Consciousness is an accompaniment of that animal and human organisation and of that material mechanism which it is the province of physiology to explore; and as long as the atoms of the brain follow their due course according to certain definite laws, there arises an inner life which springs from sensation and idea, from feeling and will. We feel this in our own cases; it strikes us in our converse with other people; we can see it plainly in the more highly organised animals; even the lowest forms of life bear traces of it; and who can draw a line in the kingdom of organic life, and say that it is here the soul ceases? With what eyes, then, is physiology to regard this two-fold life of the organised world? Shall she close them entirely to one whole side of it, that she may fix them more intently on the other? So long as the physiologist is content to be a physicist, and nothing more—using the word “physicist” in its widest signification—his position in regard to the organic world is one of extreme but legitimate one-sidedness. As the crystal to the mineralogist or the vibrating string to the acoustician, so from this point of view both man and the lower animals are to the physiologist neither more nor less than the matter of which they consist. That animals feel desire and repugnance, that the material mechanism of the human frame is in chose connection with emotions of pleasure or pain, and with the active idea-life of consciousness—this cannot, in the eyes of the physicist, make the animal or human body into anything more than what it actually is. To him it is a combination of matter, subjected to the same inflexible laws as stones and plants—a material combination, the outward and inward movements of which interact as cause and effect, and are in as close connection with each other and with their surroundings as the working of a machine with the revolutions of the wheels that compose it. Neither sensation, nor idea, nor yet conscious will, can form a link in this chain of material occurrences which make up the physical life of an organism. If I am asked a question and reply to it, the material process which the nerve fibre conveys from the organ of hearing to the brain must travel through my brain as an actual and material process before it can reach the nerves which will act upon my organs of speech. It cannot, on reaching a given place in the brain, change then and there into an immaterial something, and turn up again some time afterwards in another part of the brain as a material process. The traveller in the desert might as well hope, before he again goes forth into the wilderness of reality, to take rest and refreshment in the oasis with which the Fata Morgana illudes him; or as well might a prisoner hope to escape from his prison through a door reflected in a mirror.