The Turning of the Tide; Or, Radcliffe Rich and His Patients

by Elijah Kellogg

"I will now explain to you the use of all this. The right auricle opens into the large trunk vein of the body, that, in connection with the others, brings back the blood from the extremities, after the arteries have distributed it. It has also another opening into the right ventricle below it. The auricle on the other side of the partition (the left) is pierced by four veins that enter the lungs, called pulmonary veins, and also by another passage communicates with the ventricle beneath it. Now let us talk about ventricles. The right ventricle is entered by the great pulmonary artery that carries all the blood in the body through the lungs. The left ventricle is penetrated by the great artery, called the great aorta. In each of these cross partitions, there are valves that will permit blood to pass from the auricles into the ventricles, but not to return. There are also valves at the roots of the arteries that permit the blood to go from the heart into the arteries, but not to return. There are no valves at the roots of the veins that enter the auricles, nothing to obstruct the flowing of the blood from them into the auricles. Thus the roots of the veins arise from the auricles, and the roots of the arteries from the ventricles. Do you understand this description, because it is the foundation of all that follows—understand what a valve is?"

"Yes, sir; the clapper in our pump-box is a valve; it lets the water come up out of the well into the pump, but it won't let a drop go back."

"Well said; just so the valves in the partings of the heart permit the blood to pass from the auricles into the ventricles, but not to go back; thus, also, the valves placed at the roots of the arteries permit the passage of the blood from the ventricles into the arteries, but not the return of it to the heart. Do you understand this?"

"Yes, sir."

To make it more evident, Rich drew the heart, the veins, and the arteries entering it, with chalk, and the main branches of both.

"Now let us, for the clearer perception of what you wish to know, consider the march of the blood: and we might as well begin at the heart as anywhere."

"I think I can understand it better to commence there."

"From the right ventricle of the heart, springs the pulmonary artery, which, separating into several branches, some of them not larger than hairs, carries the blood into all portions of the lungs, where they communicate with the terminations of the pulmonary veins, which, receiving the blood from the arteries, bring it back to the left auricle, uniting, as they approach the heart, into four large veins, called the pulmonary veins. From the left ventricle rises the main artery (or great aorta), which, receiving all the blood of the body poured into it by the pulmonary veins, distributes it over the trunk and limbs, branching in every direction, the divisions gradually becoming smaller and smaller as they approach the extremities: here they communicate with the extremities of the veins which bring back the blood to the right auricle. So much for the aqueducts; now we will look at the action of the force-pump itself. The heart is a hollow muscle. All the valves and division walls we have been talking about are muscular in their texture, and moved by a network of muscles and minute tendons, tough and elastic, like the gizzard of a fowl, and capable of contraction and expansion. We will suppose the right auricle to be full of blood that has been brought by the veins from the fingers, toes, the substance of the heart itself, the lungs, and the liver, and poured into it. This blood is dark-colored; called black blood. It has washed the whole body. The instant it enters the auricle, that organ contracts and forces it into the ventricle below it; the valve holds it there: then the ventricle contracts and forces it into the pulmonary artery; the valve of the artery holds it there: the auricle expands, fills, again contracts, fills the ventricle, that, in its turn, forces the blood into the artery, and thus, by successive leaps, it passes into and through the lungs, enters the pulmonary veins, and is by them brought back to the left auricle. It is now no longer black blood, but bright, red, arterial blood: before it was venous."

"What makes it red?"

"I don't know. It is supposed by being brought in contact with the air in the cells of the lungs. When the auricle receives this red blood, it contracts, forces it into the left ventricle beneath, then the ventricle in its turn contracts, forces it into the main artery, and by this and its branches it is carried to the extremities, to come back in one continual round, as long as life lasts. It is life; for the moment the heart ceases to contract and dilate, insensibility takes place, and death instantly follows."