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. 1.
1. In shape the heart is like a pyramid, in colour a deep crimson. It is
enveloped in a smooth membrane. In this membrane there is a small quantity of
fluid, rather like urine, giving one the impression that the heart moves in a
kind of bladder. The purpose of the fluid is to protect the pulsation of the
heart, but there is just about sufficient of it to alleviate the heat of the
heat as well. The heart filters out this fluid after it has received it and
made use of it, drinking it up from the lung.