is any substance which proves destructive to the life of animals in a small quantity, either taken by the mouth, mixed with the blood, or applied to the nerves. See Medicine, No. 261, 269, 303, 322, 408, &c., &c.

Of poisons there are many different kinds, which are exceedingly various in their operations. The mineral poisons, as arsenic and corrosive mercury, seem to attack the solid parts of the stomach, and to produce death by eroding its substance: the antimonials seem rather to attack the nerves, and to kill by throwing the whole system into convulsions; and in this manner also most of the vegetable poisons seem to operate. All of these, however, seem to be inferior in strength to the poisons of some of the more deadly kinds of serpents, which operate so suddenly that the animal bit by them will be dead before another that had swallowed arsenic would be affected.

Much has been written concerning a poison made use of by the African negroes, by the Americans, and by the East Indians. To this very strange effects have been ascribed. It has been said, that by this poison, a man might be killed at any certain time; as, for instance, after the interval of a day, a week, a month, a year, or even several years. These wonderful effects, however, do not seem worthy of credit; as the Abbé Fontana has given a particular account of an American poison called ticunas, which in all probability is the same with that used in Africa and the East Indies; and from his account it is extremely improbable that any such effects could be produced with certainty.

With this poison the Abbé was furnished by Dr Heberden. It was closed and sealed up in an earthen pot inclosed in a tin-case. Within the tin-case was a note containing the following words: “Indian poison, brought from the banks of the river of the Amazons by Don Pedro Maldonado. It is one of the sorts mentioned in the Philosophical Transactions, vol. xvii. No. 12.” In the volume of the Philosophical Transactions here quoted, mention is made of two poisons little different in their activity; the one called the poison of lamas, and the other of ticunas. The poison in the earthen vessel used by the Abbé Fontana was that of the ticunas; he was also furnished with a number of American arrows dipped in poison, but whether that of the lamas or ticunas he could not tell.

Our author begins his account of the nature of this poison with detecting some of the mistakes which had been propagated concerning it.—It had been asserted, that the ticunas poison proves noxious by the mere effluvia, but much more by the steam which exhales from it in boiling or burning: that, among the Indians, it is prepared only by women condemned to die; and that the mark of its being sufficiently prepared, is when the attendant is killed by its steam. All these assertions are by the Abbé refuted in the clearest manner. He exposed a young pigeon to the smell of the poison when the vessel was opened, to the steam of it when boiling, Poison and to the vapour of it when burning to the sides of the vessel, without the animal's being the least injured; on which, concluding that the vapours of this poison were not to be dreaded, he exposed himself to them without any fear.

This poison dissolves very readily even in cold water, and likewise in the vegetable and mineral acids. With oil of vitriol it becomes as black as ink, but not with the rest of the acids. In oil of vitriol it also dissolves more slowly than in any of the rest. It does not effervescence with acids or alkalies; neither does it alter milk, nor tinge it, except with the natural colour of the poison; nor does it tinge the vegetable juices either red or green. When examined by the microscope, there is no appearance of regularity or crystallization; but it for the most part appears made up of very small, irregular, roundish bodies, like vegetable juices. It dries without making any noise, and has an extremely bitter taste when put upon the tongue.

The ticunas poison is harmless when put into the eyes; nor is it fatal when taken by the mouth, unless the quantity is considerable. Six grains of the solid poison, dissolved in water, killed a young pigeon which drank it in less than 20 minutes. Five grains killed a small Guinea-pig in 25 minutes. Eight grains killed a rabbit in an hour and eight minutes, &c. In those experiments it was observed, that much less poison was required to kill an animal whose stomach was empty than one that had a full stomach. Three rabbits and two pigeons were killed in less than 35 minutes, by taking a dose of three grains each on an empty stomach; but when the experiment was repeated on five animals with full stomachs, only one of them died.

The most fatal operation of this poison is when mixed with the blood. The smallest quantity, injected into the jugular vein, killed the animal as if by a stroke of lightning. When applied to wounds in such a manner that the flowing of the blood could not wash it away, the animal fell into convulsions and a train of fatal nervous symptoms, which put an end to its life in a few minutes. Yet, notwithstanding these seeming affections of the nerves, the poison proved harmless when applied to the naked nerves themselves, or even to the medullary substance of them slit open.

The strength of this poison seems to be diminished, and even destroyed, by mineral acids, but not at all by alkalies or ardent spirits; but if the fresh poison was applied to a wound, the application of mineral acids immediately after could not remove the pernicious effects.

So far, indeed, was this from being the case, that the application of nitrous acid to the wounded muscle of a pigeon, killed the animal in a short time without any poison at all.—The effects of the arrows were equally fatal with those of the poison itself (a).

The poison of the viper is analogous in its effects to that of ticunas, but inferior in strength; the latter killing more instantaneously when injected into a vein than even the poison of the most venomous rattlesnake.

