2. =Thymus.= The thymus is then examined by means of transverse cuts; or, when large, is dissected from below upward, turned up onto the neck, and removed later in connection with the neck organs. When no traces of thymic tissue are visible to the naked eye the thymic fat should always be cut transversely and examined for the presence of small lymphoid nodules. In the case of hypertrophic thymus the question of pressure upon the trachea becomes of very great importance, and, to settle this, the trachea should be opened above the sternum before the thymus is removed; or the thymus may be taken out in connection with the trachea and both sectioned horizontally at the same time. In cases of sudden death, in which the thymus may be an etiologic factor, it is safest to examine the trachea from above the sternum before the thorax is opened, or to fix the whole body (infant’s or child’s) in formalin and then to remove thymus with trachea, and examine by means of transverse sections. The heart is examined before the lungs chiefly for two reasons: Its blood-content can be more accurately determined, and the blood caught in the pericardial sac, so that when the pulmonary vessels are cut in the removal of the lungs there is no gush of blood into the pleural cavity. 3. =Pericardial Sac.= This is next examined with respect to the degree of intrapericardial tension. Its anterior wall is then picked up at about its middle by the thumb and index finger of left hand, and the point of the long section-knife, with cutting edge outward, is pushed through the pericardium and a small slit made into the sac. The escape of gas or air should be noted at this time. A sterile pipette may now be introduced and the fluid contents of the sac secured for bacteriologic examination; or before the pericardial sac is opened the pericardium may be seared with a hot iron and a sterile pipette pushed through it into the cavity. The longitudinal incision through the pericardium is now extended upward to its attachment to the great vessels, and through the opening thus made the character and amount of the pericardial fluid are determined. The incision is then extended to the left at its lower end by cutting the sac-wall toward the apex of the heart. Through the three-cornered incision thus made the heart is lifted out of the sac and the surfaces of the parietal and visceral layers of the pericardium examined. Localized adhesions of the pericardium may be cut or torn, extensive or complete adhesions may be separated when this is possible; if this cannot be done, the pericardial layers are cut with the heart wall.