Page:The American Cyclopædia (1879) Volume X.djvu/728

 722 LUNGS LUNT and mutilated to an excessive degree. This has given rise to the " hydrostatic test " for de- termining whether a newly horn infant, found dead, has heen born alive. The lung which has never breathed sinks in water like any other solid organ ; but if respiration has been once completely established, the lung floats, and cannot be made to sink by any ordinary method of manipulation. The application of this test, however, requires several precautions in particular cases, which are usually fully dis- cussed in works on medical jurisprudence. The lungs, as a whole, are conical in shape, their apices situated at the top of the chest and projecting slightly into the root of the neck, and their base, which is concave inform, resting upon the upper surface of the dia- phragm. They are of a pinkish gray color, and are variegated with spots and streaks of a dark ashen or blackish hue. They are quite elastic in consistency, owing to the abundant elastic fibres which they contain ; and accord- ingly, when taken out of the chest, or even when the chest is widely opened, they spon- taneously expel a portion of the air which they contained during life. Enough, however, still remains to give them the characteristic buoy- ancy by which they are distinguished. Each lung is covered, over the greater part of its surface, by a thin, smooth, moist, and polished serous membrane, the pleura, which, reflected outward at the root of the lung, also lines the internal surface of the thoracic cavity. These two free surfaces of the pleura being in con- tact with each other, or separated only by an extremely thin layer of serous fluid, the lungs and the walls of the chest slide gently over each other in the movements of respiration, without friction or injury. The lungs are sup- plied with blood from two sources. First, the pulmonary artery brings the venous blood from the right ventricle of the heart and distrib- utes it to the pulmonary capillaries, when it is returned to the left auricle by the pulmonary veins. This blood, which is in great quantity as compared with the amount of solid sub- stance in the pulmonary tissue, is brought to the lungs, not for the nutrition of these organs, but for its own aeration. Secondly, the bron- chial arteries, a number of small vessels which come off from the thoracic aorta, and follow the ramifications of the bronchi and bronchial tubes, supply these tissues with arterial blood for the purpose of their own nutrition. It is returned to the right side of the heart by the bronchial veins. The nerves of the lungs con- sist of the pulmonary branches of the pneumo- gastric nerve, and the pulmonary plexuses of the sympathetic. They are also provided with an abundant supply of lymphatic vessels ; and the lymphatic glands belonging to them, known as the " bronchial glands," of ten become very conspicuous at the root of the lungs, from the deposit in adult life of a dark pigmentary matter in their substance. The lungs are liable to a variety of acute and chronic diseases, the most important of which are pneumonia, or inflammation of the lungs, and pulmonary phthisis, or a wasting of the lungs owing to a tuberculous deposit in their substance. (See BRONCHITIS, CONSUMPTION, and PNEUMONIA.) They are also liable to be compressed by serous effusions into the cavity of the pleura, to be wounded by the extremity of a fractured rib, or to be the seat of haemoptysis or of pul- monary apoplexy. LUNGWORT (pulmonaria officinalis), a pe- rennial herb of the borage family, a native of Europe, and frequently found in old gardens. The creeping root stock throws up a large tuft of ovate-oblong leaves, which are coarsely hairy, with their dark green upper surface marked with numerous whitish spots; the flowers, which appear in spring, are in termi- nal clusters, on stems 6 to 12 in. high, rose-col- ored, changing to blue ; there are several gar- den forms, varying in the size and marking of their foliage and the color of their flowers. Lungwort (Pulmonaria officinalis). The name would indicate that the plant had at one time a medicinal reputation ; the spotted leaves were supposed by the old herbalists to resemble diseased lungs, and thus indicate its value in pulmonary diseases ; it is, like some others of the family, simply mucilaginous. Smooth lungwort (Mertemia Virginicd), for- merly classed as a pulmonaria, is indigenous in New York and southward ; it has something of the habit of the foregoing, but its leaves are smooth and spotless; its flowers are of an indescribably beautiful blue, and the plant is worthy of a place in the finest garden. LINT, George, an American author, born in Newburyport, Mass., Dec. 31, 1803. He grad- uated at Harvard college in 1824, studied law, and commenced the practice of the profession in his native town. While preparing for the bar he was principal of the Newburyport high school. He was several times a member of the state legislature, both as a representative