The Abbé has, however, observed a difference in the action of the two poisons upon blood taken out of the body. He cut off the head of a pigeon, and received its blood into warm conical glasses, to the amount of about 80 drops into each. Into the blood contained in one porringer, he put four drops of water; and into the other four drops of the poison dissolved in water as usual. The event of this experiment was, that the blood, with which the water only was mixed, coagulated in a short time; but that in which the poison was mixed did not coagulate at all. The poison of the viper also hinders the blood from coagulating, but gives it a much blacker tinge than the poison of the ticunas. The poison of the viper also proves certainly fatal when injected into the veins, even in very small quantity; but it produces a kind of grumous coagulation and blackness in the blood when drawn from a vein, though it prevents the proper coagulation of that fluid, and its separation into clathrum and serum as usual.

In the Philosophical Transactions, No. 335, we have a number of experiments which show the effects of many different poisons upon animals; from whence it appears, that many substances which are not at all accounted poisonous, yet prove as certainly fatal when mixed with the blood as even the poison of rattlesnakes, or the ticunas itself.—An ounce of emetic wine, being injected into the jugular vein of a large dog, produced no effect for a quarter of an hour. At the expiration of that space he became sick, had a continual vomiting, and evacuation of some hard excrements by stool. By these evacuations he seemed to be somewhat relieved; but soon grew uneasy, moved from place to place, and vomited again. After this he laid himself down on the ground pretty quietly; but his rest was disturbed by a return of his vomiting, and his strength greatly decreased. An hour and a half after the operation he appeared half dead, but was greatly revived by having some warm broth poured down his throat with a funnel. This, however, proved only a temporary relief; for in

(a) Mr Paterson, in his travels in Africa, in the years 1777-8-9, fell in with an European woman who had been wounded with a poisoned arrow. Great pains had been taken to cure her, but in vain; for at different periods of the year an inflammation came on which was succeeded by a partial mortification. She told him that the wound was easily healed up; but in two months afterwards there was a certainty of its breaking out again, and this had been the case for many years. The Hottentots poison their arrows with a species of euphorbia. The amaryllis disticha, a large bulbous plant growing about the Cape of Good Hope, called mad poison, is used for the same purpose. The natives take the bulbs when they are putting out their leaves, cut them transversely, extract a thick fluid, and keep it in the sun till it acquires the consistence of gum, when it is fit for use. With arrows poisoned with this gum, they kill antelopes and other small animals intended for food. After they are wounded, the animals generally run for several miles, and are frequently not found till next day. When the leaves of this plant are young, the cattle are very fond of them, though they occasion infant death. Mr Paterson mentions another shrubby plant producing a nut, called by the Dutch wolf gift or wolf poison, the only poison useful to the European inhabitants. The nuts are roasted like coffee, pulverized, and stuffed into some pieces of meat or a dead dog, which are thrown into the fields. By this means the voracious hyenas are generally killed. Poison.

A short time the vomiting returned, he made urine in great quantity, howled miserably, and died in convulsions.—A dram and a half of sal ammoniac dissolved in an ounce and a half of water, and injected into the jugular vein of a dog, killed him with convulsions almost instantly.—The same effect followed from injecting a dram of salt of tartar dissolved in an ounce of warm water; but a dram and a half of common salt injected into the jugular produced little other bad consequence than a temporary thirst.—A dram of purified white vitriol, injected into the crural vein of a dog, killed him immediately.—Fifteen grains of salt of urine dissolved in an ounce of water, and injected into the crural vein of a dog, threw him into such violent convulsions that he seemed to be dying; nevertheless he recovered from a second dose, though not without a great deal of difficulty: but an ounce of urine made by a man fasting produced no bad effect.—Diluted aquafortis injected into the jugular and crural vein of a dog killed him immediately by coagulating the blood. Oil of sulphur (containing some quantity of the volatile vitriolic acid) did not kill a dog after repeated trials. On the contrary, as soon as he was let go, he ran into all the corners of the room searching for meat; and having found some bones, he fell a gnawing them with strange avidity, as if the acid, by injection into his veins, had given him a better appetite.—Another dog who had oil of tartar injected into his veins, swelled and died, after suffering great torment. His blood was found florid, and not coagulated.—A dram and a half of spirit of salt diluted with water, and injected into the jugular vein of a dog, killed him immediately. In the right ventricle of the heart the blood was found partly grumous and concreted into harder clots than ordinary, and partly frothy. Warm vinegar was injected without doing any manifest harm.—Two drams of sugar dissolved in an ounce of water were injected into the jugular vein of a dog without any hurt.

These are the results of the experiments where saline substances were injected into the veins. Many acids proved equally fatal. A decoction of two drams of white hellebore, injected into the jugular vein of a dog, killed him like a stroke of lightning. Another dog was killed in a moment by an injection of an ounce of rectified spirit of wine in which a dram of camphor was dissolved.—Ten drams of highly rectified spirit of wine, injected into the crural vein of a dog, killed him in a very short time; he died quietly, and licking his jaws with his tongue, as if with pleasure. In the vena cava and right ventricle of the heart the blood was coagulated into a great many little clots.—Three drams of rectified spirit of wine injected into the crural vein of a small dog made him apoplectic, and as it were half dead. In a little time he recovered from the apoplexy, and became giddy; and when he endeavoured to go, reeled and fell down. Though his strength increased by degrees, yet his drunkenness continued. His eyes were red and fiery; and his flight so dull that he scarce seemed to take notice of anything; and when he was beat, he would scarce move. However, in four hours he began to recover, and would eat bread when offered him; the next day he was out of danger.—Five ounces of strong white wine injected into the crural vein of a dog made him very drunk for a few hours, but did not produce any other consequences. An ounce of strong decoction of tobacco injected into a vein killed a dog in a very short time in terrible convulsions. Ten drops of oil of sage rubbed with half a dram of sugar, and thus dissolved in water, did no harm by being injected into the blood.

