the tumour, and finally become only a single row of cells or cease entirely. When there are several layers of cells the epithelium is normal in character, the superficial row being columnar and ciliated; where there is only a single layer of cells, these are usually cubical in shape and have no cilia. Occasionally the epithelium is squamous in places. Further, polypi usually contain more or less glandular tissue, especially marked near the attachment of the growth. These glands are found in nearly every specimen, but vary greatly in amount. In some they are numerous enough to give the section the appearance of an adenoma; in others they are few and far between. They are especially numerous in the sessile growths, in which

FIG. 83.-MICROSCOPICAL SECTION OF A NASAL POLYPUS SHOWING NUMEROUS GLANDS,
SOME NORMAL, OTHERS WITH DILATED ACINI AND DEGENERATING EPITHELIUM.

actual increase of glandular tissue may occur (Billroth). They are less numerous, or may be absent, in the rapidly growing pedunculated growths. Sometimes the glands are normal; at others the lumen of the acinus is greatly distended and the lining epithelium is partially degenerated or lost. Polypi, and especially those in the posterior region of the nose, are often cystic. The cysts may be single or multiple and vary greatly in size; I have met with polypi which seemed to be merely large thin-walled cavities filled with clear fluid. The cysts are mostly the dilated acini of glands, the ducts of which are obstructed by inflammatory infiltration, or by contraction of newly formed fibrous tissue. The large cysts contain a thin albuminous fluid with a little mucin, the smaller cysts may have thick contents, consisting of fat, epithelial cells, mucus, pus and chalk. Small false cysts are also frequently met with, which have no true cyst wall,

but are simply distended areolar spaces containing serum (Okada). Kalischer has demonstrated the existence of nerve fibres in polypus.

1

From this description it will be seen that polypi consist simply of the normal structures of the mucous membrane of the nose in varying quantities and in variable arrangement with a certain amount of serous exudation and round-celled infiltration. One tissue may predominate, and the growth may be firm or jelly-like. A firm slowly growing polypus may resemble a fibroma, or if its tissue has undergone myxomatous degeneration, a myxoma. Another growth, from its excessive vascularity, may resemble an angioma; another containing an excessive quantity of glandular tissue may resemble an adenoma; and a growth, the epithelial surface of which is thickened and papillary, may resemble a papilloma. The pedunculated tumours show the most typical polypoid structure with their loose fibrous network and large spaces distended with serum. The sessile growths approximate more closely to the normal structure of the mucous membrane, but between these there is every intermediate gradation. Virchow stated that polypi contained large quantities of mucin, but Köster proved that the fluid was really serum. It is the result partly of oedema and partly perhaps of inflammatory exudation. Polypi usually contain a considerable number of eosinophile cells, and the double pyramidal crystals of cholesterin will separate out of the fluid if it is kept in a moist chamber. These Charcot-Leyden crystals are not found especially in the cases associated with asthma, but are apparently most plentiful when most eosinophile cells are present.

9. Relation to Sinus Suppuration. Grünwald states that nasal polypi are almost pathognomonic of sinus suppuration. In thirty-three cases of polypus he found definite evidence of sinus suppuration in twenty-eight; and in a further series of fifty-three cases, in forty-three, although a careful study of his records would seem to substantiate only thirty-eight. Suppuration was found most commonly in the ethmoidal cells, alone or in conjunction with other sinuses. Thus, Grünwald states that sinus suppuration was found in 82 per cent. of polypus cases; whilst in the remainder no abnormal secretion was seen in the nose. The majority of observers have come to different conclusions on this point. Alexander in 104 cases found suppuration in only one-third. Kronenberg in 44 carefully observed cases found sinus suppuration in 27, and no abnormal secretion in 6. McBride, Chiari, Skrodzi and others found suppuration in a still smaller percentage. Allowing for a considerable margin of error, especially in the older observations when the means of diagnosis were admittedly imperfect, and granting that whenever pus is seen in the nose sinus suppuration is present, it seems safe to assume that suppuration is certainly not present in more than 60 per cent., and cannot be demonstrated with certainty in more than from 30 to 40 per cent. of polypus cases.

