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of poisoning with the irritants (especially if these are attended with the discharge of blood upwards and downwards) make their appearance in the usual time, and are soon after accompanied or followed by true mercurial salivation,-it may be safely inferred that some soluble compound of mercury has been taken. Before drawing this inference, however, it will be necessary to determine with precision all the classes of symptoms, more particularly the nature of the salivation. It should also be remembered, that salivation may accompany or follow the symptoms of inflammation in the stomach, in consequence of calomel having been used as a remedy. But if proper attention be paid to the fallacies in the way of judgment, I conceive that an opinion on the question of poisoning with corrosive sublimate may be sometimes rested on the symptoms alone."

Treatment.-M. Orfila, having proved the inefficacy of the various antidotes formerly in use, was fortunately enabled some years since to discover a very efficacious one in an accessible substance, namely, the albumen contained in whites (and yelks) of eggs. This has saved several lives. He observes: 1. The precipitate of albumen and the sublimate may be taken in a large dose without danger. 2. It is poisonous (but less so than the sublimate) when dissolved in excess of albumen. 3. Therefore, animals to whom more albumen than sufficient to produce the precipitate, is given, die, if they are prevented vomiting. 4. Dogs poisoned with sublimate, to whom excess of albumen is given, in consequence of the vomiting which the combination produces, survive. 5. Animals to which an insufficient quantity of albumen has been given, die in three or four hours. 6. Although albumen does not completely neutralize the poison, it is by far the best antidote discovered, because it is harmless in itself, does not form a hurtful compound unless in excess, and because, being accessible to all, it can at once be swallowed off. Dr. Wright says, that if its administration be followed up by an astringent decoction, or infusion, the solubility of the compound in excess of albumen is diminished. In a case of poisoning, eggs copiously diluted with water, or in a gum emulsion, should be given, and the stomach distended with fluid, so as to induce vomiting. If eggs are not at hand, rice-water, flour and water, sugar and water, or milk may be used. Vomiting is better excited in these cases by abundant drinks, which allay irritation, than by emetics. They should be therefore even forced upon the patient. If the taking the poison be followed by inflammation of the alimentary canal or peritoneum, general and local bleeding, fomentations, and anodyne or emollient glysters will be required. Edwards and Dumas state they have found iron filings an efficacious antidote in their experiments. In a supplement, Orfila notices the protosulphuret of iron, recommended as a good antidote by M. Mialhe; and declares 1. That it quite destroys the poisonous properties of the sublimate, if taken in a sufficient dose immediately. 2. It is inefficacious if not given within ten minutes. 3. Although a more complete antidote than albumen, if given instantly, in almost every case it could not be procured until the latter had already began to produce its beneficial effects.

LEAD.

We shall confine ourselves here to a brief abstract of Dr. Christison's

researches upon the action which water and acids, under different circumstances, exerts upon metallic lead.

1. The Action of Air and Pure Water.-Lead exposed to the air, especially when moist, becomes tarnished by the deposit of a thin layer of carbonate of lead. Distilled water, deprived of air by ebullition, has no action on lead. If the water contain its usual gases, the surface of the metal becomes white and dull, and if it continues to have access to the air, copious white matter floats on the water or falls to the bottom. This, a carbonate of lead, forms with great rapidity. In twenty months 120 grains have been obtained from one ounce of lead kept in 24 ounces of distilled water. During all this, a minute quantity of lead is dissolved. Distilled water, therefore, for economical use, should not be kept in contact with lead.

2. Action of Solutions of Neutral Salts.-These impair the corrosive power of water, enabling us to employ lead for various economical purposes. The degree of preservative power varies much in different salts. Arseniate soda possesses it perfectly in the proportion of a 12,000th part. Phosphate of soda and hydriodate of potash are nearly effectual in the proportion of a 30,000th. Acetate of soda is only imperfectly so in 100th. Muriate of soda is a preservative in 2000th part, and sulphate lime in a 4000th. Lead, exposed for a few weeks to a solution of the protecting salt, acquires a film, after which even distilled water possesses no power over it. The protecting power depends upon the acid, not on the base of the salt, those salts possessing most preservative power, whose acids form with the lead insoluble salts. No lead can ever be detected in even weak preservative solutions.

"The general result of these experiments appears to be, that neutral salts in various, and for the most part minute, proportions, retard or prevent the corrosive action of water on lead-allowing the carbonate to deposit itself slowly, and to adhere with such firmness to the lead as not to be afterwards removeable by moderate agitation-adding subsequently to this crust other salts of lead, the acids of which are derived from the neutral salts in solution-and thus at length forming a permanent skreen, through which the action of the water cannot any longer be carried on."

