1902 Encyclopedia > Poisons


POISONS. An exact definition of the word "poison" is by no means easy. There is no legal definition of what constitutes a poison, and the definitions usually proposed are apt to include either too much or too little. Generally, a poison may be defined to be a substance having an inherent deleterious property, rendering it capable of destroying life by whatever avenue it is taken into the system ; or it is a substance which when introduced into the system, or applied externally, injures health or destroys life irrespective of mechanical means or direct thermal changes. In popular language, a poison is a substance capable of destroying life when taken in small quantity ; but a substance which destroys life by mechanical means as, e.g., powerdered glass, is not speaking, a poison.

The subject of toxicology forms one of the most important branches of MEDICAL JURISPRUDENCE (q.v.). The medical jurist should be familiar with the nature and actions of poisons, the symptoms which they the produce, the circumstances which modify their working, the pathological results of their action, and the methods of combating these.

Action of Poisons.—Poisons may exert a twofold action. This may be either local, or remote, or both local and remote. The local action of a poison is usually one of corrosion, inflammation, or a direct effect upon the sensory or motor nerves. The remote actions of poisons are usually a specific character, though some writers group the remote effects of poisons under two heads, and speak of the common and the specific remote effects of a poison. The local action of a poison of the corrosive class is usually so well marked and obvious that the fact of the administration of a poison of this class is generally unmistakable. The same may be said, in a less degree, of the irritant poisons, especially the mineral irritants ; but here the symptoms sometimes so closely simulate those of natural disease as to render the recognition of the administration of poison a matter of difficulty. Hence an accurate acquaintance with the remote specific effects of the various poisons in indispensable to the medical jurist. The class of poisons which has been administered or taken will thus be suggested to his mind by the observation of the symptoms ; and not unfrequently the specific taken will be suspected. It is almost universally admitted that absorption of a poison is necessary for the production of its specific remote effects, and the old notion that a poison may kill, by its action through the nervous system, without absorption, is abandoned.

Modifying Circumstances.—The ordinary action of a poison may be greatly modified by the largeness of the dose, by the state of aggregation, admixture, or of chemical combination of the poison, by the part of membrane to which it is applied, and by the condition of the patient. Thus, for example, opium may be a poison according to the dose in which it is given ; and a dose of the drug which may be beneficial to an adult in certain states of the system may be fatal to a child, or to an adult when suffering from some forms of disease. All barium salts, again, are poisonous, except the quite in soluble sulphate. The simple cyanides, and many double cyanides, are highly poisonous ; but yellow prussiate of potash, which is a double cyanide of iron and potassium, is almost without action upon the system. The part or tissue to which a poison is applied greatly affects the activity of the poison, owing to the varying rapidity with which absorption takes place through the cutaneous, mucous, and serous surfaces, and by the other tissues of the body. Curare, an arrow poison, may be swallowed in considerable quantity without appreciate result, whilst a minute quantity of the same substance introduced into a wound is speedily fatal. Idiosyncracy has an important bearing in toxicology. Pork, mutton certain kinds of fish, more especially shell fish-called, and mushrooms have been produced all the symptoms of violent irritant poisoning, whilst other persons who have partaken of the same food at the same time have experienced no ill effects. Some persons are stated, on good authority, to be capable of taking with impunity such poisons as opium, corrosive sublimate, or arsenic, in enormous doses,—and this irrespective of habit, which is known to have such an influence in modifying the effects of some poison, notably the narcotics. A tolerance of poisons is sometimes engendered by disease, so that a poison may fail to produce its customary effect. Thus, opium is tolerated in large quantities in tetanus, and in delirium tremens ; and mercurial compounds may in some febrile affections fail to produce the usual constitutional effects of the metal. On the other hand, disease which impede the elimination of a poison may intensity its effects.

The evidence that a poison has been administered is based upon the symptoms produced, on the appearances met with in the body after death, on the analysis of articles of food and drink of excreta and ejecta, and of the organs of the body after death, and on physiological experiments made with substances extracted from the same articles. These physiological experiments are usually made upon animals, but in some cases, as for instance when aconite. Has to be searched for, the physiological experiments must be made also upon the human subject. The evidence obtained form one or more of these sources, as compared with the properties or effects of various known poisons, will enable the medical jurist to form an opinion as to the administration or non-administration of a poison.

