_We_ refer—_Who_ refers? _What_ refers? The brain to the brain? Or one part of the brain to another part of the brain? Will the Materialists explain? It is probable that this envelope of nerves unites all the parts of the brain and by transmitting to each part the condition of all the other parts produces co-ordination of the parts and unity of action. But this membrane of nerve cannot surely be deemed by the most bigoted Materialist to constitute the Conscious Self. Professor FERRIER has proved, by a multitude of minutely detailed experiments, that not only has each ganglion its function, but that each part of each ganglion is devoted to some special duty, thus completely shattering the theory that holds every mental operation to be an act of the whole brain. He establishes at least the grand basis of modern mental Science, the assumption that the brain is the material organ of the mind; that distinct parts of the brain are devoted to distinct mental operations; that not the whole brain, but only parts of it, are employed in any mental operation. The question is still open for observation and experiment to ascertain what are the parts of the brain so appropriated and what are the precise functions of each part. Professor FERRIER has made considerable advances towards the determination of this question. His experiments have demonstrated what are the functions of the ganglia at the base of the brain, not being the seat of the Intelligence. His experiments were attended with more cruelty than I could excuse even for the important accessions they have brought to our knowledge. But they are not therefore the less valuable as contributions to Physiology and Psychology. I can but briefly describe the results of such of them as bear immediately upon the subject here treated of. Let me, however, first confirm, by the authority of Professor FERRIER, the proposition I have ventured to advance as to the various functions of various parts of the brain. “That the brain is the organ of the mind,” he says, “and that mental operations are possible only in and through the brain, is now so thoroughly well established and recognized that we may, without further question, start from this as an ultimate fact.” He proceeds: