IV Precipitated by Ammonium Sulphide. — Iron — Chromium — Thallium — Aluminium — Uranium
1. Iron
§ 875. It was Orfila’s opinion that all the salts of iron were poisonous, if given in sufficient doses; but such salts as the carbonate, the phosphate, and a few others, possessing no local action, may be given in such very large doses, without causing disturbance to the health, that the statement must only be taken as applying to the more soluble iron compounds. The two preparations of iron which have any forensic importance are the perchloride and the sulphate.
§ 876. Ferric Chloride (Fe2Cl6 = 325).—Anhydrous ferric chloride will only be met with in the laboratory. As a product of passing dry chlorine over red-hot iron, it sublimes in brown scales, is very deliquescent, and hisses when thrown into water. There are two very definite hydrates—one with 6 atoms of water, forming large, red, deliquescent crystals; and another with 12 of water, less deliquescent, and crystallising in orange stellate groups.
The pharmaceutical preparations in common use are:—
Stronger Solution of Perchloride of Iron (Liquor Ferri Perchloridi Fortior).—An orange-brown liquid of specific gravity 1·42, and containing about 58 per cent. of ferric chloride.
Tincture of Perchloride of Iron (Tinctura Ferri Perchloridi), made by diluting 1 part of the strong solution with 1 volume of rectified spirit, and adding distilled water to measure 4.
Solution of Perchloride of Iron (Liquor Ferri Perchloridi).—Simply 5 volumes of the strong solution made up to 20 by the addition of water; hence, of the same strength as the tincture.
§ 877. Effects of Ferric Chloride on Animals.—A very elaborate series of researches on rabbits, dogs, and cats was undertaken a few years ago by MM. Bérenger-Féraud and Porte956 to elucidate the general symptoms and effects produced by ferric chloride under varying conditions. First, a series of experiments showed that, when ferric chloride solution was enclosed in gelatine capsules and given with the food of the animal, it produced either no symptoms or but trifling inconvenience, even when the dose exceeded 1 grm. per kilogrm.; anhydrous ferric chloride and the ferric chloride solution were directly injected into the stomach, yet, when food was present, death did not occur, and the effects soon subsided. In animals which were fasting, quantities of the solution equal to ·5 grm. per kilogrm. and above caused death in from one hour to sixteen hours, the action being much accelerated by the addition of alcohol—as, for example, in the case of the tincture: the symptoms were mainly vomiting and diarrhœa, sometimes the vomiting was absent. In a few cases the posterior extremities were paralysed, and the pupils dilated: the urine was scanty or quite suppressed; death was preceded by convulsions.
§ 878. Effects on Man.—Perchloride of iron in the form of tincture has been popularly used in England, from its supposed abortive property, and is sold under the name of “steel drops.” It has been frequently taken by mistake for other dark liquids; and there is at least one case on record in which it was proved to have been used for the purpose of murder. The latter case957 is peculiarly interesting from its great rarity; it occurred in Martinique in 1874-1876, no less than four persons being poisoned at different dates. All four were presumed to have had immoral relations with a certain widow X——, and to have been poisoned by her son. In three of the four cases, viz., Char——, Duf——, and Lab——, the cause of death seems pretty clear; but the fourth, Ab——, a case of strong suspicion, was not sufficiently investigated. All three took the fatal dose in the evening, between eight and nine o’clock—Lab—— the 27th of December 1874, Duf—— the 22nd of February 1876, and Char—— on the 14th of May 1876. They had all passed the day in tippling, and they all had eaten nothing from mid-day, so that the stomach would, in none of the three, contain any solid matters. The chloride was given to them in a glass of “punch,” and there was strong evidence to show that the son of the widow X—— administered it. Char—— died after about thirteen hours’ illness, Duf—— and Lab—— after sixty-five hours’ illness; Ab—— lived from three to four days. With Char—— the symptoms were very pronounced in an hour, and consisted essentially of violent colicky pain in the abdomen and diarrhœa, but there was no vomiting; Duf—— had also great pain in the abdomen and suppression of the urine. Lab—— had most violent abdominal pains; he was constipated, and the urinary secretion was arrested; there was besides painful tenesmus. According to the experiments of Bérenger-Féraud and Porte,958 the perchloride in the above cases was taken under conditions peculiarly favourable for the development of its toxic action, viz., on an empty stomach and mixed with alcohol.
