hemorrhage in the substance of the root have been found. It very frequently is involved in syphilitic meningitis. In purulent meningitis infection may travel along its sheath into the inner ear and produce deafness that is usually permanent. After exposure to cold the eighth nerve is sometimes subject to a neuritis similar to that so common in the facial, which may or may not be associated in the process. The condition is marked by diminished or complete loss of hearing, but is of favorable prognosis. Artisans who work constantly amid loud noises-as boilermakers, tinsmiths, and other metal workers, engine-drivers and firemen on railroads often present a partial loss of hearing that may progressively increase. They sometimes hear better in the accustomed turmoil than in quiet places, and this is also true, but much less commonly, of ordinary deafness. The auditory nerve may be injured within the petron by the extension of inflammation from the mastoid, tympanum, or pharynx, and by basilar fractures.

Diagnosis. The first thing to be settled in a case of deafness is the integrity of the nerve. If the nerve is at fault, the condition is called nervous or nerve deafness. When there are no basilar symptoms, involvement of other cranial nerves, bulbar or cerebral indications, and when sounds of high and low pitch are not heard through the air or by bone-conduction, we may safely locate the disease in the nerve. Rinne's test (see p. 63) enables us, when the hearing is reduced, to fairly determine whether the difficulty is in the conducting apparatus or in the nerve. A great reduction of hearing, in which air-conduction remains better than bone-conduction, but in which both are deficient, points to nervous deafness. Lesions within the brain-stem and in the temporal lobe must be determined by the association of symptoms peculiar to these localities.

Treatment. In the treatment of nervous deafness we have first to investigate the aural apparatus and remove, if possible, any diseased conditions that may be present. All acute inflammatory trouble must subside before active measures are instituted. The use, then, of strychnin, preferably hypodermatically, in much the same way as for optie atrophy, can be recommended. Electricity has small claims to notice, though usually suggested. Unfortunately, very little improvement can be expected. Nerve deafness of sudden onset, whether due to syphilis, neuritis, congestion, or hemorrhage into the internal car, is sometimes favorably modified by the use of pilocarpin in full doses twice daily for a week or two.1 Free action on the skin is to be produced. In these cases quinin and the salicylates are contraindicated, though sometimes of value in the chronic forms.

Irritation of the Vestibular Portion of the Eighth Nerve -Aural Vertigo, Ménière's Disease.-The function of the semicircular canals is still subject to dispute. It can at least be accepted that their irritation or injury may cause vertigo and disturbance of equilibration. Recognition of relations to space and orientation undoubtedly are subserved by them to a considerable degree. Their innervation is

1 Dundas Grant, "Brit. Med. Jour.," Nov. 16, 1896.

by the vestibular portion of the eighth cranial nerve. It has long been recognized that disturbance in the internal or middle ear, and even in the external meatus, may cause not only tinnitus, but vertigo. The sudden inflation of the drum by the Eustachian passage, the use of interrupted galvanic currents about the ear, and any instrumentation within the tympanum may produce giddiness. The only essential common character of all these causes is that they produce irritation. If destruction of the vestibular branch takes place, the vertigo usually ceases. In some cases of aural vertigo due to middle- or internal-ear disease, external objects seem always to revolve to the right or to the left. In other instances the vertigo is subjective and the patient feels as if revolved to the right or left or as if falling forward, backward, or downward. The intensity of the vertigo varies greatly. It may be quite insignificant or it may be so pronounced that the patient holds to any neighboring person or object, staggers, or is even forcibly projected in some given direction. The attacks are usually paroxysmal, with relative freedom in the intervals. In the form described by Ménière the victim is struck down as if shot, there may be unconsciousness for a few moments, and the patient is often pale and covered with perspiration. Nausea and vomiting may occur.