The symptoms exhibited by the patient during life rarely fail to afford some clue to the poison taken. Persons may, however, be found dead of whose history nothing can be learned. Here post-mortem appearances, chemical analysis, and it may be, physiological experiments are all-important for the elucidation of the nature of the case.

Poisoning may be acute or chronic. The general conditions which should arouse a suspicion of acute poisoning are the sudden of serous and increasingly alarming symptoms in a person previously in good health, especially if there be pain in the region of the stomach, or, where there is complete prostration of the vital powers, a cadaveric aspect, and speedy death. In all such cases the aid of the analytical chemist must be called in either to confirm well-founded or to rebut ill-founded suspicions.

The made of treatment to be adopted in the case of poisoned persons varies greatly according to the nature of poison. The first indication, when the poison has been swallowed, is to evacuate the stomach ; and this may usually be done by means of the stomach-pump when the poison is not of the corrosive class ; or the stomach may be gently washed out by means of a funnel and flexible siphon-tube. In many cases emetics are valuable. Antidotes and counter-poisons may be given. The former are such substances as chalk to neutralize the mineral acids and oxalic acid ; the later have a physiological counter action, and such as atropine, which is a counter-poison to morphia. These may usually be administered most effectively by hypodermic injection. The stomach may to a certain degree by protected from the injurious effects of irritants by the administration of mucilaginous drinks ; alkaloids may be rendered sparingly soluble by means of astringent substances containing tannin ; and pain may be relieved by means of opium, unless contra-indicated by then nature of the poison. The effects of the consultant poisons, such as strychnine, may be combated by means of the inhalation of chloroform.

The classification of poisons is a matter of difficulty. Various attempts have been made to classify them scientifically, but with no signal success ; and perhaps the best system is that which groups the various poisons according to the more obvious symptoms which they produce. Our knowledge of the more intimate action of poisons is still too imperfect to admit of any useful classification according to the manner in which they specifically affect the vital organs. Poisons may in the manner indicated be classified as (1) Corrosives, (2) Irritants, (3) Neurotics, and (4) Gaseous Poisons. The subject of poisonous food has already been treated under the heading MEDICAL JURISPRUDENCE (vol. xv. pp. 781–2).

(1) Corrosives.

The typical member of this class is corrosive sublimate, the soluble chloride of mercury. In it are included also the concentrated mineral acids (sulphuric, nitric, and hydrochloric) ; oxalic acid ; the alkalies (potash, soda, and ammonia) and their carbonates ; acid, alkaline, and corrosive salts of the metals (such as bisulphate of potash, alum, butter of antimony, and nitrate of silver) ; also carbonic acid.

The symptoms produced by the mineral acids and the alkalies are almost altogether referrible to local action; but some corrosive poisons, such carbolic acid, produce, besides a local action, remote and specific constitutional effects. The symptoms of corrosive poisoning are marked and unmistakable, except in infants. Immediately on swallowing the corrosive substance, an acid, caustic, or metallic burning sensation is experienced in the mouth, fauces, gullet, and region of the stomach, and this speedily extends over the whole belly ; as a rule vomiting speedily follows. In the case of the mineral acids, and in oxalic acid poisoning, the vomit is so acid that if it falls upon a marble or concrete floor effervescence ensues. No relief follows the evacuation of the stomach. The ejected matters contain blood, and even fragments of the corroded walls of the alimentary canal. The belly becomes distended with gas, and horribly tender. High fever prevails. The mouth is found to be corroded. Death usually ensues within a few hours ; or, if the patient survives, he or she may perish miserably, months after the poison was taken, through starvation consequent upon the gradual contraction of the gullet, brought about by its corrosion and subsequent healing.

