MINERAL POISONS.
Under this head is included the greater proportion of those substances which are employed as the instruments of crime; for they are generally of easy access, require but little preparation, and are so destructive in small doses, and, at the same time, so little disgusting in flavour, as to furnish the assassin with the sure and secret means of destruction. Fortunately, however, for the ends of justice, such agents are pre-eminently the objects of successful analysis. In treating of the history of the individual substances derived from thiskingdom, we shall consider, 1st. theirexternal characters, such as form, colour, odour, taste, specific gravity; 2d. theirchemical composition, and habitudes; 3d.the tests by which their presence may be recognised;4th. the symptoms which they occasion;5th. their physiological action;6th. their different modes and forms of application;7th. the lesions of structure they occasion;8th. the phenomena presented on dissection.
The greekword Αρσενικον was employed byDioscorides, and other writers of that period, to denote a particular mineral of a reddish colour, whichAristotlehad already described by the name of σανδαρακη,[214]and his discipleTheophrastus, by that of αρρενικον. It was employed by the ancients both as a pigment and as a medicine, and appears to have been a compound of Sulphur, and a peculiar metal, to which the name ofArsenicis now exclusively applied. At what period this metal was first discovered seems very doubtful; and although a process for obtaining it is described in the Pharmacopœia ofSchroeder, published in 1649, yet its peculiar nature was examined, for the first time byBrandt, in 1733.
The metal, Arsenic, is distinguished by the following properties, viz.
It has a bluish-grey colour, not unlike that of steel, and a considerable lustre; its texture is grained, and sometimes scaly; its hardness not very considerable, but its fragility is so great that it falls to pieces under a moderate blow of the hammer, and admits of being easily reduced to a very fine powder; according toBergmanits specific gravity is 8·31. When cold, it emits no sensible odour, but if heated, it yields a strongalliaceous, or garlic-like smell, which is to be considered as the most characteristic of its properties. Its point of fusion is unknown, for it is the most volatile of all the metals, and sublimes, before it melts, at the temperature of 540° Fah., and if the process be conducted slowly in close vessels, the metallic sublimate will assume atetrahedral[215]form of crystallization; if the air be admitted, and the temperature still farther raised, it will burn with an obscure bluish flame.
Arsenic is extremely susceptible of oxidation, and, by mere exposure to the air, shortly loses its metallic lustre; and yet it may be kept under the surface ofcoldwater, for any length of time without exhibiting the signs of oxidation, or solution; a covering of this fluid, or of alcohol, is therefore considered as affording the best means of preserving the metal in a state of integrity.
Arsenic is capable of combining with two proportions of oxygen, and of forming two definite compounds, which we shall hereafter consider under the title ofArseniousandArsenicacids. The substance described by some authors as theblack oxideof this metal would seem to be an indefinite mixture of the metal itself, and the arsenious acid.
Arsenic does not appear to possess any deleterious properties, but it is almost impossible to reduce the metal to powder, so as to adapt it for exhibition without its becoming oxidized.M. Renaulttherefore, in order to decide the question, had recourse to its alloys; and he found thatMispickel(an alloy of Arsenic and Iron), when given to the extent even of two drachms, scarcely produced any effect; a result which very satisfactorily accords with the conclusion drawn byBayen, in his work on Tin, and which proves that the arsenic contained in that metal, need not excite the least alarm, since it exists in a metallic state. We have upon another occasion[216]observed, that the vapours characterised by an alliaceous odour are probably less noxious than the arsenical fumes which are inodorous; and that the little injury experienced by workmen who solder silver filligree with an arsenical alloy, may probably depend upon the deoxidized state of its fumes.
This is justly considered as the most fatal of all mineral poisons, and is the one more frequently selected than any other, as the instrument of assassination and suicide; while its numerous applications in medicine and the arts, by making it an article of general and indiscriminate sale, have rendered it an accidental as well as criminal source of suffering and death.
It is seldom prepared by the chemist, since it exists in a native state, and is moreover procured abundantly and economically, during the extraction of theother metals from their ores.[217]In the commercial world the substance is still known by the name ofWhite Arsenic; and continues to be expressed in popular language, by the simple termArsenic.
