(Pentandria Monogynia. _Nat. Ord._ Luridæ _Linn._ Solaneæ _Juss._)
Henbane is an indigenous annual, frequent on waste grounds, and at the
sides of roads, particularly on a calcareous soil, flowering in July.
The whole of the plant is poisonous when eaten; and in the recent state
the odour of the leaves occasions stupor and delirium. The root of this
plant when in full vegetation is very powerful; and there are several
cases on record, where it has been eaten in mistake for parsnips,[431]
which it strongly resembles in its sweet and agreeable flavour. Its
operation is very analogous to that of opium; producing sickness,
stupor, delirium, and coma, with dilation of the pupils.
The pulse, at first hard, gradually becomes weak and tremulous; petechiæ
frequently make their appearance, and death ensues. Late experiments
have shewn that a peculiar alkaline body constitutes the active
principle of this plant, and it has accordingly received, from its
discoverers _MM. Meissner_ and _Brandes_, the name of _Hyoscyama_.
_Boerhaave_ experienced a trembling and drunkenness, in consequence of
having prepared a plaister, into whose composition _henbane_ entered as
an ingredient; and the experiments of _M. Orfila_ have shewn that it
acts nearly in the same manner, whether applied upon the cellular
texture, introduced into the stomach, or injected into the veins. Hence
it follows that the active principle of this plant is carried into the
circulation, and exerts a remarkable action on the brain and nervous
system, producing an extraordinary state of delirium, which is succeeded
by stupefaction. The physician will never probably be called upon to
investigate a case of wilful poisoning by this narcotic; and should he
be summoned to attend a person who, through mistake or accident, had
swallowed it, we can hardly anticipate any peculiar mystery which
requires elucidation.
There are several other species of henbane, as _hyos. alb. aureus_,
_physaloides_, all of which are poisonous, although not in the same
degree as the _hyoscyamus niger_, whose history we have just considered.