Substances of a fragrant smell,[146] which produce upon the organs of taste a peculiar sensation of warmth and pungency, and occasion, when swallowed, a corresponding impulse upon the stomach, which is rapidly communicated to the remote parts of the body. The vegetable bodies which constitute the class of aromatic stimulants are very intimately related with that of tonics; indeed in the most efficient vegetables of the latter kind, the two qualities are generally blended, and the transition from these to the more pure bitters and aromatics is so imperceptible, that it is extremely difficult to arrange them in different classes; Dr. Murray has accordingly in his classification not attempted to separate substances which are so intimately connected. _Aromatic Stimulants_, however, in a practical point of view, must be distinguished from tonics, as the former are valuable for the _rapidity_, the latter, for the _permanency_ of their effects. Their characteristic properties appear to depend chiefly, if not entirely, on an essential oil which, when extracted from the vegetable, exhibits all its aromatic power in a very concentrated form. Medicines of this kind, when administered for the purpose of dispelling wind from the alimentary canal, have been termed _Carminatives_.[147] They would seem to act by imparting energy to the distended and weakened muscular coat of the stomach, by which the accumulated _gas_ is propelled through the upper orifice; for this viscus, like the bladder, when greatly distended, becomes unable to relieve itself, partly in consequence of the exhausted state of the over-stretched fibres of its muscular coat, and partly perhaps from a contraction of the _Cardia_, or upper orifice; for it has been already stated that a loss of power, and spasmodic action, are often the simultaneous results of debility. ASTRINGENTS. Substances which, when applied to the human body, corrugate and condense its fibres, and at the same time, exert a tonic influence through the medium of its living principle.