Mercury, though seemingly void of all acrimony, proves also fatal when injected into the blood. Soon after the injection of half an ounce of this mineral into the jugular vein of a dog, he was seized with a dry short cough which came by intervals. About two days after, he was troubled with a great difficulty of breathing, and made a noise like that of a broken-winged horse. There was no tumour about the root of the tongue or the parotid glands, nor any appearance of a salivation. In four days he died; having been for two days before so much troubled with an orthopnoea, that he could sleep only when he leaned his head against something. When opened, about a pint of bloody serum was found in the thorax, and the outside of the lungs in most places was blistered. Some of the blisters were larger and others smaller than a pea, but most of them contained mercurial globules. Several of them were broken; and upon being pressed a little, the mercury ran out with a mixture of a little fumes; but upon stronger pressure, a considerable quantity of fumes issued out. In the right ventricle of the heart some particles of quicksilver were found in the very middle of the coagulated blood lodged there, and the same thing also was observed in the pulmonary artery. Some blood also was found coagulated in a very strange and unusual manner between the columnæ of the right ventricle of the heart, and in this a greater quantity of quicksilver than anywhere else. In the left ventricle was found a very tenacious blood coagulated, and sticking to the great valve, including the tendons of it, and a little resembling a polypus. No mercury could be found in this ventricle by the most diligent search; whence it appears, that the mercury had passed no farther than the extremities of the pulmonary artery, where it had stuck, and occasioned fatal obstructions.—In another dog, which had mercury injected into the jugular, it appears to have passed the pulmonary artery, as part of it was found in the cavity of the abdomen, and part also in some other cavities of the body. All the glandules were very turgid and full of liquor, especially in the ventricles of the brain, and all round there was a great quantity of serum.

In like manner, oil of olives proves certainly fatal when injected into the blood. Half an ounce of this, injected into the crural vein of a dog, produced no effect in half a quarter of an hour; but after that, the animal barked, cried, looked dejected, and fell into a deep apoplexy; so that his limbs were deprived of all sense and motion, and were flexible any way at pleasure. His respiration continued very strong, with a snorting and wheezing, and a thick humour sometimes mixed with blood flowing out of his mouth. He lost all external sense: the eyes, though they continued open, were not sensible of any objects that were put to them; and even the cornea could be touched and rubbed, without his being the least sensible of it; his eyelids, however, had a convulsive motion. The hearing was quite lost; and in a short time the feeling became so dull, that his claws and ears could be bored with red-hot pincers without his expressing the least sense of pain. Sometimes Sometimes he was seized with a convulsive motion of the diaphragm and muscles subservient to respiration; upon which he would bark strongly, as if he had been awake: but this waking was only in appearance; for all the time of this barking he continued as insensible as ever. In three hours he died; and on opening his body, the bronchiae were filled with a thick froth.—An ounce of oil of olives injected into the jugular of another dog killed him in a moment; but a third lived an hour after it. He was seized with great sleepiness, snorting, and wheezing, but did not bark like the first. In all of them a great quantity of thick froth was found in the lungs.

We come now to speak of those poisons which prove mortal (B) when taken by the mouth. The principal of these are, arsenic, corrosive sublimate or muriate of mercury, glaas of antimony, and lead. What the effects of these substances are when injected into the blood, cannot be related, as no experiments seem to have been made with them in that way, excepting antimony, whose effects have been already mentioned. The effects of opium, when injected into the veins, seem to be similar to its effects when taken by the mouth. Fifty grains of opium, dissolved in an ounce of water, were injected into the crural vein of a cat. Immediately after the operation she seemed much dejected, but did not cry; only made a low, interrupted, and complaining noise. This was succeeded by trembling of the limbs, convulsive motions of the eyes, ears, lips, and almost all parts of the body, with violent convulsions of the breast. Sometimes she would raise up her head, and seem to look about her; but her eyes were very dull, and looked dead. Though she was let loose, and had nothing tied about her neck, yet her mouth was so filled with froth, that she was almost strangled. At last, her convulsive motions continuing, and being seized with stretching of her limbs, she died in a quarter of an hour. Upon opening the body, the blood was found not to be much altered from its natural state.—A dram and a half of opium was dissolved in an ounce and a half of water, and then injected into the crural vein of a lufly strong dog. He struggled violently; made a loud noise, though his jaws were tied; had a great difficulty of breathing, and palpitation of the heart, with convulsive motions of almost all parts of his body. These symptoms were succeeded by a profound and apoplectic sleep. Having untied him, he lay upon the ground without moving or making any noise, though severely beaten. About half an hour after he began to recover some sense, and would move a little when beaten. The sleepiness still decreased; so that in an hour and a half he would make a noise, and walk a little when beat. However, he died in four days, after having voided a quantity of fetid excrements, in colour resembling the diluted opium he had swallowed.

