The Papyrus Ebers, the second in size and the best preserved of all the ancient Egyptian manuscripts which have come into our possession, was written in the 16th century B. C., and contains on 110 pages the hermetic book upon the medicines of the ancient Egyptians, known also to the Alexandrine Greeks. The god Thoth (Hermes) is called “the guide” of physicians, and the various writings and treatises of which the work is composed are revelations from him. In this venerable scroll diagnoses are made and remedies suggested for the internal and external diseases of most portions of the human body. With the drugs prescribed are numbers, according to which they are weighed with weights and measured with hollow measures, and accompanying the prescriptions are noted the pious axioms to be repeated by the physician, while compounding and giving them to the patient. On the second line of the first page of our manuscript, it is stated that it came from Sais. A large portion of this work is devoted to the visual organs. On the twentieth line of the fifty-fifth page begins the book on the eyes, which fills eight large pages. We were formerly compelled to draw from Greek and Roman authors what we knew about the remedies used for diseases of the eye among the ancient Egyptians. The portion of the Papyrus Ebers just mentioned is now the only Egyptian source from whence we can obtain instruction concerning this important branch of ancient medicine. All this scarcely seems to have a place in the preface of a historical romance, and yet it is worthy of mention here; for there is something almost “providential” in the fact that it was reserved for the author of “An Egyptian Princess” to bestow the gift of this manuscript upon the scientific world. Among the characters in the novel the reader will meet an oculist from Sais, who wrote a book upon the diseases of the visual organs. The fate of this valuable work exactly agrees with the course of the narrative. The papyrus scroll of the Sais oculist, which a short time ago existed only in the imagination of the author and readers of “An Egyptian Princess,” is now an established fact. When I succeeded in bringing the manuscript home, I felt like the man who had dreamed of a treasure, and when he went out to ride found it in his path. A reply to Monsieur Jules Soury’s criticism of “An Egyptian Princess” in the Revue des deux Mondes, Vol. VII, January 1875, might appropriately be introduced into this preface, but would scarcely be possible without entering more deeply into the ever-disputed question, which will be answered elsewhere, whether the historical romance is ever justifiable. Yet I cannot refrain from informing Monsieur Soury here that “An Egyptian Princess” detained me from no other work. I wrote it in my sick-room, before entering upon my academic career, and while composing it, found not only comfort and pleasure, but an opportunity to give dead scientific material a living interest for myself and others.