the first rib, and following the irregular line of the joint around the end of the clavicle, while at the same time drawing the sternum over to the right side of the body. The right sterno-clavicular articulation is to be opened by continuing the incision of the scalpel over the upper end of the sternum and into the second joint. The advantage of this method is that there is much less danger of wounding the large vessels at the base of the neck, and thus of mingling blood with any exudation which may happen to be present in the pleural cavities. If preferred, however, the articulations can be opened and the cartilages of the first ribs cut from above before freeing the sternum from the diaphragm. In this case enter a short, sharp, narrow-bladed scalpel held vertically, but loosely, into the left joint on its upper side, starting the incision just outside of the attachment of the sternal end of the sterno-mastoid muscle, and cut around the end of the clavicle by a series of short up-and-down strokes, allowing the blade to follow the irregular line of the joint. After cutting through the joint continue the incision outward and cut through the cartilage of the first rib.

If the cartilages are calcified, use the costotome and cut through the ribs, as more room can be gained in this way, and they are more easily cut than calcified cartilages. When for any reason it is not permitted to open the thorax, the organs within it can be obtained through the opening into the abdominal cavity by freeing the diaphragm from the ribs, and removing first the heart and then the lungs. The sternum should be inspected at the time of its removal. is perhaps best to examine next, especially in children, the epiphyses of the ribs at the costochondral line for any evidence of thickening.

It

Inspection of the Pleural Cavities.-In the pleural cavities, as in the peritoneal cavity, the character and amount of any abnormal contents must be determined. If, from the clinical history or from any other reason, the presence of air in a pleural cavity is suspected, a pouch should be formed over the ribs by aid of the skin-flap and filled with water. The pleural cavity is then to be pierced with a scalpel

through the bottom of the pouch. Air, if present, will bubble up through the water.

Slight adhesions are best torn through or cut. If the lungs are firmly attached, it is best to strip off the costal layer of the pleura with the lung. This is most easily done by starting the anterior edge of the costal pleura with the handle of the scalpel, and working in first a finger and then the whole hand until the pleura is entirely free. In passing the hand into the pleural cavities protect the back of it, especially if the ribs have been cut through, by folding the skin-flap in over the edge of the ribs.

If desired, the lungs can be drawn forward, examined over their whole extent, even incised, and then replaced until the heart has been removed. In the connective tissue of the anterior mediastinum there is almost always a certain amount of emphysema due to the removal of the sternum. Emphysema due to laceration of lung-tissue is more marked in the upper half of the mediastinum, and usually extends up into the neck. The thymus gland attains its full development at the end of the second year, after which time it usually gradually disappears.

Opening of the Pericardium.-To open the pericardium, seize the sac near the middle with fingers or forceps, snip through the wall with knife or scissors, and with either instrument cut upward to where the pericardium is reflected over the large vessels, downward to the lower right border, and lastly to the apex. By gently raising the apex of the heart the amount of fluid in the pericardial cavity can be seen. The normal amount is about a teaspoonful, but it may be increased to 100 c.c. in cases where the death-agony is prolonged. Pericardial adhesions should be broken through with the fingers. If this is impossible, the heart must be incised through the pericardium.

External Inspection of the Heart.-Determine first the position, size, and shape of the heart, and the degree of distention of the different parts. The right ventricle and both auricles are usually distended with blood, which may be fluid as in death from suffocation or more or less coagu

lated. The left ventricle is contracted and empty unless the individual has died from paralysis of this part of the heart, when it will be found distended with blood (condition of greatest diastole).

Opening of the Heart.-The heart may be opened in situ or after removal from the body. Except in certain cases, to be spoken of later, it usually will be found advisable to remove the heart before making any incision into it, for the reason that it can be more perfectly opened after removal, especially by beginners, and the danger of contaminating any bacterial lesions of the valves is lessened.

To remove the heart, grasp it gently near the apex with the left hand, supporting it further, if necessary, by one or two fingers placed above the coronal suture, and lift the whole heart vertically upward. Then cut its vessels from below upward with the knife held transverse and oblique. Divide in turn the inferior vena cava, the pulmonary veins on both sides, the superior vena cava, the pulmonary artery, and the aorta. Go deep enough to remove the auricles entire, but avoid injury to the underlying esophagus.

For making the incisions to open the heart either a long, slender-bladed knife or long, straight scissors may be used. The heart should be placed on a board with its anterior surface up. The right auricle is opened by cutting from the orifice of the inferior vena cava into that of the superior, and from the latter into the auricular appendage. The first incision to open the right ventricle is made through the tricuspid valve and the wall of the ventricle along the under surface of the right border of the heart. It should be carried to the end of the ventricle, which does not reach quite to the apex of the heart. The second incision begins about the middle of the first, just above the insertion of the anterior papillary muscle (which should not be cut), and is carried through the pulmonary valve well over on the left side along the left border of a narrow, projecting ridge of fat-tissue usually present, so as to pass between the left anterior and the posterior segments of the valve.

The left auricle is opened in a manner similar to the right

by incisions joining the four orifices of the pulmonary veins and extending into the auricular appendage.

The first incision into the left ventricle is through the mitral valve along the left border of the heart (i. e. the middle of the external wall of the left ventricle), between the two bundles of papillary muscles, to the apex of the heart. The second incision begins at the termination of the first at the apex, and is carried up close to the interventricular septum, parallel to the descending branch of the

The

anterior coronary artery and about 1 cm. from it. upper portion of the incision should pass midway between the pulmonary valve and the left auricular appendage. Ordinarily, one of the aortic cusps is divided, but this may be avoided, if desired, by dissecting away to some extent the pulmonary artery from the aorta and carrying the incision well over to the right between the right posterior and anterior valve-segments. As each auricle is opened the blood and clots it contains should be carefully removed and the auriculo-ventricular valves carefully inspected from above. In certain cases-as, for instance, extreme stenosis-it may be preferable not to cut through the valve, but to begin the

incision in the ventricular wall below the valve. The ventricular cavities should in like manner be freed from clots and the valves closely inspected. The coronary arteries should always be opened by means of small, narrow-bladed, probe-pointed scissors as far as they can be followed. The examination of the descending branch of the anterior artery is especially important. The posterior coronary is best opened by placing the tip of the left fore finger in the aorta over the orifice of the artery, and cutting from without in toward the finger-tip until the vessel is reached, when it can easily be slit up. In this way injury to the aorta is avoided.

In cases of more or less sudden death with symptoms of asphyxia the pulmonary artery should always be opened in situ before removal of the heart, in order to examine for possible emboli, because they often lodge just at the point where the vessels are severed in removing the heart and lungs, and easily may slip out unobserved. The simplest operation is to thrust a sharp-pointed scalpel through the artery just above the valve on the left side in the line of incision already described, and to cut upward until the branches to the right and left lungs are reached. If desired, this incision may be extended down through the pulmonary valve and the ventricular wall along the line given for the second incision in the right ventricle.

The water-test for the competence of the valves of the heart is not very reliable, especially for the auriculo-ventricular valves, and is not so much used as formerly. Inspection and measurement of the valve after the heart has been opened will usually enable one to judge fairly accurately concerning the degree of competence. Before applying the test to the aortic valve the first incision into the left ventricle must be made and the cavity freed from clots, so that no obstruction will exist below the valve. Then the heart is to be held so that the aortic valve is perfectly horizontal, and water poured in from above to float the cusps out. If competent, they should keep the water from flowing through. If, however, in holding the heart the normal relations of the valve and the surrounding parts are not