tions of animals; hence the thorny plants are in general wholesome
and agreeable food to graminivorous animals. See note on Ilex. The
flowers or petals of plants are perhaps in general more acrid than their
leaves; hence they are much seldomer eaten by insects. This seems to have
been the use of the essential oil in the vegetable economy, as observed
above in the notes on Dictamnus and on Ilex. The fragrance of plants
is thus a part of their defence. These pungent or nauseous juices of
vegetables have supplied the science of medicine with its principal
materials, such as purge, vomit, intoxicate, &c.]

[_Urtica_. I. 191. Nettle. The sting has a bag at its base, and a
perforation near its point, exactly like the stings of wasps and the
teeth of adders; Hook, Microgr. p. 142. Is the fluid contained in this
bag, and pressed through the perforation into the wound, made by the
point, a caustic essential oil, or a concentrated vegetable acid?
The vegetable poisons, like the animal ones, produce more sudden and
dangerous effects, when instilled into a wound, than when taken into
the stomach; whence the families of Marfi and Psilli, in antient Rome,
sucked the poison without injury out of wounds made by vipers,
and were supposed to be indued with supernatural powers for this
purpose. By the experiments related by Beccaria, it appears that four
or five times the quantity, taken by the mouth, had about equal effects
with that infused into a wound. The male flowers of the nettle are
separate from the female, and the anthers are seen in fair weather to
burst with force, and to discharge a dust, which hovers about the
plant like a cloud.]

And fell LOBELIA'S suffocating breath
Loads the dank pinion of the gale with death.--
195 With fear and hate they blast the affrighted groves,
Yet own with tender care their _kindred Loves!_--
So, where PALMIRA 'mid her wasted plains,
Her shatter'd aqueducts, and prostrate sanes,

[_Lobelia. I._ 193. Longiflora. Grows in the West Indies, and spreads such
deleterious exhalations around it, that an oppression of the breast is
felt on approaching it at many feet distance when placed in the corner of
a room or hot-house. Ingenhouz, Exper. on Air, p. 14.6. Jacquini hort.
botanic. Vindeb. The exhalations from ripe fruit, or withering leaves,
are proved much to injure the air in which they are confined; and, it is
probable, all those vegetables which emit a