There have been several cases of recovery from large doses of the tincture, e.g., that of an old man, aged 72, who had swallowed 85 c.c. (3 ozs.) of the tincture; the tongue swelled, there were croupy respiration and feeble pulse, but he made a good recovery. In other cases,959 28·3 c.c. (an ounce) and more have caused vomiting and irritation of the urinary organs. The perchloride is not unfrequently used to arrest hæmorrhage as a topical application to the uterine cavity—a practice not free from danger, for it has before now induced violent inflammation and death from peritonitis.
§ 879. Elimination of Iron Chloride.—Most of the iron is excreted in the form of sulphide by the fæces, and colours them of a black hue; a smaller portion is excreted by the urine.
§ 880. Post-mortem Appearances.—In the experiments on animals already referred to, the general changes noted were dryness, pallor, and parchment-like appearance of the cavity of the mouth, the mucous membrane being blackened by the contact of the liquid. The gullet was pale and dry, not unfrequently covered with a blackish layer. The mucous membrane of the stomach was generally healthy throughout; but, if the dose was large and very concentrated, there might be one or more hyperæmic spots; otherwise, this did not occur. The internal surface of the intestines, similarly, showed no inflammation, but was covered with brownish coating which darkened on exposure to the air. The liver, in all the experiments, was large and gorged with black and fluid blood; there were ecchymoses in the lungs and venous congestion. The kidneys were usually hyperæmic, and contained little hæmorrhages. There was also general encephalic engorgement, and in one experiment intense congestion of the meninges was observed. Few opportunities have presented themselves for pathological observations relative to the effects produced by ferric chloride on man. In a case related by Christison, in which a man swallowed 42·4 c.c. (11⁄2 oz.) of the tincture, and died in five weeks, there was found thickening and inflammation of the pyloric end of the stomach.
The case of Char——, already alluded to, is that in which the most complete details of the autopsy are recorded, and they coincide very fairly with those observed in animals; the tongue was covered with a greenish fur, bordered at the edges with a black substance, described as being like “mud”; the lining membrane of the gullet was pale, but also covered with this dark “mud.” The stomach contained a greenish-black liquid; the liver was large and congested; the kidneys were swollen, congested, and ecchymosed; the cerebral membranes were gorged with blood, and the whole brain hyperæmic.
§ 881. Ferrous Sulphate, Copperas, or Green Vitriol, FeSO47H2O = 152 + 126; specific gravity, anhydrous, 3·138; crystals, 1·857; composition in 100 parts, FeO, 25·92; SO3, 28·77; H2O, 45·32.—This salt is in beautiful, transparent, bluish-green, rhomboidal prisms. The crystals have an astringent, styptic taste, are insoluble in alcohol, but dissolve in about 1·5 times their weight of water; the commercial article nearly always responds to the tests, both for ferrous and ferric salts, containing a little persalt. The medicinal dose of this salt is usually given as from ·0648 to ·324 grm. (1 to 5 grains), but it has been prescribed in cases requiring it in gramme (15·4 grains) doses without injury. Sulphate of iron has many technical applications; is employed by all shoemakers, and is in common use as a disinfectant. The salt has been employed for criminal purposes in France, and in this country it is a popular abortive. In recorded cases, the symptoms, as well as the pathological appearances, have a striking resemblance to those produced by the chloride. There are usually colic, vomiting, and purging; but in one case (reported by Chevallier), in which a man gave a large dose of sulphate of iron to his wife, there was neither vomiting nor colic; the woman lost her appetite, but slowly recovered. Probably the action of ferrous sulphate, like that of the chloride, is profoundly modified by the presence or absence of food in the stomach. Anything like 28·3 grms. (an ounce) of sulphate of iron must be considered a dangerous dose, for, though recovery has taken place from this quantity, the symptoms have been of a violent kind.
§ 882. Search for Iron Salts in the Contents of the Stomach, &c.—Iron, being a natural component of the body, care must be taken not to confound the iron of the blood or tissues with the “iron” of a soluble salt. Orfila attempted to distinguish between the two kinds of iron by treating the contents of the stomach, the intestines, and even the tissues, with cold acetic acid, and allowing them to digest in it for many hours before filtering and testing for iron in the filtrate, and this is generally the process which has been adopted. The acid filtrate is first treated with sulphuretted hydrogen, which gives no precipitate with iron, and then with sulphide of ammonium, which precipitates iron black. The iron sulphide may be dissolved by a little hydrochloric acid and a drop of nitric acid, and farther identified by its forming Prussian blue when tested by ferrocyanide of potash, or by the bulky precipitate of oxide, when the acid liquid is alkalised by ammonia. In the case of Duf——, the experts attempted to prove the existence of foreign iron in the liver by taking 100 grms. of Duf——’s liver and 100 grms. of the liver of a non-poisoned person, and destroying each by nitro-muriatic acid, and estimating in each acid solution the ferric oxide. Duf——’s liver yielded in 100 parts ·08 mgrm. of ferric oxide, the normal liver ·022—nearly three times less than Duf——’s.
