After leaving the auditory nerve in the inner meatus, the facial continues its course in the Fallopian canal, and at the geniculate ganglion turns backward and downward, crossing the posterior portion of the median wall of the tympanic cavity, and finally, after passing downward along the floor of the posterior wall of the external auditory meatus, leaves the skull through the stylomastoid foramen.

During its course through the petrous portion of the temporal bone the nerve is well protected, and is therefore little exposed to diseases other than tumors and traumatic fractures of the bone. Hence such a paralysis is an important sign of disease in the internal ear. The nerve is most exposed to disease during its passage through the middle ear.

Facial nerve palsies are often observed in acute inflammations of the middle ear, and are explained by extension of the inflammation either through the openings which exist in the canal of the facial nerve for the passage of the nerve to the stapedius and the chorda tympani, or through congenital clefts which not infrequently expose the nerve at different points in the middle ear. It has also been stated 1 that a facial paralysis may be caused by inflammatory hyperemia in the domain of the stylomastoid artery, which supplies both the tympanic cavity and the auditory nerve. The danger to the nerve is of course enormously increased if the suppuration in the middle ear is associated with carious disease of the bone, as such a complication leads to sequestration of the bony wall of the facial canal. Injury of the facial during operations can be avoided if the surgeon possesses any knowledge of the anatomic relations of the nerve and even a moderate experience in operative technic. Nevertheless, they are seen only too frequently after extirpation of the petrous portion of the temporal bone and radical operations.

DISEASES OF THE MENINGES AND OF THE CEREBRAL SINUSES.

Their Significance in Connection with the Nose, Larynx, and Ears.

Diseases of the meninges may involve the cranial nerves and thereby produce pathologic conditions in the organs under discussion.

1 Schwartze, "Die chirurg. Krankh. des Ohres," p. 174.

the labyrinth or to disease of the nerve-trunk occurs either in the course of the disease or as a sequel.

The impairment of hearing, which is often accompanied with vertigo and vomiting, symptoms due probably to implication of the vestibular segment of the labyrinth, presents no definite characteristic, but usually goes on pari passu with the rapid extension of the alterations in the middle ear and labyrinth, and attains a very high grade in a few days. Often it goes on to total deafness, affecting one or both ears, and may even render the patient deaf and dumb, because the ravages of the disease are usually so great that the power of hearing can not be restored. The statistics in deaf and dumb asylums present convincing proof of the prominent part taken by acute cerebrospinal meningitis in the medical history of their inmates.

Diseases of the Meninges in Nasal Affections.

There have been reported in the literature a small number of cases in which disease of the meninges followed disease of the nose and of its accessory cavities. The cases have been collected by Grünwald 1 and Dreyfuss, 2 the most frequent diseases being purulent meningitis, cerebral abscess, and thrombosis in a sinus, especially in the cavernous sinus. The number is, however, very small, and the cases lack uniformity. Hence it will be impossible to show the existence of a definite relationship, as will be seen to be the case in otitic cerebral diseases. Therefore it is not altogether Dreyfuss' fault that he failed in his attempt to give a systematic presentation of "diseases of the cerebrum and its adnexa following suppurations in the nose," 3 in spite of his perseverance and industry in looking up all the literature bearing on the subject.

The interior of the cranium may become infected either from the nose or from its adjacent cavities. In the former case, infection is transmitted by the lymphatic and vascular channels, which, as we have repeatedly stated heretofore, establish an intimate relationship between the upper segment of the nasal cavity and the anterior fossa of the cerebrum. Thus all kinds of inflammations, including the reactive, form due to the use of the galvanic cautery, and infectious diseases of the upper portion of the nose, 1"Die Lehre von den Naseneiterungen," Munich, 1896, p. 125. 2 Jena. Fischer, 1896. 3 Loc. cit.

rare.

which approximately corresponds to the ethmoid bone, frequently set up an irritative process in the meninges and lead to grave constitutional phenomena. Considering the frequency of galvanocaustic interference, the cases that go on to a purulent meningitis are, however, comparatively The latter complication is particularly to be dreaded after tamponade of the upper portion of the nose on account of the resulting retention of secretion, which is always of an infectious nature. The fissures which are said to be occasionally present in the cribriform plate of the ethmoid bone are, according to Dreyfuss,1 of some significance in the genesis of rhinitic cerebral complications, but the cases of Chiari and Kaiser, on which he bases his theory, did not appear to furnish a satisfactory proof, and it is difficult to believe that "the unfortunate subjects of this anomaly are in danger of contracting meningitis after any ordinary coryza,' and that "even a violent blowing of the nose is fraught with great danger in such individuals" (Dreyfuss).

