Humulus lupulus. Common Hop.

Botanical name: 

Pl. 60. Humulus lupulus. The Hop vine is not only a native of most countries in Europe, but is decidedly indigenous in America. It often occurs wild in the Atlantic states, and was found, by Mr. Nuttall, growing spontaneously on the banks of the Missouri. Sir J. E. Smith has quoted an old distich, which seems to be illustrative of the period of its introduction into practical use in England, about Henry the VIII's time; although he has no doubt of its being really native in that country.
["Turkeys, Carp, Hops, Pickerel and Beer
Came into England all in one year."]

The Hop being a medicinal article of some consequence, and one generally retained by the Pharmacopoeias; there is a propriety in introducing it in a Medical Botany of the United States.

The genus Humulus, which has only a single species, is found in the Linnaean class Dioecia, and order Pentandria. It belongs to the natural orders Scabridae, Linn, and Urticae, Juss. Its barren flowers have a calyx of five leaves and no corolla. The fertile flowers have for their calyx the scales of an ament, each two flowered; corolla of one petal, lateral; styles two; seeds solitary, invested with the corolla.

The Hop vine is an ornamental plant, much more frequently seen cultivated than wild, and climbing to a great height. The root is perennial. Stems annual, twining from right to left, angular, rough, with minute reflexed prickles. Leaves opposite, on long winding petioles, the smaller ones heart-shaped, the larger ones three or five lobed, serrated, veiny and extremely rough. Flowering branches axillary, angular and rough. Stipules two or four, between the petioles, ovate, reflexed. Flowers numerous, and of a greenish colour. Those of the barren plants are very numerous and panicled. Their calyx has five oblong, obtuse, spreading, concave leaves. Corolla wanting. Stamens short, the anthers oblong, and bursting by two terminal pores. The fertile flowers, growing on a separate plant, are in the form of an ament, having each pair of flowers supported by a calyx-scale, which is ovate, acute, tubular at base. Corolla of one scale, obtuse, smaller than the calyx and placed one on each side of it, infolding the germ by their edge. Germ roundish, compressed; styles two, short; stigmas long, subulate, downy. The scales of the calyx and corolla swell into a kind of persistent cone or strobile, each flower producing a roundish seed.

The full grown strobiles constitute the part which is preserved for use and sold in its dried state under the name of Hops. These have an aromatic, heavy odour, and a strong, bitter, but not unpleasant taste. Besides the bitterness, they have the characteristic taste which is found in the leaves and other portions of the plant. On the outside of the scales of the calyx and corolla and near their base, is secreted a semi-resinous substance in the form of minute, yellow, transparent globules. This secretion appears to be the seat of the whole bitterness for which the hops are generally prized and consumed. Dr. Smith, in the English Botany, has observed, that the fragrance and essential properties of the hop reside in this resinous substance; and more recently an interesting series of experiments has been published by Dr. A. W. Ives, of New York, to show that this portion may effectually supercede all the rest, in common practical use.

This substance, when separated from the hops by rubbing and sifting, exists in the form of a fine yellow powder. It is adhesive when rubbed between the fingers, and becomes agglutinated by moderate heat. It is very inflammable, and burns entirely out with a white flame, leaving a light cinder.

Dr. Ives has made a variety of experiments with this powder, from which he concludes that it consists of tannin, extractive matter, a bitter principle, wax, resin, and a woody fibrous substance, besides the aromatic principle, which he was unable to separate in the form of volatile oil. It may be observed, that the powder, as employed by him, being obtained from the hops by agitation and sifting, must necessarily contain a certain portion of chaff or minute fragments of the scales; and that these are apparently the seat of the tannin, the woody insoluble substance, and possibly of some other ingredients. If the pure secretion be carefully separated from the scales by brushing, and dissolved in alcohol, it does not undergo any change of colour from the sulphate of iron; although the scales themselves, as well as the leaves of the plant, strike a black colour when treated with that salt.

Hops have long been made an ingredient in malt liquors on account of the agreeable flavour they communicate, and also from a preservative quality which they are supposed to exert in preventing acescency in those liquids. Dr. Ives has shown that a prodigious saving of expense might be made by brewers, if this powder were separated at an early period, and used instead of the hops themselves. He was able, without much trouble, to separate fourteen ounces of the powder from six pounds of hops, and concludes, that if the hops were treated, during the process of gathering and drying, with a view to the preservation of the powder, they would yield at least one pound in six. He has pointed out a vast saving, which would take place in the expense of transportation and storage, if an article containing all the strength of the hop, and occupying but small compass, were substituted for one which is of more than twenty times its bulk. An enormous loss would farther be prevented, which now takes place from the absorption produced by the hops, it being calculated that one barrel of wort is absorbed by every sixty pounds of hops used in brewing. He enumerates still farther advantages which would result from the easier preservation of the article, its superior flavour, and the diminished chance of adulteration, arising from reduction of price. [The term Lupulin, by which Dr. Ives designates the powder of the hop, is convenient and not objectionable for practical use. As a chemical term, however, it does not agree with those of similar termination employed in the science; which express proximate principles of vegetables &c. and not heterogeneous bodies.]

