116. Humulus lupulus, Linn.—The Common Hop.

Sex. Syst. Dioecia, Pentandria.
(Amentum, L.—Catkin, E.—The dried strobiles. Lupulina; the yellow powder separated from the strobiles by rubbing and sifting, D.)

History.—This plant is probably the Lupus salictarius of Pliny. [Hist. Nat. lib. xxi. cap. 50, ed. Valp.] Its culture was introduced into this country from Flanders, in the reign of Henry VIII. [Beckmann, Hist, of Invent, vol. iv. p. 340.]

Botany. Gen. Char.—Dioecious. Males:—Calyx 5-partite. Stamens 5. Females:—Strobiles consisting of large, persistent, concave scales [bracts], having a single flower in the axilla of each. Ovary 1. Styles 2. Seed 1, with an arillus. Embryo spirally contorted (Bot. Gall.).

Sp. Char.—The only species.

Perennial. Stems annual, long, weak, and climbing, scabrous. Leaves petiolate, 3- to 5-lobed, serrated, veiny, rough. Flowers greenish yellow.

Hab.—Thickets and hedges in many parts of Europe. Indigenous [?]. Flowers in July.

Cultivation.—The female plant is cultivated in several counties in England, especially Kent, Sussex, Surrey, Worcestershire, and Herefordshire. The third year after planting it generally comes into full bearing. Stacking or setting the poles is performed in April or May. The gathering or picking takes place in September. The cones are dried in kilns, and are then packed in hempen sacks, called bags or pockets. This operation is called bagging. [Loudon's Encyclopaedia of Agriculture.]

Description.—The aggregate fruits of the Humulus Lupulus are strobiles or catkins (strobili seu amenta lupuli), in commerce termed hops. They consist of scales, nuts, and lupulinic glands or grains. The scales are the enlarged and persistent bracts, which enclose the nuts: they are ovate, membranous, and at their base glandular. The nuts (achenia) are small, hard, nearly globular, and covered with aromatic, superficial, globose glands. The lupulinic glands or grains (commonly termed yellow powder or lupulin) are the most important parts of the strobiles. By thrashing, rubbing, and sifting, Dr. Ives [Journal of Science, vol. xi. p. 205.] procured 14 ounces from six pounds of hops; and he therefore concluded that dry hops would yield about a sixth part of their weight of these grains. They are usually intermixed with sand. They are rounded, of a cellular texture, golden yellow, and somewhat transparent. They are sessile, or nearly so. The common centre, around which the cells are arranged, has been called the hilum. By drying they lose their spherical form. Placed in water they give out an immense number of minute globules. Under other circumstances they become ruptured, and allow an inner envelop to escape. According to Turpin, [Mémoires de l'Acad. Royale des Sciences, t. xvii. p. 104, 1840; see also Raspail, Chim. Org.] they consist of two vesicles, one enclosing the other. The inner one contains globules, an aromatic oil, and a gas. He also states that, in the bubbles of the disengaged gas, an immense number of crystals are formed.

Composition.—Payen, Chcvallier, and Pelletan [Journ. de Pharm, t. viii. p. 209; and Journ. de Chim. Méd. t. ii. p. 527.] analyzed the scales and lupulinic grains. Dr. Ives [Journal of Science, vol. xi. p. 205.] also examined the latter.

1. Volatile oil of Hops.—Resides in the lupulinic grains. Obtained by submitting these, or hops which contain them, to distillation with water. Its colour is yellowish, its odour that of hops, its taste acrid. It is soluble in water, but still more so in alcohol and ether. Its sp.gr. is 0.910. By keeping, it becomes resinified. It is said to act on the system as a narcotic. The water which comes over, in distillation, with the oil, contains acetate of ammonia, and blackens silver; from which circumstance the presence of sulphur is inferred.

2. Bitter Principle of Hops; Lupulite.—It is procured by treating the aqueous extract of the lupulinic grains, united with a little lime, with alcohol. The alcoholic tincture is to be evaporated to dryness, the residue treated with water, and the solution evaporated. The residue, when washed with ether, is lupulite. It is uncrystallizable, yellowish white, very bitter, soluble in 20 parts of water, very soluble in alcohol, and slightly so in ether. The aqueous solution froths by agitation; it forms no precipitate with either tincture of nutgalls or acetate of lead. Lupulite contains no nitrogen. It is devoid of the narcotic property of the oil. In small doses it is said to have caused loss of appetite and diminished digestive power; but a repetition of the experiment is very desirable.

3. Tannic Acid; Tannin.—In the manufacture of beer, this principle serves to precipitate the nitrogenized or albuminous matter of the barley, and, therefore, for clarification.

4. Resin.—Is of a golden yellow colour, and becomes orange-yellow by exposure to the air. It is soluble in both alcohol and ether. It appears to be the oil changed into resin, partly by oxidizement.

Chemical Characteristics.—A decoction of hops reddens litmus, owing to the presence of free acid. Sesquichloride of iron strikes an olive green colour (tannate of iron). A solution of gelatin renders the filtered decoction turbid (tannate of gelatin). Chloride of barium occasions with it a white precipitate (sulphate of baryta). Oxalate of ammonia also causes a white precipitate (oxalate of lime).