The great majority of cases of aural vertigo occur after thirty years of age. In childhood they are extremely infrequent and rapidly increase after middle life, men being affected twice as frequently as women. Gout, rheumatism, and the sclerotic changes of old age are frequently at the bottom of the symptoms. These may act directly upon the labyrinth or indirectly through the blood-supply and the pressure of the endolymph. A vasomotor element is given considerable importance by some. The irritation of the vestibular filaments is usually associated with auditory phenomena, so that tinnitus and defective hearing are almost invariably present. The close anatomical relations of the two portions of the eighth nerve explain this. In some cases the labyrinth has been found the seat of hemorrhage or local disease. Sometimes its epithelial structure is degenerated. Usually disease of the middle and external ear is wanting in the severest cases, while decreased hearing and tinnitus point strongly to involvement of the nerve itself. Some of the cases of the Ménière type show a progressive tendency, with failing hearing, first in one, then in the other ear. Complete physical disability through the vertigo and attacks of falling may ensue. some instances the disease remains at a standstill for years, and may even recede and hearing be restored. Again, when hearing is lost the vertiginous attacks may cease. Milder varieties run various courses, depend

ing upon their causation and treatment.

In

Diagnosis of an aural vertigo depends in practice mainly upon the association of auditory symptoms. Tinnitus or defective hearing, or both, are ordinarily present. The defect in hearing, as tested by boneconduction, is sometimes unexpectedly great, the ticking of a watch when placed on the mastoid being inaudible. If the vertigo is produced or increased by changing the air-pressure in the tympanum, as by firmly pressing the tragus into the meatus or by Politzerization, the significance

of that fact is great. Frequently the attack of vertigo is associated with an intensification of the tinnitus, or there are subjective sounds of a violent character, described as "pistol shots," "something breaking in the head," etc. Sometimes a quick movement of the head in a given direction produces it. This apparently has relation to a particular semicircular canal, which is mainly or alone affected. A further characteristic of aural vertigo is the fact that the subjective or objective gyrations are uniform in the given case, or the stagger or falling is always in the same direction. In epilepsy we not infrequently encounter an indescribable vertiginous aura, but never the formulated vertigo of aural disease. The epileptic attack is usually followed by mental hebetude, which is lacking in aural attacks, where the vertigo may be maintained for a long time, giving rise to distressed feelings, vomiting, and collapse. The sensorium is always clear in aural vertigo, excepting the initial momentary unconsciousness of the severest form, or in the delirium that a continuation of the extremest variety may produce in very rare instances. The persistent vomiting usually gives rise to the idea of "biliousness," and frequently a brisk cathartic, relieving all the symptoms of vertigo, is supposed to confirm the idea of intestinal or hepatic derangement, its influence on cerebral circulation being overlooked. Again, the sudden onset of the attacks in the Ménière form suggests cerebral disease or cardiac attacks, to which mistake the age of the patient and his arterial degeneracy often conduce. The repetition of the aural attack during periods of rest, and even during sleep, with absence of cardiac and cerebral symptoms in the meanwhile, will correct a misconception of this character.

The labyrinthine variety may be readily confused with ocular vertigo in some instances, as it occasionally gives rise to nystagmus, and even has produced diplopia. The patients sometimes describe oscillating movements in viewed objects, rapid in one direction with slow return, similar to the nystagmic movements of the eyeballs. The mutual dependence of space sensations and ocular impressions only needs to be mentioned to explain the secondary ocular movements. Ocular vertigo ceases the moment the eyes are closed, but this has no effect on the aural form. Vertigo is associated with numerous abdominal disturbances, particularly those of the stomach, liver, and small intestine. These forms of vertigo are usually attended by indigestion or other symptoms of a local character, and the vertigo lacks the distinctive gyratory feature of ear trouble. In some cases of aural vertigo, however, the patients complain merely of "dizziness," "giddiness," or "swimming sensaIf the vestibule alone is involved, without any implication of the cochlea, as is conceivable, all auditory symptoms default. In such cases the diagnosis must largely depend on the exclusion of other sources of vertigo.

tions.

Treatment. If aural vertigo is recognized as an irritation symptom, its rational treatment will depend on appreciating and, if possible, removing the basic disease. Cases may be relieved or even cured by Politzer's inflation, by the removal of cerumen, or by the correction of a pharyngeal catarrh. In others the sclerotic changes in the labyrinth

are irremediable and treatment is directed to reducing the irritability by bromids. Charcot strongly recommended in the Ménière type the use of quinin in large doses, but others have not had his success with that drug, and it should not be used in acute cases. He even advocated the destruction of the inner ear, producing loss of hearing, or, in other words, a removal of all irritability and the cessation of the vertigo at once, in the same way that sometimes occurs naturally. Gout and arteriosclerosis, middle-ear disease, and lesions of the auditory stem must be treated in their own several ways. Electricity is of questionable value, though it is asserted by some that the positive pole over the tragus and the negative on the back of the neck, with a current of three or four milliamperes gradually increased from zero, continued for five minutes and then decreased, has a quieting influence. All interruptions should be avoided. Cases of acute onset are sometimes benefited by pilocarpin, as in nervous deafness, with which they are usually combined.