To obtain iron from the urine, the fluid must be evaporated down to a syrup in a platinum dish, a little nitric acid added, heated, and finally completely carbonised. The residue is dissolved in hydrochloric acid. Normal urine always contains an unweighable trace of iron; and, therefore, any quantity, such as a mgrm. of ferric oxide, obtained by careful precipitation of the hydrochloric acid solution out of 200 to 300 c.c. of urine, would be good evidence that a soluble salt of iron had been taken. The hydrochloric acid solution is first precipitated by ammonia and ammonic sulphide. The precipitate thus obtained will not be pure iron sulphide, but mixed with the earth phosphates. It should be redissolved in HCl, precipitated by sodic carbonate, then acidified by acetic acid and sodic acetate added, and the solution well boiled; the iron will then be precipitated for the most part as oxide mixed with a little phosphate of iron.
Since, as before mentioned, a great portion of the iron swallowed as a soluble salt is converted into insoluble compounds and excreted by the fæces, it is, in any case where poisoning by iron is suspected, of more importance to examine chemically the fæces and the whole length of the alimentary canal, than even the contents of the stomach. In particular, any black material lying on the mucous membrane may be sulphide of iron mixed with mucus, &c., and should be detached, dissolved in a little hydrochloric acid, and the usual tests applied.
In the criminal cases alluded to, there were iron stains on certain linen garments which acquired an importance, for, on dissolving by the aid of nitric acid, they gave the reactions of chlorine and iron. Any stains found should be cut out, steeped in water, and boiled. If no iron is dissolved the stain should then be treated with dilute nitric acid, and the liquid tested with ferrocyanide of potash, &c. It need scarcely be observed that iron-mould is so common on shirts and any fabric capable of being washed, that great care must be exercised in drawing conclusions from insoluble deposits of the oxide.
2. Chromium
§ 883. The only salts of chromium of toxicological importance are the neutral chromate of potash, the bichromate of potash, and the chromate of lead.
Neutral Chromate of Potash, CrO3K2O = 194·7, containing 56·7 per cent. of its weight of chromic anhydride, CrO3.—This salt is in the form of citron-yellow rhombic crystals, easily soluble in water, but insoluble in alcohol. Its aqueous solution is precipitated yellow by lead acetate or basic acetate; the precipitate being insoluble in acetic acid. If chromate of potash in solution is tested with silver nitrate, the red chromate of silver is thrown down; the precipitate is with difficulty soluble in dilute nitric acid.
§ 884. Potassic Bichromate, CrO3K2O = 295·2, containing 68·07 per cent. of its weight of chromic anhydride, CrO3.—This salt is in beautiful large, red, transparent, four-sided tables; it is anhydrous and fuses below redness. At a high temperature it is decomposed into green oxide of chromium and yellow chromate of potash. It is insoluble in alcohol, but readily soluble in water. The solution gives the same precipitates with silver, lead, and barium as the neutral chromate. On digesting a solution of the bichromate with sulphuric acid and alcohol, the solution becomes green from the formation of chromic oxide.
§ 885. Neutral Lead Chromate, PbCrO4 = 323·5, composition in 100 parts, PbO, 68·94, CrO3, 31·06.—This is technically known as “Chrome Yellow,” and is obtained as a yellow precipitate whenever a solution of plumbic acetate is added, either to the solutions of potassic chromate or bichromate; by adding chrome yellow to fused potassic nitrate, “chrome red” is formed; it has the composition CrO32PbO. Neutral lead chromate is insoluble in acids, but may be dissolved by potassic or sodic hydrates.
§ 886. Use in the Arts.—Potassic bichromate is extensively used in the arts—in dyeing, calico-printing, the manufacture of porcelain, and in photography; the neutral chromate has been employed to a small extent as a medicine, and is a common laboratory reagent; lead chromate is a valuable pigment.
§ 887. Effects of some of the Chromium Compounds on Animal Life.—In the chromates of potash there is a combination of two poisonous metals, so that it is not surprising that Gmelin found the chloride of chromium, CrCl3, less active than the neutral chromate of potash; 1·9 grm. of the last, administered to a rabbit by the stomach, caused death within two hours, while 3 grms. of chromous chloride had no action. Subcutaneous doses of ·2 to ·4 grm. of neutral chromate (according to the experiments of E. Gergens960 and Carl Posner961) act with great intensity on rabbits. Immediately after the injection the animals are restless, and show marked dyspnœa; death often takes place within a few hours.
