Hemlock is a biennial, umbelliferous, indigenous plant, growing very commonly about the sides of fields, under hedges, and in moist shady places. It is at once distinguished from other umbelliferous plants, with which it may be confounded, by its _large_ and _spotted_ stem, the dark and _shining colour of its lower leaves_, and their _disagreeable smell_; which, when fresh and bruised is said to bear a strong resemblance to that of the urine of a cat. Many[455] cases of persons who have been poisoned by this plant are to be found in the writings of different toxicologists. The extract, if properly prepared, is a very energetic substance, and gives rise, in large doses, to all the symptoms which we have so often described as the result of narcotic poisons. In those fatal cases, where the bodies have been examined, _post mortem_, inflammation of the stomach, and sanguineous congestion in the brain, have been the most prominent phenomena. It would appear that the active element of this plant is absorbed and carried into the circulation, through which medium it exerts its action on the nervous system, and more particularly on the brain. At the same time it seems to excite a local irritation, capable of producing an inflammation more or less violent. The best antidote is vinegar, after the stomach has been evacuated, and the cerebral excitement reduced by bleeding and purging. The _Cicuta Virosa_, or _water hemlock_, with which the _conium maculatum_ has been often confounded, is still more virulent; it is however to be distinguished from the latter, by having its hollow roots always immersed in water, while those of the _conium_ never are. _M. Orfila_ has related several cases of poisoning by the _water hemlock_. NUX VOMICA. This is the seed of the _Strychnus Nux Vomica_ (Pentandria Monogynia, _Nat. Ord._ Apocyneæ, _Juss._)