(seq. 67)

58

Materia Medica

Astringents

sulpuret of ferri, /and to the third simple water, the two first
was instantaneously stopped. The other bled several hours. I
shall say a few words on the nature of astringents. Dr Cullen
supposed an acid and an earth combined to make an
astringent, this is not always the case, as for example
in the sulphuret of magnesia, the gallic acid has been
supposed the principal of astringency, but its principle is
not satisfactorily known, the oxy sulphuret of Iron detects
this principle. Green vitriol strikes a black colour, Sage
for instance, yet this vegitable will not cure the intermittant
fever and astringents are best used perhaps in substance
but sometimes it is necessary to employ the infusion or
decoction. They readily impart their qualities to water or
alcohol. We now speak of the use of astringents in diseases.
These have been recommended in debility which according
to Dr Cullen layes the foundation of dropsy, and by him
used with much advantage, but I say they are seldom
proper and often hurtfull in the beginning of the disease.
Dropsy often commences with increased arterial action
requiring bleeding &c. Astringents being more or less stimulant