as fhofe of the ancients are to us; they would foon
he commuted, for others; our experiments would be
laughed at, and pofterity would lofe the benefit of our
difcoveries. Thefe are not new truths, but fuch as
are well known, and have often been demonftrated by
others; yet they are important, as they ferve to evince
the ufes of botanical fcience. A certain and exadt know-
ledge of plants from which medicines are taken, is ftill
more neceflary with refpedt to fuch plants as are not cultivated,
but grow wild. By frequent gathering, thefe
plants are liable to be too much diminifhed, fo as not to
afford a fufficient fupply when requifite, and even to be
quite extirpated from the places in which they were firft
collected. If then we did not know the plant from which
fuch a medicine was prepared, we ffiould not be capable of
afcertaining by fearch, whether nature might not have
produced it in other fpots; and i f we were not able to find it,
we mull either be without the defired remedy or fpecific
againft particular difeafes, or elfe even wifh to have it lefs
known, on account o f its fmall quantity. The lofs would
be the more felt, as the difcoveries o f ages might perhaps
fcarcely exhibit any thing that would fb completely an-
fwer our purpofes. An extenfive knowledge of the vegetable
kingdom, acquaintance with the natural affinities
o f plants, would perhaps be the only means of leading to
the difcovery, and on fuch an occafion might compen-
fate for what we had loft; fince, if we wifh to find a remedy
that moft nearly approaches to any particular one, it
can fcarcely be looked for amongftfuch as Nature has fet
6 at
at a wide dillanee from it. The nearer the feveral parts
o f plants approach to each other in point of refemblance,
there is fo much the greater reafon for fuppofmg a fimi-
larity of their virtues. He who underftands nature, will
hardly doubt o f this: daily experience furnifhes proofs of
it, not only amongft the vegetable tribes, but alfo in the
other kingdoms of nature, and this in proportion to the
natural affinities.
The genus of plants which-1 have now the honour to
propofe to the Society, increafed by the defcriptions of
fome of the lefs known fpecies, will ferve as a further
proof o f what has been advanced.
Among the many excellent medicines which have
reached our knowledge fince the difcovery o f the New
World, the Peruvian Bark deferres undoubtedly the firft
place. It has been tried in vain to find a fubftitute for it,
fcarcely any thing having been yet difcovered which
might fuperfede its ufe. The obftacles which it met with
before it was univerfally adopted, and the different opinions
relative to its effects, are fufficiently known. As
they do not belong to my fcope, it is fuperfluous to treat
of them: the caufe of the difference in the experiments
made with the Peruvian Bark muft be afcribed in part to
the frauds which are practifed in mixing it with other ingredients
of fimilar colour and tafte, though very different
in operation, and perhaps even of a contrary nature
and of a pernicious Men, while anxious in fupport