The treatment of corrosive poisoning consists in very gently emptying and washing out the stomach by means of a soft siphon-tube. The stomach-pump cannot be used with safety in consequent of the weakening of the walls of the stomach by corrosion. Demulcents and opiates may be subsequently administered. After death from corrosive poisoning the walls of the stomach are found corroded, and even perforated.

1. Corrosive Sublimate.—Here all the sign and symptoms of corrosive poisoning are produced in their severest form. A grain or two of this poison may prove fatal. Fortunately there is an efficient antidote in white of egg, the albumen of which, if administered at once renders the salt insoluble. The eggs should be divested of their yolks, beaten up with water, and given promptly, repeatedly, and abundantly, followed by emetics. Poisoning by corrosive sublimate may be followed by the specific toxic effects of mercury, such as salivation and tremor.

Workers is mercury, such as water-gilders, looking-glass makers and the makers of barometers and thermometers, are apt to suffer from a peculiar form a peculiar form of shaking palsy, known as "the trembles," or mercurial tremor. This disease affects most frequent those who are exposed to mercurial fumes. The victim is affected with tremors when an endeavour is made to exert the muscles, so that he is unable, for instance, to convey a glass of water to the lips steadily, and when he walks he breaks into a dancing trot. The treatment consists in removal from the mercurial atmosphere, baths, fresh air, and the administration of iron and other tonics.

2. Mineral Acids.—These are oil of vitriol or sulphuric acid, aqua fortis or nitric acid, and spirit of salt or hydrochloric (muriatic) acid. These when in a concentrated form produced wellmarked symptoms of corrosion. When they are diluted, the symptoms are those of an irritant poison. Nitric acid stains the mouth and skin of a yellow colour. The treatment consists in the administration of alkalies or their carbonates, chalk, whiting, or even uncoloured plaster scraped off the walls of ceiling, with the view of neutralizing the acid.

3. Oxalic acid is a vegetable acid. When taken in the state of concentrated solution it acts as a corrosive, but when diluted as an irritant. But it also exerts a specific effect, killing the patient by cardiac syncope not unfrequently within a few minutes. When a person after taking a crystalline substance, tasting strongly acid, dies within 15 to 30 minutes, after the manifestation of great weakness, small pulse, and failure of the heart’s power, poisoning by oxalic acid is almost certain. The treatment consists in promptly administering an emetic, followed by chalk, whiting, or any substance containing carbonate of calcium. The alkaline carbonates are valueless, for the alkaline oxalates are almost as poisonous as oxalic acid itself.

4. The Alkalies.—Potash, soda, and their carbonate and sulphides produce symptoms resembling those of the mineral acids, except that purging is a usual accomplishment .

5. Carbolic acid when taken in the form of a concentrated liquid acts as corrosive, causing whitening and shrinking of all the animal membranes with which it comes in contact. The patient, however, becomes speedily comatose, the poison acting profoundly upon the great nervous centres. A curious phenomenon—black or dark green unrine—is commonly observed after the administration of this poison. Saccharated lime-water, diluted and drunk freely, and a solution of sulphate of soda are perhaps the most useful remedies.

(2) Irritants

Irritant poisons are of two classes—mettallic irritants, and vegetable and animal irritants, these latter being for convenience grouped together. Perhaps none of the irritants act purely as such, the irritant symptoms being usually accompanied by well-marked effect upon the nervous system. An irritant is as substance which causes inflammation of the part to which it is applied,—usually the alimentary canal. Arsenic is by far the most important of the metallic irritants. Other irritants are the moderately diluted acids, many metallic salts, such as those of antimony, lead, copper, zinc, and chromium. Elaterium, gamboges, aloes, colocynth, and croton oil are good examples of vegetable irritants ; and cantharides of animal irritants. Animal and vegetable food when decomposed, or infested with certain organisms known as bacteria, may produce violent irritant symptoms. The symptoms produced by irritant poisons are usually more slow in their development than where a corrosive has been administered. Usually, after an interval, greater or less according to the specific nature of the irritant swallowed, a burning pain is felt in the mouth, throat, and gullet, with a sense of constriction of the parts, and followed by burning pain in the region of the stomach. This is increased, and not alleviated, by pressure, a mark which serves to distinguish the attack from one of the ordinary colic. Nausea, vomiting, and thirst ensue, speedily followed by distension of the whole abdomen, which is exceedingly tender to the touch. Ordinary the vomiting is followed by profuse diarrhaea. Should the poison not be speedily eliminated in the vomited and faecal matters, inflammatory fever sets in, followed by collapse ; and death may ensure in a few hours.

