When this is effected, the whole may be put in contact with a heat that
will enable the operator to reduce it to a fine powder. And in order to
keep it with its virtues perfect, it will be necessary to deprive it as
much as possible of the influence of air and light. Hence it is
preserved in close glass bottles which are coated, and also placed in a
dark part of the elaboratory. Now, it is necessary that all plants
intended to be used in a dried state, should be prepared and protected
in a similar manner; and although it may be considered as a superfluous
trouble, so far as regards the more common kinds, particular attention
should be paid to these, when a small quantity is a dose, and an
over-dose a certain poison.

Other kinds of vegetables require a certain degree of fermentation, as
Tobacco. The prinicpal art of preserving it consists in this operation
being duly performed; for which purpose, as soon as the leaves of the
herb are fit, the foot-stalks are broken, and the leaves left on, in
order for the moisture in part to be evaporated. Afterwards these are
gathered and tied in handfuls, and hung up in the shade to dry; and when
sufficiently divested of moisture, the bundles are collected together
and laid in large boxes or tubs, in which these are fermented, and
afterwards taken out again and dried; when it is found fit to pack up
for the market.

The properties of Stramonium, which has been so much recommended for
curing asthma, consist pricipally in the aroma, which is only to be
preserved in a similar manner: and I have found from experience, that if
the leaves are separated from the plant in a manner similar to that of
tobacco, and the rest of the plant, noth roots, stalks, and
seed-vessels, be slit and sufficiently dried in the sun or in an oven,
and the whole fermented together, a very different article is the
produce than what it is when dried in the usual way, and left entirely
to the chance influence of the atmosphere.

In the common operation of hay-making it may also be observed, that the
continued turning it over and admitting its parts to the action of the
sun and the air, is for the purpose of getting rid of the watery
particles contained in it; and the quicker this is done, the better it
is. And although this operation is so essentially necessary, yet care
should be taken at the same time, that it be not made too dry, so as to
prevent a due degree of fermentation being allowed to take place in the