AND CHEMISTRY OF HOPS. UNIVERSTY 3 have a powerful agreeable odour and bitter taste; they appear to consist of an acid, ethereal oil, an aromatic resin, wax, extractive, and a bitter principle called lupuline. By pressure, hop heads yield a green, light, acrid oil, called oil of hops. The aggregate fruits of this plant are botanically known under the name of strobiles, in common parlance as hops. These fruits consist of scales (bracts) and achaenia, the latter of which are surrounded by yellowish aromatic glands. They are usually termed lupulinic glands, and are the most active part of hops. They contain a volatile oil, and a bitter principle called lupuline, or lupulite, to the presence of which hops owe their properties. The bracts also contain some lupuline, and are therefore not devoid altogether of active principles. The female flowers, growing on a separate plant, are in the form of a catkin, having each pair of flowers supported by a bract, which is ovate, acute, tubular at base. Sepal solitary, obtuse, smaller than the bract, and enfolding the ovary. Ovary roundish, compressed; stigmas two, long, subulate, downy. The bracts enlarge into a persistent catkin, each bract enclosing a nut enveloped in its permanent bractlet, and several grains of yellow lupuline. To the folioles or scales of the flower of the hop adhere a certain quantity of yellow powder or dust. Ives attributes to this powder alone the active principle of hops. But Payen and Chevallier are of opinion that the entire flower contains the same active principles which are found in the yellow dust. If this were not so, the hops, which in transport lose a great quantity of this yellow powder, would have but a feeble effect in the manufacture of beer. As the quality of hops depends largely upon the amount of lupuline they contain, care is necessary to select those which have been fully matured on the vine before picking, when the lupuline will be found in much greater abundance, and of better quality. When derived from the fresh hop, it is of a very brilliant light lemon colour, almost 'transparent, and of a very strong aromatic odour. When rubbed between the fingers the grains are very easily broken, and adhere to the fingers, but on exposure to the light, or when from older hops, it becomes darker in colour, more opaque, and less gummy when rubbed between the fingers, according to the age. Owing to the difficulty of separating the powder from new hops (from the tendency it has to adhere to the scales, because of the resinous exudation with which it is coated, making its yield by mechanical process smaller), and the comparatively high price of new hops, as compared with old, making it less remunerative, the powder is mostly obtained from old hops. When the hop becomes old, the resinous exudation coating the lupuline concretes, and no longer adheres to the leaf, so that it can be easily separated by whipping the strobiles and sifting. When hops have become a year old, or as soon as the new crop comes into market, they are called old, and command only about one-half the price of the new crop. When two years old, they are called old-olds, and are still less valuable; and when five years old are considered worthless to brewers, although they still contain the lupuline, which possesses a part of its bitterness, but is destitute of volatile oil. The age of hops can be told pretty accurately until they have attained three years; after that it is very doubtful. During the first year they retain their bright green colour and fine, strong aromatic smell, and the lupuline is bright yellow. The second year they become darker, more dead-like, losing their bright colour, and have a sweet, slightly cheesy odour, which is due to the oxidation of the volatile oil, converting it into valerianic acid. The lupuline is of a golden yellow colour. The third year the colour is not much changed, but the odour becomes faint, with the same cheesy smell. The lupuline is of a dark yellow or reddish tint. The female plant, which is the object of careful cultivation, on account of its bitter and odorous strobiles employed in brewing, is much richer in principles than the male plant, from which it is distinguished by its aromatic, tonic, and narcotic properties; qualities which are combined in no other substance. Economic Uses of Hops.-The roots and the stem of this plant merit also attention, as they furnish a raw material, presenting the planter with a secondary useful product. The roots removed with the plant in the course of plucking, and which are generally thrown away, not only contain a starchy substance, which may be converted into glucose and alcohol, but also a large proportion of tannin, which the tanneries might use with advantage. This substance also offers a good material for making excellent paper-pulp and cardboard. The stem possesses useful qualities; vegetable wax can be obtained from it, also a sap from which a durable reddishbrown can be made, and its ash is used in the manufacture of the Bohemian glass. Like the roots, it furnishes a very solid pulp for paper and cardboard. The useful part of the stem is its textile fibre, which easily separates from the ligneous portion, after a steeping of two or three weeks, and of this fibre ropes and coarse fabrics of the greatest strength are made. After bleaching of the combed fibre, carpets with white and brown stripes have been made of it. A M. Van der Scheldon recommended, in 1866, the following process for making a coarse cloth of good quality from the fibre of the hop. After the flowers have been gathered, the stalks are cut, made into bundles, and steeped like hemp. The maceration is the most important operation; for if it is not done with proper care, it is very difficult to separate the threads of the bark from the woody fibre. When the stalks have been well steeped, they are dried in the sun, beaten like hemp with a wooden mallet, and thus the threads are loosened easily. They are then carded, and are ready for weaving in the usual way. By this means a strong cloth is obtained. The thickest stalks also produce a thread suitable for the manufacture of rope. The young sprouts or shoots, although slightly bitter, are sometimes cooked and eaten like asparagus; and the roots, according to Lindley, have been employed as a substitute for sarsaparilla. A farmer in the north of France, having been driven by the scarcity of fodder to try to make use of whatever fell in his way for feeding his cattle, proved that hop leaves were a valuable element of food for cows when mixed with other substances. He found that whenever he gave them hop leaves he always obtained more milk, and his cows throve better than usual. The leaves must be used as soon as they are plucked, for the cows object to them when dried by the sun. The hop bine has often been suggested as a paper material, but no practical action has yet been taken on any extensive scale in the matter. In 1838, George Robert D'Harcourt included it in a patent among various other substances; and in the following year Thomas MacGauran also patented paper-making from hop bine, either by itself, or mixed with other suitable material. Again, in 1854, Thomas L. Holt and William Charlton obtained provisional protection for using the hop stem or bine with other plants, either alone or combined with rags. In 1845, a patent was taken out for using spent hops from the breweries for paper-making. An invention of Mr. Henry Dyer, of Camberwell, recently published, describes improvements in the manufacture of pulp for paper-making, and consists in the application and employment as materials for this purpose of spent hops or spent malt from breweries or distilleries, either together or separately, in combination or not with other materials, such as cotton, linen, hemp, woollen or silk rags, or esparto, diss, palm leaves, straw, wood pulp, jute, gunny, manilla, Indian grass, and waste paper. The spent hops and malt, whether employed together or separately, and with or without the other substances referred to, are to be treated by the processes and machinery usually employed for boiling, pulping, and bleaching the ordinary materials used for paper-making, and when converted into pulp may be at once made into paper, or compressed and dried for sale as half-stuff. Instead of spent hops, fresh hops may be used, in the case |