BOOK I

486^a 5

I Of the parts of animals some are simple: to wit, all such as divide into parts uniform with themselves, as flesh into flesh; others are composite, such as divide into parts not uniform with themselves, as, for instance, the hand does not divide into hands nor the face into faces.^1

^1 Cf. P. A. ii. 1 and 2; Theophr. H. Pl. i. 2; Ps.-Arist. de Pl. i. 2 and 3.
A treatise might be written on the intention and the history of the distinction here drawn by Aristotle, who had derived it from Anaxagoras (cf. Lucret. i. 830; Serv. ad Aen. iv. 625; Cic. Q. Acad. iv. 57; Galen, de Dogm. Hipp. v. 450, 673, ed. Kühn, &c.). The subject is treated more fully in the de Partibus (ii. 1, &c.), where A. distinguishes three degrees of composition or synthesis. The first is composition out of the elements, ἐκ τῶν καλ. ὑπό τινων στοιχείων, οἷον γῆς, ἀέρος, ὕδατος, πυρός: or rather of certain of these, ὑγρὸν γὰρ καὶ ξηρὸν καὶ θερμὸν καὶ ψυχρὸν ὕλη τῶν συνθέτων σωμάτων ἐστίν. The second and third stages of synthesis are, in animals, the simple tissues, bone, flesh, and the like, and the organs that are built up of these (cf. Galen, xv. 7 K.).
In Meteor. iv. 10 the simple and composite parts of plants and animals are compared with the like categories of inanimate things, the former with such ὁμοιομερῆ as gold and silver, tin and iron, καὶ ὅσα ἐκ τούτων γίγνεται. It is noteworthy that, in the Meteorologica, A. ranks wood and bark among the ἀνομοιομερῆ, together with root and leaf, face and hand, though flesh and bone, nerve and skin rank only, with fibre and muscle, among the ὁμοιομερῆ; in other words, the histological analysis is carried somewhat further on the botanical than on the zoological side. As to sap and juice and fibre and vessel and flesh, these are elementary things, so far as biology conducts us: ἀρχαὶ γὰρ αὗται, πλὴν εἴ τις λέγοι τὰς τῶν στοιχείων δυνάμεις· αὗται δὲ κοιναὶ πάντων. ἡ μὲν οὖν οὐσία καὶ ἡ ὕλη φύσις ἐν τούτοις (Theophr., l. c.). We must pass, as Galen tells us (i. 487 K.), to the de Gen. et Corr. ii, or the de Caelo i, for a discussion of the elements, and of the relation to these of the influences of wet and dry, hot and cold, &c. As Aristotle’s account of the elements remained the groundwork of the mediaeval conception of matter, so the older naturalists retained unaltered his distinction of simple and composite parts in the fabric of living things. The ὁμοιομερῆ and ἀνομοιομερῆ are the partes similares s. simplices s. primae, and the partes dissimilares s. instrumentales s. organicae s. officinales, of the naturalists. Wotton, for instance (de Diff. Anim. i. 4; 1552), gives a very fair epitome of the tissues as follows: ‘Similares numerantur hae, os, cartilago, vena, arteria, nervus, ligamentum, tendo, membrana, caro, adeps, unguis, cutis; his adduntur humores, ut sanguis, et qui in oculo sunt, crystallinus et vitreus humor.’ The division into tissues and organs of Bichat (Anat. générale, 1801) was thus quite on old lines.