Book 2
5
At the actual moment, however, the Erasistrateans are engaged in a considerable battle, not only with others but also amongst themselves, and so they cannot explain the passage from the first book of the General Principles, in which Erasistratus says, Since there are two kinds of vessels openingLit. anastomosing. at the same place, the one kind extending to the gall-bladder and the other to the vena cava, the result is that, of the nutriment carried up from the alimentary canal, that part which fits both kinds of stomata is received into both kinds of vessels, some being carried into the gall-bladder, and the rest passing over into the vena cava. For it is difficult to say what we are to understand by the words opening at the same place which are written at the beginning of this passage. Either they mean there is a junction More literally, synapse. between the termination of the vein which is on the concave surface of the liverThe portal vein. and two other vascular terminations (that of the vessel on the convex surface of the liverThe hepatic vein or veins. and that of the bile-duct), or, if not, then we must suppose that there is, as it were, a common space for all three vessels, which becomes filled from the lower vein,The portal vein. and empties itself both into the bile-duct and into the branches of the vena cava. Now, there are many difficulties in both of these explanations, but if I were to state them all, I should find myself inadvertently writing an exposition of the teaching of Erasistratus, instead of carrying out my original undertaking. There is, however, one difficulty common to both these explanations, namely, that the whole of the blood does not become purified. For it ought to fall into the bile-duct as into a kind of sieve, instead of going (running, in fact, rapidly) past it, into the larger stoma, by virtue of the impulse of anadosis.
