This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Balm is the herb of Melissa officinalis, a perennial herbaceous plant, a foot or two in height, originally from the South of Europe, but naturalized in this country, and cultivated in our gardens. The leaves have, when fresh, a very agreeable lemon-like odour, which is nearly lost when they are dried, and entirely when they are long kept. In the recent state, they have a feebly aromatic and somewhat austere taste; in the dried, impart a slight degree of roughness to water. The fresh herb contains a little volatile oil, tannic acid, and bitter matter. Water extracts all its virtues. Upon the system it exerts but a very feeble influence; and it is chiefly employed, in the form of infusion, as an agreeable drink in fevers, and, taken warm, to promote the operation of diaphoretics. The infusion may be made with half an ounce or an ounce of the herb, to the pint of water. The fresh or recently dried herb should be preferred.