Weight 304 gm. This may be done either in situ or after removal from the body. As a general thing, it is best to remove the heart before making any incisions. It is then easier to make the openings, but there is more danger of bacterial contamination occurring.

To remove the heart one grasps the apex with the left hand and lifts up the entire organ. By three or four long cuts made from below upward, first severing the inferior vena cava, then the left pulmonary vein, and finally the remaining vessels, the heart is removed. Care should be taken to wound neither the auricles nor the underlying esophagus.

In opening the heart the primary incisions are made with a knife and then united by using long straight scissors with blunt points or else a cardiotome.

The heart is then placed in a position corresponding to its normal one within the body; the apex directed toward the operator, the anterior surface being upward. The cavities are then opened in the order in which they receive the blood.

The right auricle is opened by making an incision from the inferior to the superior vena cava and then continued into the auricular appendage.

In opening the right ventricle the first cut extends through the tricuspid valve down to the end of the cavity. The second incision is made about the middle of the primary one and at almost right angles to it. This cut should be high enough up to avoid cutting through the insertion of the anterior papillary muscle. It is continued through the pulmonary valve, following along a slightly marked ridge of fat; by so doing the orifice is opened between the left anterior and the posterior leaflets.

The left auricle is opened by uniting the four pulmonary veins and continuing into the auricular appendage.

The left ventricle has the first incision made through the mitral valve between the two papillary muscles along the left border of the heart to the apex. The second incision is made by beginning at the apex at the end of the first and continuing upward close by the interventricular septum and parallel to the anterior coronary artery. The upper end of the cut should pass about midway between the pulmonary orifice and the left auricular appendage. An aortic leaflet is generally divided in so doing.

As the auricles are opened the clots should be removed and the valves carefully examined. The size of the opening should be noted, so as to determine whether or not stenosis or dilatation exists. The test of valvular competency by filling the cavity with water is unreliable.

The ventricles are freed from blood and their valves examined.

The anterior coronary artery is examined by opening with a pair of probe-pointed scissors. The posterior coronary is best seen by placing the tip of the left forefinger over the orifice of the vessel in the aorta, then cutting from without toward the finger-tip until the artery is reached. By so doing the aorta is not injured.

The heart should be weighed, its walls measured, the condition of the valves and muscle noted, and the aorta above the valves examined for atheroma.