There is danger of confounding irritant poisoning with some forms of natural disease, such as gastritis and gastric ulcer, colic, peritonitis, cholera, and rupture of the intestines.

1. Arsenic is a specific irritant poison. Almost all the compounds of this metal are poisonous. The term "arsenic" is, however, most commonly applied, not to the metal itself, but to its lower oxide, arsenious oxide, which is also known as white arsenic. By whatever channel arsenic is introduced into the system, it invariably affects specifically the stomach and intestines, causing congestion or inflammation. The common sources of arsenal poisoning are the taking of white arsenic, which causes acute poisoning, and the inhalation of dust from arsenical wall-papers and textile fabrics, whereby a chronic form of poisoning is induced.

The symptoms of acute arsenical poisoning do not come on, as in the case of corrosive poisoning, immediately after the poison is swallowed. There is usually an interval of half an hour or so before prominent symptoms supervene. Generally, after a feeling of faintness and depression, an intense burning pain is felt in the region of the stomach, which tenderness on pressure. Nausea and vomiting generally follow, increased by every act of swallowing. Unlike what occurs in ordinary vomiting, the pain and sickness are not relieved by the evacuation of the stomach. Vomiting is followed by purging, being frequently distinguishable in the evacuations. There is thirst, a feeble irregular pulse, and a perspiring clammy skin. The victim usually succumbs within eighteen to seventy-two hours ; if he survives the latter period, good hopes may be entertained of his recovery . The treatment consists in the use of the stomach-pump, emetics, such as mustard and warm water, demulcents, and the free administration of magnesia emulsion and either freshly precipitated ferric hydrate or dialysed iron. Ferric hydrate, and the solution known as dialysed iron, have the property of rendering arsenious anhydride insoluble.

Chronic arsenical poisoning is usually accidentally. The inhalation of arsenical vapours in factories, or of arsenical dust from green wall-papers and in the manufacture of artificial flowers, are common wall-papers and in the manufacture of artificial flowers, are common sources of this form of poisoning. Arsenic when thus slowly absorbed into the system produced congestion and inflammation of the mucous membranes, redness and irritation of the conjunctivae, sore throat, a peculiar eruption of the skin, and diarrhaea. The treatment consists in removal from the poisoned atmosphere, and the administration of tonics.

Arsenic-eating, or the ability of some persons to take relatively large doses of arsenic habitually, is a well-established fact. The cause of this singular immunity from the ordinary result of arsenic is quite unknown.

2. Lead.—The salts of lead, more especially the acetate (sugar or lead), are irritant poisons of no very great activity ; and, though occasionally death ensues, recovery is the rule. Chrome yellow, or lead chromate, is a powerful poison. All chromates are, indeed, irritant poisons.

Chronic lead poisoning is a much more common affection than acute irritant poisoning by lead. When lead in any form is slowly absorbed into the system,a peculiar affection results, known as saturnine poisoning, and characterized by two prominent symptoms—colic and paralysis. Worker in lead and its compounds, such as plumbers and painters, are frequently affected by this form of disease. Water, especially soft water or such as is contaminated with sewage, on being passed through leaden pipes or stored in leaden cisterns may become contaminated with lead to a dangerous extent. Acid liquids, such as cider, vinegar, &c., may also contain lead as an impurity. Potmen, who drink beer which has rested for some time in pewter, are also the occasional victims of saturnine poisoning. Water which contains lead in a soluble form to the extent of more thanone-tenth of a grain per gallon should not be used for drinking purposes. If more than this quantity be present the water when placed in a white porcelain dish wall become more as less dark in colour on the addition of a few drops of a solution of sulphuretted hydrogen.

