white enamelled Maltese cross, surmounted by a royal crown, with the Brandenburg eagle in the corner, was adopted. All the knights of the Black Eagle were received into this new order; and it was latterly decreed that only those who had been decorated with the Red Eagle, in the first instance, could be received into the black. In 1810, the order of the Red Eagle was reorganised, and two more classes were added to it. In 1830, the second class was subdivided into two, one of which only was allowed to wear a square star.

EAGLE HAWK (Morphuus or Spizaëtus), a genus or sub-genus of Falconidae, of the eagle group, but consisting of species of comparatively small size, and characterised by short wings, long slender legs (tarsi), and comparatively feeble toes and claws. Some of the species are extremely beautiful in form

incomplete facial disc, two tufts of feathers (horns or egrets) of considerable size on the head, ears with small openings (conchs), legs and toes covered with feathers, short strong curved bill, and long curved sharp claws. To this genus belong the largest of the nocturnal birds of prey. The E. O. of Europe (B. maximus) is little inferior in size to the Golden Eagle, and preys on quadrupeds such as hares, rabbits, and young deer, and on grouse, partridges, and other kinds of game. It seizes its prey with its feet, and seldom touches it with the bill till its struggles are over. It is an inhabitan of many parts of Europe and Asia, but it is only a rare occasional visitor in Britain. The loud peculiar cry of this bird, resounding strangely through the night, has obtained for it its German name of Ulu, and an intimate association from time immemorial with evil omens and superstitious terrors.-The E. O. of America (B. Virginianus), the VIRGINIAN HORNED OWL or GREAT HORNED OWL, is very similar to the species just noticed, but of inferior size, although still a large and powerful, as it is also a bold bird. It does not scruple to attack half-grown turkeys, and often succeeds in making them its prey. It carries off with ease almost any other inhabitant of the poultry-yard. It is found in almost all parts of America.

EAR, THE, ANATOMY AND PHYSIOLOGY OF. The apparatus of hearing, as it exists in man and the mammalia, is composed of three parts-the external ear, the middle ear or tympanum, and the internal ear or labyrintb

Fig. 1.

General view of the external, middle, and interna. ear, shewing the interior of the auditory canal, tympanic cavity, and Eustachian tube.

a, the auditory canal; b, the tympanum; e, the Eustachian tube, leading to the pharynx; d, the cochlea; and e, the semicir cular canals and vestibule, seen on their exterior by the removal of the surrounding bony tissue.

The external ear consists of two portions, the auricle or pinna (the part popularly recognised as the ear), and the auditory canal or external meatus.

The auricle, on its outer or more exposed surface, presents various eminences and depressions, resulting from the form of its cartilaginous framework. These have received special anatomical names, to which it is unnecessary to advert further than to mention that the deep capacious central space to which several grooves converge, is termed the concha, and that the lowest and pendulous portion of the ear is termed the lobe. The cartilage forming the basis of the external ear consists of one principal piece, in which there are several fissures, which are filled up by fibrous membrane. Several muscles are described as passing from one part of the auricle to another but they are so little developed in man that they do not require notice; there are additionally three

Fig. 3.

Interior of the Osse us Labyrinth :

V, vestibule; av, aqueduct of the vestibule; o, fovea semielliptica; r, fovea hemispherica; S, semicircular canals; s, superior; p, posterior; i, inferior; a, a, a, the ampullar extremity of each; C, the cochlea; sv, osseous zone of the lamina spiralis, above which is the scala vestibuli, communicating with the vestibule; st, scala tympani, below the spiral lamina. Magnified 34 diameters.

the semicircular canals, one of the orifices being common to two of the canals. Anteriorly, the cochlea enters it by a single opening, the beginning of the scala vestibuli. On its outer wall is the fenestra ovalis, and on its inner are the fovea hemispherica, containing several minute orifices for the entrance of filaments of the auditory nerve, and the fovea semi-elliptica.

The semicircular canals are three in number, and open at both ends into the vestibule. They vary in length, and notwithstanding their name, each is considerably more than a semicircle, the superior vertical canal being the longest. Their average diameter is about a twentieth of an inch, the extremity of each canal exhibiting a dilatation or ampulla. Each canal lies in a different plane, very nearly at right angles to the planes of the other two, hence their names of the superior vertical, the inferior vertical, and the horizontal canals.

