_Discovery of the Circulation of the Blood_.--There is a passage in
Longinus (ch. xxii.), familiar perhaps to some of the readers of the
"NOTES AND QUERIES," which indicates that the fact of the circulation of
the blood was well established in the days of Plato. The father of
critics, to exemplify, and illustrate the use and value of _trope_ in
writing, has garbled from the Timaeus, a number of sentences descriptive
of the anatomy of the human body, where the circulation of the blood is
pointed at in terms singularly graphic. The exact extent of professional
knowledge arrived at in the time of the great philosopher is by no means
clearly defined: he speaks of the fact, however, not with a view to
prove what was contested or chimerical, but avails himself of it to
figure out the surpassing wisdom of the gods in constructing the human
frame. Perhaps some of the readers of the "NOTES," who are more
thoroughly conversant with the subject, may think it worth while to
inquire how much was known on that subject before Harvey wrote his
_Exercitationes Anatomiae_. The _Prooemium_ of that author seems hardly
sufficient to satisfy the desire of every reader, who has looked with
some care to the passage in Longinus to which I have taken the liberty
of calling public attention.