CL. II. ASTRINGENT POISONS.

Lead.

This metal appears to have been known in the earliest ages; and is mentioned several times by Moses.[[346]] It has a bluish-white colour; is very brilliant when first cut with a knife, but soon tarnishes by exposure to air; when rubbed violently, it emits a peculiar smell; it is malleable and ductile, but possesses very little tenacity. It is scarcely sonorous; being the softest of all the metals, it yields readily to the hammer. Its specific gravity is 11·35; it melts at 612°. According to the experiments of Dr. Thomson,[[347]] it is susceptible of four degrees of oxidation, presenting us with four distinct, and well defined oxides, viz.

Yellow(protoxide)contains of lead91·5oxygen8·5
Yellow(deutoxide)contains of lead90·5oxygen9·5
Red(tritoxide)contains of lead88·oxygen12·
Brown(peroxide)contains of lead80·oxygen20·

Lead, in its metallic state, does not exert any action on the living system; but, when oxidized, or in the state of salt, its virulence is very considerable, producing a train of symptoms, so peculiar to itself, as to justify our placing its preparations in a separate class, under the title of astringent poisons, as explained at page [202].

Metallic lead, although per se inert, may occasion deleterious effects when introduced into the stomach, in consequence of its meeting with acids in the primæ viæ; from the same cause, liquids which are liable to become in any degree acidulous, if kept in leaden vessels, may be productive of much danger to those who drink them. Pure water, provided the air be excluded, does not appear to exert any sensible action upon this metal; but the combined influence of these agents converts the lead into a carbonate: a fact which is at once exemplified by the white line which is so constantly visible at the surface of the water preserved in leaden vessels. So well acquainted were the ancients with this fact, that we find frequent allusions in their works to the dangerous property of leaden utensils. Vitruvius[[348]] published a very strong remonstrance against leaden pipes, when used for the purpose of conveying water; and Galen cautions us continually, not to employ water that has flowed through pipes of this metal; since he had observed that the sediment of such water, (υποσταθμη του τουιουτου υδατος) rendered such as swallowed it, δυσεντερικους, subject to disorders in the intestines.

Dr. Lambe, to whom we are indebted for an important work[[349]] upon this subject, states, that there is a great diversity in the corrosive powers of different waters; in some places the use of leaden pumps has been in part discontinued, from the expense entailed upon the proprietors by the perpetual want of repair;[[350]] and if any acidity be communicated to the water, from the accidental intrusion of decayed leaves or other vegetable matter, its power of dissolving this metal will be increased to a very dangerous extent. The noted colic of Amsterdam is said by Tronchin, who has written a history of the epidemic, to have been occasioned by leaves falling and putrefying in leaden cisterns, filled with rain water. Van Swieten[[351]] has also related an instance of a whole family who were afflicted with colic from a similar cause; and Dr. Lambe[[352]] entertains no doubt but that the very striking case recorded in the Medical Commentaries,[[353]] proceeded more from some foulness in the cistern than from the solvent power of the water; in this instance, the officers of a packet vessel used water out of a leaden cistern; the men also drank the same water, except that the latter had been kept in wood; the consequence was, that all the officers were seized with colic, while the men remained healthy. Sir George Baker has furnished the following striking illustration of the subject. “The most remarkable case that now occurs to my memory, is that of Lord Ashburnham’s family, in Sussex; to which, spring water was supplied from a considerable distance in leaden pipes. In consequence, his lordship’s servants were every year tormented with colic, and some of them died. An eminent physician of Battle, who corresponded with me on the subject, sent up some gallons of that water, which were analysed by Dr. Higgins, who reported that the water had contained more than the common quantity of carbonic acid; and that he found in it lead in solution, which he attributed to the carbonic acid. In consequence of this representation, Lord Ashburnham substituted wooden for leaden pipes; and from that time his family have experienced no particular complaints in their bowels.”

But the most extensive and dangerous source of poisoning by lead, is the presence of this metal in various wines, and acescent drinks, and meats, and which may arise either from accident or design. A knowledge of the different avenues, through which this poison may gain admittance into the human body, is therefore of great importance to the forensic physician, and we shall accordingly proceed to the investigation of the subject.

