POISONS 277 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. Xo 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 consequence 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 signs and symptoms of 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 in mercury, such as water-gilders, looking-glass makers, and the makers of barometers and thermometers, are apt to suffer from a peculiar form of shaking palsy, known as "the trembles," or mercurial tremor. This disease affects most frequently 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 lie 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 (muri atic) acid. These when taken in a concentrated form produce well- marked symptoms of corrosion. When they are diluted, the symp toms are those of an irritant poison. Nitric acid stains the mouth and skin of a yellow colour. The treatment consists in the admin istration of alkalies or their carbonates, chalk, whiting, or even uncoloured plaster scraped off the walls or 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 or 30 minutes, after the manifestation of great weak ness, 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 sub stance 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 carbonates and sul phides produce symptoms resembling those of the mineral acids, except that purging is a usual accompaniment. 5. Carbolic acid when taken in the form of a concentrated liquid acts as a 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 urine 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. Irritant Poisons. Irritant poisons are of two classes metallic 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 effects upon the nervous system. An irritant is a substance which causes inflammation of the part to which it is applied, usually the alimentary canal. Arsenic is by far the most im portant 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, gamboge, aloes, colocynth, and croton oil are good examples of vegetable irritants ; and cantharides of animal irritants. Animal and vegetable food when decom posed, 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 con striction of the parts, and followed by burning pain in the region of the stomach. This is increased, and not allevi ated, by pressure, a mark which serves to distinguish the attack from one of ordinary colic. Xausea, vomiting, and thirst ensue, speedily followed by distension of the whole abdomen, which, is exceedingly tender to the touch. Ordinarily the vomiting is followed by profuse diarrhoea. Should the poison not be speedily eliminated in the vomited and faecal matters, inflammatory fever sets in, followed by collapse ; and death may ensue 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 intes tines. 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 invari ably affects specifically the stomach and intestines, causing conges tion or inflammation. The common sources of arsenical 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 faint- ness and depression, an intense burning pain is felt in the region of the stomach, with tenderness on pressure. Xausea and vomit ing 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, blood being frequently distinguishable in the evacua tions. 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 accidental. The inhala tion of arsenical vapours in factories, or of arsenical dust from green wall-papers and in the manufacture of artificial flowers, are com men sources of this form of poisoning. Arsenic when thus slowly absorbed into the system produces congestion and inflammation of the mucous membranes, redness and irritation of the conjunctiva?, sore throat, a peculiar eruption of the skin, and diarrhoea. 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