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8 living beings and surrounding influences; for "the idea of life," he observes, "presupposes something able to live, and it requires no less a certain of external influences for its fulfilment."

The nature of Vital Principle, then, is still for us, as it was for Aristotle, a great mystery; and as opinions upon it are at best but speculations, we may proceed, without further comment, to the text, which, besides miscellaneous matter, will be found to contain suggestions for reflexion and inquiry.