mon. Pain is not generally a prominent symptom. The physical signs are those which must result from the infiltration of the lung with a solid material, at the same time that the bronchial tubes are filled up or blocked by the new growth. There is dullness, with absence or deficiency of breath-sounds, vocal résonance, and tactile vocal fremitus. There is thus a general resemblance to pleural effusion, which is often very deceptive. If the growth is considerable, the resemblance is increased by expansion of the chest wall and displacement of the mediastinum; but a simple infiltration of the lung. without large masses may be accompanied with contraction of the side, and resembles rather cirrhosis or chronic pneumonia, or phthisis, or chronic pleurisy with partial absorption of fluid, and retraction of the side. Exceptionally, from the breaking down of the cancerous material, cavities are formed which produce physical signs like those arising from tubercle. Sometimes the growth is accompanied by pleuritic effusion, and a serous fluid is poured out which is very apt to contain blood from rupture of the vessels of the new growth. The bronchial, cervical, and axillary glands become enlarged; and extension to the mediastinum may lead to various symptoms of pressure, such as œdematous swelling of the head, neck, and upper extremities, abductor paralysis of the vocal cords from pressure on the recurrent laryngeal nerves, obstruction of the trachea or one bronchus, or dysphagia from pressure on the oesophagus.

Cancer of the lungs, no less than that of other organs, is accompanied by progressive emaciation and loss of strength, and ultimately, in the course of from six to twelve months, death takes place, generally from exhaustion.

Diagnosis. In cases of malignant disease of other organs, the presence of unaccountable dyspnoea should make one think of cancer of the lung; and in cases where the pulmonary symptoms are most prominent, the presence of large hard glands in the neck, or a tumor of the testis, or a rigid spine from implication of the vertebræ, may sometimes give the required clue. Extensive infiltration of the lung is most easily confounded with pleuritic effusion; and in elderly persons with the symptoms and physical signs of fluid, the possibility of cancer should not be forgotten. Exploration with the needle, or a trocar and cannula, or aspirator may be necessary, and particles may then perhaps be obtained for microscopic examination. The sputum sometimes provides similar evidence. If in an elderly person a pleural effusion returns again and again one may suspect cancer, and all the more if the serum contains much blood; but a simple pleurisy often gives blood-stained fluid, from the rupture of vessels newly formed in the lymph or adhesions.

The Prognosis is bad, and the Treatment must be confined to relieving pain and cough, procuring sleep, and supporting with good nourishing food as long as possible.

Other forms of tumor occur in the lung, and are, as a rule, secondary to

similar tumors elsewhere. Such are sarcoma, osteo-sarcoma, enchondroma, and others. Epithelioma of the oesophagus sometimes invades the lung directly.

HYDATID OF THE LUNG.

This parasite affects the lung in two ways. Firstly, a cyst may form in the lung apart from, or even without, its occurrence in any other region; secondly, the lung may be invaded by a cyst in an adjacent organ rupturing through the parts which separate them. This is most common in hydatid of

the liver.

A primary hydatid of the lung is very rare. It forms a globular cyst, with all the characteristics of the parasite as seen in the liver (see Hydatid of the Liver), but it is not generally surrounded by such a dense connective-tissue cyst. It is rather more frequent at the base than at the apex.

It may be the only cyst in the body, or there are others at the same time in the liver, spleen, brain, or elsewhere. Its symptoms depend upon its size, and upon the change it sets up in the surrounding lung. It may be so small as to yield no symptoms whatever. If larger, it must compress the lung tissue, and it gives rise not uncommonly to hemorrhages, and may cause pneumonia, or gangrene. Cough, dyspnoea, and pain are the symptoms, with hemoptysis sometimes. If the cyst ruptures, secondary cysts may be expectorated, and will at once reveal the nature of the case. The physical signs, if any, are dullness, with more or less deficiency of vesicular murmur. If the cyst ruptures and the contents are discharged by the bronchus, the distinctive signs. of cavity may be heard.

The Diagnosis is generally obscure, and the case is most likely to be mistaken for phthisis, especially if the cyst is situate at the apex. A girl with cerebral tumor in Guy's Hospital had hemoptysis, and was thought to have tubercle of the brain and pulmonary phthisis; but a hydatid cyst was found in both brain and lung.

