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the knowledge he had thus acquired served as lights to his path in his search after the great secret. The path he chose was the way he has enjoined to us—the way of experiment. This was at that time no small merit. The influence of ancient authority—of Aristotle and Galen—was then not extinct: it was needftd to assert, as Harvey did, that "the facts cognisable by the senses wait upon no opinions." Moreover, the advantages of experiment, as distinguished from mere passive observation, had not been generally recognised even in physics. The success to which it conducted Harvey was almost the first proof of its value in physiology. We cannot too much admire the largeness of grasp with which he brought all the science of his day to bear on the one point; the clearness of his mechanical conceptions; the soundness of his reasoning; the long patience with which he laboured for twelve years in perfecting his demonstration. It still remains, at the end of more than two centuries, his most fitting monument—a model for physiological investigation unsurpassed, if not unequalled.