The comment manifestation of chronic lead poisoning is lead colic,—a peculiar twisting and agonizing sensation around the navel, attended with obstinate constipation. This, like all forms of chronic lead poisoning, is almost invariably attended with a peculiar blue line on the margin of the gums, and when this is present the nature of the affection can scarcely be doubtful. The treatment consists in the free use of purgatives, opiates, and the internal use of potassium iodide, which favours the elimination of the metal through the urine. "Wrist-drop" or lead paralysis is also a common result of the ingestion of lead. It consists in a paralysis of the extensor muscles of the forearm, accompanied by a washing of that structure. A dropping of the wrist is the result of this degeneration. Baths, the use of galvanism, and the administration of potassium iodide and tonics usually afford relief. Should, however, the patient in any form of lead poisoning be exposed for a lengthened period to the effects of the metal, degenerations of the liver, kidneys, and brain supervene, with fatal results.

In all cases of lead poisoning removal of the exciting causes is indispensable ; the worker in lead must suspend his occupation for a time ; the use of contaminated articles of food or drink must cease.

3. Copper.—The soluble salts of copper, such as blue vitriol (the sulphate) and verdigris ( subcarbonate and subarcetate0, are emetic and irritant salts. Their emetic effects usually, but not invariably, secure their prompt rejection by the stomach. Occasionally fatal effects have resulted from their administration. Copper becomes accidentally mixed with articles of dietary in a variety of modes. It is also used for improving the colour of preserved fruits and vegetables. Its deleterious properties when thus used in minute quantities have been both asserted and denied. There is, however, a large body of evidence in favour of the at all events occasional poisonous effects of minute quantities of copper.

4. Zinc salts and barium salts, except the quite insoluble barium sulphate, are irritant poisons ; and barium compounds act also upon the central nervous system.

5. Chromates, e.g., bichromate of potash, are violent irritants. Chrome yellow, or lead chromate, has already been mentioned.

6. Phosphorus.—Of the two chief forms of the elements—the yellow or ordinary and the red of amorphous—the former only is poisonous. Rarely there is met with a chronic form of poisoning among workers in the material, arising from the inhalation of phosphorus vapours. Its special characteristic is a peculiar necrosis or death of the bony structure of the lower jaw. Acute phosphorus poisoning is more common. Phosphorus is used for tipping matches, and is also the basis of several vermin destroyers. When swallowed, phosphorus produces a a variable amount of irritation and disturbance of the alimentary canal. There may be a burning sensation felt in the mouth, throat, and stomach, followed by vomiting. The vomited matters, and also the excreta, may be observed to be luminous in the dark. There symptoms usually subside, and for three or four days the person appears to have recovered his or her usual health. The liver then enlarges, and this and other structures undergo fatty degeneration ; jaundice supervenes ; and the patient dies in the a few days in a semi-typhoid condition. Rarely there is recovery. Oil of turpentine is thought to be the best remedy. Most of the organs undergo fatty degeneration.

7. Vegetable Irritants.—These produce drastic purgative effects. Frequently the nature of the illness may be ascertained by the discovery of portions of the vegetable substance—recognizable by the microscope—in the matters ejected by the patient.

8. Cantharides.—The administration of CANTHARIDES (q.v.) is followed by vomiting, purging, strangury, or even entire inability to pass the urine. In the ejecta portions of the shining elytra or wing-cases of the fly may often be recognized. There is often great excitement of the sexual proclivities. The active principle of the fly, cantharidin, may be extracted from suspected matters by means of chloroform, and the reside left after the evaporation of this blisters the lip or any tender mucous surface to which it is applied. Demulcent remedies, with opiate enemata and injections, afford the best relief by way of treatment.

(3) Neurotics.

It is premature, for the present, to attempt a systematic division of this most important class, which embraces poisons so widely different in their actions as opium and strychnine. We at once proceed to details.