3. Action of Natural Waters on Lead.-Lambe stated erroneously that Rain or Snow Water does not corrode lead. Collected in its pure state in the country, it acts nearly as powerfully upon any leaden gutter or receptacle as distilled water would do; and even in towns, where the presence of some preservative salt may cause a protective incrustation of carbonate of lead, this may become dissolved by the water, if any acid emanations, from manufactories, &c. exist in the neighbourhood. From the presence of muriates and sulphates, Spring Waters usually exert little or no action upon lead, although many examples are upon record in which, owing to the salts they contained being but of a very feebly protecting character, colic and other symptoms of lead-poisoning have resulted from their employment; and Dr. Lambe, amidst many valuable observations, erroneously comes to the conclusion, that all spring water acts thus prejudicially

upon lead. This action of the water upon lead often occurs when it is kept constantly in contact with it, as in cisterns, (manifesting its action especially on the lids of these when of lead,) perhaps for months, while by merely passing over the metal it would have produced no effect upon it. Too pure spring water may thus often have this property of acting upon lead corrected by allowing it to remain in contact with the leaden receptacles for some months before it is drawn off, so that it may deposit a protecting crust of carbonate; or by filling the cisterns, &c. during the same period, with a solution containing phosphate of soda. All risk is avoided by a recent patent process for lining and covering pipes with a thin coating of tin.

4. Action of Acidulous Fluids on Lead and its Oxide.-The effect of carbonic acid is not well ascertained. Water feebly acidulated with sulphuric acid acts much less rapidly on lead than when pure, while hydrochloric acid slightly favours the solvent power. Acetic acid, even when much diluted, dissolves metallic lead, provided its oxidation be effected by due exposure to the air. Citric acts more slowly, and Tartaric still more so. These vegetable acids act much more vigorously on the Protoxide of Lead, while the presence of air is not then required. In consequence of this action of the vegetable acids, articles of food are often rendered poisonous, as e. g. milk, wine, cyder, when brought in contact with it. Lead is now abandoned in the manufacture of cyder-apparatus in this country; but the adulteration of this drink in France with lead gave rise very recently to the production of colic. The metal is also much used there for the correction of the acidity of inferior wines.

HYDROCYANIC ACID.

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The great increase of cases of poisoning by this substance of late invests it with great importance. The tests of its presence are its odour, the salts of copper, salts of iron, and nitrate of silver. The odour is a very delicate test, and, according to Orfila, is perceptible when no re-agent is delicate known some enough to detect it. Dr. Christison doubts this, and has persons insensible of any smell, even in a specimen which was tolerably strong. Hence, when the odour is resorted to as a test, it ought to be tried by several." Sulphate of Copper and a little potash form a greenish precipitate with prussic acid, which becomes nearly white on the addition of hydrochloric acid. Lassaigne states this will act on poison dissolved in 20,000 parts of water. This is a far inferior test to the salts of the mixed peroxide and protoxide of Iron, which, on the addition of a little sulphuric acid, give a deep Prussian blue colour. Common green vitriol answers very well. Nitrate of Silver is a very delicate test-the cyanide of silver being insoluble in any but boiling nitric acid, by which it is decomposed, forming nitrate of silver, and giving out prussic acid. Or, if the precipitate be dried and heated, it gives out cyanogen gas, known by its beautiful rose-coloured flame. MM. Leuret and Lassaigne and Orfila have each devised processes for detecting prussic acid in mixed fluids. Orfila protests against the conclusions which have sometimes been drawn as to the NEW SERIES, NO. II.-I.

I I

presence of this substance without the production of cyanogen gas, leaving the case as imperfect as if in testing for poisoning by arsenic the metal was not produced. He also demands whether the detection of the poison in the vomits, alimentary canal, or liver of a person supposed to have died poisoned, is sufficient to prove poisoning to have occurred. He replies it is not, for-1. It has been occasionally known to be developed in some of the secretions in persons in a state of health or even a diseased condition. 2. It has not been proved that this acid may not be generated during the process of putrefaction. He admits this last observation is of little practical value.

Action and Symptoms.-Dr. Christison has endeavoured, in repeating Magendie's experiments with concentrated acid, to mark the periods of the commencing operation of the poison, and when death occurs. He says―

"I remarked that a single drop, weighing scarce + gr. dropped into the mouth of a rabbit, killed it in 83 seconds, and began to act in 63 seconds-that 3 drops weighing gr. in like manner killed a strong cat in 30 seconds and began to act in 10,-that another was affected by the same dose in 5 and died in 40 seconds, -that 4 drops weighing 1 gr. did not affect a rabbit for 20 seconds, but killed it in 10 more, and that 25 grs. corresponding with 14 oz. medicinal acid, began to act on a rabbit as soon as it was poured into its mouth, and killed it outright in 10 seconds at farthest."

