Two sorts of argillaceous earth are directed under this name in catalogues of the materia medica: Cimolia alba seu Argilla alba, the pure white strong clay, called, from the use to which it is principally applied, Tobacco-pipe clay: and Cimolia purpurascens, a compact bolar earth, commonly of a greyish brown colour, called, from its use, Fuller's earth.

These earths appear to be nearly of the same medical qualities with the boles formerly treated of; but are rarely or never employed, at least under their own names, for any medicinal purposes. If the virtue of these kinds of sub-stances depends, as it most probably does, on their soft viscous quality, (for they do not appear to have any other, by which they can act in the bodies of animals) the white cimolia is obviously the most effectual of them all.