The oil of tobacco has generally been reckoned a very violent poison when introduced into the blood; but, from the abbe Fontana's experiments, it appears to be far inferior in strength to the poison of tucanas, or to the bite of a viper. A drop of oil of tobacco was put into a small incision in the right thigh of a pigeon, and in two minutes the animal could not stand on its right foot. The same experiment was repeated on another pigeon, and produced exactly the same effect. In another case, the oil was applied to a slight wound in the breast; three minutes after which, the animal could not stand on the left foot. This experiment was also repeated a second time, with the same success. A tooth-pick, steeped in oil of tobacco, and introduced into the muscles of the breast, made the animal fall down in a few seconds as if dead. Applied to two others, they threw up several times all the food they had eaten. Two others treated in the same manner, but with empty stomachs, made many efforts to vomit.—In general, the vomiting was found to be a constant effect of this poison: but the loss of motion in the part to which the poison is applied, was found to be only accidental. None of the animals died by the application of oil of tobacco. Dr Leake, however, affirms the contrary; saying, that this oil, which is used by the Indians in poisoning arrows, when infused into a fresh wound, besides sickness and vomiting, occasions convulsions and death. See Practical Essay on Diseases of the Viscera, p. 67.

The pernicious effects of laurel-water are taken notice of under the article Medicine, No 261. The account is confirmed by the experiments of the Abbé Fontana; who tells us, that it not only kills in a short time, when taken by the mouth, but that, when given in small doses, the animal writhes so that the head joins the tail, and the vertebrae arch out in such a manner as to strike with horror every one who sees it. In order to ascertain the effects of this water when taken into the blood, our author opened the skin of the lower belly of a pretty large rabbit, and made a wound in it about an inch long; and having slightly wounded the muscles under it in many parts, applied two or three tea spoonfuls of laurel-water. The animal fell down convulsed in less than three minutes, and died soon after. The experiment was repeated with similar success in other animals: but was always found to act most powerfully, and in the shortest time, when taken by the mouth, or

(B) Of all poisons * those which may be called culinary are perhaps the most destructive, because they are generally the least suspected. All copper + vessels, therefore, and vessels of bell metal, which contains copper, should be laid aside. Even the common earthen ware, when they contain acids, as in pickling, become very poisonous, as they are glazed with lead, which in the smallest quantity, when dissolved, is very fatal; and even tin, the least exceptionable of the metals for culinary purposes except iron, is not always quite free of poisonous qualities, it having been found to contain a small portion of arsenic. Mushrooms and the common laurel are also very fatal. The bitter almond contains a poison and its antidote likewise. The cordial dram ratafia, much used in France, is a slow poison, its flavour being procured from the kernels of peach, black cherry stones, &c.—The spirit of lauro-cerasus is peculiarly fatal. The adulteration of bread, beer, wine, porter, &c. produces very fatal consequences, and merits exemplary punishment. Next to culinary poisons, the abuse of medicines deserves particular attention. injected by way of elyfter. From these experiments, however, he concluded, that laurel-water would kill by being injected into the blood; but in this he was deceived; for two rabbits had each of them a large teaspoonful injected into the jugular vein, without any inconvenience, either at the time of injection or afterwards. It proved innocent also when applied to the bare nerves, and even when introduced into the medullary substance.

