Empedocles' Fragment 100 contains an account of ‘the way that all things breathe in and out’. It may conveniently be divided into three sections:
A. Lines 1–5, the apparatus of breathing.
B. Lines 6–8, the manner in which breathing takes place.
C. Lines 8–25, an illustration taken from the working of the klepsydra.
I shall discuss the fragment under thesethree headings.
A. The Apparatus of Breathing
These lines (1–5) are translated as follows by Diels-Kranz: ‘Also aber atmet alles ein und aus: Allen sind blutarme Fleischröhren über die Oberfläche des Körpers hin gespannt, und an ihren Mündungen ist mit vielen Ritzen durchweg durchbohrt der Haut äusserste Oberfläche, so dass zwar das Blut drinnen geborgen bleibt, der Luft aber freier Zutritt durch die Öffnungen gebahnt ist.’ Thus the picture which Diels gives us is of tubes running out to the skin all over the body, and at the ends of the tubes perforated flaps of skin which will allow the passage of air but not of blood. The tubes are, furthermore, only partly filled with blood.
This line of interpretation has been followed by most scholars since, and it appears to derive some reinforcement from Aristotle, who in his comment on the passage at de respiratione 7, p. 473, b 1 ff., says: ‘They have passages through to the outer air.’ The ‘outer air’ would appear to mean the outer air outside the body, and we might therefore be tempted to suppose that Aristotle meant to say that these tubes ended up at the surface of the skin.