Treatment.-No internal treatment is of any avail to kill the parasite. If the diagnosis of a cyst sufficiently near the surface could be made with confidence, it might be treated by the surgical methods applicable in hydatid of the liver.

The invasion of the lung by hydatias of the liver will be again mentioned in the diseases of the latter. It is sufficient to say here that the pulmonary symptoms are preceded by signs of hepatic disease, such as pain and tension in the hepatic region, some enlargement of the liver, and perhaps jaundice; and the earliest change in the lung is compression of its lower part by the enlarging cyst. Increasing pain and distress, with more or less collapse or prostration, may mark the implication of the lung itself; and soon cough of paroxysmal nature is followed by the expectoration of bile-stained hydatid skins, or small and perfect cysts. More or less pneumonia, or even gangrene

of the lung, may result, and thus the case may end fatally. But it is not uncommon for the inflammation of the lung to be limited in extent, and the whole of the hydatid may in time be expectorated through the bronchi, and the patient thus recover completely.

Treatment. Such a hydatid is commonly beyond the reach of surgical interference, and the treatment must be symptomatic, and in the main supporting.

SYPHILIS OF THE LUNG.

Apart from the ulcerations of the bronchi, with resulting stenosis which have been shown to be due to syphilis, the lung-tissue itself may exhibit the effects of the disease in two forms certainly. One is that of the ordinary gumma, which is extremely rare in adults, though more common in infants, and gives rise to no recognizable clinical symptoms. The other is the socalled white pneumonia of syphilitic infants. The lungs are enlarged, white, dense, and firm; their section is smooth and opaque; they are sometimes resistant, at others easily broken down. This condition may affect the whole lung, or one part may be uniformly altered, while the other contains only isolated areas. Ziegler describes it as a diffuse cellular inflammation of the lung, often accompanied by desquamation and fatty degeneration of the pulmonary epithelium. Wagner thought that it was entirely due to thickening of the alveolar wall, by which the cavity of the air-vesicle was gradually obliterated. As it is found chiefly in stillborn children it has but little clinical importance.

The extent to which syphilis may affect the lung in adults otherwise than by gumma has been the subject of much discussion, but remains still an open question. Clinically, it has been thought that the recurrence in syphilitic patients of a destructive or fibroid disease of the lungs, which benefited under a course of potassium iodide or mercury, went far to prove that there was a syphilitic phthisis or pneumonia. But post-mortem evidence is not as yet conclusive on this point.

DISEASES OF THE PLEURA.

PLEURISY.

Etiology.-Inflammation of the pleura arises from a number of causes, partly of a local, partly of a general character. Exposure to cold is the most common antecedent of pleurisy in persons previously healthy, although it may happen without any knowledge of such exposure on the part of the patient. Injury, as, for instance, by fractured ribs, may also produce it. Inflammatory changes in the lung which approach the surface of the pleura,

and inflammation or suppuration of connective or other tissues in contact with the parietal pleura, will readily set up pleurisy. Among those in the lung we have pneumonia, phthisis, and pyæmic abscesses; and externally, abscesses in the axilla, neck, or breast, or under the diaphragm. It is also set up by tubercle and cancer in the lung, and by hemorrhagic infarcts.

Among general diseases, scarlatina and measles may be a cause of it; it often accompanies pericarditis in severe cases of rheumatic fever; it occurs in pyæmia, both as a part of the blood infection, and as a direct result of the pulmonary abscesses; and it is a frequent complication of Bright's disease.

