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5]
But those who hold this doctrine give the sceptical occasion to object that, on this reasoning, there is no blood in living creatures, but it is generated in response to wounds by a transformation of some vapour or flesh, which causes its liquefaction and flow. Moreover, they are refuted by the experience of men who dig mines, either for sieges or for metals, and in the depths encounter rivers of water, which are not gradually collected, as must naturally be the case if they come into existence at the instant that the earth is agitated, but pour fourth in a great mass. And again, when a mountain or rock is smitten asunder, a fierce torrent of water often gushes forth, and then ceases entirely. So much on this head.