=2. The Compilations.= These were excerpts from scientific works, collections of zoölogical, literary, historical, and antiquarian data, which Aristotle and his pupils had gathered together. Only a few fragments of the total remain. There were critical notes upon the Pythagoreans, reports of extracts of Plato’s dialogues, a descriptive basis for zoölogy with illustrations, collections of previous rhetorical theories and models, histories of tragedies and comedies, discussions about Homer, Hesiod, Archilochus, Euripides, and other poets; there were historical miscellanies and reports concerning one hundred fifty-eight Greek state constitutions. =3. The Didactic Writings.= These have in part been preserved, and they make up the collection of what we have of Aristotle’s writings. They have a consistently developed terminology, but they are wanting in grace and beauty of presentation. The plan of the books is generally the same: the problem is precisely stated; then follows a criticism of various attempted solutions; then a discussion of the salient points of the problem; then a marshaling of the facts; and, finally, an attempt to get a conclusive result. The method is modern in its scientific procedure and the contrast with Plato is striking. Yet it must not be inferred that these books of Aristotle are orderly. There are repetitions, haste, unequal development of parts, and unfulfilled promises. These books were nothing else than the written notes which he had made the basis of his lectures and had intended to form into text-books in some future time. Only parts of the Logic seem to have been completed for text-book purposes. These didactic writings are simply arranged as follows (Wallace): 1. The treatise on Logic called _Organon_. 2. Speculative Philosophy. First Philosophy or Theology or Metaphysics. Mathematics (writings not extant). Physics (including the history of animals and the psychology). 3. Practical Philosophy. Ethics. Economics. Politics. 4. Poetic Philosophy. Art. Poetry. Rhetoric.