We ought now to give some account of the proper antidotes for each kind of poison; but from what has been related concerning the extreme activity of some of them, it is evident that in many cases there can be but very little hope. People are most apt to be bit by serpents in the legs or hands; and as the poison, from the Abbé Fontana's experiments, appears to act only in consequence of being absorbed into the blood, it is plain, that to prevent this absorption is the chief indication of cure. We have recommended several methods for this purpose under the article MEDICINE, No 408.; but the Abbé Fontana proposes another not mentioned there, namely, ligature. This, if properly applied between the wounded part and the heart, must certainly prevent the bad effects of the poison; but then it tends to produce a disease almost equally fatal; namely, a gangrene of the part; and our author gives instances of animals being thus destroyed after the effects of the poison were prevented; for which reason he prefers amputation. But the good effects of either of these methods, it is evident, must depend greatly on the nature of the part wounded, and the time when the ligature is applied, or the amputation performed. If the teeth of the serpent, or the poisoned arrow, happens to strike a large vein, the only possibility of escaping instant death is to compress the trunk of the vein above the wounded place, and to enlarge the wound, that the blood may flow freely, and in large quantity, in order to wash away the poison, and discharge the infected parts of the blood itself. If this be neglected, and the person falls into the agonies of death, perhaps strongly stimulating medicines given in large doses, and continued for a length of time, may enable nature to counteract the virulence of the poison. For this purpose volatile alkalies seem most proper, as acting soonest, (see MEDICINE); and perhaps a combination of them with ether might be advantageous, as by the volatility of that medicine the activity of the alkali would probably be increased. In the Philosophical Transactions, we have an account of the recovery of a dog feebly by means of the volatile alkali, when probably he was in a dying condition. This dog indeed seems to have had a remarkable strength of constitution. The poor creature had first got two ounces of the juice of nightshade, which he bore without any inconvenience. An equal quantity of the juice of hemlock was then given him without effect. He then got a large dose of the root of wolfsbane with the same success. Two drams of white hellebore root were next given. These caused violent vomitings and purgings, but still he outlived the operation. He was then made to swallow five roots of the colchicum, or meadow-larkspur, dug fresh out of the earth. The effect of these was similar to that of the white hellebore, but still he did not die. Lastly, he got two drams of opium; and he even outlived this dose. He was first cast into a deep sleep by it; but soon awakened, and was seized with violent vomitings and purgings, which carried off the effect of the opium. Seeing then that the animal had resisted the most violent poisons, it was resolved to try the effects of the bite of a viper; and he was accordingly bit three or four times on the belly a little below the navel by one enraged. The immediate consequence of this was an incipient gangrene in the parts adjoining to the wound, as appeared by the rising of little black bladders filled with a fumous matter, and a livid colour which propagated itself all around. The motion of the heart became very faint and irregular, and the animal lay without strength or sensation, as if he had been seized with a lethargy or apoplexy. In this condition his wound was cupped and scarified, and Venice treacle (a famous antidote) applied to it. In two hours after this all the symptoms were increased, and he seemed to be nearly dead; upon which half a dram of volatile salt of hartshorn mixed with a little broth was poured down his throat; and the consequence was, that in a short time he was able to stand on his feet and walk. Another dose entirely dispelled his lethargy, and the heart began to recover its strength. However, he continued very weak; and though he ate no solid meat for three days, yet at the end of that time his strength was evidently increased. The first day he drank water plentifully and greedily, and on the second day he drank some broth. On the third day he began to eat solid meat, and seemed out of danger; only some large, and foul ulcers remained on that part of the belly which was bit, and before these were healed he was killed by another dog.

From comparing this with some other observations, indeed, it would seem that volatile alkali is the best antidote against all poisons which suddenly kill by a mixture with the blood, and even of some others. Indeed its effects in curing the bite of snakes seems to be put beyond all doubt, by a paper in the 2d volume of the Asiatic Researches, p. 323. "From the effect of a ligature applied between the bitten part and the heart (says Mr Williams, the author of the paper), it is evident that the poison diffuses itself over the body by the returning venous blood; destroying the irritability, and rendering the system paralytic. It is therefore probable, that the volatile caustic alkali, in resisting the disease of the poison, does not act so much as a specific in destroying its quality, as by counteracting the effect on the system, by stimulating the fibres, and preserving that irritability which it tends to destroy."

But whatever be the mode of its operation, the medicine is unquestionably powerful. Mr Williams used either the volatile caustic alkali, or eau-de-luce; the former of which he seems to have preferred. Of it he gave 60 drops as a dose in water, and of the eau-de-luce he gave 40, at the same time applying some of the medicine to the part bitten, and repeating the dose as he found occasion. Of seven cases, some of which were apparently very desperate, only one died, and that appears to have been occasioned by bad treatment after the cure. Many of the patients were perfectly recovered in seven or eight minutes, and none of them required more than two hours: On the whole, Mr Williams says that he "never knew an instance of the volatile caustic alkali failing in its effect, where the patient has been able to swallow it." Dr Mead affirms, that the alkali counteracts the deadly effects of laurel-water: we have seen its effects in curing the bite of a viper, and of snakes; and from... from Dr Wolfe's experiments on hydrophobic patients, it may even claim some merit there. Still, however, there is another method of attempting a cure in such deplorable cases; and that is, by injecting into the veins anything which will not destroy life, but will destroy the effects of the poison. It is much to be regretted, that in those cruel experiments which we have already related, the intention seems almost always to have been to kill the animal at all events; whereas, it ought to have been to preserve him alive, and to ascertain what medicines could be safely injected into the blood, and what could not, with the effects which followed the injection of different quantities, none of which were sufficient to destroy life. But in the way they were managed, scarce any conclusion can be drawn from them. Indeed it appears that little good is to be expected from this mode; it is mere speculation, and future experiments must show whether it ever shall be used for the cure of poisons, or for any other purposes: its being now totally laid aside, seems to militate strongly against the efficacy of it; besides, the extreme cruelty of the operation will ever be a strong bar to its general introduction. See Injection.

There still remains another method of cure in desperate cases, when there is a certainty that the whole mass of blood is infected; and that is, by the bold attempt of changing the whole diseased fluid for the blood of a sound animal. Experiments of this kind have also been tried; and the method of making them, together with the consequences of such as are recorded in the Philosophical Transactions, we shall notice under the article Transfusion.

