Page:The American Cyclopædia (1879) Volume VI.djvu/359

 EAGLE WOOD raised to 900 thousandths, its weight remain- ing as before, 258 grains, of which 232-^ were pure gold ; and at these rates it continues to be coined. There are also a half eagle, first coined in 1795, a quarter eagle, first coined in 1796, and a double eagle, first coined in 1849. These coins are a legal tender for all sums. The number of coins of each kind produced at the mint and branches from their organiza- tion to June 30, 1873, is as follows: Double eagles 32,336,404 I Half eagles 18,959,842 Eagles 5,553,249 | Quarter eagles 10,417,561 The total number of pieces is 62,267,056, valued at $798,103,682 50. (See COINS.) EAGLE WOOD, a fragrant wood containing an abundance of resin and an essential oil, highly esteemed for its perfume by Asiatics, who burn it as incense. The tree from which it is obtained is a native of the East Indies, and belongs to the genus aquilaria. There are three varieties, A. Malaccensis or ovata, indigenous to Malacca and Siam, where it is called garos, and to which the name eagle wood is more generally applied ; A. agallochum, a large tree with alternate lance-shaped stalked leaves, a native of Silhet, where it is called ugoor, supposed to be the calanibac or agallo- chum of the ancients; and A. .secundaria, a tree whose wood is white and inodorous in a healthy state, but when attacked by a dis- ease to which it is subject becomes colored and gives out a powerful scent. The Cochin Chi- nese are said to make their paper from its bark. Eagle wood is largely used in India and Siam, but the greater part of it is exported to China. According to French authorities, it was burned as a perfume in the imperial palace in the time of Napoleon I. In India it is used also as a cure for the gout, and it is sometimes prescribed in Europe in rheumatic affections. Its Malayan name is agila, whence the wood was called by the Portuguese pao d'agila, which became corrupted into pao tfaguila, and finally pao cPaquila or eagle wood. EAR, the organ of hearing. Anatomists di- vide it into the external, the middle, and the internal ear. The first consists of the visible external organ, a cartilaginous and fleshy struc- ture, of the form best adapted to collect the atmospheric vibrations, and the meatus or tu- bular opening leading to the tympanum. The tympanum is a firm fibrous membrane stretched across this opening, whose office, as its name implies, is to communicate vibrations like the head of a drum. The middle ear is a cavity about the form and size of a kidney bean ; from its lower point a tubular canal descends to the side of the pharynx, where it terminates in a trumpet-like expansion ; this canal is called the Eustachian tube. Across the middle ear is stretched a chain of three small bones, con- nected with each other by cartilage and ten- don. These are the malleus or mallet, the incus or anvil, and the stapes or stirrup, each named from some fancied resemblance. The 279 VOL. vi. 23 EAR 351 office of this chain, which is attached to the tympanum at one end, and to the membrane covering the foramen ovale at the other, is to transmit the vibrations of the air; to aid in this, they are controlled by three minute mus- cles, which serve to regulate the tension of the membrane of the tympanum, and the pressure of the stapes against the membrane of the foramen ovale. The internal ear, also called the labyrinth, to which the external and mid- dle ear are but the anterooms, consists of the vestibule, the three semicircular canals, and the cochlea. The vestibule is an irregular cavity shut out from the middle ear by the membrane covering the foramen ovale, and communicating with the semicircular canals by five openings, two of these canals being joined at one end. The cochlea, as its name The Parts of the Auditory Apparatus. a, external ear; &, auditory meatus ; c, membrane of the tympanum ; <2, head of the malleus; e, bony process, and/, handle of the mal- leus ; g, incus ; h, i, short and long processes of the incus ; k, I, articulation of incus and stapes ; m, stapes ; n, o, p, semicircular canals ; q, cochlea ; r, apex of the cochlea ; 1, 2, 3, malleus, incus, and stapes, separated from each other and highly magnified. implies, is a bony structure resembling in form a snail shell ; internally it is divided by a lam- ina, bony, ligamentous, and muscular, into two cavities called the scala vestibuli and the scala tympani, which communicate at the top of the cochlea, in a curved channel called the heli- costrema. The modiolus, or bony axis of the cochlea, has numerous orifices, through which pass the filaments of the auditory nerve. The whole internal ear is lined with a delicate se- rous membrane, containing a fluid called peri- lymph. Within the vestibule and the semicir- cular canals, we find the membranous laby- rinth ; in the vestibule it consists of two mem- branous sacs, one called the utriculus and the other the sacculus, communicating with each other and extending in slender tubes through the semicircular canals, of which they only occupy about one third ; in the vestibule and in the ampullae of the semicircular canals these