Magendie has killed animals apparently instantly, and Dr. Thomson in 2 seconds. Mr. Blake declares all experiments representing the action of the poison to have begun before 10 seconds are fallacious, as he could never succeed in inducing action in less time even by injecting 30 minims into the femoral veins. But, as Dr. Christison well remarks, negative results cannot outweigh careful positive observation. In the rapid cases death took place just as tetanic symptoms, which prevail in slower cases, were commencing. Diluted acid produces the same effect when the dose is large enough. When it is smaller the animal may suffer from giddiness, insensibility, or convulsions from half an hour to a whole day. The acid acts on the brain and on the spine, producing the combination of coma and tetanus. There are few morbid appearances beyond turgidity of the cerebral vessels, and a distension of the heart and large vessels by black blood. There is difference in the statements of different observers, as to whether the irritability of the heart is exhausted or not. All animals, high or low in the scale of the creation, are destroyed by it, and much in the same manner. It is not believed to be a cumulative poison. In man, large doses extinguish life in a few seconds, or at all events in a few minutes; but if the individual survives 40 minutes he usually recovers. The fixing the period when the poison begins to act, is often a very important point in medico-legal investigations; and some very recent cases, observed by Dr. Letheby and others, would seem to show that more actions may be performed after taking large doses prior to the occurrence of death than was heretofore believed possible. In some of these, however, the exact quantity taken is a mere matter of uncertain inference and conjecture. The fixing the smallest fatal dose is important. Seven epileptics were killed in a Parisian hospital by the administration of gr. of pure acid to each, and as several did not die for 45 minutes, a less dose would probably not be fatal.

The peculiar appearance of the eye some have laid so much stress upon is thus commented upon.

"It appears that even long after death the eye, as in Hufeland's case, has a peculiar and staring expression, so as to render it difficult to believe that the individual is really dead: and this has been considered by Dr. Paris as so remarkable, as even alone to supply decisive evidence of poisoning by hydrocyanic acid.' But the accuracy of his opinion may be questioned. The appearance is indeed very general in cases of poisoning with preparations containing hydrocyanic acid. But it is not a constant appearance; for it was not observed in the seven Parisian epileptics. Neither is it peculiar; for death from carbonic acid has the same effect. I have remarked it six hours after death in a woman who died of cholera; and it has been observed in cases of death during the epileptic paroxysm.”

Treatment. This is too often hopeless on account of the rapidity of action of large and dangerous doses. The recommendation of emetics and enemata in these cases by Orfila is unintelligible. The necessity of arousing the depressed powers of the system suggested the employment of ammonia; but the experiments of Orfila tend to show this is only useful when instantly inhaled (1 part ammonia 12 water) and not swallowed. The remedy originated however with Mr. Murray in 1822. In the same year, too, Rianz proposed the inhalation of Chlorine, and Orfila has saved dogs when dying, by causing them to inspire water impregnated with a fourth of its volume of chlorine. Cold Affusion is another important means of arousing the failing powers. The coldest water should be procured, and poured upon the head and spinal column; keeping a bladder filled with ice also to the head, Mr. Banks has published a case (Ed. Journ. vol. 48), in which recovery followed the use of this means. Orfila seems to regard venesection only as proper during the ulterior treatment of the case; but others, in experiments upon animals, have found the opening the jugular vein a powerful means of relieving the engorged condition of the right side of the heart, and thus restoring its action.

"Few observations have hitherto been made on the chemical antidotes for hydrocyanic acid, or those substances which render it innoxious by converting it into an insoluble compound. It is plain that several probable antidotes of this kind exist. But toxicologists have been apparently deterred from trying them by the fearful rapidity with which the poison acts, and the consequent improbability that in practice such an antidote can be administered in time. It has lately been shown, however, by Messrs. Smith of this city, that the effects of a fatal dose may be warded off by the timely administration of the re-agents necessary for converting the acid into Prussian Blue. They found that if a solution of carbonate of potash, followed by a solution of the mixed sulphates of iron, be given to animals very soon after the administration of 30 drops of the Edinburgh medicinal acid, containing 3 per cent. real acid, recovery in general takes place, and sometimes little inconvenience seems to be sustained. The solutions they used were one of 144 gr. carb. pot. in 23 water, and another composed of 3j. sulph. protox. iron, together with 3ij. of the same salt converted into sulph. of sesquioxide by means of sulphuric and nitric acids in the usual way. About 52 minims of each solution will remove the whole acid contained in 100 gr. of Ed. medicinal acid; but for certainty, three or four times as much should be used-which may be done with perfect safety."

We need not say more in commendation of the two standard works whence we have borrowed so largely, save to repeat what a more particular

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