book 2

. cap. 6.

[2055] 1 James I. (anno 1603) cap. 18.

=Structure=—The inflorescence of the male plant constitutes a large panicle; that of the female is less conspicuous, consisting of stalked catkins which by their growth develope large leafy imbricating bracts, ultimately forming an ovoid cone or strobile, which is the officinal part. This catkin consists of a short central zigzag stalk, bearing overlapping rudimentary leaflets, each represented by a pair of stipules. Between them are 4 female florets, each supported by a bract. After flowering, the stipules as well as the bracts are much enlarged, and then form the persistent, yellowish-green, pendulous strobile. At maturity, each bract infolds at its base a small lenticular closed fruit or nut, ⅒ of an inch in diameter. The nut is surrounded by a membranous, one-leafed perigone, and contains within its fragile, brown shell an exalbuminous seed. These fruits, as well as the axis and the base of all the leaf-like organs, are beset with numerous shining, translucent glands, to which the aromatic smell and taste of hops are due.

=Description=—Hops as found in commerce consist entirely of the fully developed strobiles or cones, more or less compressed. They have a greenish yellow colour, an agreeable and peculiar aroma, and a bitter aromatic burning taste. When rubbed in the hand they feel clammy, and emit a more powerful odour. By keeping, hops lose their greenish colour and become brown, at the same time acquiring an unpleasant odour, by reason of the formation of a little valerianic acid. Exposure to the vapour of sulphurous acid retards or prevents this alteration. For medicinal use, hops smelling of sulphurous acid should be avoided, though in reality the acid speedily becomes innocuous. Liebig has refuted the objections raised by brewers to the sulphuring of hops.

=Chemical Composition=—Besides the constituents of the glands which are described in the next article, hops contain according to Etti’s elaborate investigations (1876, 1878) _humulotannic acid_ and _phlobaphene_. The former is a whitish amorphous mass, soluble in alcohol, hot water or acetic ether, not in ether. By heating the humulotannic acid at 130° C., or by boiling its aqueous or alcoholic solutions, it gives off water, and is transformed into phlobaphene, a dark red amorphous substance,

(C₂₅H₂₄O₁₃)₂ = OH₂ · C₅₀H₄₆O₂₅. humulotannic phlobaphene. acid.

The latter substance, on boiling it with dilute mineral acids, again loses water and furnishes glucose.

From raw phlobaphene ether removes the _bitter principles_ of hops, a colourless crystallizable and a brown amorphous resin, besides chlorophyll and essential oil.

By distilling hops with water, 0·9 per cent. of _essential oil_ are obtained. Personne (1854) stated it to contain _Valerol_,[2056] C₆H₁₀O, which passes into valerianic acid; the latter in fact occurs in the glands, yet according to Méhu[2057] only to the extent of 0·1 to 0·17 per cent. When distilled from the fresh strobiles the oil has a greenish colour, but a reddish-brown when old hops have been employed. We find it to be devoid of rotatory power, neutral to litmus paper, and not striking any remarkable coloration with concentrated sulphuric acid.

Griessmayer (1874) has shown that hops contain _Trimethylamine_, and in small proportion a liquid volatile alkaloid not yet analysed, which he terms _Lupuline_. The latter is stated to have the odour of conine, and to assume a violet hue when treated with chromate of potassium and sulphuric acid.

Lastly, Etti also found arabic (pectic) acid, phosphates, nitrates, malates, citrates, and also sulphates, chiefly of potassium, to occur in hops. The amount of ash afforded by hops dried at 100° C. would appear to be on an average about 6-7 per cent.

=Production and Commerce=—England was estimated as having in 1873, 63,276 acres under hops. The chief district for the cultivation is the county of Kent, where in that year 39,040 acres were devoted to this plant. Hops are grown to a much smaller extent in Sussex, and in still diminished quantity in Herefordshire, Hampshire, Worcestershire and Surrey. The other counties of England and the principality of Wales produce but a trifling amount, and Scotland none at all.

In continental Europe, hops are most largely produced in Bavaria and Württemberg, Belgium and France, but in each on a smaller scale than in England. France in 1872 is stated to have 9223 acres under hops.[2058]

[2056] A substance with which we are not acquainted.

[2057] _Thèse_, Montpellier, 1867.

[2058] _Agricultural Returns of Great Britain_, &c., 1873, presented to Parliament, 48. 49. 70. 71.

Notwithstanding the extensive production of hops in England, there is a large importation from other countries. The importation in 1872 was 135,965 cwt., valued at £679,276: of this quantity, Belgium supplied 66,630 cwt., Germany 36,612 cwt., Holland 16,675 cwt., the United States 10,414 cwt., France 5,328 cwt. During the same period hops were exported from the United Kingdom to the extent of 31,215 cwt.[2059]

=Uses=—Hops are administered medicinally as a tonic and sedative, chiefly in the form of tincture, infusion or extract.

GLANDULÆ HUMULI.

_Lupulina_; _Lupulin_, _Lupulinic Grains_; F. _Lupuline_; G. _Hopfendrüsen_, _Hopfenstaub_.

