too Apollodorus and Syllus in the first part of their Introductions to Stoic Doctrine, as also Eudromus in his Elementary Treatise on Ethics, Diogenes the Babylonian, and Posidonius. These parts are called by Apollodorus " Heads of Commonplace " ; by Chrysippus and Eudromus specific divisions : by others generic divisions. Philosophy, they say, is like an animal, Logic corresponding to the bones and sinews, Ethics to the fleshy parts. Physics to the soul. Another simile they use is that of an egg : the shell is Logic, next comes the white, Ethics, and the yolk in the centre is Physics. Or, again, they liken Philosophy to a fertile field : Logic being the encircling fence, Ethics the crop, Physics the soil or the trees. Or, again, to a city strongly walled and governed by reason. No single part, some Stoics declare, is independent of any other part, but all blend together. Nor was it usual to teach them separately. Others, however, start their course with Logic, go on to Physics, and finish with Ethics ; and among those who so do are Zeno in his treatise On Exposition, Chrysippus, Archedemus and Eudromus. Diogenes of Ptolemaiis, it is true, begins with Ethics ; but Apollodorus puts Ethics second, while Panaetius and Posidonius begin with Physics, as stated by Phanias, the pupil of Posidonius, in the first book of his Lectures of Posidonius. Cleanthes makes not three, but six parts, Dialectic, Rhetoric, Ethics, Politics, Physics, Theology. But others say that these are divisions not of philosophic exposition, but of philosophy itself : so, for instance, Zeno of Tarsus. Some divide the logical part of the system into the two sciences of rhetoric and dialectic ; while