After removal from the body the heart is placed upon the board with its anterior surface up, and the apex toward the operator. It may then be opened by the same method given above, by inserting the point of the brain-knife into the left ventricle just to the left of the septum, and cutting first the wall of the left ventricle along its left border as far as the mitral ring, exploring the mitral orifice, and then cutting it and the auricular wall into the upper left pulmonary vein with the long shears. The right ventricle, right auricle, pulmonary artery and finally the aorta are opened in succession, using the enterotome for all cuts except the first opening of the ventricle. The first incisions into the ventricles can be made very conveniently by holding the heart vertically with apex up, and the ventricle to be opened toward the prosector. The brain-knife is held vertically and its point inserted into the ventricle, just to the right or left of the septum, according to the ventricle to be opened, then carried across the cavity and pushed through the ventricular wall below the auriculoventricular ring, and the wall is then cut toward the apex. The remaining incisions are most easily made with the enterotome when the heart is held flat on the board with its anterior surface up. When the heart is opened outside of the body the Virchow method of opening in the direction of the blood-stream may also be used. (See below.) Under certain conditions other methods must be employed for the examination of the heart. In cases of suspected aneurism, pulmonary embolism, patent ductus arteriosus, etc., the thoracic organs should be removed _en masse_ and dissected on the table. They may be removed in connection with the neck-organs or alone. In the latter case the trachea is cut transversely above the sternum, the fingers of the left hand introduced into the trachea, and, while traction downward is being made with force, the œsophagus and cervical vessels are cut transversely, the trachea and vessels stripped down to the level of the clavicle, and the subclavian vessels cut on both sides. The thoracic organs are then stripped from the vertebræ down to the diaphragm and cut off just above the latter. The pulmonary artery may be examined _in situ_ before the heart is opened by thrusting a sharp-pointed scalpel through the wall of the artery just beyond the valves and cutting upward to the branches going to the right and left lungs. This incision may be extended downward through the pulmonary valve and the anterior wall of the right ventricle, and the right side of the heart first exposed.