What Harvey
proved, in short, was this (see Fig. 4)--that everybody had made a
mistake, for want of sufficiently accurate experimentation as to the
actual existence of the fact which everybody assumed. To anybody who
looks at the blood-vessels with an unprejudiced eye it seems so natural
that the blood should all come out of the liver, and be distributed by
the veins to the different parts of the body, that nothing can seem
simpler or more plain; and consequently no one could make up his mind
to dispute this apparently obvious assumption. But Harvey did dispute
it; and when he came to investigate the matter he discovered that it was
a profound mistake, and that, all this time, the blood had been moving
in just the opposite direction, namely, from the small ramifications of
the veins towards the right side of the heart. Harvey further found
that, in the arteries, the blood, as had previously been known, was
travelling from the greater trunks towards the ramifications. Moreover,
referring to the ideas of Columbus and of Galen (for he was a great
student of literature, and did justice to all his predecessors), Harvey
accepts and strengthens their view of the course of the blood through
the lungs, and he shows how it fitted into his general scheme.
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