The Cicuta Virosa, or water hemlock, with which the conium maculatum has been often confounded, is still more virulent; it is however to be distinguished from the latter, by having its hollow roots always immersed in water, while those of the conium never are. M. Orfila has related several cases of poisoning by the water hemlock.
Nux Vomica.
This is the seed of the Strychnus Nux Vomica (Pentandria Monogynia, Nat. Ord. Apocyneæ, Juss.)
The tree[[456]] which produces these seeds grows in Ceylon, upon the coast of Coromandel, and in Malabar. The nux vomica is round and flat, about an inch broad, and nearly a quarter of an inch thick, with a prominence in the middle on both sides, of a grey colour, covered with a kind of woolly matter, but internally hard and tough. The kernel discovers to the taste a considerable bitterness, but makes little or no impression on the organs of smell. There is a popular belief that this substance is poisonous to all animals, except man. Instances, however, are not wanting to illustrate its deleterious effects upon the human species. It proves fatal to dogs in a very short period; it has also poisoned hares, foxes, wolves, cats, rabbits, and even some birds. Loureiro relates that a horse died in four hours after taking a drachm of the seed in an half roasted state. Its effects, however, on different animals, and even on those of the same species, are somewhat uncertain, and not always in the proportion to the quantity given. With some animals it produces its effects almost instantaneously: with others, not until after the lapse of several hours, when laborious respiration, followed by torpor, tremblings, coma, and convulsions usually precede the fatal spasms, or Tetanus, which so especially distinguishes the operation of this poison. Hoffman reports the case of a young girl of ten years of age, who, labouring under an obstinate quartan fever, took, at two doses, fifteen grains of nux vomica, and died very shortly afterwards. MM. Pelletier and Caventou have discovered in these seeds, a peculiar proximate principle, to which their virulence is owing; it was originally named Vauqueline, in honour of the celebrated French philosopher, but in deference to the opinion of the French Academy of Sciences, the discoverers have substituted the name Strychnia,[[457]] because “a name dearly loved, ought not to be applied to a noxious principle!”
Strychnia is highly alkaline, and crystallizes in very small four-sided prisms, terminated by four-sided pyramids; its taste is insupportably bitter, leaving a slight metallic flavour, and is so powerful as even to be perceptible when a grain is dissolved in eighty pounds of water;[[458]] it has no smell. So extreme is its activity upon the animal system, that in doses of half a grain it occasions serious effects, and in larger ones, convulsions and death. It is, perhaps, the most powerful, and, next to hydro-cyanic acid, the most rapid of poisons. M. Majendie has killed a dog with one-eighth of a grain; and the editor of the Edinburgh Medical and Surgical Journal has seen one die in two minutes after the injection of one-sixth of a grain into the cavity of the pleura.
Nux vomica is supposed by Orfila to exert a specific action on the spinal marrow, thereby producing tetanus, immobility of the thorax, and consequently asphyxia, of which the animal dies. That this effect is produced by the absorption of the poison, and its passage into the circulation, is clearly established by the interesting and important experiments of M. Majendie.[[459]]
Cocculus Indicus.
This is the fruit of a shrub (Menispermum Cocculus) which grows naturally in the sand, in the midst of the rocks, on the coast of Malabar, in the island of Ceylon, and in other parts of the East Indies. The berries are imported into this country in a dry and shrivelled state. In India they are employed for killing fish, which they intoxicate and poison, when thrown into fish ponds. M. Goupil, a physician of Nemours, communicated to the Society of Medicine some interesting facts on the subject of this poison;[[460]] and he has shewn that it is not only destructive to fishes, but also to different carnivorous quadrupeds, and, very probably, to man. He also states that the poisonous principle of this substance is not sensibly changed by the gastric juices, and the vital action of the organs of digestion; but, on the contrary, that it passes into the absorbent system with all its properties unimpaired; and that the flesh of those fishes which have eaten it, irritates the stomach and bowels of the animals to which it is given, nearly in the same manner as the Cocculus Indicus itself. All the fishes who eat it do not die in an equal space of time. Roach, pollard, breme, perch, tench, and barbel, are affected in an order corresponding with that in which they are here arranged; the roach is killed the easiest of all; the barbel is the last to die, and is moreover said to be, of all fish, the one whose flesh the most frequently occasions accidents in those animals who eat it; probably, says M. Goupil, because these fish, taking a longer time to die, the poison is longer subjected to the action of the digestive juices, and a considerable quantity of it is consequently absorbed.[[461]]
Late experiments[[462]] have shewn that the active principle of the cocculus Indicus is an alkaline body, crystallizable, bitter, and extremely poisonous; to this principle, M. Boullay has given the name of picrotoxine, and the experiments of M. Orfila have confirmed the idea of its constituting the only active element of the seeds.
