Toxicology, or the history of Poisons, forms one of the most important and elaborate branches of Forensic Medicine, and in tracing the subject through all its numerous and interesting relations to Jurisprudence, we shall experience no small degree of gratification by observing, how greatly and progressively this obscure department of science has, within the last few years, been enlightened by the discoveries of Chemistry and Physiology. The labours of the modern Chemist, indeed, have enabled us to recognise and identify each particular substance by its properties and habitudes, with an infallible delicacy, which the Physicians of a former age could scarcely have anticipated, and much less practised. The Physiologist, by an invaluable series of observations and experiments, has demonstrated the particular organ, or texture, upon which each individual poison exerts its energies; and the Pathologist has been thus enabled to establish the mode in which it depraves the health, or extinguishes the life of an animal. Nor has the Anatomist withheld his contributions upon this interesting occasion, for he has demonstrated the situation, extent, and intensity of the organic lesions which result from the operation of these terrible agents upon the living body; and has pointed out several appearances which occur from natural causes, but which might be mistaken by the unskilful or superficial observer, for the ravages of poison. It remains for the Forensic Physician to converge into one focus the scattered rays which have thus emanated from so many points, and thereby to elucidate and determine the line of conduct which the medical attendant is called upon to pursue, for the relief of the patient suffering under the torments of poison, and for the establishment of the guilt or innocence of the party charged with the perpetration of a crime, which may be said to rob courage of its just security, while it transfers to cowardice the triumphs of valour. That engines so powerful and secret in their work of destruction, should have universally excited the terror of mankind is a fact which cannot surprise us, and, when we consider how intimate are the relations between fear and credulity, we need not seek farther for the solution of the many problems to which the exaggerated statements of ancient Toxicologists[111] have given origin; the most extraordinary of those relate to the alleged subtlety of certain poisons, which was believed to be so extreme as to defeat the most skilful caution, and at the same time so manageable, as to be capable of the most accurate graduation; so that, in short, the accomplished assassin was not only thus enabled to ensure the death of his victim through the most secret, and least suspicious agents, but to measure his allotted moments with the nicest precision, and to occasion his death at any period that might best answer the objects of the assassination. The writings of