1. Prussic or Hydrocyanic Acid.—Hydrocyanic acid is one of the best known poisons, and a very deadly one. In the pure state it is said to kill with lightning-like rapidity. It is met with in commerce only in a dilute state. In Great Britain two kinds of acid are commonly sold—the pharmacopaeial acid, containing 2 per cent. of anhydrous prussic acid, and Scheele’s acid, containing 4 or 5 percent. Less than a teaspoonful of the 2 per cent. acid has caused death. Given in fatal doses, the symptoms of prussaic-acid poisoning set in with great rapidity ; and, in consequence of the readiness with which the poison is absorbed from the stomach and different thorough the circulation, the onset of symptoms is reckoned by seconds rather than by minutes. Occasionally the victim may be able to perform a few voluntary actions before alarming symptoms are developed. There is first a very brief stage of difficult breathing, and slow action of the heart, with a tendency for the organ to stop in the state of dilation. With widely-dilated pupils of the eye, the patient is then seized with violent irregular convulsive movements. The rhythm of the respiratory movements is disturbed, and the countenance becomes of a bluish cast. The patient now sinks to the ground with complete loss of muscular power ; and the third or asphyxial stage is reached, in which there are slow gasping respirations, loss of pulse, and paralysis of motion. Death is frequently preceded by muscular spasms. The foudroyant character of the illness, and the speedy death of the patient, coupled with the peculiar odour of the acid in the breath and atmosphere around the body, seldom leave any doubt as to the nature of the case. The treatment consists in inhalation of the fumes of strong ammonia, drinks of warm and cold water alternately, friction of the limbs, and artificial respiration. The subcutaneous injection of injection of atropine, which acts as a cardiac stimulant, may prove serviceable.

Other soluble cyanides, more especially cyanide of potassium, a salt largely used in photography and in the arts, the equally poisonous with hydrocyanic acid, See PRUSSIC ACID.

2. Opium.—In consequence of the extent to which OPIUM (q.v.), its preparations, and its active alkaloid morphia are used for the relief of pain, poisoning by opium is of frequent occurrence. It is largely used by suicides ; and children, being very susceptible to its influence, frequently die from misadventure after administration of an overdose of the drug. The ordinary preparations of opium are the drug itself, which is the inspissated juice of the Oriental poppy, and the tincture, commonly known as laudanum. Opium contains a variety of more or less active principles, the chief of which is the alkaloid morphia, which is present in good opium to he extent of about 10 per cent. in combination with meconic acid, which is physiologically inactive. Opium is largely used by Eastern nations for smoking, and there is great discrepancy of opinion as to the extent to which opium smoking is deleterious. The preponderance of opinion is in favour of the view that opium smoking is a demoralizing degrading, and pernicious habit, and that its victims are sufferers both in body and mind from its use.

The first symptom of the administration of a poisonous dose of opium is a state of exaltation—which may not, however, be well-marked soon passing into a second stage, in which the symptoms are those of congestion of the brain. The countenance is suffused and of a bluish cast, known as cyanosis, due to imperfect aeration of the blood ; the pupils of the eyes are minutely contracted, the skin dry and warm, and the breathing slow, laboured, and becoming stertorous. The patient is apparently unconscious, and becoming but may be roused by shaking, or by shouting into the ear. When this has taken place, the breathing becomes more natural, and the skin less cyanosed. If he be left a alone there is a speedy relapse into a state of insensibility. If effective treatment be not adopted, a third stage of prostration supervenes, in which there is profound coma, and it may be impossible to arouse the patient. The pupils of the eyes are now contracted to the size of pin-points. Breathing is slow, shallow, and intermittent. The countenance is at once pallid and cyanosed, the skin bathed in perspiration. The pulse becomes more rapid with increased feeblesness, and at length all signs of it are lost, until death supervenes.

The treatment consists in the use of the stomach-pump. Emetics are usually inoperative. After this the patient must be kept awake by walking him about, applying cold and warm douches alternately to the chest, shouting into the ears, flicking the hands and feet with damp towels, and the application of the galvanic current. Circulation should be promoted by friction of the limbs and trunk. Strong infusion of coffee, ammonia, and alcoholic stimulants may be freely administered. As a last resort when the breathing intermits, artificial respiration may be performed. The hypodermic injection of full doses of atropine has proved of marked benefits,—atropine and morphia being to a certain extent counter-poisons.