It generally occurs in the form of white compact masses, opaque on their exterior surface; transparent, and presenting a vitrified aspect in the interior. Its taste is acrid and corrosive, but not to a degree corresponding with its virulence.Specific gravity3·7. When reduced to powder it bears a strong resemblance to refined sugar, for which it has sometimes been fatally mistaken, and with which it has been often mingled for criminal purposes. At the temperature of 383°Fah.it is volatilized, and is capable of crystallizing in tetrahedrons with truncated angles, or rather in octohedrons; by a strong heat, in close vessels, it is vitrified and becomes pellucid, and acquires the specific gravity 5·000[218]; but when exposed to the air, it shortly returns to its former appearance.In the state of vapour it is quite inodorous, although the contrary is positively asserted in several chemical works of high authority, and it is stated to be characterised by a smell like that of garlic; the fact is, that thealliaceous or garlic-like smell is wholly confined to metallic arsenic in a state of vapour; and whenever the arseniousacid seems to yield such an odour, we may very confidently conclude that its decomposition has taken place, and that it has been reduced to itsmetallicstate. Such a reduction will generally happen when it is projected upon ignited charcoal, or when heated in contact with those metallic bodies which readily unite with oxygen, such asAntimony,Zinc, &c. It is stated byOrfilaand other writers, that if it be projected upon heated copper the alliaceous odour is evolved. This assertion is undoubtedly true, but the fact requires to be explained with more precision, or we may fall into an important error respecting it. The author has shewn by several experiments, already published in hisPharmacologia,[219]that the phenomenon takes place only when the copper is in a state of ignition, at which temperature its affinity for oxygen enables it to reduce the arsenious acid, and consequently to develope the metallic odour. We have ascertained by repeated experiments that if a few grains of arsenious acid be heated on a plate of copper, by means of a spirit lamp or the blow-pipe, no odour is perceptible; for, in this case, the whole of the acid will be dissipated before the copper can acquire a temperature sufficiently exalted to deoxidize, and reduce it. If the arsenious acid be heated on a plate of zinc, the smell will not be evolved until the latter metal is in the state of fusion. If, instead of the foregoing surfaces, we employ in our experiments those of gold, silver, or platina, no alliaceous smell whatever is produced, at any temperature, provided every source of fallacy be carefully avoided; but it deserves particular notice, that the author has found the flame of the spirit lamp to be in itself, capable of decomposing the arsenious acid, inconsequence, it is presumed, of the operation of its hydrogen;[220]a fact which is very likely to betray the experimenter, as in the first instance it did the author, into a belief that the arsenious acid does actually yield the odour in question.
The term Arseniousacidwas first bestowed upon this substance byFourcroy, since it was found to possess many of the essential habitudes of an acid; as for instance, that of combining with the pure alkalies to saturation. It dissolves in water; but, according toKlaproth, although it requires for its solution 400 parts of that fluid, at the temperature of 60°Fah.it requires not more than 13, at 212°; and it moreover appears that if 100 parts of water be boiled on the arsenious acid, and suffered to cool, it will retain 3 grains in solution, and deposit the remainder in crystals. This fact shews the great importance of employing boiling water in every chemical examination of substances supposed to contain arsenic. It proves also that a fatal dose of the poisonous mineral may be very easily administered in any watery vehicle, a fact which was denied on the trial ofOgilvyandNairne[221]byDr. James Scott, who deposed that “Arsenic would not dissolve in warm water, but almost instantly subside to the bottom of the vessel,” although, at the same time, he acknowledged that “if it were put into tea with milk and sugar, and stirred about, itmightbe suspended long enough to kill those who should drink the potion.” It is soluble in alcohol, and in fixed oils, the former taking uptwo per cent. By the addition of an alkali, anarseniteof great solubility will result, and a solution of extreme virulence may be thus effected. Withlime-waterarsenious acid produces a white precipitate ofarsenite of lime, but which is soluble in an excess of the acid. Withmagnesiait also forms a very soluble, and extremely active,arsenite.
Hahnemann, in his work on Arsenic, proposes a classification of its effects founded on their relative duration and violence, and which it is our intention to adopt on the present occasion, without any other alteration than that of reversing the order of the classes.
Poisoning by Arsenic may accordingly be considered as admitting of three degrees of intensity, viz. 1st. Where the case, although attended with dangerous symptoms, does not terminate fatally. 2d. Where death does not follow until after a lapse of twenty-four hours. 3d. Where death takes place within twenty-four hours after the exhibition of the poison.
1.Symptoms of the first and lowest degree.In the slighter cases in which the operation of arsenic is recorded as producing poisonous effects, the symptoms were, uneasiness of the præcordia; cholics; thickness, redness, and stiffness of the palpebræ; soreness of the gums; ptyalism; itching over the surface of the body, sometimes attended with a slight eruption; restlessness; cough; head-ache; strangury, andardor urinæ. Where the dose of poison has been somewhat greater, although still inadequate to the destruction of life, violent vomiting is commonly the first symptom, preceded in some instances with a sense of heat and dryness in the fauces; in suchcases where the vomiting has very shortly succeeded the ingestion of the Arsenic, and the stomach has at the same time been filled with food, the patient may owe his escape to the poison being discharged before it had time to act.Morgagnirelates a case of poisoning at an Italian feast, where the dessert was intentionally sprinkled with Arsenic instead of flour; those who had previously eaten but little speedily perished, but those who had eaten heartily were saved by vomiting. Although in this degree of poisoning the life of the patient may be spared, yet a variety ofconsecutivesymptoms may continue to harrass him for a longer or shorter period, such as indigestion, debility, partial paralysis, and epilepsy. The history[222]of the cases ofMr. Turnerand his family, of Chancery lane, for the poisoning of whomEliza Fenningwas executed, will afford a striking illustration of this fact. The hair of the head has also beenobserved, in some cases, to fall off.Dr. Maleis also of opinion that the long protracted and injudicious use of this mineral, as a medicine, will induce exostosis and caries of the bones.
