Imagens da página



The Cape of Good-Hope, the most fertile source of curious and beautiful plants, affords numerous species of Wood Sorrel, and among others the present one, which is distinguished for the largeness of its blossoms; they are of a fine yellow colour, and when expanded by the influence of the sun, make a very conspicuous figure in the green-house; it begins to flower early in April, and continues about two months in bloom, many flowering stems arising from the same root.

This species is of free growth, and increases plentifully by bulbs, which are produced on the crown of the root as well as on its fibres; these when the plant decays should be taken up, and two or three of the largest planted in the middle of a pot filled with a mixture of bog earth and rotten leaves, well incorporated; towards winter the pots should be placed in the green-house, or in a frame so secured as perfectly to keep out frost.

Toxicologists (says Dr. Taylor on Poisons, p. 523) have not enumerated these plants among vegetable poisons; they have been commonly treated as pot-herbs. Wibmer states that they have a slightly irritant action on the stomach. Mr. Hanks has reported two cases, in one of which very serious symptoms were induced in a child who had eaten common sorrel (Rumex acetosa). A child, astat. 6, suddenly lost his appetite, complained of sickness and heaviness in the head, and soon afterwards fainted. When he recovered he was unable to stand, and vomited a quantity of greenish-coloured matter. Insensibility came on with convulsions of the extremities. The cause of his illness was not then suspected, and the patient continued to suffer for several days, complaining of soreness of the epigastrium, and pain extending from the fauces to the stomach. There was also great thirst, and he occasionally vomited green vegetable matter. He recovered under treatment in about ten days. In the second case the patient suffered chiefly from severe pain in the bowels. The symptoms were soon relieved by the action of an emetic—which in this, as in all other cases of vegetable irritant poisoning, is the appropriate remedy. (Med. Gaz. vol. xl. page 69).

It appears somewhat difficult to refer these effects to the small quantity of binoxalate of potash present in these plants, yet, as in other instances, the recent vegetable may have a more powerful action than the quantity of the poisonous salt actually contained in it, would indicate. In the first of the two cases it was remarked by Mr. Hanks that four leeches which were applied to the skin, dropped off dead. A similar fact has been observed in poisoning by oxalic acid. This gentleman refers to a case of recent occurrence in Bath, in which the plant proved fatal to a child. Sorrel was found in its stomach, the lining membrane of which was injected and diffusely tinged.

Analysis.—The leaves and shoots of these plants admit of identification only by their botanical characters. If the quantity eaten be large, binoxalate of potash may be separated from the contents of the stomach by making a decoction. This must be filtered hot, as six-sevenths of the salt are precipitated from a hot solution by cooling.

"There is in Professor Kalm's Travels in North America, an account given of a species of Sumach called the poison-ash. Of this tree you may have perhaps heard, as its noxious qualities are supposed to have suggested the many tales that formerly obtained belief respecting the upas-tree. . The shadow of this tree was said to cast death or sickness upon all over whom it fell; and every living creature who unwisely wandered under it was reported to fall an almost immediate victim to its dangerous properties. Several species of Sumach are planted in England, but the Rhus toxicodendron will not, I believe, flourish in our country, although it has been successfully cultivated in France, and used there medicinally.

"An incision being made into the tree," says the Professor, " a whitish-yellow juice, which has a nauseous smell, comes out between the bark and the wood. This tree is not known for its good qualities, but greatly so for the effect of its poison, which, though it is noxious to some people, yet does not in the least affect others; and therefore one person can handle the tree as he pleases,—cut it—peel off the bark—rub it, or the wood, upon his hands—smell it—spread the juice upon his skin, and make more experiments with no inconvenience to himself; another person, on the contrary, dares not meddle with the tree while its wood is fresh; nor can he venture to touch a hand which has handled it, nor even to expose himself to the smoke of a fire which is made with this wood, without soon feeling its bad effects, for the face, the hands, and frequently the whole body, swells excessively, and is affected with very acute pain. Sometimes blisters arise in great quantity, and make the sick person look as if he were infected with the leprosy. In some persons the external skin or cuticle peels off in a few days, as is the case when any person has burnt or scalded any part of his body. Nay, the nature of some persons will not allow them to approach the place where the tree grows, or to expose themselves to the wind when it carries the effluvia or exhalations of this tree with it, without letting them feel the inconvenience of the swelling which I have just now described. Their eyes are shut up for one or two days together by the swelling. I know two brothers, one of whom could, without danger, handle the tree in what manner he pleased, whereas the other could not come near it without swelling. A person sometimes does not know that he has touched this poisonous plant, or that he has been near it, before his face and hands show it by the swelling. I have known some old people who were much more affected by this tree than a viper; and I was acquainted with a person who, merely by the noxious exhalations of it, was swelled to such a degree that he was stiff as a log of wood, and could only be turned about in sheets.

