This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Mint: a perennial herb; with square stalks; serrated leaves set in pairs; and spikes of monopetalous flowers, each of which is cut into four sections, and followed by four seeds inclosed in the cup,
1. Mentha. 101. Mentha sativa Pharm. Lond. & Edinb. Mentha angustisolia spicata C. B. Mentha viridis Linn, Mint, hartmint, spearmint: with oblong, narrow, pointed leaves, joined close to the stalk; and small purplish flowers standing in long spikes on the tops. It is a native of the warmer climates, common in our gardens, and flowers in June and July.
This herb has a strong agreeable aromatic smell, and a bitterish, roughish, moderately warm taste. It is in general used as a restringent stomachic and carminative: in vomitings and weakness of the stomach, there are, perhaps, few simples of equal efficacy. Some report that it prevents the coagulation of milk, and hence recommend it to be used along with milk diets, and even in cataplasms and somentations for re-solving coagulated milk in the breads: upon experiment, the curd of milk, digested in a strong infusion of mint, could not be perceived to be any otherwise affected than by common water, but milk, in which mint leaves were set to macerate, did not coagulate near so soon as an equal quantity of the same milk kept by it-self.
The leaves are sometimes taken in substance, beaten with thrice their weight of fine sugar into a conserve. Moderately bruised, they yield upon expression about two thirds their weight of a turbid, brown-coloured, somewhat mucilaginous juice; which is commonly supposed to retain the full virtues of the mint, but which, though participating of the bitterness and sub-astringency of the herb, is found to have little or nothing of the peculiar aromatic flavour in which the principal virtue of this plant resides. The leaves lose in drying about three fourths of their weight, without suffering much loss of their smell or taste; nor is the smell soon dissipated by moderate warmth, or impaired in keeping.
Cold water, by maceration for six or eight hours on the dry herb, and warm water in a shorter time, become richly impregnated with its flavour: if the maceration be long continued, the grosser parts of the mint are extracted, and the liquor proves less grateful: on boiling the mint in water till the aromatic matter is dissipated, the remaining dark-brown liquor is found nearly similar to the recent juice; un-pleasant, bitterish, subastringent, and mucilaginous. By distillation, a pound and a half of the dry leaves communicate a strong impregnation to a gallon of water: † the distilled water proves rather more elegant if drawn from the fresh plant in the proportion of ten pints from three pounds‡ than from the dry plant, though the latter is frequently made use of as being procurable at all times of the year. Along with the aqueous fluid, an essential oil distils, of a pale yellowish colour, changing by age to a reddish, and at length to a dark red, in quantity near an ounce from ten pounds of the fresh herb in flower, smelling and tailing strongly of the mint, but somewhat less agreeable than the herb itself.
Dry mint, digested in rectified spirit, either in the cold, or with a gentle warmth, gives out readily its peculiar taste and smell, without imparting the grosser and more ungrateful matter, though the digestion be long continued. The tincture appears by day-light of a fine dark green, by candle-light of a bright red colour: a tincture extracted from the remaining mint by fresh spirit appears in both lights green: the colour of both tinctures changes, in keeping, to a brown. On gently infpiffating the filtered tinctures, little or nothing of their flavour rises with the spirit: the remaining extract possesses the concentrated virtues of about ten times its weight of the dry herb; and differs from the products obtained by distillation with water, in this, that the bitterness and subastringency of the mint, which are there separated from the aromatic part, are here united with it.
Aq. menthae sativ. Ph. Lond. †
Ph. Ed. ‡ Ol. menthae sativ. essen-tiale Ph. Lond. & Ed.
Proof spirit extracts the smell and taste of mint, but not its green colour. The tincture is brown, like the watery infusions; and, like them also, it becomes ungrateful, if the di-gestion is long continued. On gentle distilla-tion, the more spirituous portion, which rises at first, discovers little flavour of the mint; but as soon as the watery part begins to distil, the virtues of the mint come over plentifully with it. Hence the officinal spirituous water, prepared by drawing off a gallon of proof spirit from a pound and a half of the dried leaves, proves strongly impregnated with the mint.