2.Symptoms of the second degree.In this case where the patient lives two or three days, or perhaps longer, as in the case ofWilliam Mitchellabove described (p.190), the earliest symptoms are heat and thirst, or vomiting, and inexpressible uneasiness and anxiety, the former of which is less frequently observed than the two latter; purging, or sometimes a repeated but ineffectual desire to go to stool; wandering pains; quick, but feeble pulse; head-ache; distended and painful abdomen; priapism; towards the close of the scene the patient often becomes more tranquil and is inclined to sleep, although, in some instances,the pains, attended with convulsions, continue to the latest moments. In general, death takes place suddenly. In cases where the effects of the poison are not immediately fatal, we must necessarily expect the occurrence of many phenomena, indicative of the re-action of the system, and which will be better illustrated by a reference to the history of individual cases, such for instance, as those ofWilliam Mitchell, (p.190) andMr. Blandy, (Appendix) than by any general description which can be given in this place. It is also worthy remark that in such cases, from the length of time, there will necessarily occur a greater opportunity for the co-operation of other contingent causes, whether they be connected with previously existing diseases, or the action of remedies; and the intelligent practitioner will not neglect to appreciate their influence in modifying the character of each particular case. There are besides symptoms highly characteristic when they do arise, but which are of comparatively rare occurrence, such as the ulcerated condition of the fundament, as in the case ofMr. Blandy, and the inflamed eyes and state of the mucous membranes, in that ofWilliam Mitchell.
3.Symptoms of the third and highest degree.Soon after a large dose of Arsenic has been swallowed, an austere taste, and a sense of heat and constriction of the pharynx and œsophagus are perceived; in a short period excruciating pains in the stomach and bowels, accompanied with vomiting of the most violent character, the matter voided being generally of a brown colour, and not unfrequently mixed with blood; with these symptoms are conjoined an inexpressible anxiety about the præcordia, and frequent faintings; the stomach at the same time acquires such a high degree of irritability, as to reject the mildest fluids.The alvine discharges now become frequent and painful, and consist of dark and extremely fœtid matter, frequently mixed with blood. The thirst is unquenchable, and the heat of the surface becomes extreme. The pulse is small, frequent, and irregular; palpitations of the heart, violent cramps in the legs, sometimes a painful strangury and bloody micturition ensue. The powers of life begin to fail, respiration becomes laborious, cold sweats break out, hiccup occurs, the countenance assumes a singular character of anxiety and distress, a livid circle appears around the eyes, the pulse is imperceptible, the body swells and sometimes becomes covered with a species of miliary eruption, or with dark purple spots. In some cases convulsions ensue, but delirium, or loss of reason, is very rarely the consequence of this species of poisoning, and the unfortunate sufferer is conscious until a few moments before the termination of his existence. Such are the general symptoms, but it is rare to see them all united in the same case; sometimes the greater part of them are absent.M. Chaussierreports the case of a robust middle aged man, who swallowed a quantity of arsenious acid in large lumps, and died without discovering any other symptom than slight syncope; other cases are related where only vomiting and purging[223]have been observed, and the symptoms have been mistaken for those ofcholera spontanea.
The practitioner is therefore not to withhold his belief in a case of poisoning, on account of the absence of several of those symptoms which are enumerated in systematic works on Toxicology.
It is only by the study of individual cases, that hecan learn to appreciate the just value of those pathognomonic combinations which afford the least exceptionable evidence upon such occasions.
It has been proved by numerous experiments that the life of an animal may be destroyed with equal certainty by arsenious acid, whether it beinternallyadministered, orexternallyapplied to abraded surfaces, sores, or bleeding wounds; and it has been, moreover, shewn, that in either instance the symptoms will be analogous, except in the latter case they will often be more rapid in their course.
