[123] Emp. Frag. v. 135, Kar.
[124] Plato, Menon. p. 76 A.; Aristot. Gen. et Corr. i. 8, p. 324, b. 30 seq.
[125] Ἐμπεδοκλῆς ἐξ ἀμεταβλήτων τῶν τεττάρων στοιχείων ἡγεῖτο γίγνεσθαι τὴν τῶν συνθέτων σωμάτων φύσιν, οὕτως ἀναμεμιγμένων ἀλλήλοις τῶν πρώτων, ὡς εἴ τις λειώσας ἀκριβῶς καὶ χνοώδη ποιήσας ἰὸν καὶ χαλκῖτιν καὶ καδμείαν καὶ μίσυ μίξειεν, ὡς μηδὲν ἐξ αὐτοῦ μεταχειρίσασθαι χωρὶς ἑτέρου.
Galen, Comm. in Hippokrat. De Homin. Nat. t. iii. p. 101. See Karsten, De Emped. Phil. p. 407, and Emp. Fr. v. 155.
Galen says, however (after Aristot. Gen. et Corr. ii. 7, p. 334, a. 30), that this mixture, set forth by Empedokles, is not mixture properly speaking, but merely close proximity. Hippokrates (he says) was the first who propounded the doctrine of real mixture. But Empedokles seems to have intended a real mixture, in all cases where the structure of the pores was in symmetry with the inflowing particles. Oil and water (he said) would not mix together, because there was no such symmetry between them — ὅλως γὰρ ποιεῖ (Empedokles) τὴν μίξιν τῇ συμμετρίᾳ τῶν πόρων· διόπερ ἔλαιον μὲν καὶ ὕδωρ οὐ μίγνυσθαι, τὰ δὲ ἄλλα ὑγρὰ καὶ περὶ ὅσων δὴ καταριθμεῖται τὰς ἰδίας κράσεις (Theophrastus, De Sensu et Sensili, s. 12, vol. i. p. 651, ed. Schneider).
Physiology of Empedokles — Procreation — Respiration — movement of the blood.
Empedokles farther laid down many doctrines respecting physiology. He dwelt on the procreation of men and animals, entered upon many details respecting gestation and the fœtus, and even tried to explain what it was that determined the birth of male or female offspring. About respiration, alimentation, and sensation, he also proposed theories: his explanation of respiration remains in one of the fragments. He supposed that man breathed, partly through the nose, mouth, and lungs, but partly also through the whole surface of the body, by the pores wherewith it was pierced, and by the internal vessels connected with those pores. Those internal vessels were connected with the blood vessels, and the portion of them near the surface was alternately filled with blood or emptied of blood, by the flow outwards from the centre or the ebb inwards towards the centre. Such was the movement which Empedokles considered as constantly belonging to the blood: alternately a projection outwards from the centre and a recession backwards towards the centre. When the blood thus receded, the extremities of the vessels were left empty, and the air from without entered: when the outward tide of blood returned, the air which had thus entered was expelled.[126] Empedokles conceived this outward tide of blood to be occasioned by the effort of the internal fire to escape and join its analogous element without.[127]
[126] Emp. Fr. v. 275, seqq. Karst.
The comments of Aristotle on this theory of Empedokles are hardly pertinent: they refer to respiration by the nostrils, which was not what Empedokles had in view (Aristot. De Respirat. c. 3).
[127] Karsten, De Emp. Philosoph. p. 480.