That certain wines were occasionally liable to produce endemic colics, is a fact which has been long known; although the disease was universally ascribed to a mistaken origin, until the publication of the elaborate researches[[354]] of Sir George Baker, into the cause of the Devonshire colic; which, like the same disease observed in other countries, was attributed to the acidity of the liquor so abundantly drunk[[355]] in these districts. This celebrated physician, however, was early led to entertain doubts with respect to the truth of this doctrine: “when I consider,” says he, “that this colic of Devonshire is precisely the same disease as that which is the specific effect of all saturnine preparations, and that there is not the least analogy between the juice of apples and the poison of lead, it seems to me very improbable that two causes, bearing so little relation to one another, should make such similar impressions on the human body.” The investigation of the subject completely established the justness of these views; and no doubt remains, but that the endemic colic, which harrassed the cyder drinkers in Devonshire for some years, was the effect of saturnine impregnation, derived from the lead used in the construction of the apple mills and cyder presses; and in some cases, from the pernicious practice of introducing a leaden weight into the cask, or even racking the cyder into leaden cisterns, where the liquor fretted too much, and was thereby in danger of becoming acetous. Sir G. Baker also states that the custom of boiling the must in vessels capped with lead, affords another source of saturnine impregnation; and he informs us that, a few years ago, this very practice produced the Devonshire colic in the county of Kent. Some cyder, which had been made in a gentleman’s family, being thought too sour, was boiled with honey in a brewing vessel, capped with lead. All, who drank this liquor, were seized with this disease; some more, others less violently; one of the servants died very soon in convulsions: several others were cruelly tortured a long time. The master of the family, notwithstanding all the assistance which art could give him, never recovered his health; but died miserably, after having for nearly three years languished under a tedious and incurable malady. Dr. Lambe observes, that the saturnine colic is not endemial in Devonshire, or the other cyder countries, during the whole year, but is confined to those months when the liquor is still new, crude, and the fermentation incomplete. When the liquor becomes fine, the noxious matter in a great measure separates, and is carried to the bottom of the vessel, as the feculencies subside. Tartar is generated during the vinous fermentation, the acid of which, uniting with the lead, forms a salt, scarcely, if at all, soluble in water; and hence the purification which the liquor receives. But although this new salt is insoluble in water, it is otherwise in regard to vinegar; for this acid dissolves a small quantity, and forms a triple compound, an aceto-tartrate of lead;[[356]] and since no cyder, or perhaps wine, is wholly destitute of vinegar, it necessarily follows that if the liquor has been once contaminated during the first stages of fermentation, it is impossible for it ever to become entirely pure, except by processes which would render it unfit for drinking.[[357]] It has very lately been discovered, that Gallic acid and tannin are capable of combining with lead in solution, and of forming a perfectly insoluble substance, which falls to the bottom of the cask; hence all liquors which have been kept in oak casks, for a certain time, must be freed from lead. This explains a fact with respect to the effect of new rum in the West Indies, of some importance. This spirit, when newly distilled, is found to contain traces of lead, derived from the leaden rims of the coppers, and the leaden worm, used for its condensation; but, by keeping about twelve months in oaken casks, it loses its deleterious properties, and no longer exhibits any traces of this metal.[[358]]

Another source, from which acescent liquids may contract saturnine impregnation, is afforded by the metallic glazing of earthenware[[359]]; that for instance of the common cream coloured ware is composed of an oxide of lead,[[360]] and is accordingly easily acted upon by vinegar, and saline compounds; jars and pots of this description ought therefore never to be used for preserving pickles, jellies of fruits, marmalade, and similar conserves. For the same reason, Sir George Baker protests against the custom of baking fruit tarts in such ware.[[361]] Stone ware is glazed with muriate of soda, and is therefore not liable to such an objection.[[362]]

The custom which prevails in some parts of England of keeping milk in leaden vessels, is extremely improper; Dr. Darwin[[363]] has illustrated this subject by the following case; “A delicate young girl, the daughter of a dairy farmer, who kept his milk in leaden cisterns, used to wipe off the cream from the edges of the lead, and frequently, as she was fond of cream, licked it from her finger. She was seized with the saturnine colic, and semi-paralytic wrists, and sunk from general debility.” We are informed by Mr. Parkes,[[364]] that in Lancashire the dairies are furnished with milk-pans made of lead; and that when he expostulated with some individuals on the danger of this practice, he was told that leaden milk pans throw up the cream much better than vessels of any other kind.

There is, says Dr. Darwin, a bad custom in almost all families, and public houses, of washing out their wine bottles by putting a handful of shot corns into them, and by shaking them about forcibly to detach the super-tartrate of potass from their sides; that such a practice may occasionally give origin to serious consequences, will become evident by the relation of the following case.[[365]] “A gentleman who had never in his life experienced a day’s illness, and who was constantly in the habit of drinking half a bottle of Madeira after his dinner, was taken ill three hours after dinner with a serious pain in the stomach and violent colic, which gradually yielded within twelve hours to the remedies prescribed by his medical attendant. The day following he drank the remainder of the same bottle of wine which was left the preceding day, and within two hours afterwards he was again seized with the most violent pains, head-ache, shiverings, and great pain over the whole body. His apothecary becoming suspicious that the wine he had drunk might be the cause of the disease, ordered the bottle, from which it had been decanted, to be brought to him, with a view that he might examine the dregs, if any were left. The bottle happening to slip out of the hand of the servant, disclosed a row of shot, wedged forcibly into the angular bent-up circumference of it. On examining the beads of shot, they crumbled into dust, the outer crust (defended by a coat of black lead with which the shot is glazed) being alone left unacted on, whilst the remainder of the metal was dissolved. The wine, therefore, had become contaminated with lead, and perhaps arsenic, for in order to form shot the former metal is alloyed with the latter.”[[366]]

