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on the just principles of demonstration and reason. It is very certain that oral instructions and ocular illustrations render science easier, are more convincing, and make a more durable impression than the best wrote treatises.
A course of reading and observation is not sufficient, without other instruction, to qualify young men for practice; since many of the books of medicine are full of obscurity, or crouded with absurdities, which puzzle the unexperienced reader, and often lead young minds astray.
As the most precious metals in a state of ore are mixed with dross, so the choice truths of Medicine are frequently blended with a heap of rubbish. How valuable and necessary is an experienced professor who knows how to clear this away; to present those truths simple and pure from mixture; to trace them out under the various appearances they put on at different times, and to discover to students the clue of reasoning which they ought to pursue, in winding through a labyrinth of obscurity, before they can arrive at a clear knowledge of the more difficult parts of their profession! That is to teach them how to philosophize justly in medicine.
The greatest genius left to itself is like the earth, when destitute of the fun, incapable of bringing its productions to a perfect maturity. A course of re-