Diarrhœa does not seem, as a rule, to follow when the salt is administered by subcutaneous injection to animals; but Gmelin’s rabbits had considerable diarrhœa when 1·9 grm. was introduced into the stomach. The same quantity, injected beneath the skin of a dog, caused loss of appetite, and, after six days, there was a dry exanthem on the back, and the hair fell off in patches; there was, however, neither diarrhœa nor vomiting. Bichromate of potash causes (according to the researches of Pelikan)962 symptoms similar to those produced by arsenic or corrosive sublimate; it acts as a powerful irritant of the stomach and intestinal canal, and may even cause inflammation; on its absorption a series of symptoms are produced, of which the most prominent are albuminuria, bloody urine, and emaciation. From ·06 to ·36 grm. (1-51⁄2 grains) is fatal to rabbits and dogs.
§ 888. Effects of some of the Chromium Salts on Man—Bichromate Disease.—In manufacturing potassic bichromate, the workmen exposed to the dust have suffered from a very peculiar train of symptoms, known under the name of “bichromate disease.” It was first described in England by Sir B. W. Richardson.963 It appears that if the workmen inspire the particles chiefly through the mouth, a bitter and disagreeable taste is experienced, with an increase of saliva. This increase of the buccal secretion gets rid of most of the poison, and in that case but little ill effect is experienced; but those who keep the mouth closed and inspire by the nose, suffer from an inflammation of the septum, which gradually gets thin, and ultimately ulcerated; finally the whole of the septum is in this way destroyed. It is stated that when a workman has lost his nasal septum, he no longer suffers from nasal irritation, and has a remarkable immunity from catarrh. The Chemical Works Committee of Inquiry report (1893) that the manufacture of bichromate of potash or soda is practically in the hands of three firms at Glasgow, Rutherglen, and Falkirk, and that they visited all of them, and found “that almost all the men working where dust was prevalent, more especially between the furnaces and the dissolving tanks, had either perforation of the septum of the nose, or had lost the septum altogether.” The bichromate also causes painful skin affections—eruptions akin to eczema or psoriasis; also very deep and intractable ulcerations. These the workers call “chrome holes.” These cutaneous maladies start from an excoriation; so long as the skin is not broken, there seems to be little local effect, if any. The effects of the bichromate are also seen in horses employed at the factories; the salt getting into a wound or crack in the leg, produces ulceration: horses may even lose their hoofs.
§ 889. Acute poisoning by the chromates is rare. In the ten years ending 1892, in England and Wales, 4 accidental deaths are ascribed to potassic bichromate and 1 to chromic acid. Falck has, however, been able to find in medical literature 17 cases, 6 of which were suicidal, 10 accidental, and in 1 the bichromate was used as an abortive. In a case of poisoning by the chromate of potash (related by Maschka),964 in which a woman, aged 25, took for a suicidal purpose a piece of potassic chromate, which she described as the size of a hazel-nut (it would probably be at least 6 grms. in weight), the chief symptoms were vomiting, diarrhœa, pain in the stomach, and rapid collapse; death took place fourteen hours after swallowing the poison.
In poisoning by potassic bichromate, there may be much variety in the symptoms, the more usual being those common to all irritant poisons, i.e., vomiting, diarrhœa, and collapse, with cramps in the limbs and excessive thirst; and the rarer affecting more especially the nervous system, such as narcosis, paralysis of the lower limbs, and dilatation of the pupils; occasionally there is slight jaundice.
In a case recorded by Dr. Macniven,965 a man took a lump of bichromate of potash, estimated to be over 2 drachms (7·7 grms.). The symptoms commenced in fifteen minutes, and consisted of lightness in the head, and a sensation of great heat in the body, which was followed by a cold sweat; in twenty minutes he vomited; he then suffered from great pain in the stomach, giddiness, specks before the eyes, a devouring thirst, and there was loss of power over the legs. These symptoms, again, were followed by severe rigors and great coldness of the extremities. On the patient’s admission to hospital, two hours after taking the poison, it was noted that the pupils were dilated, the face pale and cold, and the pulse feeble. He complained of intense epigastric pain, and a feeling of depression; there was some stupor; the stomach was emptied by emetics and by the stomach-pump, and the patient treated with tepid emollient drinks, whilst subcutaneous doses of sulphuric ether were administered. He made a good recovery.
