Unquestionably it is a deep marvel and a mystery, that impalpable spirit should act upon gross matter; but it is a mystery of humanity as well as of Godhead. What moves the hand? Contraction of the muscles. But what causes contraction of the muscles? The influence transmitted from the brain by the nerves. But what sends that influence? It is mind, which somewhere, somehow, moves animal tissues--tissues consisting of carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulphur. At some point of our frames, we know not yet where, mind does act directly on matter. It is a law of Nature that it should so act _there_. But if God exists, His mind must, by the same law, act on matter _somewhere_. Can we call it an offence against law if it acts on matter elsewhere than in that mass of organized pulp which we call brains? If no possibility of communication between mind and matter could anywhere be found in Nature, we might call such communication contrary to natural law. In other words, if it were one of the properties of matter that it could not receive motion from that which is not matter, its motion without a material cause would be supernatural. But since it is of the very essence of existence that matter in certain combinations should be capable of being endowed with life, and by such endowment become capable of being affected in motion by mind, it is indisputable that such capability is one of matter's properties, and that its being so affected falls within and not without Nature's laws.