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him to have conducted his researches according to the method and rules laid down by the great expounder of the inductive philosophy, and that he had kept steadily before his eyes that golden precept of LORD BACON, "Non fingendum aut excogitandum quid natura faciat aut ferat, sed observandum et experiendum." He did not attempt, like STAHL, BOERHAAVE, CULLEN, BROWN, and a host of others, to find out the secrets of nature by some lucky guess; to discover some single principle from which all the animal movements might be deduced; or to explain them by the laws of mechanics or chemistry. He examined every organ and investigated every structure, tracing them through their successive stages of development, and pursuing their varieties in all classes of animals. He observed the action of each part, both in its natural and its pathological states, and continued his inquiries, when simple observation failed, by means of well-contrived experiments. When he had proceeded as far as he could, under the guidance of observation and experiment, he chose to stand still, rather than enter the dark region of conjecture and hypothesis. He was contented with finding out how living beings are constructed; how their organs act; how the various processes in the animal economy are accomplished; how the species is continued. The nature of life he left to the speculators. "Life," he says, "is a simple property of animal matter, of which we can form no adequate
