When bacteriologic examinations of the heart-contents are to be made the wall of the auricles or right ventricles can be seared with a cautery and a pipette introduced through the seared area; or the heart can be opened with a sterile knife, care being taken not to introduce the fingers into the opening or to permit the entrance of water. Excellent preparations for the museum or for demonstration purposes can be made by distending the heart with alcohol or formalin. Blood and blood-clots should first be washed out. When fixed the heart may be sectioned in various planes, leaving the segments attached by the epicardium posteriorly, or openings may be cut in the walls. A very good picture of hypertrophy and dilatation is obtained by making a transverse cut through the ventricles midway between apex and base. Alterations in the form and position of the ventricular septum are best seen by this method. After the opening of the heart and the inspection of the orifices, valves and auricular and ventricular septa, the coronary vessels should be examined by transverse cuts, or opened by fine probe-pointed scissors, beginning at their origin in the aorta. The auricular septum should be carefully examined for possible defects. While this is being done the wall should not be put on the stretch, but should be lax. The auricular appendages should be cut open from the auricles and examined for thrombi, which are of not infrequent occurrence in them. The mouths of the coronary veins and the veins of Thebesius should be examined also. The cardiac muscle is examined by parallel, vertical or horizontal incisions. The papillary muscles should be cut longitudinally from apex to base. The cardiac plexus and the ganglion of Wrisberg should be examined before the heart is removed. When the heart is in a state of rigor mortis the contraction should be made to pass away by kneading or by the application of heat, before the organ is opened, or before any measurements are taken. After the heart has been opened it may be removed for weighing. The heart may be removed first and then opened outside of the body. The organ is grasped in the left hand and lifted vertically and upward toward the head as far as possible, putting all of the attachments on the stretch. The vessels are then cut from below upward, first the inferior vena cava, then the pulmonary veins, the superior vena cava, pulmonary artery and lastly the aorta. (See Fig. 39.) The vessels should be cut as closely as possible to their exits through the pericardium, and care must be taken to get out the auricles entire. [Illustration: FIG. 39.—Removal of Heart. Dark line shows incision through vessels. (After Nauwerck.)]