No other physician has ever occupied the commanding position of "Clarissimus" Galenus. For fifteen centuries he dominated medical thought as powerfully as did Aristotle in the schools. Not until the Renaissance did daring spirits begin to question the infallibility of this medical pope. But here we must part with the last and, in many ways, the greatest of the Greeks--a man very much of our own type, who, could he visit this country today, might teach us many lessons. He would smile in scorn at the water supply of many of our cities, thinking of the magnificent aqueducts of Rome and of many of the colonial towns--some still in use--which in lightness of structure and in durability testify to the astonishing skill of their engineers. There are country districts in which he would find imperfect drainage and could tell of the wonderful system by which Rome was kept sweet and clean. Nothing would delight him more than a visit to Panama to see what the organization of knowledge has been able to accomplish. Everywhere he could tour the country as a sanitary expert, preaching the gospel of good water supply and good drainage, two of the great elements in civilization, in which in many places we have not yet reached the Roman standard. CHAPTER III -- MEDIAEVAL MEDICINE THERE are waste places of the earth which fill one with terror--not simply because they are waste; one has not such feelings in the desert nor in the vast solitude of the ocean. Very different is it where the desolation has overtaken a brilliant and flourishing product of man's head and hand. To know that . . . the Lion and the Lizard keep The Courts where Jamshyd gloried and drank deep