=Botanical Origin=—_Humulus Lupulus_ L. (see preceding article). The minute, shining, translucent glands of the strobile constitute when detached therefrom the substance called _Lupulin_.

=History=—The glands of hop were separated and chemically examined by L. A. Planche, a pharmacien of Paris, whose observations were first briefly described by Loiseleur-Deslongchamps in 1819.[2060] In the following year, Dr. A. W. Ives of New York[2061] published an account of his experiments upon hops and their glands, to which latter he applied the name of _Lupulin_. Payen and Chevallier, Planche and others, made further experiments on the same subject, endorsing the recommendation of Ives that lupulin (or, as they preferred to call it, _Lupuline_) might be advantageously used in medicine in place of hops.

[2059] _Annual Statement of the Trade of the United Kingdom_ for 1872. 49. 93.

[2060] _Manuel des Plantes usuelles et indigènes_, 1819. ii. 503.

[2061] Silliman’s _Journ. of Science_, ii. (1820) 302.

=Production=—Lupulin is obtained by stripping off the bracts of hops, and shaking and rubbing them; and then separating the powder by a sieve. The powder thus detached ought to be washed by decantation, so as to remove from it the sand or earth with which it is always contaminated; finally it should be dried, and stored in well-closed bottles. From the dried strobiles, 8 to 12 per cent. of lupulin may be obtained.

=Description=—Lupulin seen in quantity appears as a yellowish-brown granular powder, having an agreeable odour of hops and a bitter aromatic taste. It is gradually wetted by water, instantly by alcohol or ether, but not by potash or sulphuric acid. By trituration in a mortar the cells are ruptured so that it may be worked into a plastic mass. Thrown into the air and then ignited, it burns with a brilliant flame like lycopodium.

=Microscopic Structure=—The lupulinic gland or grain, like the generality of analogous organs, is formed by an intumescence of the cuticle of the nuculæ and bracts of hop (see p. 552). Each grain is originally attached by a very short stalk, which is no longer perceptible in the drug. The gland, exhausted by ether and macerated in water, is a globular or ovoid thin-walled sac, measuring from 140 to 240 mkm. It consists of two distinct, nearly hemispherical parts; that originally provided with the stalk is built up of tabular polyhedric cells, whilst the upper hemisphere shows a continuous delicate membrane. This part therefore easily collapses, and thus exhibits a variety of form, the greater also as the grains turn pole or equator to the observer.[2062]

The hop gland is filled with a thick, dark brown or yellowish liquid, which in the drug is contracted into one mass occupying the centre of the gland. It may be expelled in minute drops when the wall is made to burst by warming the grain in glycerin. The colouring matter, to which the wall owes its fine yellow colour, adheres more obstinately to the thinner hemisphere, and is more easily extracted from the thicker part by means of ether.

=Chemical Composition=—The odour of lupulinic grains resides in the essential oil, described in the previous article. The bitter principle formerly called _Lupulin_ or _Lupulite_ was first isolated by Lermer (1863) who called it the _bitter acid of hops_ (_Hopfenbittersäure_). It crystallizes in large brittle rhombic prisms, and possesses in a high degree the peculiar bitter taste of beer, in which however it can be present only in very small proportion, it being nearly insoluble in water, though easily dissolved by many other liquids. The composition of this acid, C₃₂H₅₀O₇, appears to approximate it to absinthiin; it is contained in the glands in but small proportion. Still smaller is the amount of another crystallizable constituent, regarded by Lermer as an alkaloid.

The main contents of the hop gland consist of wax (_Myricylic palmitate_, according to Lermer), and resins, one of which is crystalline and unites with bases.

A good specimen of German lupulin, dried over sulphuric acid, yielded us 7·3 per cent. of ash. The same drug exhausted by boiling ether, afforded 76·8 per cent. of an extremely aromatic extract, which on exposure to the steam-bath for a week, lost 3·03 per cent., this loss corresponding to the volatile oil and acids. The residual part was soluble in glacial acetic acid and could therefore contain but very little fatty matter.

=Uses=—The drug has the properties of hops, but with less of astringency. It is not often prescribed.

=Adulteration=—Lupulin is apt to contain sand, and on incineration often leaves a large amount of ash. Other extraneous matters which are not unfrequent may be easily recognized by means of a lens. As the essential oil in lupulin is soon resinified, the latter should be preferred fresh, and should be kept excluded from the air.

[2062] For a full account of the formation of the glands, see Trécul, _Annales des Sciences Nat._, Bot., i. (1854) 299. An abstract may be found in Méhu’s _Etude du Houblon et du Lupulin_, Montpellier, 1867.

ULMACEÆ.

CORTEX ULMI.

_Elm Bark_; F. _Ecorce d’Orme_; G. _Ulmenrinde_, _Rüsterrinde_.