But we have, hitherto, only directed the reader’s attention to the different sources from which wine, and acescent liquors, may accidentally derive saturnine impregnation. We have now to state that such liquors have, in different ages and countries, been fraudulently adulterated with lead. It appears to have been early discovered, that wines which have become morbidly acescent may be corrected by the addition of lead; whence, in those countries where Rhenish, Moselle, and other similar wines are drunk, the saturnine colic has been endemic. The celebrated colic which raged in the province of Poitou, towards the end of the sixteenth, and in the beginning of the seventeenth century, was evidently the effect of such adulteration.[[367]] We find that, in the year 1487, there was a Recessus Imperii promulgated at Rotenberg; and, in the year 1498, at Friberg; which was enacted, in the year 1500, at Tubingen; and, in the year 1508, at Frankfort; and, in the year 1577, in the same place. By which decrees it was made a capital crime to adulterate wines with litharge, or to use bismuth in the fumigation of them; it having been, at several periods, represented to the Emperors, that great mischief had accrued from such adulterations; and that they had been the cause of insuperable and mortal diseases. It should seem, that these laws were not carried into strict execution; and, indeed, that in the latter end of the seventeenth century, it was hardly known in Germany that such laws existed. In consequence of which, an epidemic colic arose, which was at length traced to the effects of lead in the wines.[[368]] A representation of this fact having been made to the Duke of Wirtemberg, it was ordained a capital crime to mix litharge with wine, or even to sell it in the shops, by a decree, bearing date March 10, 1696. But, notwithstanding the severity of this law, we are informed by Zeller, that in the year 1705, the same dangerous experiments were repeated in the circle of Zwaabe, with a view to correct the acidity of the weaker wines. Bishop Watson[[369]] informs us that, in the year 1750, the Farmers general in France being astonished at the great quantities de vin gaté which were brought into Paris, in order to be made into vinegar, redoubled their researches to find out the cause of the great increase in that article; for nearly thirty thousand hogsheads had been annually brought in for a few years preceding the year 1750, whereas the quantity annually brought in forty years before, did not exceed 1200 hogsheads. They discovered that several wine merchants, assuming the name of vinegar merchants, bought these sour wines, and afterwards, by means of litharge, rendered them potable, and sold them as genuine wines.[[370]] Dr. Warren[[371]] has related the cases of thirty-two persons in the Duke of Newcastle’s family, who were residing in Hanover in June, 1752, and were seized with the Colica Pictonum, after having used, as their common drink, a small white wine that has been adulterated with lead. Nor has the English vintner been less regardless of the health of his employer. In a popular work on wine making by Graham,[[372]] which has gone through six editions, and may therefore be supposed to have done some mischief, we find under the article of vintner’s secrets, the following receipts.—

“To hinder wine from turning,

“Put a pound of melted lead, in fair water, into a cask, pretty warm, and stop it close.”

“To soften green wine,

“Put in a little vinegar, wherein litharge has been well steeped, and boil some honey to draw out the wax. Strain it through a cloth, and put a quart of it into a tierce: and this will mend it, in summer especially.”

We have already alluded to the presence of lead[[373]] in the new rum of the West Indies, as the cause of the disease known in that country by the name of the dry belly-ache; it remains for us to state that the excise officers frequently avail themselves of the peculiar power of the sub-acetate of lead to precipitate colouring matter, in order to remove from seized Holland gin, the colour which it obtains by being long kept in the tubs in which it is smuggled over. A practice which it is said renders the gin liable to gripe.

According to the important experiments of Proust,[[374]] it appears, that if lead be associated with tin, it will be incapable of furnishing to acids any saturnine impregnation. The following are the interesting conclusions at which this philosopher has arrived, viz.

“That the tinning, which contains even so large a proportion as an equal part of lead, cannot be dangerous; since it is sufficient that the lead should be combined with tin, in order to prevent it from being dissolved, either in lemon juice, or vinegar, the two acids most to be feared. The tin, being more oxidable than the lead, dissolves exclusively in these acids, and prevents the second from being attacked. The lead cannot appropriate to itself an atom of oxygen, but the tin would carry it off in an instant.”

Sugar of Lead—Saccharum Saturni—Cerussa Acetata—Plumbi Super-acetas.

This salt of lead, to whose presence the numerous accidental maladies above enumerated are to be chiefly attributed, occurs in commerce in the form of irregular masses resembling lumps of sugar, being an aggregation of acicular four-sided prisms terminated by dihedral summits; its taste is sweet and astringent. It is soluble in 25 parts of water, hot, or cold; when common spring water, however, is employed for such a purpose, a white precipitate occurs from the presence of a certain proportion of sulphates and carbonates.

When this salt is exposed to the action of heat, it undergoes aqueous fusion, then dries, and at length is decomposed, leaving a globule of metallic lead, mixed with the yellow protoxide, and an acid product of a fetid smell. This decomposition is similar to that which vegetable substances undergo when heated for some time. The quantity of metallic lead, thus obtained, will be more considerable if the salt has been previously mixed with charcoal, and particularly if it be submitted for a long time to the action of a powerful heat. The strong sulphuric acid of commerce, when poured upon sugar of lead in powder, decomposes it with effervescence, and disengages vapours of acetic acid.