Lionardo di Capoarelates the case of a child killed by the violent vomiting and purging arising from a slight wound made in the head by a comb, wet with oil in which arsenic had been infused for the purpose of killing vermin; and we have numerous instances on record, where the application of arsenical cerates and ointments has been followed by violent and dangerous symptoms. We also learn from the different historians of the Plague of London, that the arsenical amulets which were worn, as preservatives, on that occasion, were sometimes attended with deleterious consequences;Crato[224]observed an ulcer of the breast produced by them.Verzascha, violent pains and syncope.Diemerbroeck,[225]and Dr.Hodges,[226]death itself. Amongst the foreign authors who have related cases of poisoning by the external application of arsenic we may mentionDesgranges,[227]who records the history of a chambermaid, poisoned by havingrubbed her head with an arsenical ointment for the purpose of destroying vermin; andRoux,[228]who confessed to have killed a girl of eighteen by an application of the “Pâte Arsenicale” to a cancerous breast.M. Renaulthas also given us the results of his experiments upon Arsenic when applied externally to dogs; when the skin was sound, it excited a pustular eruption without inflammation; but, when the skin was broken, more serious effects followed, both general and local, and in some cases death.[229]. In an experiment performed by Mr.Hunter, and Mr.Home, in which arsenic was applied to a wound in a dog, the animal died in twenty-four hours, and the stomach was found to be considerably inflamed. Mr.Brodierepeated the experiment several times, always with the precaution of tying a bandage, to prevent the animal licking the wound; the results were uniform; the stomach was, in every case, not only more violently, but more rapidly, inflamed, than when the poison had been internally administered, and it even preceded any inflammatory appearance of the wound. In theJournal de Medecine, the following case is related of a woman who was killed by her husband having insinuated powdered arsenic into the vagina,[230]at the moment of enjoying the conjugalrites. “A woman atLeneux, departement de l’Ourthe, aged forty, having died after a short illness, attended with considerable tumefaction of the genital parts, uterine hemorrhage, vomiting, and purging, the body was inspected by order of the mayor, when the surgeons reported that they found the vulva in a state of gangrene, the abdomen much distended with air, and the intestines inflamed and gangrenous. The culprit was arrested, convicted, and executed.” In theActs of the Society of Copenhagen, a similar crime stands recorded, and which was also committed by a peasant; in this latter case, although some small pieces of arsenic were found within the vagina, yet some doubts arose respecting the possibility of such a species of poisoning, and the magistrates accordingly consulted the College of Medicine of Copenhagen, who decided the question in the affirmative, having first instituted a series of experiments upon horses.
Death may also be produced by the introduction of arsenic into the rectum; it is said that SirThomas Overbury, after the failure of the various poisons[231]that were administered to him, was at last despatched by an arsenical glyster.
With respect to the quantity of arsenic required for the production of such effects it is difficult to offer a decided opinion, as its operation must in every case be liable to contingency; but a very few grains are in general amply sufficient.
Physiological action of Arsenious Acid.
It had long been supposed that arsenic occasioned death by inflaming the stomach; but Mr.Brodie[232]has very satisfactorily proved, that its influence arises from its being absorbed, and that it must be regarded as avitalrather than as achemicalagent, and as having a constitutional, not a local mode of operation.
In the first place, he has in many instances found the inflammation of the stomach so slight,[233]that on a superficial examination it might have been easily overlooked; and in most of his experiments with arsenic, death took place in too short a period to be considered as the mere effect of inflammation. In the next place we have already shewn that in whatever manner the poison is applied, whetherexternallyto a wound, orinternally, to the alimentary canal, the same inflammatory appearance will be visible in the stomach; a fact which can only be explained by admitting that the poison is absorbed, and that it acts upon these organs through the medium of the circulation; it acts at the same time upon the brain, and heart, but with different degrees of force in different cases; so that it is sometimes difficult to ascertain which of these organs is the first to fail in its functions. According then to these experiments and observations, inflammation of the alimentary canal is not to be considered as the general cause of death in poisoning by arsenic; and yet cases will occur, where the local affectionmay prove fatal, the animal having survived the effects produced on the organs more immediately subservient to life, as the brain and heart. Mr.Henry Earlecommunicated to Mr.Brodiea case highly illustrative of this fact, which occurred in St. Bartholomew’s hospital; a woman had taken arsenic, and having recovered from the alarming symptoms which first occurred, died at the end of four or five days, when upon dissection, there appeared extensive ulcerations of the stomach and bowels. This then was evidently a case of “Consecutive” poisoning.
