HOPPIN, James Mason, American scholar and author: b. Providence, R. I., 17 Jan. 1820; d. 1906. He was graduated from Yale in 1840, studied law at the Harvard Law School (1841-42), theology at the Union and Andover seminaries (1843-45) and the University of Berlin (1847-49), was ordained to the Congre gational ministry in 1850 and was pastor at Salem, Mass., in 1850-59. In 1861-79 he was professor of homiletics at Yale, in 1861-63, also pastor of the college church, and from 1879 until his retirement as professor emeritus in 1899 professor of the history of art. His publications include 'Notes of a Theological Student' (1854) ; 'Old England: Its Art, Scen ery and People' (1867) ; 'The Office and Work of the Christian Ministry' (1869) ; 'Life of Rear-Admiral Andrew Hull Foote' (1874) ; 'Homiletics' (1881) ; 'Pastoral Theology' (1889) ; 'The Early Renaissance' (1892) ; 'Greek Art on Greek Soil' (1897) ; 'The Read ing of Shakespeare' (1904).
HOPS (Humulus lupulus) are the strobiles or catkins of a climbing plant, often met with in the wild state in northern Europe and in North America. The hop belongs to the nettle family and it is the sole representative of its genus, but is cultivated in many varieties. It is a dicecious plant, that is, the pistillate (female) and staminate (male) inflorescence are borne by different plants. In American and English hop-gardens it is customary to grow a sprinkling of male plants, but these are rigorously excluded on the Continent. In the former case the pistillate inflorescence becomes impregnated and forms seeds, in the latter they do not. In good hops the seeds are scarce, small, shrunken and sterile, that is. incapable of propagating the plant. Many be lieve that the formation of seed ought to be prevented, as the seeds are useless to the brewer, the main consumer of hops, and besides they cnly add weight to the hops, and this, indeed, is the chief reason for growing them. Their presence, however, grades the hops to a lower price so that the net result is a loss.
The hop is a perennial herbaceous planP. which produces each year several long, twisting, striated stems, 15 to 30 feet in length, which clamber over hedges, brush, etc., with ease. The leaves are stalked, opposite, generally three lobed (sometimes five- to seven- lobed) and coarsely dentate. They are, like the stem, rough to the touch. The male inflorescence forms a panicle; the flowers enclose five stamens in a small greenish five-parted perianth. At an early stage the female inflorescence is less con spicuous. The strobile or catkin consists of several small acute bracts or leaves at whose base are situated two sessile ovaries, each sub tended by a rounded bractlet. These bracts are one-half to three-quarters of an inch long and are attached to the extremity of the stem in such a way as to lap and form a cone.
The ovary and the base of the bracts are covered with a. yellowish powder, the °hop
meal'o or lupulin, which is the active principle of the plant.
Hops contain hop-oil, hop-resins, acids, hop tannin, hop-bitter, hop-wax, nitrogenous bodies, carbohydrates and mineral substances. Dias tase (an enzyme) has also been found, which is especially valuable in ale brewing. Hop-oil, the principal constituent of the lupulin, present in 0.2 per cent to 0.8 per cent, is obtained by dis tilling the hops with water. It is colorless and hardly soluble in water. The characteristic agreeable aromatic flavor of the hops depends on this oil. If exposed to air the oil turns to resin, passing to valerianic acid, to which the cheesy odor of old hops can be traced. Ac cording to Hayduck, there are three resins in hops, the a f3 and y, of which- the first two are soft and the latter hard. The preserving, antiseptic effect of hops is due .to the two soft resins, as they are distinctly prejudicial to the growth of butyric acid and many other bacteria, but do not have much effect on acetic acid bac teria and sarcina. In old hops valerianic acid, malic acid, citric acid and succinic acid are present. Hop-tannin is chiefly stored in the leaves of the strobile and is a pale brown amorphous powder soluble in dilute alcohol, which through oxidation passes into phlobaphen. The hop-bitter is obtained from the two soft resins, and imparts a pleasant bitter taste to the beer, without which it would be flat and in sipid. They are present in the dry hops up to 15 or 17 per cent. Hop-wax is present in con siderable proportions in hops, but, since it is insoluble in water and even in 90 per cent alcohol, it has no value in beer. Nitrogenous constituents of hops are about 2 per cent to 4 per cent, which calculated to albumen are 12 per cent to 24 per cent, of which 0.75 per cent to 1.6 per cent are soluble. Bungerer maintains that 30 per cent of the nitrogenous substances are asparagin. Behrens says that trimethylamin and free ammonia are also pres ent. Griess and Harrow have discovered cholin in hops. Brown and Morris have shown the presence of an enzyme similar to diastase, which will saccharify starch, that is, change it into sugar. This enzyme is chiefly accumu lated in the seeds. The carbohydrates contained are cellulose, sugar, dextrin. According to Brown and Morris there is present 1.55 per cent dextrose and 2.10 per cent levulose, together 3.65 per cent of inverted sugar. According to Thausing hops contain 5.3 per cent to 15.3 per cent of ash and an average of 7.54 per cent, of which over one-third is potash, one-sixth phosphoric acid, one-sixth silica, and some sodium, lime, magnesia, iron oxide, sulphuric acid and chlorine. The presence of an alkaloid in the seed has been ascertained by Dr. Ernst Hantke, but research on this point is still pro gressing.