This must be considered as an active preparation, and may, when administered in doses of a few drachms, speedily occasion death. At the same time, like other poisons, it may by judicious administration, become a valuable remedy. See Pharmacologia, art. Plumbi Super-acetas.

In consequence of the sweet taste of this salt, children have been induced to swallow it.

Goulard’s Extract. Liquor Plumbi Sub-acetatis.

This liquor is a saturated solution of the sub-acetate of lead. Spring water, from the salts which it contains, produces with it a very milky and turbid appearance; and even when distilled, in consequence of the carbonic acid diffused through it, it will occasion precipitation. It is principally used as an external application to diminish inflammation, an effect which it probably produces by paralysing the nerves of the part. Cases have occurred where this lotion has been accidentally swallowed, and the usual symptoms of saturnine poisoning have supervened. How far its external application may be capable of occasioning mischief, will form a subject of inquiry under the consideration of the physiological action of the preparations of lead.

White Lead. Sub-Carbonate of Lead. Cerusse.

The substance, known in commercial language by the name of White Lead, has received at different times, very various appellations, in consequence of the fluctuating opinions which have prevailed respecting its composition. Thus it has been successively styled a sub-acetate, an oxide, and a sub-carbonate; of which the last is unquestionably the correct name. In the large way it is prepared by exposing sheets of metallic lead to the fumes of vinegar. The sub-carbonate so produced appears as a white, brittle, and scaly substance, on the surface of the lead; which is scraped off, and afterwards ground in mills fitted for the purpose. Formerly, it was ground dry, and the workmen suffered severely from the operation; it is now ground in water, and the sub-carbonate is afterwards dried in earthen pans placed in stoves, heated by means of flues; still, however, persons employed in grinding white lead, as well as painters[[375]] who are constantly using it, occasionally suffer severely, from the want of cleanliness in not washing their hands before eating, by which some of the white lead is introduced into the stomach with their food.

Litharge. Semi-vitrified Oxide of Lead.

This is a yellow protoxide of lead, which has been melted, and left to crystallize by cooling. It is in the form of small reddish, or yellowish scales, which are brilliant and vitrified. Its character is so peculiar that it cannot easily be mistaken. It is employed for various purposes in the arts, and is the saturnine preparation more usually selected for the purpose of removing acidity from wines, as above related.

When treated with a muriatic salt, and submitted to a high temperature, a muriate of lead is produced, of a bright yellow colour, the brilliancy of which may be much heightened by grinding it as usual with oil. In this state it forms the pigment known by the name of Turner’s yellow, or patent yellow.[[376]] It is very poisonous.

Red Lead. Minium.

This red oxide of lead is easily distinguished by its colour, weight, and the facility with which it yields metallic lead, when heated with carbonaceous matter. Common red wafers, which derive their colour from this oxide, afford a striking illustration of this fact, for if burnt in a candle, globules of metallic lead will be observed to flow from them. It is poisonous; and we have already alluded to a case where Gloucester cheese[[377]] occasioned deleterious effects, in consequence of its adulteration with red lead. (p. [277]) It is destructive also to inferior animals, apparently in very small quantities; red wafers prove poisonous to birds who may pick them up; and the same paste is sold for the purpose of destroying beetles, in which it succeeds very effectually. Since it is employed as a pigment, it may on many occasions prove an accidental cause of poisoning; there is indeed one very common and dangerous source, mentioned by Sir George Baker,[[378]] which deserves to be particularized in this place, viz. the practice of painting toys with red lead, and other poisonous substances; children, observes this distinguished physician, are apt to carry every object which gives them delight to their mouths, the painting of toys, therefore, with poisonous colours, is a practice which ought to be abolished, and is the more open to censure, as it is of no real utility.

Symptoms of poisoning by the different preparations of Lead.

The effects of this poison will vary considerably according to the quantity swallowed, and the circumstances under which it is taken. We shall, therefore, first consider its operation, in doses sufficiently large to occasion at once violent effects; and then describe its agency as an accumulative poison, where it is introduced into the system gradually, and in small quantities, so as to act slowly and imperceptibly, and to lay the foundation of irreparable mischief, before any alarm is occasioned.

1. Symptoms which follow a large dose. Where a salt of lead has been taken in a considerable dose, the patient soon experiences excruciating pains in the abdomen, accompanied with sickness and vomiting; the colic increases to a violent degree, but admits of temporary alleviation by pressure, a circumstance which at once distinguishes it from the effects of corrosive poison. Although it is necessary to observe, that inflammatory symptoms may afterwards occur, where the dose has been very considerable, and the consequences direct and speedy.

