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.