In a case recorded by Mr. Wilson,966 a man, aged 64, was found dead in his bed twelve hours after he had gone to rest. During the night he was heard to snore loudly; there were no signs of vomiting or purging, and bichromate of potash was found in the stomach.967
§ 890. Chromate of lead has also caused death. In one case968 the breathing of chromate of lead dust seems to have been fatal; and there is also a double poisoning recorded by Dr. Linstow,969 of two children, aged three and a half and one and three-quarter years respectively, who ate some yellow ornaments,970 which were used to adorn a cake, and which contained chrome yellow (chromate of lead). The younger died in two and the elder in five days. The symptoms were redness of the face, dulness, and an inclination to sleep; neither complained of pain; the younger one had a little diarrhœa, but the elder neither sickness nor purging.
§ 891. Post-mortem Appearances.—We possess some very exact researches971 upon the pathological changes induced by subcutaneous injections of solutions of potassic bichromate on animals, and especially on the changes which the kidneys undergo. If the animal is killed, or dies a few hours after the injection, there are apparently no striking appearances, but a closer microscopical examination shows considerable changes. The epithelium of the tubuli contorti exhibits a yellow cloudiness, and the outline of the cells is irregular and jagged. The glomeruli are moderately injected, and their capsules contain an albuminous exudation; the canaliculi are filled with round cells imbedded in a fluid which, on heating, coagulates, and is therefore albuminous or fibrinous; probably this is the first stage of the formation of fibrinous casts.
In the case quoted of the woman who poisoned herself with potassic chromate, very striking changes were found in the stomach and intestines. The stomach contained above a litre of dark chocolate fluid of alkaline reaction; the mucous membrane, in the neighbourhood of the cardiac and pyloric extremities, was swollen and red in sharply defined patches; portions of the epithelial layer were detached, the rest of the mucous membrane was of a yellow-brown colour, and the whole intestine, from the duodenum to the sigmoid flexure, was filled with a partly bloody, partly treacly-looking fluid; the mucous membrane, throughout its entire extent, was swollen, with numerous extravasations, and in places there were losses of substance. Similar appearances to these have been found in other instances; the anomalous case recorded by Mr. Wilson (ante) is an exception. In this instance a pint of inky, turbid liquid, which yielded to analysis potassic bichromate, was found in the stomach; but there were no marked changes anywhere, save a slight redness of the cardiac end of the gullet. In Linstow’s two cases of poisoning by lead chromate, there were found in both fatty degeneration of the liver cells, and red points or patches of redness in the stomach and intestines. In the elder boy the changes in the duodenum were very intense, the mucous membrane was swollen and easily detached, in the upper part strongly injected with blood; in one place there was a perforation, and in several places the membrane was extremely thin. In the younger boy the kidneys seem to have been normal, in the elder congested and containing pus. Although it was clear that the two children died from lead chromate, a chemical analysis gave no result.
§ 892. Detection of the Chromates and Separation of the Salts of Chromium from the Contents of the Stomach, &c.—If in the methodical examination of an acid liquid, which has been already filtered from any precipitate that may have been obtained by sulphuretted hydrogen, this liquid is made alkaline (the alkali only being added in slight excess), and hydrated chromic oxide is thrown down mixed, it may be with other metals of the second class, the precipitate may then be fused with nitre and potassic carbonate, and will yield potassic chromate, soluble in water, and recognised by the red precipitate which it gives with silver nitrate, the yellow with lead acetate, and the green colour produced by boiling with dilute sulphuric acid and a little alcohol or sugar. If by treating a complex liquid with ammonium hydrosulphide, sulphides of zinc, manganese, and iron are thrown down mixed with chromic oxide, the same principles apply. If a chromate is present in the contents of the stomach, and the organic fluid is treated with hydrochloric acid and potassic chlorate, chromic chloride is formed, and dissolving imparts a green colour to the liquid—this in itself will be strong evidence of the presence of a chromate, but it should be supplemented by throwing down the oxide, and transforming it in the way detailed into potassic chromate.
A general method of detecting and estimating both chromium and barium in organic matters has been worked out by L. de Koningh.972 The substances are burnt to an ash in a platinum dish. The ash is weighed; to the ash is added four times its weight of potassium sodium carbonate and the same amount of potassium nitrate; and the whole is fused for fifteen minutes. The fused mass is boiled with water and filtered; if chromium is present, the filtrate is of a more or less pronounced yellow colour, but manganese may produce a green colour and mask the yellow; this colour is removed by boiling with a little alcohol. The liquid is concentrated down to 20 c.c., filtered into a test-tube, and a colorimetric estimation made of the chromium present by imitating the colour by a solution of potassium chromate of known strength. To prove that the colour is really due to chromium, acetic acid and lead acetate are added, when the yellow chromate of lead is at once thrown down. (If lead was in the ash, a yellow precipitate may appear on the addition of acetic acid.) To the portion of ash insoluble in water strong hydrochloric acid is added, and to the acid solution a large excess of calcium sulphate is added; this precipitates barium as sulphate free from lead sulphate, for, if the latter should be present, it does not, under the circumstances, come down, being soluble in strong hydrochloric acid.
