And what is erudition without the power to correct errors by appealing to Nature, to arrange methodically, to use wisely? It would be a shame to mention any name in illustration of its insignificance. Our shelves bend and crack under the load of unwise and learned authorship. There are two stages in every student's life. In the first he is afraid of books; in the second books are afraid of him. For they are a great community of thieves, and one finds the same stolen patterns in all their pockets. Though often dressed in sheep's clothing, they have the maw of wolves. When the student has once found them out, he laughs at the pretensions of erudition, and strides gayly up and down great libraries, feeling that the most blustering folio of them all will turn as pale as if it were bound in law-calf, if he only lay his hand on its shoulder. Nor, lastly, can any elevation of aim, any thirst for the divine springs of knowledge, enable a man to dispense with the sober habits of observation and the positive acquirements that must give him the stamina to attempt the higher flights of thought. The eagle's wings are nothing without his pectoral muscles. It is not Swedenborg and his disciples that legislate for the scientific world; they may suggest truth, but they rarely prove it, and never bring it into such systematic forms as narrow-minded Nature will insist on laying down. That all these qualities which go to make up our ideal should exist in absolute perfection in any single man of mortal birth is not to be expected. But there are names in the history of Science which recall so imposing a combination of these several gifts, that, comparing the men who bore them with the civilization of their time, we can hardly conceive that uninspired intellect should come nearer the imaginary standard. Such a man was Aristotle. The slender and close-shaven fop, with the showy mantle on his ungraceful person and the costly rings on his fingers, who hung on the lips of Plato for twenty years, and trained the boy of Macedon to whatever wisdom he possessed,--whose life was set by destiny between the greatest of thinkers and the greatest of conquerors,--seems to have borrowed the intellect of the one and the universal aspirations of the other. But because he invaded every realm of knowledge, it must not be thought he dealt with Nature at second-hand. He was a collector and a dissector. He could display the anatomical structure of a fish as well as write a treatise on the universe or on rhetoric, or government or logic, or music or mathematics. Dethroned we call him; and yet Mr. Agassiz quotes his descriptions with respect, and confesses that the systematic classification of animals makes but one stride from Aristotle to Linnaeus.