The cochlea, which derives its name from its resemblance to a common snail-shell, forms the anterior portion of the labyrinth. It consists of an Osseous and gradually tapering canal, about an inch and a half in length, which makes two turns and a half spirally around a central axis, termed the modiolus, which is perforated at its base for the entrance of the filaments of the cochlear portion of the auditory nerve. This spiral canal is about onetenth of an inch at its commencement, and gradually diminishes towards the apex of the cochlea. At its base, it presents two important openings, one into the vestibule, and the other (closed by a membrane except in the dry bone), and communicating with the tympanum, being the fenestra rotunda already described. Its interior is subdivided into two passages (scala) by an osseo-membranous lamina, extending from the modiolus to the periphery, and taking the same spiral course as the canal itself. This is the lamina spiralis, which divides the cochlea into an upper passage, the scala vestibuli, and a lower one, the scala tympani. At the apex, these two passages communicate by an opening to which the term helicotrema has been applied. For a notice of the membranous portion of the lamina spiralis, we

Fig. 4.

Membranous Labyrinth of the Left Side, with its Nerves

and Otoliths.

sw, superior semicircular canal, with the ampulla and ite nerve at one end, and the other end joined by p, the posterior canal, to form a common tube; i, inferior or horizontal canal, with the ampulla and its nerve at one end, and the other entering the utriculus separately; c, powdery otolith seen through the transparent wall of the utriculus or common sinus; s, powdery otolith of the sacculus, seen with its nerve in a similar way; n, cochlear division of the auditory nerve, cut through; d, portio dura, or facial nerve, leaving the auditory nerve, or portio mollis, to enter the aqueduct of Fallopius. Magnified."

consists of two sacs, an upper and larger one, of an oval shape, termed the utricuius, or common sinus, and a lower and smaller one of a more globular shape, called the sacculus.

The membranous semicircular canals resemble in form and arrangement the osseous canals which enclose them, but are only one-third of the diameter of the latter. The ultimate filaments of the Auditory Nerve (q. v.) mainly go (see fig. 4) to the utriculus, to the sacculus, and to the ampulla of the canals.

The membranous labyrinth is filled by a fluid which is termed the endolymph; and in certain spots, especially at the terminations of the vestibular nerves, we observe, both in man and the lower animals, calcareous matter either in a powdered or solid form. In man and mammals generally, and in birds and reptiles, it occurs as a powder, and is termed otoconia or ear-powder, and it always consists of carbonate of lime.

We now proceed to consider the different func. tions or offices of the various parts of the organ of hearing.

1. Of the External Ear.-A true auricle only exists in the mammalia, and in this class it varies from little more than an irregularly shaped cartilag inous disc, with little or no motion, as in man aud the quadrumana, to an elongated funnel-shaped eartrumpet, movable in all directions by numerous large muscles, as in the horse, the ass, and the bat

The mode in which we see it employed by those animals in which it is highly developed, sufficiently indicates that its main function is to collect and concentrate the sounds which fall upon it. But the experimental investigations of Savart, with an apparatus constructed to resemble the tympanic membrane and the external auditory apparatus, shew that these parts are also adapted to enter into vibrations in unison with those of the air; and he suggested that the human auricle, by the various directions of different parts of its surface, could always present to the air a certain number of parts whose direction is at right angles with that of the molecular movement of that fluid, and therefore is the most favourable position for entering into

vibrations with it.

2. Of the Tympanum and its Contents.-Savart's experiments shew that the membrane of the tympanum is thrown into vibration by the air, and that it always executes vibrations equal in number to those of the sonorous body which excites the oscillations in the air. He further ascertained that the malleus participates in the oscillations of the tympanic membrane, and that these vibrations are propagated to the incus and stapes, and thus to the membrane of the fenestra ovalis. The malleus has further the office of regulating, through the tensor tympani muscle, the tension of the tympanic membrane; and to allow of the motion necessary for this purpose, we find movable joints between it and the incus, and again between the latter bone and the stapes. The contraction of the stapedius muscle similarly modifies the tension of the membrane of the fenestra ovalis; and as compression exercised on this membrane extends to the perilymph, and is propagated through it to the fenestra rotunda, the tension of the membrane of the latter opening is also influenced by the muscle in question. The incus is much more limited in its motions than either of the other bones, and its use seems to be to complete the chain of ossicles in such a manner as to prevent any sudden or violent tension of the membranes, such as we can easily conceive might occur, if the conductor between the membranes were a single bone. The presence of air in the tympanic cavity serves a double purpose: in the first place, it preserves a uniform temperature on the outer surfaces of the fenestral membranes, and thus supports a fixed elasticity in them, which would not be the case if they were freely exposed to ordinary atmospheric changes; and secondly, the action of the chain of ossicles as conductors of sound is materially increased by their being completely surrounded by air, as is obvious from the first principles of

acoustics.

