(seq. 75)

66

Materia Medica

Astringents

of explanation as I have seen them produce good effects even when
they seem not to produce or exert any tonic power, they have
been used in wounds and received the title of Vulneraries by
some old authors, they are serviceable in old ulcers, Cortex Sinchoric,
or bark given internally have the effect of disposing them to
heal, they are used externally with the same good effect we
may suppose they act by stimulating the parts into a more
healthy action, to secrete good puss, and absorb the more fluid
or watery parts. Dr Darwin says they produce costiveness as a
general effect. I can positively assert they do not, on the
contrary I have known them to excite intestinal evacuation.
I can scarcely employ them as tonics, without combining Opium
with them. Galls, Columbo, and Allum, very often purge. I shall
now proceed to speak of the particular astringents, they have
been divided by Dr Cullen into vegitable and mineral, the
mineral astringents of Dr Cullen I shall transfer to my class of
Tonics. Nature has been bountifull in bestowing a portion of
astringency on all vegitables, even the roots and leaves of strawberry
contain it, the astringent principle resides in greatest abundance
in the bark of vegitables according to their botanical affinity, to this