foreign body, tracheotomy should be performed, and then efforts to dislodge it should be made by inversion of the patient, shaking, etc.

DISEASES OF THE BRONCHI.

BRONCHITIS.

Etiology.-Bronchitis, or inflammation of the bronchi, occurs at all ages, and may arise from a variety of causes, among which the most frequent is exposure to cold or wet, or both combined. Under such circumstances it may be associated with simultaneous inflammation of the larynx and nasal mucous membrane, or the inflammation may commence in the latter, and spread downward to the bronchi. Another cause is contact of the bronchial mucous membrane with irritating vapors, as air carrying solid particles, such as dust, fog, or the air of mines and of certain manufactories. Bronchitis may also be set up by the presence of foreign bodies actually in the bronchial tubes; this is comparatively rare, but blood effused into the tubes may act in this way, and it constantly occurs as a result of the deposit of tubercle or cancer in the substance of the lung. Certain infectious diseases, already described, are frequently accompanied, by bronchitis-namely, typhoid fever, measles, scarlet fever, diphtheria, and whooping-cough; it often occurs in Bright's disease, and it forms a part of the epidemic disease influenza.

Among causes that may be called predisposing are age, habits, the general health, and preceding conditions of the lungs and heart. Bronchitis is especially prevalent among infants, young children, and elderly people; whereas young adults and the middle-aged are much less subject to it. Habits of luxury, confinement to warm rooms, undue wrapping up, render the subject liable to contract bronchitis on comparatively slight exposure; and those in weakly health, or depressed from insufficient food, exhausting occupations or bad sanitary conditions, easily acquire it. Such conditions are more common among the poor than among the wealthy. Lastly, the preëxistence of heart disease, impeding the circulation in the lungs, and of former attacks of bronchitis-all the more if they have left behind them emphysema or dilated tubes-will tend to the ready development of the disease. Some other cónditions of aetiological importance are those which involve constant exposure to the exciting causes, such as residence in towns, in cold, damp, and changeable climates, employment in mines, in wool and steel manufactures, and other such industries. Bronchitis is much more common in winter than in

summer.

Pathology. The mucous membrane is the part most affected, but in severe or prolonged cases the submucosa is involved, and rarely the cartilages

be compressed at the same time by growth or aneurism. The special liability of the left bronchus to compression by an aneurism of the arch of the aorta, under which it passes, is of importance. Foreign bodies more frequently fall into the right bronchus, because the dividing ridge between the two bronchi is somewhat to the left of the middle line, and hence objects falling down the centre of the trachea are directed into its right branch. They may be driven up into the trachea during coughing, and fall back into the same. bronchus or the opposite one. If the object is impacted in the bronchus it proves a permanent obstruction, and may cause ulceration and sloughing of the mucous membrane. The symptoms of obstructed bronchus vary with the degree of obstruction; and since the opposite tube is often free, and thus only half the respiratory area is interfered with, the bronchus is often much more completely obstructed than the trachea can be. There may be no stridor, but the vesicular murmur over the corresponding lung is very deficient or absent; and tactile vibration is diminished, though the percussion note over the chest remains normal. In extreme cases all the air may become absorbed from the lung, which becomes completely collapsed, while the chest shrinks, with percussion dullness, and entire loss of breath and voice sounds, and vocal fremitus. Another result of stenosis of a bronchus is dilatation of the several smaller bronchi in connection with it; pus forms abundantly in them, and the lung may become pneumonic or gangrenous. Dr. S. Coupland has recorded a case in which the dilated tubes produced in this way communicated through one of the intercostal spaces with the subcutaneous tissue on the front of the chest, and an abscess was opened, from which a quantity of offensive pus was discharged. Foreign bodies lodged in the bronchi may bring about symptoms and results similar to those described, from mere obstruction of the tubes in which they lie. But they have occasionally set up diffuse suppurative pneumonia, or worked their way to the surface of the lung, perforated the pleura, and caused pleurisy or pneumothorax.