Dr Mead, finding that many pretenders to philosophy have called the goodness of the Creator in question, for having created substances whose manifest and obvious qualities are noxious and destructive, remarks, by way of answer, that they have also salutary virtues. But, besides their physical effects, they are likewise food for animals which afford us good nourishment, goats and quails being fattened by heliobore, starlings by hemlock, and hogs innocently eating henbane; besides, some of those vegetables, which were formerly thought poisonous, are now used in medicine, and future discoveries may probably increase the number. The poison of many vegetables is their only defense against the ravages of animals; and by means of them we are often enabled to defend useful plants from the destroying insect; such as by sprinkling them with essential oil of turpentine; and by means of some substances poisonous to them, we are enabled to destroy those insects which infect the human body, and the bodies of domestic animals, &c.—As for poisonous minerals, arsenic for example, Dr Mead observes, that it is not a perfect mineral, but only an active substance, made use of by nature in preparing several metals in the earth, which are of great service to mankind; and, after confirming this by several instances, he concludes by saying, the case will be found much the same in all natural productions of this kind. As for poisonous animals, &c., their noxious qualities may easily be accounted for, by reflecting that it is their only mode of self-defense.

Poison of Copper. This metal, though when in an undissolved state it produces no sensible effects, becomes exceedingly active when dissolved; and such is the facility with which the solution is effected, that it becomes a matter of some consequence to prevent the metal from being taken into the human body even in its proper form. It doth not, however, appear that the poison of copper is equally pernicious with those of arsenic or lead; much less with some others treated of in the last article. The reason of this is, that it excites vomiting so speedily as to be expelled, even though taken in considerable quantity, before it has time to corrode the stomach. Roman vitriol, which is a solution of copper in the vitriolic acid, has been used as a medicine in some diseases with great success. Verdigris also, which is another very active preparation of the metal, has been by some physicians prescribed as an emetic, especially in cases where other poisons had been swallowed, in order to procure the most speedy evacuation of them by vomit. Where copper is not used with this view, it has been employed as a tonic and antipathodic, with which it has been admitted into the Edinburgh Dispensatory under the title of Cuprum Ammoniacale. The effects of the metal, however, when taken in a pretty large quantity, and in a dissolved state, or when the stomach abounds with acid juices sufficient to dissolve it, are very disagreeable and even dangerous; as it occasions violent vomitings, pains in the stomach, faintings, and sometimes convulsions and death. The only cure for these symptoms is to expel the poison by vomiting as soon as possible, and to obviate its acrimony; for which purpose drinking warm milk will probably be found the most efficacious remedy. In order to prevent the entrance of the poison into the body, no copper vessels should be used in preparing food but such as are either well tinned or kept exceedingly clean. The practice of giving a fine blue or green colour to pickles, by preparing them in copper vessels, ought not to be tolerated; for Dr Falconer, in a treatise on this subject, affirms us, that these are sometimes so strongly impregnated by this method of preparing them, that a small quantity of them will produce a slight nausea.—Mortars of brass or bell-metal ought for the same reason to be avoided, as by this means a considerable quantity of the pernicious metal may be mixed with our food, or with medicines. In other cases, an equal caution ought to be used. The custom of keeping pins in the mouth, of giving copper halfpence to children to play with, &c., ought to be avoided; as thus a quantity of the metal may be infensibly taken into the body, after which its effects must be uncertain.—It is proper to observe, however, that copper is much more easily dissolved when cold than when hot; and therefore the greatest care should be taken never to let any thing designed for food, even common water, remain long in copper vessels when cold; for it is observed, that though the confectioners can safely prepare the most acid syrups in clean copper vessels without their receiving any detriment whilst hot, yet if the same syrups are allowed to remain in the vessels till quite cold, they become impregnated with the pernicious qualities of the metal.

To what has now been said relative to the effects of mineral poisons, we shall add an account of some experiments, showing that a mineral poison may produce sudden and violent death, although the noxious matter cannot be detected by chemical tests in the contents of the stomach. As the subject of this investigation is of great importance in many points of view, we shall make no apology for laying the whole detail before our readers without without abridgement. The experiments were made by Dr Botstock of Liverpool, and the account of them is given by the author in a letter to the editor of the Edinburgh Med. and Surg. Journal, v. 14.

"In compliance with your request, I fend you an account of some of the experiments which I made to illustrate the question, which was proposed to me at the late memorable trial at Lancaster, whether it was possible that a mineral poison might produce a sudden and violent death, and yet be afterwards incapable of detection in the contents of the stomach? You have already seen, in the pamphlet that was published by Drs Gerard and Rutter, Mr Hay, and myself, the effect which was produced upon dogs by corrosive sublimate. We there relate the result of two experiments, in which it was given to dogs in solution; vomiting, purging, and the symptoms of violent pain ensued, which after some hours were terminated by death. The contents of the stomach, it is stated, were analysed by me, but none of the sublimate could be detected. In the first experiment, 1/4 grains of the salt were given, and in the second 4 grains; this latter being the larger quantity, and also the one in which the process was conducted with the most accuracy, I shall confine myself to relate the circumstances of this alone.

"When the stomach of the dog was opened, a small quantity of water was added to wash out its contents more completely, making the whole somewhat less than one ounce. It was deeply tinged with blood, and I let it remain at rest for 30 hours, in order that the colouring matter might subside from it. It had then acquired a very fetid smell, and not being much clearer than at first, I added to it about an equal quantity of water, and passed it, first through a linen strain, and afterwards through a paper filter. It was now nearly transparent, but slightly tinged with blood.