The second mode of infection of the cerebrum, from the accessory cavities of the nose, follows caries of the walls of the cavities, a frequent sequel of chronic suppuration. The danger of infection to the brain from the diseased cavities necessarily depends on their anatomic relations with respect to the interior of the cranium and the thickness of their walls, as in some cases of chronic suppuration with caries several cavities are affected at the same time, so that it is often impossible to determine the exact spot from which the suppuration has extended to the cerebrum. The possibility of such an etiologic connection must be considered in all diseases of the meninges in patients who are the subjects of chronic suppuration from the nose. The frontal sinus, the ethmoidal cells, and the sphenoidal sinus represent the cavities which are in direct relation with the base of the skull, and which therefore constitute a more or less serious menace to the cerebrum according to the thickness of their walls.

When, as a consequence of caries, there are evident defects in these walls through which the pus can find entrance into the interior of the skull, the mode of infection is manifest, but there are other cases of purulent meningitis in which, as I have myself seen, the path followed by

1 Jena. Fischer, 1896, p. 47.

Such changes have been observed in pachy- and leptomeningitis and in tubercular and syphilitic meningitis, and recently the opinion is becoming more and more prevalent that serous meningitis is often responsible for palsies of the cranial nerves. Thus, paralysis of the vocal cords has been observed in various diseases: in epidemic cerebrospinal meningitis irritative conditions in the muscles of the larynx may occur, as observed by Oppenheim (quoted by Kraus), along with irregular twitchings in the lower distribution of the facial nerve, in the uvula, and in the vocal cords, taking the form of continuous rhythmic and isochronous contractions in the vocal cords. Occasionally olfactory disturbances are reported as signs of involvement of the olfactory nerve, but the most frequent sequelae of diseases of the meninges are found in lesions of the auditory nerve or of the labyrinth. Hence, in any case of greatly diminished hearing or deafness acquired in early youth, we should always take into account the possibility of an antecedent inflammation of the meninges if there is no history of an infectious disease.

The aural disturbance may originate in disease either of the auditory nerve or of the labyrinth, since it is well known that the sheath of the auditory nerve and the aqueducts of the vestibule and of the cochlea present a natural pathway for the spread of the disease from the interior of the cranium to the internal ear.

In cases where it is doubtful whether the seat of the aural disturbance is to be sought in the trunk of the auditory nerve or in the labyrinth, a coexistent facial paralysis may point to the localization of the lesion in that part of the trunk of the acusticus which lies in close proximity to the seventh nerve.

Among the diseases of the meninges acute cerebrospinal meningitis plays a very important rôle, and I take up the consideration of this disease now rather than among the infectious diseases, because it gives rise for the most part to the same varieties of secondary disease of the cranial nerves as a meningitis due to other causes.

We learn from studies on the etiology of epidemic cerebrospinal meningitis that the nose plays an important part in the genesis of the disease, the meningococcus intercellularis (Weichselbaum) being constantly found in the nose and its accessory cavities. Although the significance of

this bacteriologic finding is somewhat weakened by the fact that Schiff1 found virulent cocci in 4 out of 28 cases of persons who were not suffering with epidemic cerebrospinal meningitis, it is nevertheless probable that infection very frequently takes place through the nose, because the disease often begins with coryza (Strümpell); and we have Weigert's authority for the statement that catarrhal inflammations are frequently found in the accessory cavities of the nose at the autopsy.

It is quite possible that the ear as well as the nose may in some cases afford entrance to the pathogenic microorganisms of acute cerebrospinal meningitis. The meningococcus intercellularis has, indeed, been found in isolated cases in the aural secretion, 3 but not with sufficient frequency to warrant a general conclusion as to its primary significance in the production of a secondary meningitis. As pointed out by Leyden 4 and Schwabach, 5 purulent otitis media occasionally coexists with the general disease, so that the thought naturally suggests itself that both affections are produced by the same pathogenic microorganism. Schwabach was able to prove in one case, in which the internal auditory meatus and dura mater were found to be entirely free from pus at the autopsy, that the suppuration of the middle ear was not a secondary inflammation due to extension from the cerebrum.

Purulent otitis media is, however, comparatively rare as a complication of acute cerebrospinal meningitis, and far less frequent than the other form of the disease which is due to direct extension of the purulent process from the meninges to the internal ear.

It has been proved by numerous anatomic investigations 6 that the inflammation extends either along the sheath of the acusticus or through the aqueducts of the labyrinth where the purulent or hemorrhagic inflammatory process is followed by extensive tissue-destruction. As we have just stated, the suppurative process in the middle ear often begins in the first stage of the systemic disease; the deafness which must be attributed either to suppuration within 1Centralbl. f. inn. Med.," 1898, No. 22. 2" Deutsche Arch. f. klin. Med.," XXX.

3 Fromann, "Congr. f. inn. Med.," 1897.

4 Nothnagel's "Spec. Path. u. Therap.," vol. x.
5"Zeitschr. f. klin. Med.," XVIII.

6 Comp. Moos, "Schwartze's Handb.," 1, p. 575.