Colonial North America: Countway Library of Medicine

50

Materia Medica

Astringents

Astringents. I now proceed to speak of Materia Medica properly so called, this as it is the most important is also the most difficult part of my course, I shall begin with the class Astringentia. In doing so I follow Dr Cullen, Gregory, and Speedman. In this class we shall treat of several articles that might perhaps with greater propriety be placed under some other head, as among the tonics. Indeed the imperfection of the class of astringents is so great that it has been proposed to abolish it altogether the time will come when this may be done. But we should be guarded against inovations of this kind. Dr Darwin has made a new class of medicines in which he includes astringent and which he calls sorbentia, this is a beautifull class but by no means correct astringents may be defined such substances as when applied to the living fibres produce in it contraction and condensation. Dr Cullen supposed they acted on living as on dead matter (statics). Chemically this as a general rule is not true, their action on living and on dead matter is very different. I think it probable that some portion of the astringent principle is absorbed in tanning and this is rendered probable by the