eminent physician intrusted his son to my care. The hearing was extremely imperfect, the voice thick and nasal, and the articulation so indistinct as to be almost unintelligible to strangers. The tonsils were permanently enlarged, and the mucous membrane generally was in a state of chronic inflammation. The most approved medical and topical treatment had failed in affording relief. The protruding portion of the left tonsil was excised, after which every symptom gradually subsided."

In that case the negative certainly counterbalanced the positive signs.

In reply to Mr. Yearsley's doctrine, Mr. Harvey, in his book on the subject referred to in page 36, states, that "extirpation of the tonsil in the young has led to pernicious results, such as giving rise to bronchial and pulmonary disease, with other mischiefs to be mentioned in this work; and, notwithstanding high authorities in favour of extirpating the tonsils or uvula, for the relief of deafness, the operation has almost uniformly proved a

failure."

But, without bandying opinions or citing authorities on this subject, I appeal to every practical physician and surgeon, as to whether patients with chronic enlargement of the tonsils are more prone to deafness than other persons with similar constitutional tendencies.

Wishing to investigate the subject on a large scale, I lately applied to Drs. Mayne and Kirkpatrick, physicians to the Dublin Workhouses, for an opportunity of examining the tonsils of any cases which might offer among the numerous children and young persons under their care; and they have informed me, that chronic enlargement of the tonsils is almost unknown among the pauper poor and the lower orders: and they attribute the enlargement of these glands, seen in the middle and upper ranks of life, to high feeding.

Polypus of the nose does not cause deafness when of the ordinary gelatinous kind; but I have seen deafness induced by a large fleshy polypus which passed down into the pharynx.

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CHAPTER VII.

DISEASES OF THE INTERNAL EAR.

Anatomy of the Osseous Labyrinth. The Cochlea, Vestibule, and Semicircular Canals.— The Membraneous Labyrinth.-The Seventh Pair of Nerves.-The Auditory Nerve. -Congenital Malformations of the Internal Ear.-Wounds and Injuries.—Inflammations: Internal Otitis; Otorrhoea.--Caries.-Malignant Growths.-Tinnitus.-Otalgia.--Hypercusis.-Nervous Deafness: Its Diagnosis, Symptoms, and Treatment -The Opinions of Kramer and Schmalz.-The Medicated Air-Douche.-The Ether Cure.

THE middle ear or labyrinth contains the ear-bulb or true sen

tient apparatus of hearing, to which all the other portions are accessory. The osseous labyrinth is situated in the petrous portion of the temporal bone, near its cerebral surface, and between the meatus auditorius internus, for the transmission of the auditory nerve and the internal wall of the tympanic cavity, with which space it communicates by the round and oval apertures already described under the head of the Anatomy of the Cavitas Tympani. This bony case, in which the membranous labyrinth and the terminal expansion of the auditory nerve, with its surrounding fluid, is situated, is divided into three compartments, distinguished as the cochlea, the semicircular canals, and the vestibule. This latter space communicates with the two former, and also with the tympanum through the foramen ovalis, which, in the recent state, is closed by the end of the stapes and its surrounding membrane and ligaments. For wise purposes in the animal economy, this osseous labyrinth is curiously fashioned out of the densely hard, solid bone, and can only be studied with effect upon elaborately carved preparations, or in casts made of metal, run into the bony tubes, spires, and chambers of which it is composed. As, however, it is never the seat of surgical operation, and cannot be examined during life, the relative situations and proportions of its parts are of less practical importance to the surgeon than either of those portions of the ear already described.

The vestibule, a small, irregular chamber, varying in size in

different individuals, but averaging about the one-sixth of an inch in its longest diameter, is situated immediately behind the foramen ovalis; it has three dilatations, called ventricles or horns,—a superior and two inferior; one before and the others behind. Its inner wall consists of the sieve-like plate which separates it from the internal meatus auditorius, and through which pass the filaments of the portio mollis and some blood-vessels. Anatomists have described with great minuteness each hole, elevation, or depression in this portion of the internal ear, the enumeration of which, in a practical work of this description, would be out of place.

The semicircular canals are three tubes, each somewhat more than the half of an irregular circle, which exist in the temporal bone, toward the upper and posterior side of the vestibule, into which they open by both extremities; but, as two of them have a common aperture, there are but five openings from these tubes into that chamber. Two of these canals have their arches turned upwards, and hence their position is described as vertical,—the one superior, the other posterior; the third, or shortest, is horizontal.

