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Show [ J06 J vVhat time the eve her gauze pellucid fpreads O'er the di1n flowers, and veils the mifiy 1neads ; Slow o'er the twilight fands or leafy walks, With gloo1ny dignity DrcTAMNA fialks; In fulphurous eddies round the weird dame Plays the light gas, or kindles into flame. Diaamnus. I. 184. Fraxinella. In the {till evenings of dry feafons this plant emits an inflammable air or gas, and fla(hes on the approach of a candle. There are infl:ances of human creatures who have:: taken fire fpoutaneoufly, and been totally confumcd. Phil. Tranf. The odours of many flowers, fo delightful to our fenfc of fme\1, as well as the difagreeable fcents of others, are owing to the exhalation of their effcntial oil s. Thcfc effcntial oils have greater or lcfs volatility, and arc all inflammable; many of them arc poifons to us, as thefe of L aurel and Tabacco; other poffefs a narcotic quality, as is evinced by the oil of cloves infl:antly relieving flight tooth-achs; from oil of cinnamon relieving the hiccup; and balfam of peru relieving the pain of fome ulcers. They are all deleterious to certain infects, and hence their ufe in the vegetable economy, being produced in flowers or leaves to proteCt them from the depredations of their voracious enemies. One of the effential oils, that of turpentine, is recommended, by M. de Tho(fe, for the purpofe of defiroying infects which infect both vegetables and animals. Having obferved that the trees were attacked by multitudes of fmall infeCts of different colours (pucins ou pucerons) which injured their young branches, he deftroyed them all entirely in the following manner: he put into a bowl a few handfuls of earth, on which he poured a fmall quantity of oil of turpentine; he then beat the whole together with a fpatula, pouring on it water till it became of the confiftence of foup ; with this mixture he moifl:ened the ends of the branches, and both the infects and their eggs were defiroyed, and other infects kept aloof by the fcent of the turpentine. He adds, that he deftroyed the fleas of his puppies by once bathing them in warm water impregnated with oil of turpentine. Mem. d'Agriculture, An. q87, Tremefi. Printemp. p. 109. I fprinkled fome oil of turpentine, by means of a brufh, on fome branches of a nectarine tree, which was covered with the aphis; but it killed both the infeCt and the branches: a folution of arfenic much diluted did the fame. The fhops of medicine are fupplied with refins, balfams, and effential oib; and the tar and pitch, for mechanical purpofes, are produced from thefe vegetable fecretions. [ 107 ] If refl:s the traveller his weary head, Grim MANCINELLA haunts the moffy bed, Brews her black hebenon, and, fiealing near, Pours the curfi venom in his tortured ear.- Wide o'er the mad'ning throng URTICA flings Her barbed iliafts, and darts her poifon' d flings. Mancinella. 1. 188. Hyppomane. With the milky juice of this tree the Indians poifon their arrows; the dew-drops which fall from it are fo caufl:ic as to blifler the !kin, and produce dangerous ulcers; whence many have found their death by fleeping under its fhade. Variety of noxious plants abound in all countries, in our own the deadly night-fhade, henbane, hounds-tongue, and many others, are feen in almoft every high road untouched by animals. Some have alked, what is the ufe of fuch abundance of poifons? The naufeous or pungent juices of fome vegetables, like the thorns of others, are given them for their defence from the depredations of animals ; hence the t1wrny plants are in general wholefome and agreeable food to granivorous animals . . See note on Ilex. The flowers or petals of plants are perhaps in general more acrid than their leaves; hence they arc much feldomer eaten by infects. This feems to have been t'he ufe of th~ effential oil in the vegetable economy, as obferved above in the notes on Dictamnus and Ilex. The fragrance of plants is thus a part of their defence. Thefe pungent or naufeous juices of vegetables have fupplied the fcience of medicine with its principal materials, fuch as purge, vomit, intoxicate, &c. Urtica. I. 191. Nettle. The fting has a bag at its bafe, and a perforation near its point, exaa!y like the ftings ofwafps and the teeth of adders; Hook, Microgr. P· 142. Is the fluid contained in this bag, and preffed through the perforation into the wound, made by the point, a cauflic effential oil, or a concentrated vegetable acid? The vegetable poifons, like the animal ones, produce more fudden and dangerous effects, when infl:illed into a wound, than when taken into the ftomach; whence the families of Marfi and Pfilli, in antient Rome, fuckcd the poifon without injury out of wounds made by vipers, and were fuppofcd to be indued with fupernatura!'powers fo: this purpofe . . By the experiments related by Beccaria, it appears that four or five t1mes the quanttty, taken by the mouth, had about equal effects with that infufed into a wound. The male flowers of the nettle are fcparatc from the female, and the anthers are feen in fair weather to burfi with force, and to difcharge a dufl:, which hovers about the plant like a cloud. p ~ |