§ 6. From the time of Aristotle to Plutarch we know comparatively little of the works of the early philosophers, or of the habit of quoting from them. There is abundant evidence, however, that they were studied; the positions and sayings of Herakleitos especially seem to have attracted much attention. The works extant under the name of Hippokrates are attributed by some writers to a period even before Aristotle. In these works there are allusions to the positions of Empedokles and Anaxagoras, and Book I of the treatise περὶ διαιτῆς contains much Herakleitean material. There is scarcely one direct quotation (cf. Fr. 60), and Bernays cannot be said to be successful in reconstructing phrases of Herakleitos from this source. The book, however, is a comparatively early witness to the work of Herakleitos, and doubly important because it is independent of that Stoic study to which is due most of our knowledge of him. § 7. More than the other schools that succeeded Aristotle the Stoics devoted themselves to the history of philosophy, and they were interested in Herakleitos for the same reason that Aristotle had been interested in Anaximandros, because they regarded him as a precursor in their own line of thought. Herakleitean phrases occur already in the hymn of Kleanthes to Zeus, thus showing that they had already been adopted into the Stoic phraseology.[114] Philodemos (vii. 81) quotes Chrysippos also as giving a quotation from Herakleitos. It is only from later writers, however, that we can ascertain how much Herakleitos was studied in this period. Apparently collections were made of his sayings, which soon displaced the more complete form of his writings. Indeed, it is hard to prove that his book existed at all in later times, although Sextus Empiricus quotes a passage of some length which is considered to be the beginning of the work. Further, the works of at least some Stoic writers must have abounded in quotations from Herakleitos. In the writings of Philo there are numerous allusions to sayings of Herakleitos; and the Stoic context, the connection with Stoic ethics, as well as Philo’s general interest in the Stoic school, make it probable that he finds his Herakleitos in his Stoic sources. But while Philo is thus an important witness to the study of Herakleitos among the Stoics, he is of little value in reconstructing the text of the Ephesian philosopher. The carelessness of his method of quotation is shown by the form in which he gives three lines of Empedokles (48-49, 386). To seven fragments of Herakleitos (1, 22, 24, 46, 56, 64, 70) Philo makes a mere allusion; in another series of instances (10, 67, 69, 79, 80, 82) a phrase, often a single word, of Herakleitos is worked into the context. Fr. 68 and 85 are quoted very carelessly, and 76 and 89 have assumed a form very different from that which they originally had. Commonly the name of the author (Herakleitos) is not given.