Physiological Effects.—The odorous emanations (vapour of the volatile oil) of hops possess narcotic properties. Hence a pillow of these cones promotes sleep, as I have several times witnessed. Moreover, we are told that stupor has occasionally been induced in persons who have remained for a considerable time in hop warehouses.

The lupulinic grains are aromatic and tonic. They appear also to possess soothing, tranquillizing, and, in a slight degree, sedative and soporific properties. But the existence of any narcotic quality has been strongly denied by Dr. Bigsby, [Lond. Med. Rep. vol. iv. p. 287.] Magendie, [Formulaire.] and others. "I have tried, at different times," says Magendie, "both the lupuline [lupulinic grains] in substance, and its different preparations, on animals, but I have never observed that it is a narcotic, although this property is one which is most strikingly displayed in experiments on animals." Dr. Maton [Observations on Humulus Lupulus, by A. Freake, 2d edit.] found that it allayed pain, produced sleep, and reduced the frequency of the pulse from 96 to 60 in twenty-four hours.

Both infusion and tincture of hops are mild but agreeable aromatic tonics. They sometimes prove diuretic, or, when the skin is kept warm, sudorific. Their sedative, soporific, and anodyne properties are very uncertain.

Uses.—A pillow of hops (cervicale seu pulvinus, pulvinar lupuli) is occasionally employed in mania, and other cases in which inquietude and restlessness prevail, and in which the use of opium is considered objectionable. In hop countries it is a popular remedy for want of sleep. The benefit said to have been obtained from it by George III., for whom it was prescribed by Dr. Willis, in 1787, brought it into more general use.

Hops are given internally to relieve restlessness consequent upon exhaustion and fatigue, and to induce sleep in the watchfulness of mania and of other maladies; to calm nervous irritation; and to relieve pain in gout, arthritic rheumatism, and after accouchement. Though they sometimes produce the desired effect, they frequently fail to give relief. Dr. Maton used it, with good effect, as an anodyne in rheumatism.

As a tonic, it is applicable in dyspepsia, cachectic conditions of the system, or any other maladies characterized by debility.

Hops have been applied, topically, in the form of fomentation or poultice, as a resolvent or discutient, in painful swellings and tumours. Freake employed an ointment, composed of lard and the powder of the hop, as an anodyne application to cancerous sores. [Op. cit. p. 13; see also Annals of Medicine, vol. ii. p. 403.]

But the principal consumption of hops is in the manufacture of beer and ale, to which they communicate a pleasant, bitter, and aromatic flavour, and tonic properties; while, by their chemical influence, they check the acetous fermentation. Part of the soporific quality of beer and ale is usually ascribed to the hops used in the manufacture of these beverages.

Administration.—The best preparation of hops, for internal use, is the yellow powder (lupulinic grains or lupulin). The infusion and tincture are less eligible modes of exhibition. The extract is still more objectionable. Well-hopped-beer is a convenient mode of administering hops, when fermented liquors are not contra-indicated (see ante, p. 118).

1. INFUSUM LUPULI, L.; Infusion of Hops.—(Hops ʒvj; Boiling Distilled Water Oj [Hops ℥ss; Boiling Water Oj, U. S.]. Macerate for four [two, U. S.] hours in a vessel lightly covered, and strain.)—Dose, f℥j to f℥1J.

2. TINCTURA LUPULI, L. [U.S.]; Tinctura Humuli; Tincture of Hops.—(Hops ℥vj [℥v, U. S.]; Proof Spirit Oij. Macerate for seven days, and strain.)—Dose, fʒjss to fʒij.

3. EXTRACTUM LUPULI, L. E.; Extractum Humuli, D.; Extract of Hops.—(Hops lb jss [lb j, E.]; Boiling Distilled Water Cong, ij [Cong, j, E.]. Macerate for twenty-four hours, then boil down to a gallon [Oiv, E.], and strain the liquor while hot; lastly, evaporate [in the vapour bath, E.] to a proper consistence. The directions of the Dublin College are nearly the same as those of the Edinburgh College.)—Dose, grs. v to ℈j. Whatever virtue this preparation possesses is owing to the bitter principle or lupulite.

4. LUPULINA; Yellow Powder; Lupilinic Grains or Glands.—(Separated from the strobiles by rubbing and sifting.)—Dose, grs. vj to grs. xij, taken in the form of powder or pills.

5. TINCTURA LUPULINAE, D.; Tinctura Lupuli, E.—(Lupulin ℥v; Rectified Spirit Oij. Macerate for fourteen days, strain, express, and filter, D.—Take any convenient quantity of Hops, recently dried; separate by friction and sifting the yellowish-brown powder attached to the scales. Then take of this powder ℥v [℥iv, U. S.]; and of Rectified Spirit Oij; and prepare the tincture by percolation or digestion, as directed for tincture of capsicum. Ph. Ed.)—Dose, ʒss to ʒj.

The Elements of Materia Medica and Therapeutics, Vol. II, 3th American ed., was written by Jonathan Pereira in 1854.