3. Thallium
§ 893. Thallium was discovered by Crookes in 1861. Its atomic weight is 204; specific gravity, 11·81 to 11·91; melting-point, 290°. It is a heavy diamagnetic metal, very similar to lead in its physical properties. The nitrate and sulphate of thallium are both soluble in water, the carbonate less so, requiring about 25 parts of water for solution, while the chloride is sparingly soluble, especially in hydrochloric acid.
§ 894. Effects.—All the salts of thallium are poisonous. One of the earlier experimenters on the physiological action, Paulet, found 1 grm. (15·4 grains) of thallium carbonate sufficient to kill a rabbit in a few hours; there were loss of muscular power, trembling of the limbs, and death apparently from asphyxia. Lamy973 used thallium sulphate, and found that dogs were salivated, and suffered from trembling of the limbs, followed by paralysis. The most definite results were obtained by Marmé,974 who found that ·04 to ·06 grm. of a soluble thallium salt, injected subcutaneously or directly into the veins, and ·5 grm. administered through the stomach of rabbits, caused death. The action is cumulative, and something like that of mercury: there are redness and swelling of the mucous membrane of the stomach, with mucous bloody discharges; hæmorrhage may also occur from the lungs. Thallium is eliminated through the urine, and is also found in the fæces; it passes into the urine from three to five minutes after injection: the elimination is slow, often taking as long as three weeks. It has been found in the milk, in the tears, in the mucous membrane of the mouth, of the trachea, in the secretion of the gastric mucous membrane, and in the pericardial fluid; and in these places, whether the poison has been introduced by subcutaneous injection, or by any other channel. It seems probable that the reason of its being detected so readily in all the secretions is the minute quantity which can be discovered by spectroscopic analysis.
§ 895. Separation of Thallium from Organic Fluids or Tissues.—The salts of thallium, if absorbed, would only be extracted in traces from the tissues by hydrochloric acid, so that, in any special search, the tissues are best destroyed by either sulphuric or nitric acid, or both. In the ordinary method of analysis, when an acid liquid is first treated with sulphuretted hydrogen, and then made alkaline by ammonia and ammonic sulphide, thallium would be thrown down with the manganese and iron of the blood. From the mixed sulphides, thallium may be separated by oxidising and dissolving the sulphides with nitric acid, evaporating off the excess of acid, dissolving in a very little hot water, and precipitating thallous chloride by solution of common salt. The ease, however, with which thallium may be separated from solutions of its salts by galvanism is so great as to render all other processes unnecessary: the best way, therefore, is to obtain a deposit of the metal on platinum by a current from one or more cells, and then to examine the deposit spectroscopically. Thallium gives, when heated in a Bunsen flame, a magnificent green line, the centre of which corresponds with wave length 534·9; a second green line, the centre of which coincides with W.L. 568, may also be distinguished.
4. Aluminium
§ 896. Aluminium and its Salts.—A strong solution of acetate of alumina has irritant properties, and has given rise to accidents. The term alum, in a chemical sense, is given to a class of bodies of the type of AlKSO4. Common alum is at the present time ammonia alum, NH4Al(SO4)2 + 12H2O; when made anhydrous by heat it is known by the name of burnt alum, and possesses caustic properties.
§ 897. Action of Alum Salts.—Death or illness has hitherto only taken place from the ingestion of large doses of alum or the acetate, and the symptoms in these cases have been those of an irritant poison; we are, however, indebted to Paul Siem975 for a research on the absorbed substance, in which the local effects as far as possible have been reduced.
Siem’s research was made on frogs, cats, and dogs. For frogs he employed a double salt, consisting of sodic and aluminic lactate, to which he ascribed the formula Al2(C3H5O3)3(C3H4NaO3)3, equal to 15·2 per cent. of Al2O3. Twenty to thirty mgrms., administered by subcutaneous injection to frogs, caused death in from ten to twenty-four hours. After the injection there was restlessness, and, ultimately, general paralysis of the central nervous system. The circulation was not affected; the heart was the last to die.
