8. =Costal Cartilages.= Note color (ochronosis), degree of ossification, anomalies, separations, fractures, caries, tuberculosis, alteration in shape (pigeon-breast, emphysema, Pott’s Disease, erosions of tumors or aneurisms, rickets, etc.). The costochondral edges are thickened as a result of rachitis (rachitic rosary). In old age the costal cartilages may undergo the so-called “asbestos-like” degeneration, becoming yellowish- or grayish-brown, streaked with shining whitish granules, with calcification or ossification and new-formation of blood-vessels. Degeneration cysts (senile) are not infrequent, and the cartilages sometimes appear as if soaked with oil, soft and translucent. Fibroid or calcified areas may be present. Spaces and clefts within the cartilage may be filled with new-formed bone-marrow. 9. =Sternum.= Note shape (pigeon-breast, “shoemaker’s,” rounded, scaphoid, bifid, anomalies of ensiform, etc.), fractures (in marked osteoporosis the bones may break during removal), erosions (aneurisms, tumors), tuberculous and syphilitic caries, gummata, perforations, etc. Under surface of sternum should be smooth, shining, translucent and grayish. In chloroma the under surface may present a uniform greenish layer ½-1 cm. thick. Bone-marrow of sternum is normally red and lymphoid in character; may be green in chloroma, pyoid in leukæmia, hyperplastic in severe anæmias. Sclerosis and osteoporosis of sternal bones are not rare. In the former condition the marrow may be entirely absent; in the latter hyperplastic. CHAPTER VIII. THE EXAMINATION OF THE THORAX. I. METHODS OF EXAMINATION. 1. =Thoracic Cavity.= As soon as the sternum is removed the =anterior mediastinum= and the =pleural cavities= are examined, noting first the =position= and =relation= of the =thoracic organs=, quantity and character of mediastinal fat, the contents of the pleural cavities, pleuritic adhesions, etc. Pleuritic exudates should be removed before they have become mixed with blood from the cut vessels or heart; and the pleural surfaces should be examined before their appearance has been changed by exposure to the air or to fluids. Pleuritic adhesions should be broken or cut, beginning with the left side and then on the right, and the entire surface of both lungs wholly freed.