"A solution of corrosive sublimate was prepared, containing 1/8 of its weight of the salt. Into a quantity of this solution the recently prepared muriate of tin was dropped, which produced an immediate and very copious precipitation. Caustic potash also threw down a precipitate, although in small quantity. The same tests were then added to the fluid taken from the stomach, but no effect was produced by the muriate of tin for some hours, when at length it became, in some degree, opake. The effect here, both as to time and the nature of the appearance, was quite different from the precipitate in the solution of corrosive sublimate, and I considered it as depending upon the action of the muriate of tin upon the mucus. In proof of this, when the stomach fluid had potash added to it, instead of having a precipitate thrown down, it was rendered more transparent than before the experiment. The solution of corrosive sublimate was subjected to the action of galvanism, by having a piece of gold placed in it, clasped by zinc wire; in an hour the gold was obviously whitened by the precipitation of the mercury upon it. The fluid taken from the stomach was submitted to the same process for three hours, but no effect was produced (c). The fluid from the stomach did not exhibit either acid or alkaline properties; it was copiously precipitated by the nitrate of silver, shewing that it contained muriatic acid.

"On the following day, a slight brown precipitate had subsided from the stomach fluid, and the whole had become very opake. The precipitate was dissolved by potash, at the same time that the fluid was rendered more transparent. It was become extremely putrid. The putridity increased; and, in two days more, a scum was formed on the surface, and the sides of the glass were also encrusted with a gray matter. The experiments were performed between the 17th and 22nd of August.

"The following experiments were then made on the corrosive sublimate, with every possible attention to accuracy. Two grains of the salt were dissolved in 600 grains of distilled water. This I call solution No 1. Ten grains of No 1. were then added to 90 grains of water, forming solution No 2, in which the fluid would contain 1/6 of its weight of the sublimate. Into 10 drops of No 2, two drops of the muriate of tin were added, and caused a very obvious precipitate. Ten grains of No 2. were added to 90 grains of distilled water, making the fluid to contain 1/6 of its weight of the salt. Into 10 drops of this solution, two drops of the muriate of tin were added, and an immediate gray cloud was perceptible in the fluid, although no precipitate was thrown down. The galvanic process was repeated with the solution No 3.; it remained six hours, and I thought I perceived a whiteness on one part of the gold; but it was not very distinctly visible.

"From these experiments, we may draw the following conclusions:

"1. The fluid taken from the dog's stomach contained muriatic acid, probably in the form of common salt, and animal matter, probably mucus, in considerable quantity.

"2. The tests that were employed to discover the corrosive sublimate, were capable of detecting it in a fluid, when it composed only 1/6 of its weight.

"3. These tests did not detect any corrosive sublimate in the fluid taken from the dog's stomach; it may therefore be concluded,

"4. That an animal may be suddenly killed by receiving a metallic poison into the stomach, and yet that the nicest tests may not be able to detect any portion of the poison after death, in the contents of the stomach.

"This conclusion appears incontrovertible; and though some analogous facts had occasionally been noticed*, it is so different from the generally received opinion upon the subject, that I think it must have considerable influence on all future judicial proceedings, in which the question of poisoning is agitated."

Poison of Lead. See Medicine, No 303.

Poison-Tree. See Rhus, Botany Index.

Poison-Tree of Java, called in the Malayan language bohun upas, is a tree which has often been described by naturalists; but its existence has been very generally doubted, and the descriptions given of it, containing much of the marvellous, have been often treated as idle fictions. N. P. Forster, however, in an account of it, written in Dutch, affirms that it does exist; and

(c) This experiment was performed at the suggestion of Dr Wollaston. Poison tells us, that he once doubted it as much as any person; but, determined not to trust general opinions, he made the most particular inquiries possible; the result of which was, that he found that it is situated in the island of Java, about 27 leagues from Batavia, 14 from Soura Charta, the emperor's seat, and about 19 from Tinkjoe, the residence of the sultan of Java. It is surrounded on all sides by hills and mountains, and the adjacent country for 12 miles round the tree is totally barren. Our author says he has gone all round the spot at about 18 miles from the centre, and on all sides he found the country equally dreary, which he attributes to its noxious effluvia. The poison procured from it is a gum, issuing from between the bark and the tree; and it is brought by malefactors who have been condemned to death, but who are allowed by this alternative to have a chance for their life. An old ecclesiastic, our author informs us, dwelt on the outside of the surrounding hills, whose business it was to prepare the criminals for their fate, if death should be the consequence of their expedition. And indeed so fatal are its effluvia, that he acknowledged that scarcely two out of 20 returned from above 700 whom he had dismissed.

Mr. Foerch farther tells us, that he had seen several of the criminals who had returned, and who told him, that the tree stands on the borders of a rivulet, is of a middling size, and that five or six young ones of the same kind stand close to it. They could not, however, see any other plant or shrub near it; and the ground was of brownish sand, full of stones and dead bodies, and difficult to pass. The Malays think this tract was thus rendered noxious and uninhabitable by the judgment of God, at Mahomet's desire, on account of the sins of the inhabitants. No animal whatever is ever seen there; and such as get there by any means never return, but have been brought out dead by such of the criminals as have themselves escaped death.

