(B) “It has, as already stated, three cavities, the largest of them is on the right, the smallest on the left, the middle-sized one in the middle; they have all, also the two small ones, passages (τετρημένας) towards the lung, very evidently as respects one of the cavities. In the region of the union [with the great vein and the aorta] the largest cavity is connected with the largest vein (near which is the mesentery); the middle cavity with the aorta.
(C) “Canals (πόροι) from the heart pass to the lung and divide in the same fashion as the windpipe does, closely accompanying those from the windpipe through the whole lung. The canals from the heart are uppermost.
(D) “No canal is common [to the branches of the windpipe and those of the vein] (οὐδεὶς δ’ ἐστὶ κοινὸς πόρος) but through those parts of them which are in contact (τὴν σύναψιν) the air passes in and they [the πόροι] carry it to the heart.
(E) “One of the canals leads to the right cavity, the other to the left.
(F) “Of all the viscera, the heart alone contains blood [in itself]. The lung contains blood, not in itself but in the veins, the heart in itself; for in each of the cavities there is blood; the thinnest is in the middle cavity.”
Book iii. 3.—(G) “Two veins lie in the thorax alongside the spine, on its inner face; the larger more forwards, the smaller behind; the larger more to the right, the smaller, which some call aorta (on account of the tendinous part of it seen in dead bodies), to the left. These take their origin from the heart; they pass entire, preserving the nature of veins, through the other viscera that they reach; while the heart is rather a part of them, and more especially of the anterior and larger one, which is continued into veins above and below, while between these is the heart.
(H) “All hearts contain cavities, but, in those of very small animals, the largest [cavity] is hardly visible, those of middling size have another, and the biggest all three.
(I) “The point of the heart is directed forwards, as was mentioned at first; the largest cavity to the right and upper side of it, the smallest to the left, and the middle-sized one between these; both of these are much smaller than the largest.
(K) “They are all connected by passages (συντέτρηνται) with the lung, but, on account of the smallness of the canals, this is obscure except in one.
(L) “The great vein proceeds from the largest cavity which lies upwards and to the right; next through the hollow middle part (διὰ τοῦ κοίλου τοῦ μέσου) it becomes vein again, this cavity being a part of the vein in which the blood stagnates.