The dissertation ofDr. Jaeger, to which we have before alluded, contains the result of a very extensive series of experiments, in illustration of the physiological action of the arsenic. He diligently examined its effects upon all classes of organized beings, as well of the vegetable as of the animal kingdoms. The general conclusions which he has drawn from his experiments on vegetables are, that arsenic is in most cases a rapidly destructive poison to them, with the exception perhaps of a few of the simplest forms of existence;[234]and that their death was induced by means of the gradual absorption and distribution of the poison by the vessels and cellular membrane, so that the parts died in succession, as the particles of the poison reached them.Dr. Jaegaralso found that arsenic was a quick and destructive poison to animals, and that death was preceded, in every instance, from the infusory animalcula up to man, by inordinate motions; and that the secretion was most remarkably increased from the mucous membranes.His experiments also proved that arsenic exerted the most powerful effects, when it was injected into the veins, or applied to a bleeding wound; next, when it was introduced into the stomach; but less so, when injected into the large intestines, which have fewer absorbing vessels.[235]
The examination of the bodies of persons poisoned by arsenic, must not be expected to furnish constant and uniform results, since they will be found to vary very considerably in different cases. As we have already considered the value of accelerated and retarded putrefaction, as an indication of poisoning, we shall at once proceed to the description of the morbid phenomena which are presented by the internal organs on dissection. The stomach and intestines are the parts in which we may expect to find the most decided marks of the ravages from arsenic. The former viscus will be found more or less inflamed; in some instances, the dusky redness will appear in patches, interspersed with points and streaks of a brighter hue; the villous coat of the stomach will be almost always softened, and, as if macerated, can be easily rubbed off in pieces with the fingers from the coats beneath; actual ulceration and sloughing are, according to the observations ofMr. Brodie, never found unless where death is late in taking place, in which case extensive ulceration of all the coats, amounting to actual perforation, may be expected to happen. This statement agrees with the observation ofRuysch, who says that where there had been sufficient time, he found the stomach ulcerated in thosewho had died from the effects of arsenic, but that if death supervened earlier, he only discovered bloody points, distant from each other, throughout the viscus. On the subject of sloughs upon such occasions, our enlightened author remarks, that anatomists have often been betrayed into a fallacy respecting their true nature; on opening the stomach of a dog which had taken a large quantity of arsenic,Mr. Brodieobserved a dark brown spot about an inch in diameter, having all the appearance of a slough; on a closer examination, however, it appeared that this spot was no other than a very thin layer of coagulated blood, of a dark colour, and adhering very firmly to the surface of the mucous membrane, and having a few particles of arsenic entangled in it. He states that he has at several times observed a similar appearance but occupying a less extent of surface; and he informs us that, in the Hunterian museum, there is a human stomach, which was preserved for the sake of exhibiting what was considered a slough, produced by the action of arsenic; but that, on examining the preparation carefully, the dark coloured spot was discovered to be simply a layer of coagulated blood, similar to that before described.Dr. BaillieandDr. Yellolyhave found the stomach thickened in several parts, as if by coaguable lymph, and in one case the thickening of the coats was the only alteration of structure observable; andM. Renaultrelates a case, where the arsenic was taken in large pieces, which produced no other effect than slight syncope on the approach of death; and that, upon opening the body, the arsenic was found in the state it was swallowed, but there was neither inflammation nor erosion of the stomach. Where the arsenic has been swallowed in substance, it will be generally found attached to themembrane of the stomach by a peculiar glairy fluid; if the poison should have been administered in solution, the same organic lesions will be discovered, but the presence of the arsenic in the stomach can scarcely be expected, although the contents of the viscus, as well as all the matter ejected from the body before death, must be carefully examined by a chemical process to be hereafter described. The duodenum, like the stomach, generally affords evidence of the same inflamed and disorganized condition; and the whole track of the intestinal canal will be found more or less affected, according to the quantity of arsenic that has been administered, the period of time which has elapsed before death, and other circumstances which have been already enumerated as capable of modifying the action of this destructive substance. It however deserves notice that in many cases the rectum appears to be more affected than the other intestines;Dr. Male[236]states, that he has frequently found it abraded and ulcerated, and even more inflamed than the stomach itself;Mr. Brodielikewise observed, in his physiological experiments upon this substance, that the inflammation produced by it was greatest in the stomach and the rectum.Dr. Bailliehas recorded several instances where a mortification of the rectum followed as an effect of this poison; and in the case ofMr. Blandy, detailed in theAppendix, p. 237,Dr. Addingtonstated, that the extremity of the rectum was extremely painful, and surrounded by excoriations and ulcers.
Mr. Brodiehas stated, in the paper to which we have so often alluded, that the organic lesions occasioned by arsenic are confined to the stomach andintestines,and that henever found any appearance of inflammation in the pharynx or œsophagus. This statement, however, is at variance with a great weight of authority; we have ourselves witnessed cases in which dissection has demonstrated extensive inflammation in these parts; indeed it would appear, that this poison acts more particularly on the mucous membranes; and it is reasonable therefore to conclude, that those with which it comes in actual contact will not escape its virulence. The serous membranes which receive less blood, and more lymphatics, are necessarily less affected by it.