3. Of the Labyrinth. —Sound is conducted to the labyrinth in three ways: first, by the chain of bones; secondly, by the air in the tympanic cavity; and thirdly, through the bones of the head.

Müller has shewn, by very ingenious experiments on an apparatus constructed to resemble, on a large scale, the middle and internal ear, that while the air in the tympanum conducts sound to the cochlea, through the fenestra rotunda, the chain of bones form a much better conductor of it to the vestibule, through the fenestra ovalis (see the chapter on Hearing in his Physiology). Hence, we infer that the vestibule is adapted to receive sounds from the membrane of the tympanum and the external ear, while the cochlea, on the other hand, as its structure and connections indicate, may be regarded as that part of the labyrinth which is specially affected by Bounds communicated through the bones of the head. That the vestibule is the essential or fundamental part of the organ of hearing, is sufficiently proved by its constancy, other parts gradually disappearing

as we descend the animal scale, and by the central position in the ears of the higher animals. The use of the otoconia or ear-powder is to strengthen the sonorous undulations, and to communicate to the membranous vestibule and the ampullæ, and to their nerves, stronger impulses than the perilymph alone could impart. The action of otoliths or ear-stones, such as occur in osseous fishes, must be still more decided, and is well illustrated by the following experiment of Camper. Fill a bladder with water, The slighest impulse and place a pebble in it. communicated to the bladder disturbs the pebble, which consequently produces a greater impression on the hand supporting the bladder than the water alone could do.

Nothing certain is known regarding the functions of the semicircular canals, but their constant existence and number* in the vertebrated animals indicate their importance; and in most cases of congenital deafness they are more or less defective. The fact of their position corresponding with the three dimensions of a cube-namely, its length, breadth, and height-has led to the opinion that they are concerned in conveying a knowledge of the direction of sounds. This view is supported by Professor Wheatstone, who believes that we distinguish best the direction of those sounds which are sufficiently intense to affect the bones of the head, and that it is from the vibrations which are transmitted through these bones that our perception of direction is obtained. Thus, if the sound be transmitted in the plane of any one canal, the nervous matter in that canal will be more strongly acted on than in either of the other two; or if it be transmitted in a plane intermediate between the planes of this canal and the adjacent one, the relative intensity with which these two canals will be affected will depend upon, and indicate the direction of the intermediate plane.

The range of hearing, like that of vision, varies remarkably in different persons. Some persons are insensible to sounds which others can readily hear. The ordinary range of human hearing comprised between the lowest notes of the organ and the highest known sound emitted by insects includes, according to Wollaston, more than nine octaves, the whole of which are distinctly perceptible by most ears. He relates, however, several cases in which the range, in reference to the perception of high notes, was much less. In one individual, the sense of hearing terminated at a note four octaves above the middle E of the pianoforte, the F above it being inaudible, although his hearing in other respects was as perfect as that of persons in general; another case was that of a lady who could never hear the chirping of the field-cricket; and in a third case the chirping of the common house-sparrow could not be heard. See his Memoir on Sounds Inaudible by Certain Ears, Phil. Trans. 1820.

The sensation of sound, like that of light, frequently lasts longer than the exciting cause. We have familiar proof of this fact in the noise which remains in the ears after a long journey in a coach or railway; and it was clearly demonstrated by Savart, who found, in his experiments on toothed wheels, that the removal of one tooth did not produce any interruption of the sound.

For diseases of the ear, see DEAFNES.

meaning the possessing of a sensitive, just, and EAR, in Music, is a figurative expression, delicate appreciation of sound and measure.

The only exceptions that we can call to mind are those presented by the myxine or hag and the lamprey-the former has only one, the latter two semicircular canals. Both are fishes of very low organisation.