Poisonous Mushrooms.
The common mushroom, or champignon, (Agaricus Campestris) has been long esteemed an article of epicurean delicacy; and is eaten in its fresh state either stewed or boiled; and as a preserve, in the form of pickle or powder. Its juice, moreover, furnishes the sauce so well known by the name of ketchup,[[463]] or catsup. Mr. Miller informs us that the true eatable mushroom may be easily distinguished from the poisonous and unpleasant species by the following characters. “When young, it appears of a roundish form, smooth, like a button; which together with its stalk, is white, especially the fleshy part of the button; the gills within, when broken, are livid. As it grows larger, it expands its head by degrees into a flat form; the gills underneath are at first of a pale flesh-colour, but become blackish on standing.” There are besides a vast number of species which may be eaten with perfect impunity; the Agaricus Procerus, or tall mushroom, is sometimes exposed for sale in Covent Garden market, and is quite harmless; although, when preserved in pickle, it is very apt to run into the vinous fermentation. With equal safety the Agaricus Pratensis, or Scotch bonnet, as it has been called, may be eaten; it occurs in those patches which are well known by the popular name of fairy rings. The Agaricus deliciosus is considered by Withering to have been the mushroom which formed the vehicle of poison to Claudius Cæsar, as related at page [134] of this volume, and which has been celebrated by the satiric pen of Juvenal, and the epigrammatic muse of Martial; a species of mushroom, observes Withering which is still highly esteemed in modern Italy, as it was in ancient Rome. Schæfer and Clusius, however, consider the plant in question to have been the Agaricus Xerampelinus, a species which although esculent, has a strong, and by no means an agreeable flavour. The common champignon has never, as far as we can learn, produced any mischief, although a popular opinion prevails that soil, shade, and other local circumstances, may render it virulent. If any unpleasant symptoms were to follow its ingestion, we should be inclined to regard them as the result of the peculiar idiosyncrasy of the individual, rather than as the consequence of an absolute poison; indeed a question has been raised how far such an explanation may not apply to all the cases of poisoning from this tribe of plants; for it has been observed that in many parts of Europe several of those species of mushroom are eaten with impunity, that are regarded by us as most virulent poisons; of this number we may reckon the Agaricus Piperatus, or Pepper Agaric, which is eaten in great quantity by the Russians, who fill large vessels with them in the autumn, seasoning or pickling them with salt, and then eating them in the ensuing lent.[[464]] There is, however, too much direct evidence in favour of the existence of an acrid poison in certain Agarics, to allow the supposition of their being relative[[465]] in their operation, as exemplified in the history of the Agaricus Muscarius, or Bugagaric, which is so called from its power in destroying these insects; and for which purpose the inhabitants of the north of Europe infuse it in milk, and set it in their windows. It constitutes the Mouchomore of the Russians, Kamtschadales, and Koriars, who use it for the sake of intoxication; upon some occasions they eat it dry, but generally it is steeped in a liquor made with the Epilobium Angustifolium; upon drinking which, they are seized with convulsions in all their limbs, followed by raving delirium: an effect which renders it a desirable potation[[466]] to those who intend to accomplish any desperate act, or premeditated assassination. It is also stated that those who drink the urine of persons intoxicated by this agaric, experience the effects of the mushroom. Withering,[[467]] who has been very assiduous in the display of this species, acknowledges ten varieties, all of which are natives of Britain. The Agaricus Semi-globalus of this botanist, and which is identical with the A. Glutinosus of Curtis, is extremely poisonous, and has proved fatal in several instances in this country. There are a great many other species equally destructive, but notwithstanding the labour that has been bestowed upon this branch of natural knowledge, much remains to be explained. The ancients appear to have taken considerable pains in discriminating between esculent and poisonous fungi; among the moderns, Clusius has furnished a mass of information. Withering has described with great botanical minuteness and accuracy the different species and varieties of this extensive genus of the cryptogamia; but he has failed in pointing out the poisonous, from the esculent and harmless species. Orfila, in his late lessons on Poisons,[[468]] has bestowed considerable labour with a view to establish a practical distinction, and has enriched his work with highly illustrative engravings. Upon the present occasion, it is scarcely necessary to observe, that it would be foreign to the plan of this work to enter into such botanical details as the full elucidation of this subject would require; the research would, in itself, occupy a quarto volume; we must therefore rest satisfied with general observations. The following indications should excite a suspicion of mushrooms. A marshy and shady locality; an ugly or lurid physiognomy; a glairy or moist surface; a change of colour when cut, and a soft, porous, and moist texture; a virulent smell; a bright colour, or a combination of distinct colours. We ought also to reject as dangerous all those which have bulbous and soft stems, or which have fragments of skin glued to their surface.