This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Cauda equina. Equisetum palustre longioribus Jetis C. B. Hippuris vulgaris Linn. Horsetail: a plant, with a thick hollow straight stalk, full of joints; and long, slender, rough, stiff, jointed, rush-like leaves, Handing several round every articulation in form of a star. It is perennial, and common in watery places.
The leaves of equisetum have been accounted powerfully astringent, and hence recommended in different fluxes and hemorrhagies: the dole commonly directed is a dram of the dry leaves in powder, or two ounces of the expressed juice. They appear, indeed, from their sensible qualities, to have some virtues of this kind, but in a very low degree: in the leaves themselves, the astringency is so weak, that the tasle scarcely gives any notice of it, though solution of chalybeate vitriol renders it apparent by the inky blacknefs it receives from them: the astringent matter is extracted both by watery and spirituous menstrua, and when concentrated by inspissating the infusions, proves still of so weak a kind, and in so little quantity, that the plant can be ranked only among the milder restringent corroborants. In this intention, an infusion of the dried herb may be used as tea.