278 POISONS cause of this singular immunity from the ordinary results of arsenic is quite unknown. 2. Lead. The salts of lead, more especially the acetate (sugar of 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 irritant poison. All cliro mates 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 satur nine poisoning, and characterized by two prominent symptoms colic and paralysis. Workers 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 vessels, are also the occasional victims of saturnine poisoning. Water which contains lead in a soluble form to the extent of more than one-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 will become more or less dark in colour on the addition of a few drops of a solution of sulphuretted hydrogen. The commonest 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 wasting 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, how ever, 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 cause 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 subacetate), 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 Kalis 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 or amorphous the former only is poisonous. Rarely there is met with a chronic form of poison ing 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 variable amount of irri tation 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. These 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 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 dis covery 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 residue 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 com monly sold the pharmacopceial acid, containing 2 per cent, of anhydrous prussic acid, and Scheele s acid, containing 4 or 5 per cent. Less than a tcaspoonful of the 2 per cent, acid has caused death. Given in fatal doses, the symptoms of prussic-acid poisoning set in with great rapidity ; and, in consequence of the readiness with which the poison is absorbed from the stomach and diffused through 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 dilatation. 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 coun tenance 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 respira tions, loss of pulse, and paralysis of motion. Death is frequently pre ceded 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 con sists 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 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, are equally poisonous with hydrocyanic acid. See PKTJSSIC 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 influ ence, 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 the extent of about 10 per cent, in combination with meconic acid, which is phy siologically 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 symp toms 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 con tracted, the skin dry and warm, and the breathing slow, laboured, and becoming stertorous. The patient is apparently unconscious, 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 alone there is a speedy relapse into a state of insensibility. If effective treatment be not adopted, a third stnge 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 feebleness, and at length all signs of it are lost, until death supervenes.
The treatment consists in the use of the stomach-pump. Emetics