The patient describes the pain as if produced by a boring instrument, and the abdominal muscles become knotted, and sometimes painfully retracted with all the contents of the abdomen towards the spine.[[379]] The sphincter muscles of the bladder and anus are always affected; sometimes strangury and tenesmus are the consequences; at other times, a total incapacity of making any water at all, and so great a contraction of the sphincter ani that a clyster can hardly be introduced. After suffering these torments for a period of an indefinite duration, delirium and cold sweats may supervene, and the patient die in convulsions. If, however, the treatment has been prompt and judicious, and the quantity of poison has not been excessive, he may recover from its immediate effects, and live to testify the severity of the consecutive phenomena. A most inveterate constipation of the bowels will continue for a considerable period, and there will be an occasional recurrence of colic; at length a peculiar species of palsy will supervene in the upper extremities, especially affecting the muscles of the fore arm, and wrist,[[380]] Citois has given us a striking description of this stage of the saturnine disease. “Per vicos, veluti larvæ, aut arte progredientes statuæ, pallidi, squalidi, macilenti conspiciuntur, manibus incurvis et suo pondere pendulis, nec nisi arte ad os et cæteras supernas partes sublatis, ac pedibus non suis, sed crurum muculis, ad ridiculum, ni miserandum, incessum compositis, voce clangosa et strepera.” It does not appear that the train of symptoms above described has ever been excited by any other external cause than the one here assigned. Whenever we meet with colic, attended with paralytic symptoms of the extremities, we may at once conclude that it has arisen from the influence of lead.

The disease has been described by authors under the name of the colic of Poitou,[[381]] or colica Pictonum,[[382]] from the circumstance of its having raged with such epidemic fury in that province, in consequence of the adulteration of its wines with lead. It is also mentioned as the painter’s colic, since this class of artists is very commonly visited by the disease, in consequence of the white lead contained in their pigments. At the Lead Hills, it is known to the miners, under the provincial name of milreek; and in Derbyshire, under that of belland.[[383]]

2. Symptoms arising from the introduction of lead into the system, by small and repeated doses.

The effects produced upon various artists by the imperceptible operation of lead, sufficiently shew the power which this metal possesses of accumulating in the human system, and it is probable, says Sir George Baker, that from an observation of such slow, but certain effects of lead, the French and Italians derived the hint of preparing their celebrated poisons, called “Poudres de Succession;”[[384]] the basis of which has been supposed to have been some preparation of that mineral. Zeller mentions a certain chemical operator, near the confines of Bohemia, who, after having diligently applied himself to the composition of poisons, did, by means of lead, combined with some more volatile and corrosive substance, prepare a most slow poison, which given to dogs and other animals, had the power of destroying them, without producing any violent symptoms, after several weeks, or even months.[[385]]

The following-curious case,[[386]] communicated by Dr. Wall, of Worcester to Sir George Baker, will serve to illustrate the present subject, and to shew that lead may gain admittance into the human body, unobserved, and even unsuspected. “A gentleman of Worcester was the father of a numerous offspring, having had one and twenty children, of whom eight died young, and thirteen survived their parents. During their infancy, and indeed until they had quitted the place of their usual residence, they were all remarkably unhealthy; being particularly subject to disorders of the stomach and bowels. The father, during many years, was paralytic; the mother, for as long a time, subject to colics and bilious obstructions. She died at last of an obstinate jaundice. This disease had been several times removed by the use of the Bath water; but it always came on again soon after her return to Worcester; and at last eluded every method and medicine which was tried. After the death of these parents, the family sold the house which they had so long inhabited. The purchaser found it necessary to repair the pump. This was made of lead; and, upon examination, was found to be so corroded, that several perforations were observed in the cylinder, in which the bucket plays; and the cistern in the upper part was reduced to the thinness of common brown paper, and was full of holes like a sieve. The waters of this town are remarkably hard. It is then more than probable that the water of this pump, thus impregnated with lead, occasioned the unhealthiness of the family who drank it. I have been just informed by the plumber,” adds Dr. Wall, “that he had several times repaired the pump in question; and that he had done so not more than three or four years before the gentleman’s death; when he found it nearly in the same state as it has been described; so that the corrosion was effected in a short time; and consequently the water must have been very strongly impregnated with the noxious quality of the metal.”

Organic lesions discovered on dissection.

The reports of the dissection of those who have been destroyed by saturnine poisons are far from being satisfactory. Where the person has died from the primary effects of a large dose of the acetate of lead, the stomach has betrayed a state of inflammation, similar to that which results from the action of a corrosive poison; black points and spots, from venous extravasation, have been also observed in the interior of this viscus; M. Orfila states that he has seen in the stomach of animals who have taken a large dose of the acetate of lead, and have not vomited, a membraneous lining tolerably thick, of an ash colour, easily detaching in small pieces; the origin of which appeared to be owing to the decomposition of a part of the acetate of lead by the mucous, bilious, and other fluids, contained in this viscus. The mucous membrane lying under this lining, was of a dark grey colour throughout its whole thickness, and appeared to have exercised the same action on the acetate of lead. The case is very different in those who have died from the slow action of this metal; all anatomists agree in reporting, that in the colica pictonum, the digestive canal exhibits no vestige of inflammation;[[387]] but the diameter of the large intestines, especially that of the colon, is generally contracted; thus displaying the effects of that operation, which is supposed to be characteristic of the compounds of lead, and which has bestowed upon them the peculiar designation of astringent poisons. Foderé states that the mesentery and its glands; and the lacteal and lymphatic vessels, are inflamed and obstructed, and the thoracic duct almost obliterated; the liver, spleen, pancreas, and lungs often inflamed, tumefied and purulent, and even the heart shrivelled;[[388]] and the whole body, in consequence of the constriction of the chyliferous vessels, in a state of complete marasmus. Upon this passage Orfila makes the following observation. “We are under the necessity of declaring, that almost all these signs are wanting in the majority of the cases of simple colic of lead, terminated by death.” Fourcroy, in a note to his translation of Ramazzini, “De Morbis Artificum,” observes that the intestines have, in these cases, been discovered distended by air, parched, and slightly altered in colour; and that in the larger ones, balls of dry, dark coloured, excrementitious matter, have been found.