The researches of Dr. Ives are entitled to great commendation, as they seem to promise a highly economical improvement in an important branch of domestic manufacture. In Great Britain, where malt liquors are more extensively consumed than, perhaps, in any other country, the saving must be an object of more consequence, than with us. It remains to be ascertained whether any effectual and economical method of separating the powder from the strobiles can be brought into practical use.

In medical practice the hop has been found a decided and useful tonic. A fermented decoction, known by the name of hop beer, and usually formed from this article with the simple addition of treacle, is much used in the New England states. When made sufficiently bitter with the hops, and taken as a common drink at meals, it promotes digestion more than any of the table liquors in common use. It is serviceable in dyspeptic complaints, and is particularly adapted to obviate the lassitude and debility felt by persons of relaxed habit in the spring, or on the approach of warm weather. A simple infusion has been employed for this purpose, but the fermented liquor derives a quality from the presence of carbonic acid, which renders it more agreeable, both to the palate and stomach.

The bitter principle of the Hop, in which its tonic property appears to reside, is abundantly soluble in water. Alcohol not only extracts this portion, but dissolves also the resinous constituents of the medicine. The tincture of hops is found to be bitter and aromatic, and to exert not only a strengthening effect on the viscera, but to influence considerably the nervous system in the character of an anodyne and soporific medicine.

I have employed the tincture of hops very often in practice, and have, on the whole, had quite as much reason to be satisfied with its tonic operation, as with that of any of the bitter tinctures in common use. Its narcotic power is slight when compared with that of opium, yet it nevertheless has, in certain cases, a decided property of procuring sleep. I have particularly found it effectual in the case of persons advanced in life, who had been accustomed to the moderate, but increasing use of spirituous liquors; and who at length have considered it impossible to procure a quiet night's sleep without a preparatory draught of this kind taken warm at bed time. In such cases I have found a teaspoonful of the tincture of hops to go as far in its composing effect, as two or three ounces of ardent spirit.

Mr. Freake, who published in the Medical and Physical Journal some account of the properties of this medicine, states that he had found it decidedly advantageous in erysipelas, in gout and in some other diseases. He considers its beneficial effects to arise from its alterative and tonic power on the system. He thinks it sedative, aperient and diuretic; and a good antiseptic and corroborant in bowel complaints. In his practice he had found pain to be eased and rest procured with this medicine, when opium did not succeed.

Dr. Maton found that besides allaying pain and procuring sleep, the preparations of hops were capable of reducing the frequency of the pulse, and increasing its firmness in a direct manner. One drachm of the tincture and four grains of the extract given once in six hours reduced the pulsations from ninety six to sixty in the course of twenty four hours. He found the extract very efficacious in allaying the pain of of articular rheumatism.

Some experiments of Dr. Bigsby and others have not been found to confirm the previous character of this article in all the foregoing respects, and its sedative powers have been called in question. As in most new medicines, its virtues have doubtless been exaggerated by its earliest advocates; yet it is not on this account to be discarded from use. Although the narcotic powers of the hop are not of the most energetic kind, they nevertheless do exist, and the very circumstance of their mild and temperate influence renders them, in many cases, safer than those of more active drugs.

In regard to the lithontriptic power which has been imputed to hops both alone, and through the medium of malt liquors, it is not probable that they have any operation of this sort, beyond that of a palliative.

The external application of hops has long had the popular reputation of being anodyne and composing. A pillow of hops is thought instrumental in procuring sleep, but with what justice I am unable to say. Poultices and fomentations made of them are in repute as sedative applications for painful swellings. When steeped in hot brandy and held in the mouth, they sometimes relieve the pain of a carious tooth. For all these purposes, no doubt, they often fail, yet there is little temerity in asserting that they are equally to be depended on in such cases, with the rest of the articles of the Materia Medica.

The most common form for internal use, where a sedative effect is desired, is that of the saturated tincture. The powder separated from the hops may be given in substance with a certainty of securing all their medicinal effects. This powder must be given in small doses, to be retained on the stomach and bowels. Dr. Bryorly found that twenty or twenty five grains left a sense of acrimony in the throat, and were followed by a good deal of nausea, and in some instances by purging.

The vine of the hop has been appropriated to some economical uses. In spring, when the young shoots first emerge from the ground, they are boiled and eaten as asparagus, and are accounted very salubrious. The fibres of the vine are strong and flexible and have been manufactured into a coarse cloth in Sweden and England, particularly for the sacks in which the hops are carried to market.

Botanical References.

Humulus lupulus, Linn. Sp. pl.
Smith, Engl. Bot. t.. 427.
Miller, Illustrations, t. 88.
Michaux, ii.
Pursh, i. 199.
Nuttall, ii. 237.
Lupulus mas et faemina, Ray, Syn. 137.

Medical References.

Freake, Med. and Phys. Journal, xiii. 432.
Thompson, London Dispensatory, 200.
Bigsby, London Medical Repository, v. 97.
Bryorly, Inaug, Diss. Philad. 1803.
Ives, in Silliman's Journal, ii. 302.

American Medical Botany, 1817-1821, was written by Jacob Bigelow, M. D.