fore a thing can exhibit properties which do not belong to it, the very admission that living matter exhibits physical properties includes the further admission that those ply- sical or dead properties are in themselves vital in essence, really distinct, but in appearance only different." The impassable chasm between the living and the dead, which this hypothesis of a vital force assumes, and then attempts to bridge over, appears to be a human figment, arising out of the mecha- nical mode by which alone man can work upon material; but, says Newton,* "The main business of natural philosophy is to argue from phenomena without feigning hypotheses, and to deduce causes from effects until we come to the first cause, which certainly is not mechanical." Science may probably never be able to give an account of the primitive germs of living things, if only because the primeval conditions of the world. cannot repeat themselves for our investigation; but it is not improbable that the con-
- Optics, p. 344, 1718.
