On the Heart, or De
Corde trans. by I.M. Lonie in Lloyd, G.E.R., Hippocratic Writings.
London: Penguin Books, 1978, pp. 347-351, ch. 10.
10. The rest of my account will be concerned with the hidden membranes of the
heart - a piece of craftsmanship deserving description above all others. There
are membranes in the cavities, an fibres as well, spread out like cobwebs
through the chambers of the heart and surrounding the orifices on all sides and
emplanting filaments into the solid wall of the heart. In my opinion these
serve as the guy-ropes and stays of the heart and its vessels, and as
foundation to the arteries. Now there is a pair of these arteries, and on the
entrance of each three membranes have been contrived, with their edges rounded
to the approximate extent of a semicircle. When they come together it is
wonderful to see how precisely they close off the entrance to the arteries.
And if someone who fully understands their original arrangement removes the
heart from a cadaver and while propping up one membrane he leans the other
against it he will find that neither water nor air can be forced into the
heart. This is especially true in the case of the membranes in the left
chamber, which are engineered more precisely.
This is what one would expect: for man's intelligence, the principle which
rules over the rest of the soul, is situated in the left chamber.