Since the time of Burman it has been amongst the aims of Phaedrian scholarship to endeavour to make good the imperfections of the direct tradition by recourse to the indirect. That losses have been sustained, one piece of evidence is enough to show. In the sixth line of his Preface to Book I. Phaedrus says that trees speak in his fables; but no trees speak in any fable now left to us, either in the five books as handed down in PR or in the Perottine Appendix.