Morbid Anatomy.-The first stage of pleurisy consists of dilatation of the vessels of the pleura, quickly followed by exudation of the white corpuscles and fibrin on to the free surface. Thus the membrane is at first minutely injected, but in the earliest visible stage, the naturally shining surface is rendered dull by the fibrin, which can be detached as an extremely delicate membrane. If the exuded material is more abundant, it forms thicker layers, firm or pasty, generally rough on the surface, or villous, or reticular. Pleurisy may go no further than the formation of fibrin on the surface, and is then called "dry;" more often, the fibrin is soon followed by the exudation of a serous or sero-fibrinous fluid, which may accumulate to the extent of two or three pints or more in the pleural cavity. This fluid has a yellow or greenish-yellow color, a specific gravity of 1005 to 1030, often 1015 to 1018, and it becomes almost solid on boiling, from the albumin it contains. Not unfrequently there are a few flakes of fibrin, or a quantity is deposited from the liquid a short time after its removal. The liquid is quite clear, or it is opalescent or turbid from the presence of corpuscles. In other cases the corpuscles are in sufficient quantity to form a thick layer at the bottom of the fluid that is withdrawn, and there is every gradation between this and the formation of real pus.

This effusion of fluid is one of the most important results of pleurisy. Confined within the cavity of the pleura, it must displace the lung from its relations to the diaphragm and the wall of the chest, and, in proportion as more fluid is effused, the lung becomes collapsed. This is not at first due to the actual pressure of the fluid, but to the elasticity of the lung, which naturally favors its contraction; and, indeed, it may be found that even a considerable quantity of fluid in the chest may fail to escape, or escape but slowly, on puncture, being held in, as it were, by the natural retraction of the lung toward the mediastinum. But with a larger quantity a point is reached beyond the elastic collapse of the lung, and then this organ and the surrounding parts are actually subject to the positive pressure of the fluid, and the most extreme changes of position take place. An important difference in the effects upon the lung is that the larger quantities of liquid compress the bronchial tubes, whereas with lesser amounts only the air-vesicles are deprived

PLEURISY.

427 of air; and this explains some differences in the physical signs. The pressure which forces the lung toward the mediastinum, pushes the mediastinum itself, with the heart and great vessels toward the opposite side, bulges the wall of the thorax outward, distends the intercostal spaces, and forces downward the diaphragm with the subjacent liver or spleen.

In a large number of cases pleurisy recovers by absorption of the effused products. The liquid disappears in the course of days or weeks, and the lung and the chest-wall finally come into contact either by expansion of the former, or by a gradual sinking in of the latter, or by a combination of both processes. The layers of fibrin covering the two surfaces have already probably become partly organized by the growth of new vessels from the pleura, and the formation of fibrous tissue; and uniting together, they form in time a permanent layer of adhesion between lung and chest-wall.

A purulent pleurisy, usually known as empyema, appears often to arise out of a serous pleurisy, or simple effusion, but sometimes is found so soon after the onset of the disease as to appear really primary. Its termination is by no means so favorable as that of simple effusion. Occasionally, no doubt, absorption takes place—that is, the fluid is taken up, the. pus corpuscles become granular and fatty, and a caseous mass remains behind; or calcareous salts may be deposited in the residue. Sometimes an empyema finds its way through the pleural sac, either perforating the lung, so that the pus is expectorated; or "pointing" in one of the intercostal spaces, often the fifth, and bursting spontaneously, if not opened by the surgeon. In either case, air may find its way into the pleural cavity, and give rise to pyo-pneumothorax. Rarely an empyema opens through or behind the diaphragm into the abdomen. But, if unrecognized or untreated, it may remain a long time without perforating, with incomplete absorption, rendering the patient cachectic, and preparing the way for lardaceous degeneration of the viscera.

Both in serous and purulent effusions, the cavity is occasionally divided into two or more separate spaces, by adhesions between the lung and the parietes. The fluid is then said to be loculated; and the condition is of importance when the case is treated surgically.

Symptoms.-The onset of pleurisy is characterized by a chill or rigor, with severe pain in the side, caused or aggravated by the act of breathing. In cases presumably due to cold, the pain is at first commonly at the side of the chest, over the lower ribs; but in pleurisy determined by other lesions— as, for instance, phthisis-the pain may be situated elsewhere. The pain is cutting or tearing, and is intensified not only by breathing, but by coughing, sneezing, and every kind of exertion. The patient generally lies on his back or on the healthy side. There is mostly some pyrexia, with the usual accompaniments, furred tongue, loss of appetite, and malaise. On examining the chest some impairment of movement on the affected side and deficiency of vesicular murmur at the painful spot are observed; but the characteristic