Prognosis. This is very unfavorable, the commoner causes being little amenable to treatment; but the rare cases of abscess compressing the trachea or bronchus may recover on the bursting of the abscess.

Treatment. The indications are (1) to remove the cause, if possible; (2) to open the trachea below the obstruction where this is in the upper part ; and (3) to relieve symptoms and secondary results.

A thyroid tumor may be removed, and enlarged glands or growths in the neck; and abscesses, where accessible, may possibly be opened; but such opportunities are infrequent. If an aneurism is diagnosed, the treatment for that condition should be employed; and for obvious stricture, active antisyphilitic treatment by means of mercury and potassium iodide. The latter drug should be employed in any case which does not present sufficient data for a positive diagnosis as to the cause of the obstruction. In the case of a

foreign body, tracheotomy should be performed, and then efforts to dislodge it should be made by inversion of the patient, shaking, etc.

DISEASES OF THE BRONCHI.

BRONCHITIS.

Etiology.-Bronchitis, or inflammation of the bronchi, occurs at all ages, and may arise from a variety of causes, among which the most frequent is exposure to cold or wet, or both combined. Under such circumstances it may be associated with simultaneous inflammation of the larynx and nasal mucous membrane, or the inflammation may commence in the latter, and spread downward to the bronchi. Another cause is contact of the bronchial mucous membrane with irritating vapors, as air carrying solid particles, such as dust, fog, or the air of mines and of certain manufactories. Bronchitis may also be set up by the presence of foreign bodies actually in the bronchial tubes; this is comparatively rare, but blood effused into the tubes may act in this way, and it constantly occurs as a result of the deposit of tubercle or cancer in the substance of the lung. Certain infectious diseases, already described, are frequently accompanied, by bronchitis-namely, typhoid fever, measles, scarlet fever, diphtheria, and whooping-cough; it often occurs in Bright's disease, and it forms a part of the epidemic disease influenza.

Among causes that may be called predisposing are age, habits, the general health, and preceding conditions of the lungs and heart. Bronchitis is especially prevalent among infants, young children, and elderly people; whereas young adults and the middle-aged are much less subject to it. Habits of luxury, confinement to warm rooms, undue wrapping up, render the subject liable to contract bronchitis on comparatively slight exposure; and those in weakly health, or depressed from insufficient food, exhausting occupations or bad sanitary conditions, easily acquire it. Such conditions are more common among the poor than among the wealthy. Lastly, the preëxistence of heart disease, impeding the circulation in the lungs, and of former attacks of bronchitis-all the more if they have left behind them emphysema or dilated tubes-will tend to the ready development of the disease. Some other conditions of aetiological importance are those which involve constant exposure to the exciting causes, such as residence in towns, in cold, damp, and changeable climates, employment in mines, in wool and steel manufactures, and other such industries. Bronchitis is much more common in winter than in

summer.

Pathology. The mucous membrane is the part most affected, but in severe or prolonged cases the submucosa is involved, and rarely the cartilages

of the bronchial tubes, and adjacent parts of the lungs. The first effect is increased vascularity and swelling of the mucous membrane, and after a short time a free secretion from the surface takes place. This catarrhal secretion is provided (according to Ziegler) partly by the blood-vessels, and partly by the epithelial cells and mucous glands in the large divisions. It consists chiefly of mucus, and contains leucocytes and shed epithelial cells. In later stages the secretion becomes more and more opaque from the presence of increasing numbers of leucocytes, extravasated, according to most writers, from the blood-vessels, but according to others (Socoleff and Hamilton), produced by germination from flat cells in contact with the swollen basement membrane after the superficial layers of the epithelium have been shed. The secretion may also contain cells in a state of fatty degeneration, or cells containing particles of soot or dirt derived from the inspired air. The process of inflammation is often transitory, but if it continues, so as to become chronic, the fibrous coats of the bronchi become thickened, and infiltrated with leucocytes; the muscular fibres become atrophied by pressure; and the cartilages and mucous glands disappear from the same cause. Ultimately, in many cases, the bronchial tubes become dilated, and form fusiform or cylindrical wide channels, often quite up to the surface of the lung.

