, would only be in very minute quantities.