=Botanical Origin=—_Ulmus campestris_ Smith, the Common Elm, a stately tree, widely diffused over Central, Southern and Eastern Europe, southward to Northern Africa and Asia Minor, and eastward as far as Amurland, Northern China, and Japan. It is probably not truly indigenous to Great Britain; but the Wych Elm, _U. montana_ With., is certainly wild in the northern and western counties;[2063] the latter is, according to Schübeler, the only species indigenous to Norway.

History—The classical writers, and especially Dioscorides, were familiar with the astringent properties of the bark of πτελέα, by which name _Ulmus campestris_ is understood. Imaginary virtues are ascribed by Pliny to the bark and leaves of _Ulmus_. Elm bark is frequently prescribed in the English Leech-books of the 11th century, at which period a great many plants of Southern Europe had already been introduced into Britain.[2064] Its use is also noticed in Turner’s _Herbal_ (1568) and in Parkinson’s _Theater of Plants_ (1640), the author of the latter remarking that “all the parts of the Elme are of much use in Physicke.”

In the Scandinavian antiquity the fibrous bark of _Ulmus montana_ used to be made up into ropes.[2065]

=Description=—Elm bark for use in medicine should be removed from the tree in early spring, deprived of its rough corky outer coat, and then dried. Thus prepared, it is found in the shops in the form of broad flattish pieces, of a rusty yellowish colour, and striated surface especially on the inner side. It is tough and fibrous, nearly inodorous, and has a woody, slightly astringent taste.

=Microscopic Structure=—The liber, which is the only officinal part, consists of thick-walled, tangentially-extended parenchyme, in which there are some large cells filled with mucilage, while the rest contain a red-brown colouring matter. The mucilage forms a stratified deposit within the cell. Large bast-bundles, arranged in irregular rows, alternate with the parenchyme, and are intersected by narrow, reddish, medullary rays consisting of 2 or 3 rows of cells. The bast-bundles contain numerous long tubes about 30 mkm. thick, with narrow cavities; and besides these, somewhat larger tubes with porous transverse walls (cribriform vessels). Each cubic cell of the neighbouring bast-parenchyme encloses a large crystal, seldom well defined, of oxalate of calcium.

[2063] On the word _elm_, Dr. Prior remarks that it is nearly identical in all the Germanic and Scandinavian dialects, yet does not find its root in any of them, but is an adaptation of the Latin _Ulmus_.—_Popular Names of British Plants_, ed. 2. 1870. 71.

[2064] _Leechdoms, Wortcunning and Starcraft of Early England_, edited by Rev. O. Cockayne, ii. (1865) pp. 53. 67. 79. 99. 127 and p. xii.—In the Anglo-Saxon recipes, both _Elm_ and _Wych Elm_ are named in the Welsh “_Meddygon Myddfai_” (see Appendix). Elmwydd or Ilwyf and “Ulmus romanus,” Ilwyf Rhufain, are met with.

[2065] Schübeler, _Pflanzenwelt Norwegens_, 1873-75, p. 216.

=Chemistry=—The chief soluble constituent of elm hark is mucilage with a small proportion of tannic acid, the latter, according to Johanson (1875), probably agreeing with that of oak bark and bark of willows. The concentrated infusion of elm bark yields a brown precipitate with perchloride of iron; the dilute assumes a green coloration with that test. Starch is wanting, or only occurs in the middle cortical layer, which is usually rejected.

Elms in summer-time frequently exude a gum which, by contact with the air, is converted into a brown insoluble mass, called _Ulmin_. This name has been extended to various decomposition-products of organic bodies, the nature and affinities of which are but little known.[2066]

=Uses=—Elm bark is prescribed in decoction as a weak mucilaginous astringent, but is almost obsolete.

CORTEX ULMI FULVÆ.

_Slippery Elm Bark._

=Botanical Origin=—_Ulmus fulva_ Michaux, the Red or Slippery Elm, a small or middle-sized tree,[2067] seldom more than 30 to 40 feet high, growing on the banks of streams in the central and northern United States from Western New England to Wisconsin and Kentucky, and found also in Canada.

=History=—The Indians of North America attributed medicinal virtues to the bark of the Slippery Elm, which they used as a healing application to wounds, and in decoction as a wash for skin diseases. It is the “Salve Bark” or “Cortex unguentarius” of Schöpf.[2068] Bigelow, writing in 1824, remarks that the mucilaginous qualities of the inner bark are well known.

=Description=—The Slippery Elm Bark used in medicine consists of the liber only. It forms large flat pieces, often 2 to 3 feet long by several inches broad, and usually ¹/₂₀ to ²/₂₀ of an inch thick, of an extremely tough and fibrous texture. It has a light reddish-brown colour, an odour resembling that of fenugreek (which is common to the leaves also), and a simply mucilaginous taste.

In collecting the bark the tree is destroyed, and no effort is made to replace it, the wood being nearly valueless. Thus the supply is diminishing year by year, and the collectors who formerly obtained large quantities of the bark in New York and other eastern states have now to go westward for supplies.[2069]

[2066] Gmelin, _Chemistry_, xvii. (1866) 458.

[2067] Fig. in Bentley and Trimen’s _Med. Plants_,