To give an exact and particular Account of the Nature and Manner of acting of Poisons, is no easie Matter; but to Discourse more intelligibly of Them than Authors have hitherto done, not very difficult. One may without much Pains shew their Effects to be owing to something more than the bare Qualities of Heat or Cold; and Discover the Footsteps of Mechanism in those surprizing Phænomena which are commonly ascribed to some Occult or Unknown Principle. But to Unravel the Springs of the several Motions upon which such Appearances do depend, and Trace up all the Symptoms to their First Causes, requires some Art as well as Labour; and that both upon the account of the Exquisite Fineness, and marvellous Composition, of the Animal Machine in which they are Transacted, and of the Minuteness of those Bodies which have the force to induce in it such Sudden and Violent Alterations.