The original galley proofs have been revised and corrected from different viewpoints by Fielding H. Garrison, Harvey Cushing, Edward C. Streeter and latterly by Leonard L. Mackall (Savannah, Ga.), whose zeal and persistence in the painstaking verification of citations and references cannot be too highly commended. In the present revision, a number of important corrections, most of them based upon the original MS., have been made by Dr. W.W. Francis (Oxford), Dr. Charles Singer (London), Dr. E.C. Streeter, Mr. L.L. Mackall and others. This work, composed originally for a lay audience and for popular consumption, will be to the aspiring medical student and the hardworking practitioner a lift into the blue, an inspiring vista or "Pisgah-sight" of the evolution of medicine, a realization of what devotion, perseverance, valor and ability on the part of physicians have contributed to this progress, and of the creditable part which our profession has played in the general development of science. The editors have no hesitation in presenting these lectures to the profession and to the reading public as one of the most characteristic productions of the best-balanced, best-equipped, most sagacious and most lovable of all modern physicians. F.H.G. BUT on that account, I say, we ought not to reject the ancient Art, as if it were not, and had not been properly founded, because it did not attain accuracy in all things, but rather, since it is capable of reaching to the greatest exactitude by reasoning, to receive it and admire its discoveries, made from a state of great ignorance, and as having been well and properly made, and not from chance. (Hippocrates, On Ancient Medicine, Adams edition, Vol. 1, 1849, p. 168.) THE true and lawful goal of the sciences is none other than this: that human life be endowed with new discoveries and powers. (Francis Bacon, Novum Organum, Aphorisms, LXXXI, Spedding's translation.) A GOLDEN thread has run throughout the history of the world, consecutive and continuous, the work of the best men in successive ages. From point to point it still runs, and when near you feel it as the clear and bright and searchingly irresistible light which Truth throws forth when great minds conceive it. (Walter Moxon, Pilocereus Senilis and Other Papers, 1887, p. 4.)