After mint has been repeatedly infused in water, rectified spirit still extracts from it a green tincture, and a sensible flavour of mint: on the other hand, such as has been first di-gested in spirit, gives out afterwards to water a brown colour, and a kind of nauseous mucilaginous taste very different from that which distinguishes mint. The spirituous tinctures mingle with watery liquors without precipitation or turbidness; but spirituous liquors impregnated with its pure volatile parts by distil-lation, turn milky on the admixture of water.
Spiritus men-thae fativae Ph. Lond,
2. Mentha aquatica five Mentastrum Pharm. Paris Mentha aquatica five sisymbrium J. B. Mentha rotundifolia palustris five aquatica major C. B. Mentha aquatica Linn. Water mint: with somewhat oval leaves set on pedicles, and long stamina standing out from the flowers.
3. Mentastrum hirsutum; Auricularia officinarum Dale: Mentha palustris folio oblongo C. B. Hairy water-mint: with long hairy leaves having no pedicles; and broad spikes of flowers.
Both these plants grow wild in moist meadows, marshes, and on the brinks of rivers, and flower towards the end of summer. They are less agreeable in smell than the spearmint, and in taste bitterer and more pungent: the second sort approaches in some degree to the flavour of pennyroyal. They yield a much smaller proportion of essential oil: from twenty pounds of the water-mint were obtained scarcely three drams. With regard to their virtues, they appear to partake of those of spearmint; to which they are obviously far inferiour as sto-machics. The hairy water-mint is supposed to be the auricularia, planta zeylanica, or earwort, celebrated by Marloe for the cure of deafness: though probably not more effectual against that complaint, than the other water-mint against nephritic ones, in which it is said to have been formerly an empyrical secret (a).
4. Mentha piperitis Pharm. Lond. & Edinb. Mentha spicis brevioribus & habitioribus, foliis menthae fufcae sapore fervido piperis Raii synops. Mentha piperita Linn, Pepper-mint: with acuminated leaves on very short pedicles; and the flowers set in short thick spikes or heads. It is a native of this kingdom; and, so far as is known, of this kingdom only: it is much less common, however, than the other wild mints; but having been of late received in general practice as a medicine, it is now raised plentifully in gardens, and does not appear, like many of the other plants that grow naturally in watery places, to lose any thing of its virtue with this change of foil.
(a) In the first volume of Linnaeus's Amaenitates Academicae, the auricularia is said to be not at all of the mint kind, but a stellated plant, akin to galium.
This species has a more penetrating smell than any of the other mints; and a much stronger and warmer taste, pungent and glowing like pepper, and finking as it were into the tongue. It is a medicine of great importance in flatulent colics, hysteric depressions, and other like complaints; exerting its activity as soon as taken into the stomach, and diffusing a glowing warmth through the whole system; yet not liable to heat the constitution near so much as might be expected from the great warmth and pungency of its taste.
By maceration or infusion, it readily and strongly impregnates both water and spirit with its virtue; tinging the former of a brownish colour, and the latter of a deeper green than the other mints. In distillation with water, it yields a considerable quantity of essential oil, of a pale greenish yellow colour, growing darker coloured by age, very light, subtile, possessing in a high degree the specific smell and penetrating pungency of the pepper-mint*(a): the decoction remaining after the separation of this active principle, is only bitterish and subastringent, like those of the other mints. Rectified spirit, drawn off with a gentle heat from the tincture made in that menstruum, brings over little of the virtue of the herb, nearly all its pungency and warmth remaining concentrated in the extract, the quantity of which amounts to about one fourth of the dried leaves. A simple and a spirituous distilled water, drawn in the same proportions as those of spearmint, and the essential oil, are kept in the shops.
* (a) Some particles of a true camphor were procured from dried pepper-mint by cohobation. Gaubii Adversar.
Ol. essentiale menthae pi-peritidis Ph. Lond. & Ed.