Opium is a drug to which its victims may become habituated by the use of gradually increasing doses ; and the practice or opium-eating, as it is termed, is a pernicious one. An atrophied condition of the body usually results. The only remedy is abstinence from the drug.

3. Strychnine and Strychnine-yielding Plants.—The alkaloids strychnine and brucine, as well as the plants, as well as the plants in which they are found, all act in the same manner, being highly poisonous, and causing death after spasms or a severe character. Strychnine was first extracted from the seeds of Strychnos Nux-Vomica in 1819, by Pellectier and Caventou. It exists in larger quantity in other species of the genus Strychnos, and notably in Strychnos Ignatii. From the bark of Strychnos Nux-Vomica, known as false Angostura bark, another alkaloid, brucine, is also extracted. This bark was at one time wrongly supposed to be the bark of Brucca anti dysenterica ; hence the name brucia or brucine. Its effects are similar to those of strychnine, but its physiological activity is not so great. Many vermin-killer contain strychnine as their active ingredient.

Strychnine, and all substances containing that alkaloid, produce their effects within a very minutes—usually within ten or fifteen minutes. The patient complains of stiffness about the neck, and his aspect exhibits terror. There is an impression of impending calamity or death. Very speedily the head is jerked back, the limbs extended, the back arched (opisthotonos), so that body may rest on the head and heels only. The mount is drawn ; and the condition is one known as tetanus. In a few moments these symptoms pass off, and there is complete relaxation of the spasm. The spasmodic condition speedily returns, and is brought about by the slightest touch or movement of the patient. Accessions and remissions of the titanic state ensue rapidly till the patient succumbs, usually within half an hour of the administrations of the poison. The best treatment is to put, and keep, the patient under the influence of chloroform till time is given for the excretion of the alkaloid, having previously given a full dose of chloral hydrate.

4. Aconite Poisoning. The ordinary blue rocket, wolfsbane, or monkshood, Aconitum Napellus, and an alkaloid extracted from it, aconitine, are perhaps the most deadly of known poisons. One sixteenth of a grain of aconitine has proved fatal to a man. All the preparations of aconite produce a peculiar burning, tingling, and numbness of the parts of which they are applied. When given in large doses they pruduce violent vomiting, as a rule, more or less paralysis of motion and sensation, and great depression of the heart, usually ending in death from syncope. Intelligence remains unaffected till almost the last. The treatment consists in the hypodermic injection of tincture of foxglove (Digitalis) or its active principle digitalin, which is a counter-poison in its action upon the heart. The root of aconite has been eaten in mistake for that of horse-radish.

5. Belladonna.—The belladonna or deadly nightshade, Atropa Belladonna, contains an alkaloid, atropine, which is largely used by oculists to procure dilatation of the pupils of the eye. The bright scarlet berries of the plant have been eaten by children, who are attracted by their tempting appearance. Belladonna produces dilatation of the pupils, rapid pulse, hot dry flushed, with an eruption not unlike that of scarlatina, soreness of the throat, with difficulty of swallowing, intense thirst, and gay mirthful delirium. The treatment consists in evacuation of the poison by means of the stomach-pump, and the hypodermic injection of morphia as a counter as counter-poison.

(4) Gaseous Poisons.

The effects of these are varied,—some of them acting as irritants, while others have a specific effect, apparently in consequence of their forming chemical compounds with the red pigment of the blood, and thus destroying its capability of acting as a carrier of oxygen.

1. Chlorine and bromine act as powerful irritants. They provoke spasm of the glottis when inhaled, and subsequently induce inflammation of the respiratory mucous membrane, which may prove speedily fatal. Inhalation of diluted ammonia vapour is the best remedy.

2. Hydrochloric or muriatic acid gas and hydrofluoric or fluoric acid gas are irritating and destructive to life. Then former is more destructive to vegetable life than ever chlorine. They are emitted in many process of manufacture, and especially in the manufacture of carbonate of soda from common salt by Le Blanc’s process, in the slat-glazing of earthenware, and in the manufacture of artificial manures.