CHAPTER IX.

DISEASES OF THE GLOSSOPHARYNGEAL, VAGUS, AND ACCESSORY NERVES.

It

Anatomical Considerations.-The glossopharyngeal and pneumogastric nerves and the bulbar portion of the spinal accessory should be considered as one mechanism. Their nuclei in the medulla are practically inseparable, and they continuously subserve sensation and motion for the gastro-intestinal tract from the pharynx to the duodenum. In addition they furnish motor filaments, which all come from the accessory portion, to the lungs, larynx, and heart. They are visceral nerves. is to be kept clearly in mind that the spinal portion of the accessory is a pure motor nerve to the skeletal muscles of the neck, and is only locally associated with the pneumogastric. The interrelations of the glossopharyngeal-vagus-accessory group are so complex, their distribution so wide-spread, and their indirect disturbances so vague that they furnish many perplexities. A short outline of the glossopharyngeal is first given, and then the vagus and true accessory are discussed together.

DISEASES OF THE GLOSSOPHARYNGEAL NERVE.

The ninth cranial nerve is still a source of anatomical contention and physiological doubt. In consequence its diseased conditions are uncertain and obscure. Practically, in man, it is never alone diseased. If its relations to other cranial nerves are considered, this fact is readily understood. Through Jacobson's nerve it forms, with the sympathetic, the tympanic plexus, whence a branch connects it through the Vidian

with the facial nerve, and another branch through the small petrosal connects it with the otic ganglion. It is connected with the pneumogastric at the petrous ganglion of that nerve, and also in the pharyngeal plexus. Its nuclei are intimately associated with those of the vagus and accessory nerves. It probably subserves sensation in the upper part of the pharynx and in the tympanum, and nausea is associated with its disturbance. Probably through its distribution to the root of the tongue it peripherally carries the fibers of the special sense of taste for that area, but these are not embraced in its root. They reach the brain by a circuitous route, probably entering the petrous ganglion of the glossopharyngeal nerve from the middle branch of the fifth through the tympanic plexus and otic ganglion. It seems to have some motor control of the upper portion of the pharynx, and, perhaps, of the palate.

Intracranial disease and cranial fractures may implicate the glossopharyngeal, causing weakness and some insensitiveness in the upper pharynx and in the palate. Its nuclei in the medulla usually suffer in bulbar palsy, and thus are produced, at least in part, the pharyngeal symptoms of that disease.

DISEASES OF THE VAGUS AND BULBAR PORTIONS OF
THE ACCESSORY.

The

Pharyngeal Branches.-The pharyngeal branches of the pneumogastric follow below the glossopharyngeal, and with it form the pharyngeal plexus, supplying motion and sensation to the uppermost portion of the intestinal tube. These branches are paralyzed by nuclear disease and in diphtheric palsy, but seldom otherwise. The bulbar involvement is invariably attended by symptoms in other cranial nerves. pharynx is more or less insensitive and motionless. The pharyngeal reflex is lost. Food tends to accumulate and lodge in the gullet or overflows into the larynx, producing spasmodic cough and strangling. If the palate at the same time is weakened, food and fluids may be forced into the nasal passages and regurgitate through the nose. Α pharyngeal spasm furnishes the condition commonly noted in hysteria as "globus," or esophagismus, and is always functional. At times it may be mistaken for pharyngeal paralysis, or the difficulties in swallowing in the latter may be attributed to spasm. The use of a sound will at once clear the doubt. The decided pharyngeal grasp of health is increased in spasm and lost in paralysis. Moreover, spasm is temporary

or recurrent, and paralysis is continuous.

Laryngeal Branches.-The larynx is innervated by two branches of the pneumogastric: (1) The superior laryngeal governs the movements of the epiglottis and controls tension in the vocal cords through the cricothyroid, which is the only intrinsic laryngeal muscle supplied by this nerve. It also furnishes sensation to the larynx above the vocal cords. (2) The recurrent laryngeal, which turns about the aorta on the left side and the subclavian artery on the right side, supplies sensation