1 Archiv für Laryngol., 1895, ii. p. 260.

2 Berliner klin. Woch., 1881, p. 526.

10. Changes in the Bone. Although as early as the seventeenth century the observation was made that the removal of a lamina of bone was the best means. of preventing the recurrence of nasal polypus, no systematic examination of the bone was made until quite recent times. Woakes was the first to draw attention to this point. He claimed that polypus was not a disease per se, but only a prominent symptom of a disease of the ethmoid bone, which he called "necrosing ethmoiditis." He described a series of morbid changes beginning with fibrosis, going on to obliteration of the arteries, and absorption of the bone, with development of bony cysts, polypus, and granulation tissue, until finally interstitial death of the bone, or necrosis, resulted. Woakes described the clinical features of the disease as first an enlargement, then a cleavage, of the middle turbinate, with swelling of the overlying mucous membrane; from the cleft in the bone polypi might project. A fine probe inserted into this cleft would detect bare, friable, carious bone, which might also be found by passing the probe under the turbinate into the anterior ethmoidal cells, or above it into the posterior ethmoidal cells. The clinical evidence was supported by microscopical examination. Thurston examined three specimens of bone removed. by Woakes, and found signs of bone disease in all. Martin examined twenty portions of bone, and reported that in ten there was absorption of bone, and in two necrosis; in eight the bone showed no evidence of disease. In a few cases there were cysts in the bone, and in all the muco-periosteum showed profound changes, chiefly of the nature of fibrosis, with thickening of the arteries.

These observations have been much disputed.

Zuckerkandl examined

the bone underlying polypi, and stated that it was usually healthy, although it might show changes due to hyperplastic periostitis. Luc found no evidence of bone disease in two cases. Others state that, as a matter of clinical experience, they have never seen definite necrosis of the ethmoid in cases of polypus, and others again, without advancing any argument to support their views, state that bone changes occur in a small percentage, but that they are the result, and not the cause, of the polypi. Hajek examined twelve cases and found bone disease in eight, in three rarefying osteitis, and in five condensing osteitis. In the other four cases there were signs of periostitis. Chiari, whilst admitting that the bones were often affected in polypus, considered that there was no causal relationship. Baumgarten has also found changes in the bone underlying polypoid mucous membrane. Heymann and Alexander agree that bone changes may occur, and assert that they are of the nature of rarefying osteitis. They have never seen caries or necrosis, and further, they have seen polypus without bone changes. Reichert examined thirty cases, and came to substantially the same conclusions as Woakes.

Histological Evidence. The subject seemed so worthy of further investigation that during the years 1898 and 1899 I carried out a considerable amount of work on the subject, examining the bone in thirty

cases of nasal polypi. These investigations I have subsequently continued. The bone was removed, either with the snare or by curettement, and was subsequently fixed, decalcified, embedded in paraffin, and sections cut. The sections were stained by Ehrlich's haematoxylin, and counter-stained with rubin and orange or by van Gieson's method. In every case of polypus, whether suppuration was present in the nose or not, definite changes were found in the underlying bone (Figs. 84 and 85). the study of a series of sections it seems probable that the affection

commences in the periosteum, the deeper layer of which becomes thickened and converted into two or three layers of large cells. The bone in contact with this thickened periosteum becomes more cellular, apparently from increased size and number of the bone cells. Soon the edge of the bone becomes roughened, little bays or cup-shaped depressions are formed, and are filled with large cells, having one, two, or more nuclei. These cells are undoubtedly osteoclasts, and seem to eat their way gradually into the bone, forming large indentations along its edges. As the process advances, the bone becomes infiltrated with cells and breaks up, and frequently quite tiny fragments-mere microscopic spicules of bone-may be seen surrounded by large multinucleated cells. These appearances indicate a definite rarefying osteitis, which proceeds until the bone becomes disintegrated, breaks up into small fragments, and ultimately becomes absorbed. The

soft parts surrounding the bone show the changes commonly met with in chronic inflammation. In places there are large areas of fibrous tissue, part of which may have undergone myxomatous degeneration; in other places there is young fibrous tissue, and in others diffuse round-celled infiltration. The fibrous tissue forms a loose network, its meshes being distended with serous exudation. The vessels have greatly thickened walls, and are often surrounded by masses of round cells. The mucous glands are surrounded

Showing late

by similar cells, and in places their acini are dilated and the epithelium degenerating.

In a few specimens, in which a single polypus of old standing was removed from the nose, together with a piece of the underlying bone, another change was noted. The bone was very dense and difficult to divide with the snare, and on microscopic section it appeared thicker and denser than normal, but there was often no evidence of active osteitis. This suggests that osteitis had occurred, and had passed off, leaving a sclerosis of the bone. Clinical Evidence. Thus, microscopical examination shows that changes in the bone are a constant accompaniment of nasal polypi, and clinical evidence of this association may also be obtained. The most reliable method is digital examination of the nose. When this was possible, that is, when a general anaesthetic had been given, the finger was pushed well