3. Sulphurous-Acid Gas.—The gas given off by burning sulphur is most suffocating and irritating. Its inhalation even in a highly diluted state, may cause speedy death from spasmodic closure of the glottis.

4. Nitrous vapours, or gaseous oxides of nitrogen (except nitrous oxide), are given off from galvanic batteries excited by nitric acid ; also in the process of etching on copper. They produce, when diluted, little immediate irritation, but are exceedingly dangerous, setting up extensive and fatal inflammation of the lungs.

5. Ammonia gas is highly irritant, but does not often prove fatal.

6. Carbonic acid gas is heavier than atmospheric air, is totally irrespirable when pure, and is fatal when present in large quantities in respired air. It is given off from burning fuel, accumulates in pits and wells as choke-damp, and constitutes the deadly after damp of coal-mines. It is also formed, during alcoholic fermentation, and hence accumulates in partially filled vats in which fermented liquors are stored. When it is breathed in a concentrated, state, death is almost instantaneous. Persons descending into wells foul with this gas sink down powerless, and are usually dead before they can be removed from the vitiated atmosphere. In these cases there is true asphyxia ; but carbonic acid is also a narcotic gas. Persons exposed to an atmospheric partially composed of this gas, but not long enough to produce fatal results, are affected with stertorous breathings, oppressions, flushed face, prominent eyes, swollen tongue, and feeble pulse. The proper treatment is removal from the foul atmosphere, atmosphere, alternate cold and tepid douches to the chest, friction of the limbs and trunk, and artificial respiration. When animation is restored the patient should be put to bed and kept quiet, but should be carefully watched in case of relapse.

7. Carbonic oxide gas is given off by burning charcoal and other forms of fuel. mixed with carbonic acid. The poisonous effect of charcoal fumes are perhaps due rather to the more poisonous to the more poisonous carbonic oxide than to the less poisonous carbonic acid. An atmosphere containing less than 1 per cent. of carbonic oxide would doubtless be fatal if breathed for many minutes. Carbonic oxide forms with haemoglobin, the red pigment of the blood, a bright scarlet compound is very stable, and the oxide cannot be displaced by atmosphere oxygen. Hence the blood after death from the inhalation of carbonic oxide is of a bright arterial hue, which is retains on exposure to air.

8. Coal-gas acts as an asphyxiant and narcotic. The appearances met with after death—more especially the fluid state of the blood—are similar to those observed after death from carbonic oxide gas, which is a constituent of coal-gas, and to which the chief effect of coal-gas may be due.

9. Sulphuretted hydrogen gas is highly poisonous by whatever channel it gauns access to the body. In a concentrated form it produces almost instant death from ashyrxia. Even in a diluted state it produces colic, nausea, vomiting, and drowsiness. This may pass into insensibility with lividity and feeble respiration. The skin is cold and clammy, or bathed in perspiration. The red blood corpuscles are disintegrated. The treatment consists in removal from the contaminated atmosphere, friction to the surface of the body, warmth, and the administration of stimulants. The inhalation of chlorine gas has been recommended on chemical grounds; but it must be remembered that chlorine is itself poisonous.

10. Anaesthetics.—Nitrous oxide, or laughing gas, and the gases or vapours of other anaesthetic substances, such as chloroform, produce death by asphyxia, and perhaps otherwise. Obviously, as a rule, medical assistance is at hand. The treatment consists in artificial respiration, and the use of galvanic current.

11. Vapours of Hydrocarbons.—The volatile vapours of the natural hydrocarbons known as benzoline, petroleum, &c., are poisonous when inhaled for lengthened periods (T.S.*)

The above article was written by: Thomas Stevenson, M.D.; Lecturer in Medical Jurisprudence, Guy's Hospital; Scientific Analyst, Home Office; author of A Treatise on Alcohol; editor of Tayor's Principles and Practice of Medical Jurisprudence.

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