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Rh they reason about the problems they have to solve.

I have called the subject of the course "Life in Motion." We must take care at the outset not to outset into difficulties about what is implied by the word Life. We shall not inquire, in the meantime at all events, whether life may be considered as something independent of matter, or whether it is the outcome of material arrangements. It will be better at first to use the words Living Matter instead of the word Life, and to define our subject of study as Living Matter in Motion, or the Motions of Living Matter. We might study other aspects of living matter, as, for example, the chemical changes occurring in it, the forms it assumes, its arrangements for different purposes, or its wonderful connection in some conditions, as in the brain, with consciousness. We shall, however, limit ourselves to the consideration of its motions; and we shall refer to the other properties of living matter only in so far as these throw light on the secret mechanism by which it moves.

We are familiar with motion every day of our lives. We know, first of all, of great