In the case ofWilliam Mitchell, as related atpage188, the patient complained of soreness of the eyes, heat and uneasiness in the mouth and throat; and the surgeon observed the membrane on the palate and uvula to be detached; so in that, again, ofMr. Blandy,Dr. Addingtonfound on inspection that “his tongue was swelled, and his throat inflamed and excoriated; his lips, especially the upper one, dry and rough, and having angry pimples on them; the inside of his nostrils in the same condition, and his eyes a little blood shot.” (Append.l. c.). In the celebrated Scotch case ofOglivyandNairne(see page184)Peter Meik, surgeon of Alyth, deposed, that, upon inspecting the body four or five days afterwards, he found “the tongue swelled beyond its natural size, and cleaving to the roof of the mouth, which he had never observed after a natural death.” Many more instances might be adduced to shew that the fauces, pharynx, and œsophagus are very frequently inflamed and excoriated by the ingestion of arsenic. Mortification of the pudenda[237]has beensaid to be an effect peculiar to the action of arsenic; certain it is that in males, priapism is sometimes a symptom of this poison, and the penis is found swollen and red after death, as was observed in the case ofWilliam Mitchell(p.190). The scrotum was also enlarged and of a dark colour. We have been long aware that persons exposed to the fumes of arsenic, or accustomed to handle any of its preparations, have been liable to a peculiar affection of these parts, but we have generally explained the fact by supposing that the poison had in such cases, been locally applied to them. The author has been lately informed by his friendMr. Parkes, that several persons in his establishment were thus attacked, during the time they were engaged in preparing an arsenical solution, as a dye for the calico printers; and we have stated on another occasion,[238]that the smelters and workmen engaged in the copper works, and tin burning houses of Cornwall, are occasionally affected with a cancerous disease in the scrotum, somewhat similar to that which infests chimney sweepers. It is also singular thatStahl, in describing the putrescent tendency in the bodies of those who die from this poison, mentions in particular the gangrenous appearances of the parts of generation. The other organs of the body do not exhibit any particular appearances, which ought to be regarded as characteristic of death by arsenic; we must necessarily expect to find the traces of morbid action, especially where life has been unusually protracted; and the serous effusions found in the body ofWilliam Mitchell, are to be referred to such a cause.
Mr. Brodiehas stated that, in animals killed by arsenic, the blood is usually found fluid in the heartand vessels after death; this agrees with the observation ofRuysch, who says that he never found the blood coagulated in the human body, after death occasioned by this poison; as well as with that ofDr. Jaeger, who describes the cavities of the heart, especially of the right side, to be, upon these occasions, turgid with blood, but that coagula are very seldom found in them.
A question, of a very considerable importance in a forensic point of view, has arisen with respect to the means, by which we may distinguish whether arsenic, found in the body, had been introduced into the digestive canal during life, or after death. In general, this fact is placed beyond suspicion by the testimony of those to whose care the body had been confided, previous to dissection. But cases have occurred where a poisonous substance has been introduced into the rectum of a dead body, with the diabolical intention of accusing an innocent person of having been the perpetrator of the poisoning. We are not aware of any English case of this kind, butM. Orfilastates that in the proceedings of the Criminal Court of Stockholm such a case stands recorded. Fortunately there would not be much difficulty in detecting the crime; for were the arsenic applied to the rectum after death, the change of structure would not extend beyond the part in actual contact with it, but would be distinctly separated from the rest of the intestineby a well defined line of demarcation, which can never happen where the arsenic has acted during life; for, in this latter case, the transition from the diseased to the healthy structure will be gradual, and the limits of each imperceptible.
Before we conclude our observations upon the organic lesions occasioned by arsenic, we may cautionthe anatomist not to confound the red or violet colour which characterises inflammation, with that which has been occasionally found to arise from the ingestion of certain coloured drinks. The following case related byFoderé, and cited byOrfila, may serve to illustrate this subject. “A private person of Châlons sur-Marne, who was in a state of convalescence from a disease under which he had laboured, took a slight purgative, and died very shortly afterwards. He was believed to have been poisoned through some error in the medicine, and in order to be assured of this, the body was opened. The œsophagus and stomach were found to be red, and in certain places livid, as if in a state of gangrene. These appearances at first induced a belief that the deceased had died from poison; butM. Varnier, a physician of Châlons, concluded from the appearances, that death was the consequence of the disease, and that the apparent convalescence was only an insidious respite. It became therefore necessary to give some account of the state of the œsophagus and stomach; and having learnt that the deceased was in the habit of using astrong infusion of red poppies, the idea immediately struck him that the extraordinary colour of these organs might possibly depend on this infusion. In order to determine the validity of this explanation, he caused a dog to swallow, several times, a similar infusion; when upon opening its body, he discovered that the corresponding parts of this animal had assumed the same colour as had been observed in the stomach of the deceased above-mentioned, and, moreover, that this violet red colour was so firmly fixed that it resisted the action of repeated washings.”Tincture of Cardamomswill also be liable to occasion a coloured appearance in thestomach, as described inMr. Stanley’scase of the death of a woman by a dose of opium.[239]
This poison may either be submitted to the judicial physician for examination, in its solid form, or in that of solution; and in this latter state it may be mixed with various alimentary substances, whose presence will necessarily embarrass the inexperienced operator, and multiply the apparent difficulties of his task. It becomes our duty, therefore, upon this occasion, to enter very fully and minutely into the history of the various processes, which have been proposed for the solution of the important problem under consideration; to appreciate the relative value of each, and to point out the sources of fallacy and failure, to which they are severally exposed.