Physiological action of Lead Poisons.

The preparations of lead seem to act upon the nervous system, destroying its energy, and thereby producing paralysis. Whether this is effected through the medium of the circulation, or whether they produce their effects without being absorbed, appears to us to be a question which has not hitherto received a satisfactory answer. It must, however, be admitted that they act upon the alimentary canal, by coming into contact with its nerves; and in some cases, where the dose of the acetate has been large, it may have produced death by the local injury which it inflicted. Dr. Lambe observes upon this subject, that “certain facts render it probable that lead does not operate entirely through the medium of the circulation, nor by nervous sympathy; but also topically, affecting the part to which it is applied more than the other parts of the body.” This latter position is clearly established by the beneficial effects occasioned by the topical application of lead to inflamed surfaces; nor can any doubt exist as to the fact of such applications having produced local paralysis. There is a paper in the third volume of the Medical Transactions by Dr. Reynolds, in which the case of a gentleman is detailed, who brought on a temporary paralysis of the sphincter ani, by freely using Goulard’s lotion for the cure of piles. Foreign writers have also maintained that saturnine applications have frequently occasioned impotence; for further information upon this subject the reader may refer to Istitutione di Medicina Forens: di Tortosa, vol. 1, p. 58; also Fritze Compend: sopra i Malat. Vener. p. 189; and Monteggia Annotat. sopra i Mali Venerei, p. 36. Sir George Baker states that he has some reason to doubt, whether litharge, the common basis of our plasters, when used for the purpose of dressing issues, has not, in certain irritable constitutions, produced some of the ordinary effects of saturnine preparations taken internally. There have been instances of children thrown into convulsions, by cerusse, sprinkled on excoriated parts. Zeller quotes, on the authority of Molingius, a remarkable instance of the pernicious effects of litharge, externally applied.[[389]] Sir George Baker met with a most violent and obstinate colic, which seemed to have been occasioned by some litharge, mixed in a cataplasm, and applied to the vagina, with a view to allay a troublesome itching; and he says that he was informed by Dr. Petit that Goulard’s poultice applied for some time to a patient’s knee, in St. George’s hospital, occasioned violent pain in the bowels, which did not cease until the poultice had been removed; nor are authorities deficient to prove, that the fashionable application of cerusse to the skin has been followed by obstinate colics, pains, and tremors. We have been desirous of laying before our readers the above authorities, in proof of the constitutional effects which may be occasionally produced by the external application of lead, since the fact has been questioned, and is still considered by many as involved in doubt and uncertainty. Dr. Lambe is inclined to believe, that “to the production of the saturnine colic, it is necessary that the metal should be applied immediately to the stomach and intestines.” If this hypothesis be just, he excludes nervous sympathy, as well as absorption, as a proximate cause of saturnine colic; and, consequently, no dependence can be placed on the accounts given by the above pathologists with regard to the production of such an effect by lotions and cataplasms of lead.

Of the chemical processes, by which the presence of lead may be detected.

These will necessarily vary according to the different states of combination in which it may be supposed to exist; we shall, therefore, proceed to consider the modes of establishing its presence, 1, In solution in water; wine; spirit; and oils. 2. In a state of mixture with various solids. 3. Combined with solid or liquid aliments.

1. The lead exists in some unknown state of combination in solution in water. We are greatly indebted to Dr. Lambe[[390]] for the able directions which he has afforded us for ascertaining the presence of minute portions of lead in water; and we recommend the practitioner, who may be engaged in such an investigation, to peruse his work with attention. The following are the reagents through which our analysis must be conducted.

(a) Sulphuretted hydrogen. A solution of this gas in distilled water is a very delicate test for lead, throwing down a precipitate of a very dark brown colour, approaching to black. The competency, however, of this test to the discovery of very minute quantities of lead, in certain states of combination, has been questioned by Dr. Lambe; who was enabled to detect the presence of this metal, by other methods, in water that manifested no indication with sulphuretted hydrogen. He detected it, for instance, in the precipitate occasioned in such water by the carbonate of potass or soda. In operating on these waters, he noticed the following appearances.

1. The precipitate, produced as above stated, when re-dissolved in nitric acid, formed a dark cloud with sulphuretted hydrogen.

