ame time. It should, however, be observed, that the principal art of
drying hops is in doing it as quickly as possible, so as not to injure
them in their colour. As soon as they are dried, it is considered
necessary to put them up into close and thick bags.

It should be observed, that all vegetables contain at every period of
their growth two distinct species of moiture: the one called by
naturalists the common juice, which is the ascending sap, and is replete
with watery particles: the other is termed the proper juice, which
having passed up through the leaves, and being there concocted and
deprived of the watery part, contains the principle on which various
properties and virtues of the plant depend. We therefore find that the
operations above described only go to this, that the watery particles in
the common juice should be evaporated, as being a part necessary to be
got rid of; and the proper juice being of a volatile nature, the less
time the plants are exposed for that purpose, the less of this precious
material will be lost: and as those parts are flying off continually
from all dried vegetables, there should be one general rule made with
regard to their peparation; for, if we instance mint, balm, pennyroyal,
&c., the longer these are kept in the open air, the weaker are they
found to be in their several parts.

From hence we may naturally infer, that the usual mode in which the
generality of herbs are dried, is not so good for the purpose, as one
would be if contrived on similar principles, as, during the length of
time necessary for the purpose, a great deal of the principal parts of
the plants must of course be evaporated and lost; for little else is
regarded than to dry them so as to prevent putrefaction. Although the
generality of herbs met with are prepared as above described, yet in
such articles as Digitalis, Hyoscyamus, Conium, Toxicodendron, &c.,
where the quantity necessary for a dose is so small, and so much depends
on its action, practitioners are often obliged to prepare it themselves.
I shall therefore relate the following mode as the best adapted to that
purpose. The Digitalis is prepared by collecting the leaves in the
summer, and stripping them off from the foot-stalks; these should be
then carefully exposed to a slow heat, and the watery extract slowly
thrown off; in which they should not be exposed to any great degree of
heat, which by its action will deprive them of their fine green colour.