These have in their elements, the characters of inflammation elsewhere, but modified by the relation of parts. Catarrh is somewhat common, and may be acute or more chronic. The exudation varies according to the severity of the in flammation, being mucous or mucopurulent. The catarrh may be localized mainly in the Eustachian tube, which may be obstructed by the swelling of the mucous membrane. The exudation may distend the tympanic cavity and cause bulging of the membrane. It will also interfere with the movements of the ossicula.

Chronic inflammations also occur which have little of the catarrha character, but rather that of a chronic productive inflammation. These conditions are sometimes described as Chronic, dry or adhesive catarrh. These are associated with Adhesions and Sclerosis of the mucous surfaces. The inflamed surfaces are thickened, and wherever they come in contact they tend to coalesce. In this way fibrous adhesions are formed which may unite the membrana tympani or the ossicula to the opposite wall of the cavity. Like other connective tissues formed in inflammations this has a tendency to shrink and become dense, a process expressed in the term sclerosis. The pliant mucous membrane thus becomes rigid, and stiffens the membrana tympani, the ossicula, and the membrane of the fenestra rotunda. There is in some cases a new-formation of bone, so that thickenings and projections of the osseous wall of the cavity occur. There is not infrequently in the dense shrunken tissue a deposition of lime salts, a Calcification similar to that so frequently seen in chronic endocarditis. All these changes, by rendering rigid the structures concerned in propagating the sonorous vibrations, contribute to the causation of deafness.

Acute suppurative inflammation of the middle ear is a frequent result of scarlet fever, and more rarely of the other acute fevers. In these cases it arises by propagation upwards of an acute phlegmonous inflammation from the pharynx. In some cases the affection is ascribed to cold and ordinary catarrh of the nares or naso-pharynx, and in these the nature of the irritant is obscure. There is an acute inflammation of the mucous membrane going on to suppuration and always resulting in Perforation of the membrana tympani. The middle ear is, in fact, converted into a kind of abscess cavity and the pus finds its way out through the membrane. The inflammation may extend partly to the external and internal ears. The perforated membrane may afterwards heal, but in many cases there is considerable destruction of tissue, and when the inflammation subsides a permanent gap is left in the membrane, sometimes involving its entire extent.

Chronic suppurative inflammation of the middle ear, or Otorrhoea is a common result of the acute disease. The perforation of the membrana tympani, brought about in the way mentioned above, has far-reaching consequences. The mucous membrane of the*middle ear is exposed to the varied influences from without. It is liable to catarrhs, and, as the resulting exudation is exposed to the air, septic changes readily occur in it. The consequence of these septic changes is a suppurative inflammation, which, when once fully established, is likely to be permanent. The septic discharges lingering in all the complicated parts of the middle ear keep up the inflammation. The discharges are, consequently, in many cases exceedingly putrid. The mucous mem-brane is by degrees converted into a succulent granulation tissue from whose vessels the pus is exuded. Various important consequences are liable to occur in this condition, such as polypi, caries, and abscess of the brain.

Mucohs polypi are here, as in other places, outgrowths of vascular tissue from the inflamed mucous membrane (see Fig. 488). They protrude through the perforation in the membrane, into the meatus, and may even present at the external orifice. They are usually single mucous polypi, consisting of a very cellular connective tissue, in which mucous glands may be present, sometimes forming cysts. They are more rarely fibrous in structure, and in that case contain no glands. A polypoid myxoma is an exceedingly rare form.

Caries and Necrosis of the underlying bone not infrequently occur. There may be gradually advancing inflammation of the bone, leading to erosion by a process of rarefying ostitis. Thus a considerable erosion of the temporal bone may ensue. In other cases necrosis of considerable portions of the temporal bone results, the dead bone being perhaps discharged (see Fig. 489). These processes are most liable to occur in the mastoid cells, where the discharges readily lie and decompose. In these parts the inflammation may, after a time, become acute, so that something in the nature of an abscess may form and come to the surface of the mastoid process.

Fig. 488. - Large mucous polypus, which dilated the external auditory canal and protruded from external orifice. (Barr).

Fig. 489. - Sequestrum consisting of annulus tympanicus and part of mastoid process, removed from a child. (Barr).

Sometimes the suppuration extends outside rather than inside the mastoid process, so that there is a suppurative over this over this process, but without necrosis or caries.

In some cases there may be a Formative ostitis, so that new-formation of bone occurs, leading to thickenings, and sometimes to condensation of the cancellated mastoid structures (see Fig. 490). This may even occur coincidently with caries and necrosis, a rarefying and a condensing ostitis co-existing here as in other cases.

If Healing occurs in this disease there are liable to be the consequences of chronic inflammation already referred to. Healing will only occur if septic decomposition is got rid of. Unless the tympanic membrane closes, which it sometimes does by cicatricial new - formation, there is apt, at intervals, to be a renewal of the septic process and of the suppuration.

From the nearness of the structures concerned to the dura mater and brain, there is occasionally an Extension of the septic process to the parts within the skull. These consequences have already been referred to under Abscess of the Brain. They are chiefly Septic thrombophlebitis, which may result in pyaemia, Suppurative meningitis, which may be associated with thrombophlebitis, and Abscess of the brain, which may arise by thrombophlebitis but also occurs without this. Paralysis of the facial nerve occasionally results from extension to the Fallopian canal.