2. Although the sulphuretted hydrogen formed no cloud, the precipitate itself became darkened by it.

3. The precipitate re-dissolved in nitric acid, (as in 1) formed, with sulphuretted hydrogen, a white cloud.

4. Sulphuretted hydrogen neither formed a cloud, nor darkened the precipitate.

5. In the cases 2, 3, 4, if the precipitate be heated to redness, in contact with an alkaline carbonate; and after dissolving out the carbonate, it be redissolved in nitric acid; then sulphuretted hydrogen will form a dark cloud with the solution. In these experiments it is necessary that the acid used to redissolve the precipitate be not in excess; if it should so happen, the excess must be saturated, before the test is applied. It is better to use so little, that some precipitate may remain undissolved. The nitric acid, used in these experiments, should be perfectly pure; and the sulphuretted hydrogen test should be recently prepared by saturating distilled water with the gas.

(b) Sulphate of soda, or potass. This test will produce a white precipitate in water, containing one hundred-thousandth of its weight of lead; and is considered by Dr. Thomson as the most unequivocal reagent of that metal which we possess. “The precipitate is a fine dense powder, which speedily falls to the bottom, and is not re-dissolved by nitric acid; no other precipitate can be confounded with it, except sulphate of baryta, and there is no chance of the presence of baryta in solution in water.”[[391]]

(c) Muriate of soda. One of the methods of analysis proposed by Dr. Lambe, consists in precipitating the lead by common salt; but as the muriate of lead is partly soluble in water, this test cannot be applied to small portions of suspected water. The precipitate must, therefore, be collected from two or three gallons, and heated to redness with twice its weight of carbonate of soda. The alkaline carbonate is then to be dissolved out, and nitric acid added, in order to saturate any superfluity; the sulphuretted hydrogen test will then produce its indication.

(d) Reduction of the metal. This is undoubtedly the most satisfactory of all the tests; and, except the trouble of collecting a large quantity of precipitate, is not embarrassed with any difficulty. The precipitate may be mixed with its own weight of alkaline carbonate, and exposed either with, or without, the addition of a small proportion of charcoal, to a heat sufficient to melt the alkali. On breaking the crucible, a small globule of lead will be found reduced at the bottom. The precipitate from about fifty gallons of water yielded Dr. Lambe about two grains of lead.

2. The lead is dissolved in wine. For the detection of this dangerous fraud, the reagent invented by Dr. Hahnemann affords a ready and convenient test. It consists of water saturated with sulphuretted hydrogen gas, and acidulated with muriatic acid;[[392]] this latter ingredient is added for the purpose of preventing the precipitation of any iron, which the wine might accidentally contain. This liquor will, if added in the proportion of one part to two of wine, produce with the smallest quantity of lead, a dark coloured, or black precipitate; which, if collected, dried, and fused before the blow-pipe on a piece of charcoal, will yield a globule of metallic lead. Or we may modify the experiment by passing a current of sulphuretted hydrogen gas through the wine, having previously acidulated it with muriatic acid, to prevent the precipitation of the iron.

A farther proof of the presence of lead in wines is the occurrence of a precipitate, on adding a solution of the sulphate of soda.

The most satisfactory proof, however, is derived by distilling off the alcohol, and calcining the residuum with charcoal, in order to obtain the metallic lead.

The quantity of lead which has been detected in sophisticated wine, may be estimated at forty grains of the metal in every fifty gallons,[[393]] but this will of course be liable to vary with the degree of acidity it was intended to correct.

3. The lead is dissolved in oils. In this case the lead may be detected by shaking, in a stopped phial, one part of the suspected oil, with two or three parts of water, impregnated with sulphuretted hydrogen. This test will announce the presence of the deleterious metal, by occasioning a dark brown, or black colour.

4. The lead is mixed with alimentary matter. M. Orfila has furnished us with the following directions for assaying the matter vomited, or that which may be found in the digestive canal, after death. “After having expressed the fluid portion through a piece of fine linen, it must be assayed by the tests, which have been already enumerated as being capable of detecting the salts of lead; and if the precipitates obtained are of a nature to induce a belief, that the fluid contains some preparation of this kind, it must be evaporated to dryness, and calcined with charcoal in a crucible; when, at the expiration of three quarters of an hour, metallic lead will be obtained. If all the experiments made on the fluid portion of the matter vomited, for the discovery of this poison, should be fruitless, the whole of the solid portions, previously dried, should then be calcined with potass and charcoal, by which means metallic lead will be obtained.”

VEGETABLE POISONS.

The poisons of which we are about to offer the physiological and chemical history, although more numerous than those which belong to the mineral kingdom, are, notwithstanding, of far less importance in a forensic point of view. With the exception of opium, and some few others, they must be considered as objects of accidental, rather than of criminal poisoning; and even with respect to the former narcotic, it may be said to afford more frequently the means of destruction to the suicide, than to the assassin.

The sensible qualities of smell, taste, and sometimes colour, which so eminently characterise deleterious plants, must necessarily render them ill calculated to favour that secresy, which constitutes the indispensable companion of crime; while their bulk, and the pharmaceutical preparation which they require, are alike inconsistent with the hope of concealment.

Thus we receive, as it were, from Nature, that protection which art can no longer supply; and the commission of crime is either prevented or discovered, in cases where the powers of chemistry would fail in its detection.

