Of Poisoning with False Angustura Bark.
Besides these poisons of the genus Strychnos, the present group comprehends another, of the same properties, which was once supposed to be derived from a plant of a different family, the Brucea antidysenterica.
A species of bark, commonly called the false angustura bark, was introduced by mistake into Europe instead of the true angustura, cusparia, or bark of the Galipea officinalis. It was long supposed to be the bark of the Brucea antidysenterica; but it is now known to be the bark of S. nux vomica.[[2362]] It is a poison of great energy. It gave rise to so many fatal accidents soon after its introduction, that in some countries on the continent all the stores of angustura were ordered to be burnt. It contains a less proportion of strychnia, but more of the alkaloid brucia than nux vomica, the seed of the plant.
According to Andral, brucia is twenty-four times less powerful than strychnia;[[2363]] but the bark itself is as strong nearly as nux-vomica, for Orfila found that eight grains killed a dog in less than two hours.[[2364]]
The symptoms it induces are the same as those caused by nux vomica. They are minutely detailed in a paper by Professor Emmert of Bern.[[2365]] It appears that during the intervals of the fits the sensibility is remarkably acute: a boy who fell a victim to it implored his physician not to touch him, as he was immediately thrown into a fit. Professor Marc of Paris was once violently affected by this poison, which he took by mistake for the true angustura to cure ague. He took it in the form of infusion, and the dose was only three-quarters of a liqueur-glassful; yet he was seized with nausea, pain in the stomach, a sense of fulness in the head, giddiness, ringing in the ears, and obscurity of vision, followed by stiffness of the limbs, great pain on every attempt at motion, locked-jaw, and impossibility of articulating. These symptoms continued two hours; and abated under the use of ether and laudanum.[[2366]]
Some interesting experiments were made by Emmert with this poison to show that it acts on the spine directly, and not on that organ through the medium of the brain. If an animal be poisoned by inserting the extract of false angustura bark into its hind-legs after the spinal cord has been severed at the loins, the hind-legs as well as the fore-legs are thrown into a state of spasm; or if the medulla oblongata be cut across and respiration maintained artificially, the usual symptoms are produced over the whole body by the administration of it internally or externally,—the only material difference being that they commence more slowly, and that a larger dose is required to produce them, than when the medulla is not injured. On the other hand, when the spinal cord is suddenly destroyed after the symptoms have begun, they cease instantaneously, although the circulation goes on for some minutes.[[2367]]
The true angustura bark has a finer texture than the other, and is darker coloured, aromatic, pungent, and less bitter. The ferro-cyanate of potass causes in a muriatic infusion of the false bark a precipitate, which is first green and then becomes blue; and the same reagent converts into blue the reddish powder which lines the bark. No such effects are produced on the true angustura bark. Nitric acid renders the rusty efflorescence of the spurious bark deep dirty blue, but has no such effect on the true bark; which, besides, never exhibits a yellow efflorescence.
With the preceding poisons Orfila has arranged also some poisons used by the American Indians; but, as in Europe they are mere objects of curiosity, it is scarcely necessary to treat of them particularly here.
The most interesting and best known of them is the wourali poison of Guiana, variously called woorara, urari, or curare, by different authors. It is believed to have been traced by Martius to a new species of strychnos, the S. guianensis, and more recently by Dr. Schomburg to a different species, the S. toxicaria of that traveller. But the action it exerts does not correspond exactly with what would be expected of a plant belonging to that genus.
The effects of wourali have been investigated by Sir B. Brodie in the Philosophical Transactions for 1811–12, in Orfila’s Toxicology, in Magendie’s Memoir on Absorption, and in Fontana’s Traité des Poisons. But the most detailed inquiry is that by Emmert, published in 1818. It produces, not convulsions or spasm of the muscles, but on the contrary paralysis, and probably occasions death in this way by suspending the respiration, in the same way as hemlock and conia. According to Emmert’s experiments the spine only is acted on, and not the brain also.[[2368]] Some remarkable experiments were made in 1839 by Mr. Waterton, to show the power of artificial respiration in accomplishing recovery from its effects. After the animals had fallen down motionless from the action of the poison introduced through a wound, and when the action of the heart had become so feeble as not to affect the pulse, artificial respiration, continued in one instance for seven hours and a half, and in another for two hours, had the effect of restoring the animals to health.[[2369]]