As a result of bronchitis, the lung itself undergoes important structural changes. Acute bronchitis leads to lobular collapse and broncho-pneumonia; chronic bronchitis is followed by vesicular emphysema, and sometimes by chronic interstitial pneumonia. The last three will be spoken of separately.

Lobular collapse occurs in isolated lobules, when the bronchial tubes leading to them are blocked with mucus. One theory explains the collapse by supposing that the plug of mucus moves up and down in a somewhat conical tube, that it is easily displaced upward to a wider part of the tube by the expired air, but on inspiration is sucked into a narrower portion, which it blocks, and so prevents further ingress of air; hence all the air goes out of the lobule, and none comes in. But it is much more probable that when a tube is plugged with mucus, the retained air, being stagnant in contact with the pulmonary capillaries, simply undergoes absorption, just as air is absorbed which has escaped into the subcutaneous cellular tissue. One may, indeed, believe with Dr. Fagge, that air will get absorbed from any portion of lung which ceases to act, even without obstruction of the bronchial tube which leads to it.

Symptoms.-Bronchitis may be divided into acute and chronic, and a specially severe form of acute bronchitis is distinguished as capillary bronchitis.

ACUTE BRONCHITIS.

Acute bronchitis begins with some malaise, and a sensation of tightness of the chest; and cough soon occurs. In mild cases the general disturbance may be but slight, and the illness is confined to cough, expectoration of

mucus or muco-pus, with very little, if any, dyspnoea. But in severe cases there is slight fever the temperature rising to 100° or 101°, the appetite failing, the tongue furred, the bowels inactive, and the urine scanty. The cough is at first hard and dry, and is often attended with pain behind the sternum and in the muscles of forced expiration from the strain put upon them. The expectoration is then but scanty, consisting of thin, frothy mucus, with, possibly, an occasional streak of blood. After a few days the cough becomes easier and looser, and the expectoration is more abundant, more opaque, and yellow or green, from the addition of increasing quantities of leucocytes. In slighter cases the expectoration is generally more in the morning, from the accumulation during sleep, and in towns this sputum is frequently black with pigment derived from the atmosphere. Dyspnoea is often considerable, requiring the patient to sit upright in bed (orthopnœa), and calling for great muscular efforts of inspiration and expiration. After a time the secretion of muco-pus becomes less, the cough is less frequent, and the symptoms gradually subside.

Physical Signs.-These are chiefly the result of the narrowing which the tubes undergo, and of the presence within them of the mucous or mucopurulent secretion. On inspection of the chest of one suffering from acute bronchitis, the breathing is seen to be quickened, the chest is symmetrical, and generally in a state of moderate over-distention. The accessory muscles of respiration are seen to be in strong action. Percussion, as a rule, yields. a normally resonant note, but there is occasionally slight hyper-resonance from temporary over-distention of the air-vesicles; and rarely there is a little impairment of resonance at the base from accumulated secretion or from collapse. Auscultation shows that both inspiration and expiration are accompanied by sibilant or sonorous rhonchi, or various kinds of râle, or both combined (see p. 346). The coarser rhonchi are often felt by the hand placed upon the chest, and may be even heard by the patient himself, or those standing near him. Like the rhonchi, the râles may occur both in large and small tubes. The larger or coarser râles are heard with both expiration and inspiration, the finest râles only with inspiration. These sounds are not equally present in all cases or in all stages of the disease. In many cases rhonchi alone are present, and when both occur the rhonchi appear first, the râles later; this is explained by the course of the changes in the bronchi already described. The sounds may be heard in severe cases, variously mixed over the whole chest, and may entirely drown the vesicular In very mild cases they may be entirely absent.

murmur.

Capillary Bronchitis.—This is distinguished by severe dyspnoea, high temperature, great lividity, rapid exhaustion, and tendency to a fatal termination. It is especially frequent in children and old people. It often begins with chilliness, and the temperature may rise as high as 103.5° or 104°, but runs no typical course. The cough is frequent, often paroxysmal; and the