The objects which constitute the vegetable kingdom differ from every species of mineral matter, not only in their peculiar organized structure, but in the chemical arrangement of their elements; those of inorganic matter are generally combined in very simple proportions, as one and one, or one and two, &c. whereas in organized bodies, their proportions are much more complicated; and Dr. Ure observes,[[394]] that such substances derive the peculiar delicacy of their chemical equilibrium, and the consequent facility with which it may be subverted and new modelled, to the multitude of atoms grouped together in a compound; hence too, as Mr. Children[[395]] has observed, is one reason of our utter inability to reproduce even the simplest body of this class, when once its elements have been separated; it is not in the diversity of these elements, but in the manner in which they are grouped, that this peculiarity consists, for, continues the accomplished chemist last mentioned, “vegetable substances seldom contain, as essential, more than three principles—oxygen, hydrogen, and carbon, and sometimes azote. With four simple elements then, a brief alphabet for so comprehensive a history! has a bountiful Omnipotence composed the beautiful volume of the living world, where, turn to what page we may, fresh loveliness meets the eye, fresh cause of admiration and delight.”

The analysis of vegetable bodies resolves itself into two parts, each of which constitutes an equal object of interest to the forensic physician; who, it will be shewn, may occasionally derive important information from both. The first relates to the discovery of the proximate principles of a vegetable substance. The second, to that of its ultimate elements. By the proximate, or, as they are sometimes termed, the immediate principles, we mean those compound substances which exist in the living plant in a state identical with that, under which chemical processes exhibit them, and are chiefly separable by the action of different solvents. The number of these principles is considerable, as gum, starch, sugar, gluten, extractiue, tannin, oils, acid, &c. &c. By the ultimate elements, we understand those, of which the proximate are composed, as oxygen, hydrogen, carbon, and azote. In submitting a plant to destructive analysis, for the purpose of obtaining its ultimate elements, we shall derive compounds, which formed no part of the vegetable structure, and which result from a new arrangement of the elements composing it; acetic and carbonic acids, for example, are obtained by the destructive distillation of several vegetable substances, in which neither of these acids existed ready formed, but only their elements.[[396]] It may easily be imagined to what numerous fallacies such a law of composition must have given origin, in the earlier periods of chemical inquiry; and it is equally evident, that the utmost refinement of chemical science, and the most rigorous methods of analysis, will be required to enable us to deduce any satisfactory conclusion with respect to the quality of a plant, from these data. Such perfection, indeed, has not hitherto been attained, but the period is probably not far distant, when our most sanguine anticipations upon this point may be realised. We have only to trace the history of this branch of chemistry for the last century, to become satisfied of its gradual and important progress towards such an epoch, and of the improvements of which this department of vegetable analysis is farther susceptible; let us, for the sake of illustration, only compare the rude results obtained by the academicians of Paris, at about the commencement of the seventeenth century, with those of MM. Gay-Lussac and Thenard[[397]], or with those, very lately instituted in this country by Dr. Ure,[[398]] and we shall perceive that while the former of these experimentalists, by the aid of heat, were unable to form the slightest distinction between the most inert, and the most poisonous species of plants, the latter, by means of the same agent, aided by the modern doctrine of equivalent ratios, has succeeded in establishing the proportions in which the elements of each vegetable body combines; and with such accuracy, as to discriminate between substances, which bear the greatest analogy to each other; as between the varieties of sugar, and those of oil; and even between common flax, and the same substance prepared according to the improved process of Mr. Lee. This statement is sufficient to show the capability of ultimate analysis, on certain occasions, to identify vegetable bodies; but we are, at present, scarcely advanced far enough in such an investigation, to make it subservient to the detection of vegetable poisons. Nor has our knowledge with regard to proximate analysis, been less successfully advanced. The late researches of the French and German chemists have demonstrated the existence of several new alkaline bodies in the class of vegetable poisons, to which some of these plants appear to be exclusively indebted for their activity, as the poppy, hellebore, colchicum, &c.; and whose characters are so distinct and striking, as to enable the chemist to recognise their presence by appropriate re-agents. In other cases, the virulence of a plant would appear to depend upon the combination of several[[399]] proximate principles; while in some few instances there exist in the same individual vegetable, two distinct elements of activity, as illustrated by the interesting history of tobacco.

In cases of vegetable poisoning it will occasionally occur, that some remains of the plant may be collected; and seeds, portions of the fungi, and leaves, may be found in the contents of the stomach; whence a knowledge of botany becomes indispensable. This branch of science is, moreover, important to the toxicologist, as enabling him to pursue the study of plants with greater precision; for experience has shewn that there is a wonderful analogy between the structure of those plants which resemble each other in medicinal operation. Thus those which, from their dismal and dusky appearance, have been arranged under the title of Luridæ, are in general highly poisonous; they also possess a very peculiar and disagreeable smell, so that Nature has, upon this occasion, kindly given us notice of approaching danger, by means of our senses.

Of equal importance with the knowledge of the generic and specific characters, is that of their sensible qualities, and the changes which these latter undergo by pharmaceutical preparation.