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In the vena cava the blood from the food-tube, rich in food, but poor in oxygen, mixes with the impure, or used-up, blood brought back by the veins from all over the body and, passing into the right side of the heart, is pumped by the heart through a large blood-pipe to the lungs.
This is ornamented on each side of the entrance of the tomb with four pilasters cut in relief in the solid rock, each pair being connected by a semicircular arch also in relief. On the pilasters is incised a pattern of circles and V-shaped signs. A somewhat similar arrangement of pilasters is seen in two rock-tombs at Cava Lavinaro in the same district.
This point in particular may be observed more clearly than the noonday sun: the vena cava enters the heart at its lower part, the artery quits it at the superior part; the vein being now seized either with forceps or between the finger and the thumb, and the course of the blood for some space below the heart interrupted, you will perceive the part that intervenes between the fingers and the heart almost immediately to become empty, the blood being exhausted by the action of the heart; at the same time the heart will become of a much paler colour, even in its state of dilatation, than it was before; it is also smaller than at first, from wanting blood: and then it begins to beat more slowly, so that it seems at length as if it were about to die.
Some it sends to the blood, some to the lymphatic vessels, some to the lacteal vessels of the mesentery, and some down to the intestines. Then the chyle, conveyed through the thoracic duct from its cistern in the mesentery, is carried to the vena cava, and so to the heart.
In these days of easy travelling there lies a choice of two routes to Paestum and its temples: one by driving thither direct from La Cava or Salerno, in the mode of our forefathers; and the other by taking the train to the little junction of Battipaglia, and thence proceeding southward by the coast line to the station of Pesto itself, that stands almost within a stone’s throw of the chief gate of Poseidonia.
As the blood-vessels, therefore, are the canals and agents that transport the blood, they are of two kinds, the cava and the aorta; and this not by reason of there being two sides of the body, as Aristotle has it, but because of the difference of office, not, as is commonly said, in consequence of any diversity of structure, for in many animals, as I have said, the vein does not differ from the artery in the thickness of its walls, but solely in virtue of their distinct functions and uses.
Harvey, by resorting to vivisections of lower animals and reptiles, soon demonstrated beyond question the fact that the veins do carry the return blood. "But this, in particular, can be shown clearer than daylight," says Harvey. "The vena cava enters the heart at an inferior portion, while the artery passes out above.
From these capillaries the blood is carried by small veins which unite into a large trunk, the hepatic vein, which opens into the inferior vena cava. The portal circulation is thus not an independent system, but forms a kind of loop on the systemic circulation.
The two largest veins in the body, the superior vena cava and the inferior vena cava, open into the right auricle. These two veins bring venous blood from all parts of the body, and pour it into the right auricle, whence it passes into the right ventricle.
Accordingly during the summer weeks there is much poring over guide-books to Italy; much weighing of the merits of this place of residence and of that. Shall it be Sorrento? Shall it be La Cava? or Pisa? or Ravenna? or, for the matter of that, would not Seven Dials be as happy a choice as any, if only they could live and work side by side?
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