"A robust mental strength requires various and solid food. The best growth is symmetrical. There is a common bond--_quoddam commune vinculum_--in the circle of knowledge, that cannot be overlooked. Men do not know best what they know only in its isolation. Even Kant offset his metaphysics by lecturing on geography; and Niebuhr, the historian, struggled hard and well to keep his equilibrium by throwing himself into the whole circle of natural science and of affairs. Such, also, are the interdependencies of scholarship, that ample knowledge without our specialty is needful to save us from blunders within. Olshausen was a brilliant commentator, and the slightest tinge of chemistry should have kept him from suggesting that the conversion of water into wine at Cana was but the acceleration of a natural process. A smattering of optics would have prevented Dr. Williams from repeating the old cavil of Voltaire, that light could not have been made before the sun. A moderate reflection upon the laws of speech and the method of Genesis would have restrained Huxley from sneering at the 'marvelous flexibility' of the Hebrew tongue in the word 'day,' and a New York audience from laughing at the joke rather than the joker. Some tinge of ethical knowledge should have withheld Max Müller from finding the grand distinctive mark of humanity in the power of speech. The merest theorist needs some range of reality for the framework of his theories, and the man of broad principles must have facts to generalize. Indeed, a good memory is the indispensable servant of large thought, and however deficient in certain directions, the great thinkers have had large stores. 'The best heads that have ever existed,' says an idealist,--'Pericles, Plato, Julius Cæsar, Shakespeare, Goethe, Milton,--were well read, universally educated men, and quite too wise to undervalue letters. Their opinion has weight, because they had the means of knowing the opposite opinion.' "While every year increases the impossibility of what used to be called universal knowledge, it also emphasizes the necessity of a scholarship that has its outlook toward all the vast provinces of reading and thought. It cannot conquer them, but it can be on treaty relations with them. The tendency of modern science is, of necessity, steadily toward sectional lines and division of labor. It is a tendency whose cramping influence is as steadily to be resisted, even in later life, much more in early training. We are to form ourselves on the model of the integer rather than the fraction of humanity. The metaphysician cannot afford to be ignorant of the 'chemistry of a candle' or the 'history of a piece of chalk,' nor the chemist of the laws of language, the theologian of astronomy and geology, nor the lawyer of the most ancient code and its history. Mill himself made complaint of Comte's 'great aberration' in ignoring psychology and logic.