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Mackenzie's water hemlock
(Cicuta virosa)
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Hemlock, Water
The leaves of the Water Hemlock are
sometimes found admixed with those of Conium. This is a semi-aquatic
plant growing in ditches and on the banks of pools and rivers, though
not very common in England. It has similar properties to the true
Hemlock.
Water Hemlock is a perennial, with a short, thick, vertical, hollow
rootstock, in shape somewhat like a parsnip, giving off whorls of
slender, fibrous roots. The erect, very stout, hollow stem, rising
2 to 4 feet high or more, is smooth, branched and slightly furrowed.
The lower leaves are large, 1 to 2 feet long and long-stalked; they
are tripinnate, like the Hemlock. The upper leaves are divided into
three leaflets, and each again into three (twice ternate). The flowers
are pure white, arranged in rather large, longstalked umbels of
12 to 16 long, slender, curved rays. There is no general involucre.
The Water Hemlock may be distinguished from the true Hemlock as
follows: (i) The pinnae of the leaves are larger and lanceshaped;
(ii) the umbel of the flowers is denser and more compact; (iii)
the stem is not spotted like the true Hemlock; (iv) the odour of
the plant resembles that of smallage or parsley.
Both plants are poisonous; but while the root of the Water
Hemlock is acrid and powerfully poisonous in its fresh state, though
it loses its virulent qualities when dried, that of the true Hemlock
possesses little or no active power.
The Water Hemlock produces tetanic convulsions, and is fatal to
cattle. In April, 1857, two farmer's sons were found lying paralysed
and speechless close to a ditch where they had been working. Assistance
was soon rendered, but they shortly expired. A quantity of the Water
Hemlock grew in the ditch, where they had been employed. A piece
of the root was subsequently found with the marks of teeth in it,
near to where the men lay, and another piece of the same root was
discovered in the pocket of one of them.
A resinous body has been obtained from Cicuta virosa named
Cicutoxin, an amorphous substance of acid reaction, of slight odour,
but disagreeable taste; the dry root yields 3 to 5 per cent. The
presence of a volatile alkaloid termed Cicutine has also been traced.
AMERICAN COWBEAN
The American Cowbane is closely analogous to the European species,
and also possesses very poisonous properties. In several instances,
children have been fatally poisoned by eating its roots. It is said
to be the most poisonous plant native to the United States.
Although it has been recommended as a remedy in nervous and sick
headaches, it is very rarely used.
No complete analysis of the plant has been published, but the
alkaloid termed Cicutine, present in the European species, is said
to exist in it. The seed is stated to contain an alkaloid identical
with Coniine.
The root of this American variety is even more virulent than the
English one.
Other Name: Cowbane.
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