Such a review of the subject would, moreover, appear to be essentially necessary at the present period, since the evidence, lately delivered on an extraordinary trial,[240]has, to a certain extent, very unjustly shaken the public confidence in the tests of chemistry. We shall therefore proceed to consider the processes which are calculated to lead to the detection ofArsenic, in relation to the different circumstances under which it may be presented for investigation, viz. 1, In a solid form; 2, In the simple state of solution; and 3, In the state of combination with various alimentary substances.
1.The Arsenic is in a solid form.This is the most simple case which can occur, and the experiments bywhich its presence is to be demonstrated, will constitute the basis of the inquiry, which we shall be hereafter called upon to institute, for the detection of the same substance under other circumstances of mixture and combination.
The order of succession to be observed in the different experiments which we are about to describe, must, in a great measure, be regulated by the quantity of the material to be submitted to examination. Should it be small, it will be prudent to reserve the process of metallization, by which a considerable loss must necessarily arise, until we have submitted it to the various re-agents which are calculated to afford indications of its nature. If, on the contrary, the quantity of the substance exceed two or three grains, it will be adviseable to proceed in its examination by the following processes, reserving a portion for future analysis.
A.By its reduction to a metallic state.Mix a portion of the suspected substance in powder, with three times its weight ofblack flux[241]; put the mixture into a thin glass tube, about eight inches in length, and a quarter of an inch in diameter, and which is hermetically sealed[242]at one end. Should any of thepowder adhere to the sides of the tube it must be carefully brushed off with a feather, so that the inner surface of its upper part may be perfectly clean and dry. The closed end of the tube, by way of security, may be thinly coated with a mixture of pipe-clay and sand[243]; but this operation is not absolutely necessary. The open extremity of the tube is to be loosely plugged with a piece of paper. The coated end must now be submitted to the action of heat, by placing it in a chaffing dish of red hot coals, for ten minutes, or a quarter of an hour; when, if our supposition respecting the nature of the substance has been correct, metallic arsenic will sublime, and be found lining the upper part of the tube with a brilliant metallic crust. The glass tube, when cold, may be separated from its sealed end by the action of a file, which will enable us to collect and examine the metallic sublimate. If a portion of this brilliant matter be laid on heated iron, it will indicate its nature by exhaling in dense fumes, having a powerful smell of garlic. Another portion should be reserved for future experiments.
This method of detecting the presence ofArsenious acidhas been considered the most decisive, and indeed the only unexceptionable one, but of this we shall speak hereafter; at present we have only to observe, that it is very far from being a minute test,forDr. Bostock[244]confesses that where less thanthree-fourths of a grainwere used, he could not say that the metallic crust was clearly perceptible; andDr. Black[245]appears to have considered thatone grainwas the smallest quantity which could be distinctly recognised by such a process.
Chemists were formerly[246]in the habit of at once projecting any substance, supposed to beArsenic, on some burning body, in order to develope the alliaceous odour; we have accidentally stumbled upon an instance of this kind, in the fourth volume of theLondon Medical and Physical Journal, which may serve as an illustration; it is a case communicated byF. Thackeray, Esq.of a child poisoned by arsenic, in which the author says, “the inner surface of the stomach was very red, and was studded throughout with a white powder, whichwhen exposed to the flame of a candle, yielded fumes, and a garlic odour was emitted, proving it was arsenic; of which there can be no doubt, as the girl afterwards confessed that she had given arsenic to the infant.”
After the facts we have offered with respect to thealliaceous odourof arsenical fumes, it is only necessary to state, in this place, that such a test, when conducted in the manner just related, must be considered as extremely equivocal.
Another method of identifying “White Arsenic,” by metallization, is to form at the moment of its reduction, an alloy with copper, which may be easily effected in the following manner: Mix the suspected powder withblack flux, as in the former experiment, and place the mixture between two polished plates of copper; bind them tightly together by iron wire, and expose them to a low red heat; if the included substance contain arsenic, a silvery white stain will be left on the surface of the copper, which is an alloy of the two metals. In this, as in the former experiment, the presence of analkaliin the flux is essential, since it forms immediately anarsenite of potass, and thereby fixes the arsenious acid, and prevents it from being volatilized before the temperature is sufficiently high to enable the charcoal to decompose it; we therefore differ withDr. Bostock, when he states thatpowdered charcoalmay be substituted for theblack flux.
