It was only through long hard work that the writer arrived at conclusions which the reader may be disposed to accept as very natural, under the circumstances. It is possible that the reader may, nevertheless, be interested in the manner in which the suggestion here advanced was reached. The writer had for several years been working at the premier edition of the fragments of Numenius, in reasonably complete form, with translation and outline. After ransacking the accessible sources of fragments, there remained yet an alleged treatise of Numenius on Matter, in the library of the Escoreal, near Madrid. This had been known to savants in Germany for many years; and Prof. Uzener, of Bonn, in his criticism of Thedinga's partial collection of fragments, had expressed a strong desire that it be investigated; it had also been noticed by Zeller, and Bouillet, as well as Chaignet. If then I hoped to publish a comparatively reliable collection of the fragments of Numenius, it was my duty, though hailing from far America, and though no European had shown enough interest therein to send for a photographic copy, to go there, and get one, which I did in July, 1913. I bore the precious fragment to Rostock and Prof. Thedinga in Hagen, where, however, we discovered that it was no more than a section of Plotinos's Enneads, iii. 6.6 to end. The manuscript did, indeed, show an erasure of the name of Plotinos, and the substitution of that of Numenius. After the first disappointment, it became unavoidable to ask the question why the monk should have done that. Had he any reason to suppose that this represented Numenian doctrine, even if it was not written by Numenius? Having no external data to go by, it became necessary to resort to internal criticism, to compare this Plotinian treatment of matter with other Plotinian treatments, in other portions of the Enneads. This then inevitably led to a close scrutiny of Plotinos's various treatments of the subject, with results that were very much unlooked for. This part that we might well have had reason to ascribe to Numenian influence, on the contrary, turned out to be by far more Plotinian than other sections that we would at first have unhesitatingly considered Plotinian, and, as will be seen elsewhere, the really doubtful portions occur in the very last works of Plotinos's life, where it would have been more natural to expect the most genuine. However, the result was a demonstration of a progress in doctrines in the career of Plotinos, and after a careful study thereof, the reader will agree that we have in this case every element of probability in favor of such a development; indeed, it will seem so natural that the unbiased reader will ask himself why this idea has not before this been the general view of the matter. * * * * *