For warm-blooded animals he used the double tartrate of sodium and aluminium. Beginning with a small dose subcutaneously administered, he gradually increased it, and found, under these circumstances, that the lethal dose for rabbits was 0·3 grm. per kilo. of body weight; for dogs 0·25 grm., and for cats 0·25 to 0·28 grm.; if, however, a single dose was administered, then cats could be killed by 0·15 grm. per kilo. The symptoms commenced ten to twelve hours after the injection of a large dose, but with a medium dose the symptoms might be delayed for from three to four days, then there was loss of appetite, constipation, emaciation, languor, and a disinclination to move. Vomiting and loss of sensation to pain followed, the power of swallowing even saliva was lost, and a condition supervened similar to bulbar paralysis. However true this picture may be when large doses are given subcutaneously, it does not follow that hydrate of alumina in small doses, given by the mouth, mixed with food, produces any symptoms whatever.
Alum baking-powders, containing from 30 to 40 per cent. of alum mixed with carbonate of soda, are in commerce, and have been for a long time, many tons being sold yearly. When water is added to such powders decomposition takes place, the result being sodic sulphate and aluminic hydrate, carbonic acid being given off. Were the hydrate, in small doses, capable of producing indigestion or disease of the central nervous system, it seems astonishing that, considering the enormous number of persons who use alum baking-powders, there should not be some definite evidence of its effect. The author and his family for months together have used alum baking-powders without any apparent injury, and there is little doubt that alumina hydrate passes out of the system mainly by the bowel, without being absorbed to any great extent. In a trial with regard to an alum baking-powder at Pontypridd (1893), the prosecution advanced the theory, and supported it by eminent scientific opinion, that aluminium hydrate was dissolved by the hydrochloric acid of the gastric juice, forming chloride of aluminium, some of which might be absorbed and enter the circulation; that which was not absorbed in the stomach passed on, and, meeting the alkaline fluids of the intestines, was again separated as aluminium hydrate, and as such absorbed.
If this does occur, still there is no direct evidence of its toxic influence in the small quantities used in baking-powder. It may be pointed out, also, that with regard to the possible lethal effect of a non-corrosive salt of alum, presuming that the lethal dose for man is the same as that for a cat, the amount of alumina to kill a 68-kilogramme man would have to be equal to 17 grms., or about 3 ozs. of ammonia alum. This important question can only be settled by careful feeding of animals carried on for a long period of time.
§ 898. Post-mortem Appearances.—In the few cases in which persons have been killed by large doses of alum or its salts there have been found corrosion of the mouth, throat, and stomach, and hyperæmia of the kidneys and intestine. In the animals experimented upon by Paul Siem, hyperæmia of the intestine, fatty degeneration of the liver and hyaline degeneration of the kidneys were the chief changes noted.
§ 899. Detection of Alumina.—In all operations for the detection of alumina, glass and porcelain vessels are to be avoided. The substances should be burned to an ash in a platinum dish, the ash treated with hydrochloric acid, the acid driven off by heat, and a few drops of nitric acid added, and dissolved in hydrochloric acid, and the solution boiled and filtered. If organs of the body are operated upon, iron and phosphoric acid will be present in the ash; this will, indeed, be the case with most organic substances. The filtered solution is boiled, and, while boiling, poured into a strong solution of sodic hydrate contained in a silver or platinum dish; the iron will now separate as oxide, and can be filtered off. To the filtrate is added a little sodic phosphate; it is then feebly acidified with hydrochloric acid, and ammonia added just sufficient to render it alkaline; a light whitish cloud of alumina phosphate, should alumina be present, is thrown down, and can be collected, thoroughly washed, dried, ignited, and weighed as alumina phosphate.976 The alumina phosphate is then fused with sodic sulphate in a platinum dish or crucible, and the fused mass treated with hot water; the sodic phosphate dissolves, and the alumina oxide may be filtered off and dissolved in a little hydrochloric acid or sulphuric acid.
A solution thus prepared has the following properties:—
Ammonium sulphide; white precipitate of hydroxide.
Potash or soda; white precipitate, soluble in excess.
Ammonia; white precipitate, only slightly soluble in excess.
There is also a blowpipe-test: if a little of the hydroxide be collected, moistened with cobalt nitrate, and heated on charcoal by the oxidising flame, alumina, under these circumstances, becomes of a blue colour.
5. Uranium
§ 900. Uranium.—The salts of uranium are intensely poisonous. The nitrate of uranium is used in photography and the arts, and is a common reagent in chemical laboratories.