The property ofwhiteningcopper is regarded as a very satisfactory test of the presence of arsenic; butDr. Bostockhas pointed out some circumstances attending it, which we shall here enumerate for the instruction and satisfaction of the less experienced operator. “It may be necessary,” says he, “in the firstplace, to describe the phenomena that take place when copper is heated according to the process that is described above, but without the addition of the arsenic. Two copper disks, of nearly an inch and a half in diameter, scoured bright with sand, had one grain of powdered charcoal, made into a paste with oil, placed between them; they were bound together with an iron wire, and then kept red hot for ten minutes. When they were withdrawn from the fire, the metal was found to have lost its former appearance, and to have acquired the dull white colour of lead or zinc; the insides of the disks were found to present the same whitish appearance, except on the spot where the charcoal was placed, a small part of which still remained unconsumed. As the disks cooled the whitish matter which covered them began to separate, and fly off with some force, in the form of small scales, leaving a clean surface of the proper copper colour. The charcoal was rubbed off, and the surface below it was found smooth and polished; it had acquired a light colour, resembling that of brass; and, near the centre, there was a small spot, which approached to a steel grey. This appearance still continued, after it had been rubbed with fine sand. The above description,” concludesDr. Bostock, “will probably impress the Society[247]with the same idea, that, I confess, it gave to myself, that if I had performed this experiment upon a substance, which had been suspected to contain arsenic, and I had not been aware of the appearance that I was to meet with, I should have conceived that I had detected its presence. Upon repeating the process, in precisely a similar manner, except that one grain ofarsenic was added to the charcoal, the oxidation of the copper took place as before, and a small part of the charcoal remained unconsumed; but upon rubbing it, the white stain was perfectly visible. However, when these disks were compared with those in which the former experiment had been made, the difference between them seemed more indegreethan inkind; so that I should not choose to decide upon the presence of arsenic, as indicated by this test, unless the result were more obvious than we can ever expect to find it, where the quantity of arsenic is so small. It may be proper to observe, that copper, whitened in this manner by arsenic, is very subject to tarnish; in three days I could with difficulty distinguish which of the disks had been employed in these two experiments.”
In connection with the different modes of identifying arsenic by metallization, we may relate a test lately proposed byMr. A. Thomson, which, as a collateral proof, merits some attention. “Into any solution, in which arsenic may be suspected, stir a moderate quantity of charcoal powder; allow it to settle; then pour off the clear supernatant liquor, or filter the mixture; and when the powder which remains on the filter is dry, sprinkle some of it on a red hot poker; if the solution contain arsenic, the odour of garlic will be rendered sensible. This effect becomes more obvious if a few grains of dry sub-carbonate of potass be added to the dried charcoal powder.”[248]
If, instead ofBlack flux, or charcoal, the arsenious acid be heated in a glass tube with quick-lime, a sudden ignition will take place, when one part of thewhite arsenic will be metallized, and the other farther acidified, so as to produce anarseniate of lime; in this case, therefore, a certain portion of the arsenious acid is robbed of its oxygen to complete the acidification of the rest.
The habitudes of arsenious acid with thenitrates, as first observed byKunkel, deserve also some attention. If they be heated together, the former will be oxygenated at the expense of the nitric acid, nitrous acid vapour will be disengaged, and anarseniate of potassremain. The forensic chemist may avail himself of these facts, and obtain a very useful test, which may be applied in the following manner.[249]Take a grain or two of the suspected powder, and mix it with double the quantity ofNitrate of Potass; introduce this mixture in a small glass tube, and apply the flame of a spirit lamp under the powder; when, if it contain arsenic, the nitrate will be decomposed, nitric oxide and nitrous acid be evolved in a gaseous form, and an arseniate of potass remain.
The acid vapour may be easily recognised by its colour and smell, or by placing a piece of moistened litmus paper within the tube. Thearseniatemay be identified by thebrick-redprecipitate, produced in its solution, byNitrateof Silver. So small is the quantity of arsenic required for this latter mode of trial, thatMr. Smithson, in a late paper, observes “that a drop of a solution of arsenious acid in water, which at the height of 54·5Fah.contains not more than 1/80th of the acid, put to nitrate of potass in a platina spoon, and fused, affords a considerable quantity ofarseniateof silver. Hence when no solid particleof oxide of arsenic can be obtained, the presence of it may be established by infusing in water the matters which contain it.”[250]