Our author relates a circumstance which happened in the year 1775, to about 400 families (1600 souls), who refused to pay some duty to the emperor, and who were in consequence declared rebels and banished; they petitioned for leave to settle in the uncultivated parts round Upas: the consequence of which was, that in less than two months their number was reduced to about 300 souls, who begged to be reconciled to the emperor, and were again received under his protection. Many of these survivors Mr. Foerch saw, and they had just the appearance of persons tainted with an infectious disorder.

With the juice of this tree arrows, lancets, and other offensive weapons, are poisoned. With lancets thus poisoned, Mr. Foerch observes, that he saw 13 of the emperor's concubines executed for infidelity to his bed in February 1776. They were lanced in the middle of their breasts; in five minutes after which they were seized with a tremor and subfulvus tendinum, and in 15 minutes they were dead. Their bodies were full of livid spots, like those of petechiae, their faces swelled, colour blue, and eyes yellow, &c. Soon after he saw seven Malaysians executed in the same way, and saw the same effects follow; on which he resolved to try it on other animals, and found the operation similar on three puppies, a cat, and a fowl, none of which survived more than 13 minutes. He also tried its effects internally on a dog seven months old; the animal became delirious, was seized with convulsions, and died in half an hour. From all which our author concludes, that it is the most violent of all vegetable poisons, and that it contributes greatly to the unhealthiness of the island in which it grows. By means of it many cruel and treacherous murders are perpetrated. He adds, that there exists a fort of cajoc-upas on the coast of Macassar, the poison of which, though not near so violent or malignant, operates nearly in the same manner.

Most of our readers will probably consider this whole account as highly incredible; but we have to add, that it has been directly controverted in all its parts in a memoir of Lambert Nolst, M.D., fellow of the Batavian Experimental Society at Rotterdam, (see Gentleman's Mag. May 1794, p. 433.) This memoir was procured from John Matthew à Rhyn, who had been 23 years, from 1763 to 1786, resident in the island, and therefore had every opportunity of informing himself on the spot. In this memoir we are told, that Foerch's account of the tree is extremely suspicious, from a variety of circumstances: 1. Though he had letters of introduction, he went to no considerable house, and afterwards privately withdrew among the English. 2. When the emperor was asked respecting Foerch, and the facts he relates, he answered, that he had never heard either of him or of the tree. 3. The distances given to mark the situation of the tree are not accurate. 4. The execution of criminals is different from what he represents. 5. The circumstance of several criminals returning when Foerch was there, has a suspicious appearance. 6. There exists no such tradition, as that the tree was placed there by Mahomet. 7. There were no such disturbances in 1775 as Foerch represents, the tract to which he alludes having submitted to the Dutch East India Company as early as 1756. 8. The island is not unhealthy, as Foerch affirms; nor are violent or premature deaths frequent. 9. The Javanese are a curious and intelligent people, and of course could not be ignorant of this tree if it had any existence. 10. The assertions and pretended facts of Foerch have no collateral evidence; and everything which we gather from the accounts of others, or from the history of the people, invalidates them. For these and other reasons, Dr. Nolst concludes, that very little credit is due to the representations of Foerch, and that the island of Java produces no such tree, which, if it really grew there, would be the most remarkable of all trees.

We must notice also, that the account of this very remarkable tree has been still farther controverted by Sir George Staunton, who, during his stay at Batavia, made the most particular inquiries concerning it, and found, that the existence of such a tree had never been known there. (Embassy to China). The fabulous history of this tree, however, has produced a most beautiful description from the muse of Dr. Darwin, whose harmonious verses on the subject we shall present to our readers.

Where seas of glass with gay reflections smile Round the green coasts of Java's palmy isle, A spacious plain extends its upland scene, Rocks rise on rocks, and fountains gush between; Soft zephyrs blow, eternal summers reign, And showers prolific blest the soil,—in vain! —No spicy nutmeg scents the vernal gales, Nor towering plantain shades the mid-day vales; No grassy mantle hides the fable hills, No flowery chaplet crowns the trickling rills; Nor tufted moss, nor leathery lichen creeps In rufflet tapestry o'er the crumbling steeps. —No step retreating, on the sand impreg'ned, Invites the visit of a second guest; No refulgent star the unpeopled stream divides, No revolant pinion cleaves the airy tides; Nor hallowed moles, nor beaked worms return, That mining paws the irremediable bourn.— Fierce in dread silence on the blasted heath Fell UPAS fits, the HYDRA-TREE of death. Lo! from one root, the envenom'd foil below, A thousand vegetative serpents grow; In shining rays the scaly monster spreads O'er ten square leagues his far-diverging heads; Or in one trunk entwists his tangled form, Looks o'er the clouds, and hisses in the storm. Steep'd in fell poison, as his sharp teeth part, A thousand tongues in quick vibration dart; Snatch the proud eagle towering o'er the heath, Or pounce the lion, as he stalks beneath; Or strew, as marshall'd hosts contend in vain, With human skeletons the whitened plain. —Chain'd at his root two fiend-demons dwell, Breathe the faint hiss, or try the shriller yell; Rise fluttering in the air on callow wings, And aim at insect-prey their little flings.

Loves of the Plants, canto iii.