"I have tried experiments of every kind with the poison-tree on myself. I have spread its juice upon my hands—cut and broke its branches—peeled off its bark, and rubbed my hands with it—smelt it—carried pieces of it in my bare hands, and repeated all this frequently without feeling the baneful effects so commonly annexed to it; but I, however, once experienced that the poison of the Sumach was not entirely without effect upon me. On a hot day in summer, when I was in some degree of perspiration, I cut a branch of the tree, and carried it in my hand for about half an hour together, and smelt at it now and then. I felt no effects from it in the evening, but next morning I awoke with a violent itching of the eye-lids and the parts thereabouts. It ceased after I had washed my eyes for awhile with cold water, but my eye-lids were very stiff all that day. At night the itching returned, and in the morning when I awoke I felt it as ill as the morning before, and I used the same remedy against it. However it continued almost for a whole week together, and my eyes were very red, and my eyelids with difficulty recovered during that time."

The Professor adds that he never had heard that the effects of the tree were more lasting than a few days. In some places the tree is destroyed, that it may not injure those who are obliged to labour near it.

This Sumach, whose pernicious influence was indeed scarcely exaggerated by the accounts of the Upastree, is a native of Pennsylvania, New Carolina, and some other places both of the eastern and western hemispheres, and is described as a tall and beautiful tree.

The fragrance of flowers is a source of continual delight to all accustomed to seek their enjoyment in the open air, either of the field or the garden. It affords surely as plain a manifestation of the goodness of God towards us as may be evinced by any indication of the usefulness of plants; since it proves that it is the design of God that life should not only be supported, but enjoyed. James Montgomery has beautifully said that " Flowers are in the book of Nature what the words ' God is love' are in that of Revelation." Yet the poisonous effluvia that I have mentioned as proceeding from some plants, and the offensive scents emitted by others, may at first sight appear to be at variance with my remarks on the benevolence by which the usual operations of nature are directed.

With regard to the poisonous influence diffused on the air, I may remark that it is evidently designed as a warning that we may not eat the plant; that the poison itself is in many instances very useful in medicine, when judiciously administered; and that in many cases, where it appears to render no service to man, it his owing to his ignorance of the purposes to which it might be applied. Many new and interesting discoveries are daily occurring which should convince us, that in the application of poisons there is yet much for the investigations of other days to reveal.

The scent of the carrion plants may, as Sir James Smith observes, be agreeable to the Hottentots, in whose country they abound; and you will not consider this surmise improbable, when you remember that to the Chinese a dish of rotten eggs, however revolting to our tastes, offers a dainty repast. Even where it is impossible to account for fetid odours by these means, we must consider that they are so placed as that it is in our power to avoid them; and that they do not, like the various sweet plants with which our earth is covered, meet us at every step of our country walk. Above all, we must never forget that tliis world is not in the state in which it came out from the hand of God, when, having looked upon all the works which he had made, he pronounced them "very good." There were no poisons in the Garden of Eden, for death or sickness would never have entered there; and it was not until God had cursed the earth for man's transgression that it bore briers and thorns. Beautiful and pleasant to the eye and ear as is nature, even yet,— retaining much to win our love and admiration of its beneficent Author,—it yet bears the traces of man's disobedience and consequent punishment.

« AnteriorContinuar »