een 50 and 60 pages of a small quarto in
Latin, and is as terse and concise as it possibly can be--when you come
to look at Harvey's work, you will find that he had long struggled with
the difficulties of the accepted doctrine of the circulation. He had
received from Fabricius, and from all the great authorities of the day,
the current view of the circulation of the blood. But he was a man
with that rarest of all qualities--intellectual honesty; and by dint of
cultivating that great faculty, which is more moral than intellectual,
it had become impossible for him to say he believed anything which he
did not clearly believe. This is a most uncomfortable peculiarity--for
it gets you into all sorts of difficulties with all sorts of
people--but, for scientific purposes, it is absolutely invaluable.
Harvey possessed this peculiarity in the highest degree, and so it was
impossible for him to accept what all the authorities told him, and he
looked into the matter for himself. But he was not hasty. He worked at
his new views, and he lectured about them at the College of Physicians
for nine years; he did not print them until he was a man of fifty
years of age; and when he did print them he accompanied them with a
demonstration which has never been shaken, and which will stand till the
end of time. 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