The cochlea, so called from its resemblance to a snail-shell, lies contiguous to the vestibule, and rather in front of the tympanum. It is a conical tube, above an inch and a half long, closed at the distal extremity, and making two turns and a half round a central pillar, the axis or modiolus; its direction is from left to right in the right ear, and from right to left in that upon the opposite side. The first turn of the tube of the cochlea produces that bulging upon the inner wall of the tympanum already described as the promontory. Around the axis or modiolus a thin plate of bone winds like the thread of a screw,-the lamina spiralis, the shelf formed by which is, in the recent state, completed by membrane, and thus the passage is divided by this spiral septum into two scale. The superior, or external, or vestibular scala, opens into the vestibule; the larger, or scala tympani, which is inferior and internal, opens into the cavity of the tympanum by the fenestra rotunda. These two divisions of the cochlea formed by the spiral lamina communicate at the extremity, in consequence of that bony shelf separating from the axis and turning outward, so as to present a hook-like termination.

Two delicate canals likewise exist in this portion of the petrous bone, the aqueduct of the cochlea,-a mere venous conduit, which extends from that tube, near the fenestra rotunda, to the margin of the jugular fossa; and the aqueduct of the vestibule, which leads from the posterior wall of that cavity, near the common opening of the two semicircular canals, to the upper surface of the petrous bone, a little behind the internal meatus, where it is lined by a reflection of dura mater.

In the recent state, the whole extent of the osseous labyrinth is lined by a fine fibro-serous membrane, which is intimately adherent to its surface, extends into the aqueducts, completes by a double layer the spiral septum of the cochlea already alluded to, forms the inner lamina of the membrane of the fenestra rotunda, and also covers the base of the stapes at the fenestra ovalis. Its external surface acts as a periosteum, and its internal secretes the perilymph or liquor Cotunnii. This fluid permeates the entire labyrinth, passing by the heliocotrema or that passage which exists round the top of the modiolus, and thus completes the circuit between the stapes at the fenestra ovalis, and the tympanic cavity at the fenestra rotunda.

Occupying two portions of the osseous labyrinth, and to a certain degree supported by the perilymph, we find a membranonervous texture, called the membranous labyrinth, which is the fundamental or true essential portion of the organ of hearing. It is composed of a small bag, denominated the common or vestibular sinus, which sends tubuli through the semicircular canals, and is in contact with its osseous surrounding walls only where the latter are pierced by those nervous filaments which ramify within it; but it does not enter the cochlea.

The labyrinth receives its vascular supply from arteries derived from the basilar, and sometimes the cerebellar, which enter by the internal auditory foramen.

The seventh pair of nerves, having arrived at the meatus auditorius internus, divides into the portio mollis or the auditory, and the portio dura or facial. The latter, separating from the former, enters the aqueduct of Fallopius, which leads forwards and outwards to the hiatus Fallopii, where it enlarges into the form of

a ganglion. Its subsequent course, around the roof and posterior wall of the tympanum to the stylo-mastoid foramen, has been al ready described. The portio mollis divides in the meatus auditorius externus into two branches, which are separated by a bony ridge: the large anterior one proceeding to the cochlea; the lesser posterior branch having its destination in the vestibule and semicircular canals, and being chiefly distributed upon the membra nous labyrinth, and in the enlargements denominated ampullæ, at the commencement of the membranous tubes of the semicircular canals. The anterior branch or nerve of the cochlea proceeds to the base of the axis, and, dividing into a number of delicate filaments which pass through the substance of that stem of bone, are distributed between the osseous plates of the laminæ spiralis, at the edge of which they terminate, by a very free anastomosis, in minute fibrillæ, and finally end in delicate papillæ in the membranous portion of the spiral lamina.

MALFORMATIONS OF THE INTERNAL EAR.

Congenital malformations of the labyrinth have received much attention, and minute dissections of such are accumulating from year to year; but as yet pathologists have not been able to connect the peculiar deficiencies in hearing with the post-mortem appearances observed. The entire labyrinth has been found one undivided cavity, without a vestige of either cochlea, vestibule, or semicircular canals, and not having any communication with the tympanum. In other cases the labyrinth has been altogether deficient, and there was, consequently, a total absence of the essential parts of the organ of hearing. The fenestræ are sometimes deficient, or their membranes ossified. The osseous labyrinth has been found but imperfectly developed, so that the membraneous labyrinth was partially uncovered. The cochlea occasionally forms but one turn and a half; and has also been found in a mere rudimentary state, presenting an irregular cul de sac, without any axis or spiral. The semicircular canals are, however, the portion of the internal ear most frequently found malformed; they have been observed smaller than natural, altogether wanting, partially im pervious, or only two out of the three existing. The aqueducts have