This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
Hirudo-The Leech. - 1, Sanguisuga medici-nalis, the Speckled Leech; and, 2, Sanguisuga officinalis, the Green Leech. Collected chiefly in France, Spain, Italy, and Hungary.
Characters.-Body elongated, two or three inches long, tapering to each end, plano-convex, wrinkled transversely; back olive-green, with six rusty-red longitudinal stripes. 1, belly greenish-yellow spotted with black; 2, belly olive-green not spotted.
The leech is employed to abstract blood, each leech removing, directly and by subsequent haemorrhage, an average of half an ounce of blood. Leeching is depletive, and to some extent counter-irritant in effect; and is employed in a variety of congestive or inflammatory affections, superficial and visceral, as well as in cardiac distension and distress.