According to Kowalewsky,977 the acetate of uranium possesses an unusual power of uniting with albumin; the other soluble uranium salts act also in a similar way. Hence concentrated solutions of uranium salts corrode the mucous membranes, transforming, for example, the walls of the stomach into a dead uranic albuminate. If a non-corrosive salt of uranium is injected subcutaneously, glycosuria is produced, with fatty degeneration of the walls of the blood-vessels, and fatty changes in the kidneys, liver, &c. The animal wastes and ultimately dies; 0·5 to 2·0 mgrms. of UO3 per kilogrm. will kill a cat, dog, or rabbit, if injected subcutaneously. The nitrate or acetate, when given by the mouth, produces gastro-enteritis and nephritis, with hæmorrhages in the substance of the kidney. Uranium is not used in medicine.
§ 901. Detection and Estimation of Uranium.—Uranium forms uranous and uranic salts. Both classes of salts are not precipitated by SH2, but are precipitable by ammonium sulphide, and, therefore, in toxicological analyses are likely to be met with in conjunction with iron.
The sulphides of iron and uranium may be dissolved in strong hydrochloric acid, boiled to expel SH2, and the solution then oxidised with a little nitric acid; the solution is now alkalised with ammonium carbonate, which precipitates the iron as oxide and leaves the uranium in solution. On now acidifying with nitric acid in slight excess, a solution of sodic phosphate will precipitate uranium phosphate as a white precipitate, alkalies will give a yellow precipitate, alkaline carbonates a yellow precipitate soluble in excess. Barium carbonate also gives a precipitate, and is useful in separations. Uranium oxide gives a green glass in the oxidising flame with borax or with sodic metaphosphate.
Notes
956 “Étude sur l’empoisonnement par le perchlorure de fer,” par MM. Bérenger-Féraud et Porte, Annales d’Hygiène Publique, 1879.
957 Fully reported in Bérenger-Féraud’s paper, loc. cit.
958 Dub. Med. Press, February 21, 1849.
959 Provincial Journal, April 7 and 21, 1847, p. 180; see also Taylor’s Principles and Practice of Medical Jurisprudence, vol. i. p. 320, 2nd Edition.
960 Arch. f. experiment. Pathol. u. Pharmakol., Bd. 6, Hft. 1 and 2, § 148, 1875.
961 Virchow’s Archiv f. path. Anat., Bd. 79, Hft. 2, § 333, 1880.
962 Beiträge zur gerichtl. Medicin, Toxikol. u. Pharmakodynamik, Würzburg, 1858.
963 Brit. and For. Med. Chirurg. Review, Oct. 1863. See also a paper by the same writer, read before the Medical Society, reported in the Lancet, March 11, 1882.
964 Prager Vierteljahrsschr. f. d. prakt. Heilk., Bd. 131, § 37, 1877; Schmidt’s Jahrb. 1878, Bd. 178, § 237. See also Schuchardt in Maschka’s Handbuch, Bd. ii. p. 3.
965 “On a Case of Poisoning with Bichromate of Potash,” by Ed. O. Macniven, M.B., Lancet, Sept. 22, 1883.
966 Med. Gazette, vol. 33, 734.
967 See also cases recorded by Dr. M’Lachlan, Glasgow Med. Journ., July 1881; Dr. M’Crorie, ibid., May 1881; Dr. R. A. Warwick, Lancet, Jan. 31, 1880; and Dr. Dunbar Walker, ibid., Sept. 27, 1879—a summary of all of which may be found in Dr. Macniven’s paper, loc. cit.
968 Ueber tödtliche Vergiftung durch Einathmen des Staubes von mit Chromsäuren Blei-Oxyde gefärbten Garne.—Vierteljahrsschr. f. ger. Med., 1877, Bd. xxvii. Hft. i. p. 29.
969 Ibid., Bd. xx. s. 60, 1874.
970 The ornaments were imitations of bees; each contained ·27 grm. gum tragacanth, ·0042 grm. neutral lead chromate.
971 C. Posner, op. cit.
972 Arch. Pharm. (3), xxvii. 944.
973 Chem. News, 1863.
974 Göttinger Gelehrt. Nachrichten, Aug. 14, No. 20.
975 Ueber die Wirkungen des Aluminiums u. Berylliums, Inaug. Diss., Dorpat, 1886; Schmidt’s Jahrbuch, vol. ccxi. 128.
976 One part of al. phosphate is equal to 0·42 Al2O3, 3·733 ammonia alum, and 4·481 potash alum.
977 Ztschr. f. Anal. Chemie, xxiv., 1885, p. 551.