Thirdly, the evidence in favour of the localisation of the different mental organs given by cranioscopy, physiological experiment, and pathology. The proofs in this category are as yet defective; for cranioscopy, though following strictly the boasted inductive method, is to a large extent inapplicable, from anatomical hindrances, and it shares, with the other two departments, in the difficulty that the brain-functions are so excessively complicated, that we cannot yet get to what are the ultimate elements of thought, the very simplest we know being themselves complex, and involving numberless cells in different parts of the whole organ. Experiment and pathological observation are thus vitiated to such a surprising degree, that it would seem, from the recent observations of BrownSequard, that almost any lesion of any part of the brain and its appendages will produce excitement or paralysis of almost any mental or motor function. And it would seem that elementary psychical, sensory, and motor centres are diffused through the whole brain. Nevertheless, as we see that vasomotor centres are widely distributed through the spinal marrow and sympathetic ganglia, yet that that does not preclude the existence of a single controlling centre in the medulla oblongata, so we may imagine that similar compound controlling centres may be discovered in the brain forming the separate organs of the mind, which are unquestionably inherited and developed in different proportions in different individuals. In fine, it may be held as proved in physiology, that for reach their highest development in man. It might appear that, considering the extreme agility of some animals, such as the apes, and the necessity for delicate sensations for man, it should have been the sensorial paths of cerebral nervefibres which should have been most developed. But consider the extraordinary complexity of the nerve-stimulation, both excitory and inhibitory, which go to produce the co-ordinated movements of speech; also, the equally delicate and manifold natures of the stimuli which shall direct the hand, so that it shall execute the purpose and thoughts of the musician, the artist, the artisan, and the surgeon ! every feeling, every thought, and every volition, a correlative change takes place in the nerve-matter; and, given this special change in every respect identical, a similar state of consciousness will always arise; that this process occupies time; that it requires a due supply of oxygenated blood; that it is interrupted or destroyed by whatever impairs the integrity of the nerve-matter; and, lastly, that it is exhausted by its own activity and requires rest. The supposed proof of the existence of a spiritual essence given by the power of mind over body, exhibited by the suppression of signs of emotion, or resistance to instinctive movements under the power of will or strong emotion, is now explained by the existence of inhibitory nerves and centres; and these are not confined to the higher mental operations, but form a necessary part in the reflex rhythmical actions of the lower functions. The clearness of mind before death, also one of the popular proofs, is nothing more than a sign that the brain escapes disorder in many fatal diseases, as do all the other organs in their turn. It also arises from the removal of inhibitory and disturbing influences upon the brain, which sometimes (though rarely) happens at the approach of death. All these facts are directly in favour of the Materialist view. But we cannot reduce the difficulties of the question to those of mere plant life. We may, and must, it is true, reduce mental acts to the interaction of two factors; the stimulus on one hand, and the susceptible living nerve-matter on the other; the former acting through excitement of the centripetal nervefibres, while the result of mental activity is expressed by excitation of the ideo-motor efferent-fibres. Mind, therefore, consists in the complicated reflex activities which are the link between centripetal and centrifugal excitations, and which are attended with the incomprehensible phenomenon of consciousness, which is the cardinal distinction of animal from plant life. Not, however, the necessary dependence of mental as well as organic life on the interactions of the living matter with the environment, including the stimuli. This is as essential to the existence of mind as of life in its lower forms. Without the stimulus of sensation there would be no mind. There are no innate ideas.. This may be stated absolutely. There are innate capacities which, with the concurrence of the external stimuli, give rise to ideas, but without them would have remained dormant; and, although mentality may be said to be innate, yet mentation, which is the equivalent for mind, cannot exist without the other factor. If Beethoven had never heard musical sounds, he would never have had a musical idea; but hardly one in many hundred millions of human beings who hear musical sounds all their lives have the connate capacity of a Beethoven. In fact, the operation of the stimulus of the senses for the first time may be compared to conception in rousing and setting a-going a train of actions, which continue without necessary recurrence to the original stimulus for an indefinite time. Thus the word conception, as applied to ideation, may have a closer analogy with its other sense than one thinks at first. The external world, through the special senses, is not the only source of the stimulus factor, which is furnished also by the whole bodily organs, connected as they are through the nerves of organic sympathy with the cerebrum. Thus the whole body may, in one sense, be considered the seat of the mind, and the reciprocal action which takes place between the great viscera, the heart, the stomach, the liver, and the reproductive organs, form a most important feature in the moods and emotions of the mind, and, ultimately, of its pathological states. And there is another source of internal stimulation in the cerebral cells themselves, viz., memory, whereby they interact upon each other, and produce that continuity of conscious thought which distinguishes the cerebral from the sensori-motor reflex actions.* It is, however, not solely to the protoplasmic molecular positions on which memory depends that this is owing, but to their union with consciousness and to the implied knowledge which that confers. For the physical basis of memory, if we may so express ourselves, is not exclusively a mental phenomenon, but is found also in simple reflex organs, and even in organic life. And thus, in fact, we may explain the instinctive movements, desires, and intuitive thoughts which were supposed to be the stronghold of the Natural-Spiritualist theory of the mind. I have already said that the germinal faculty of the living matter is not spontaneously active, but is also under the dominion of its proper stimuli. Just as a special stimulus to any of the bodily organs may modify its nutrition, so that it shall re-act differently in its function for an indefinite time, so the proper stimuli to the sensori-motor reflex centres promotes their germinal development in such manner that, with repetition, the co-ordinated movements, at first imperfect, become at last complete; and, the thus acquired automatic activity may be defined as organised past experience. This may be termed memory without consciousness, and the same process, no doubt, explains mental memory, with the addition of the unfathomable mystery of consciousness. Now, although the organisation of past experience will account for a large part of our mental acquire * If we consider that conscious perception and ideas are always the resultant of two factors, and that this very resultant constitutes mind, it is difficult to understand how the celebrated contest about the existence of the external world can be still waged. The fallacy of the belief in a spontaneously active mind, in which the whole idea of the external world may be formed, lies in this :- 1st. That the excitation from the senses persists for a time after the stimulus is withdrawn. 2nd. The internal stimuli continue always in action. 3rd. Memory. "We believe in the existence of matter only by a process of memory, whereas this very process furnishes intuitive evidence of the existence of mind." (Fletcher.) The argument from spectral illusions is also a fallacy, for here there are always internal stimuli adequate to account for the excitation of the ideational cells, preternatural though they may be. ments, still it will not account for them all, and there still remain a number of instincts and intuitions which cannot possibly have been acquired in the life-time of the individual, and in the short time before they are displayed in perfection, although, as is shewn by the admirably ingenious experiments of Mr. Spalding, they still require some stimulus of sensation. In the chick, for example, the instinctive movements become perfect under the stimulus of sensation in less than twenty-four hours; whereas, a human child is not similarly master of its movements in as many months. In the former, it is as if a skilled musician out of practice re-acquired in a few days the skill painfully gained in as many years. Here the organisation of past experience is fixed by hereditary influence in the embryonic stage. A similar process, no doubt, takes place even in the higher faculties of man, and men of exceptional genius appear to learn as if a reminiscence was roused in them, so great is their connate aptitude for particular ideas. We are, therefore, thrown back on the hereditary organisation of past experience for this phenomenon; and as the transmission of acquired habits is a fact known to occur, we have thus an explanation of the alleged innate ideas on which the Natural-Spiritualists rest so much of their theory. And, as before said, nutrition being a kind of fissiparous generation, may we not in this see an analogy with parthenogenesis? In the hereditary organisation of past experience do we not see, in the influence of stimuli upon the plastids of certain organs and tissues, that the modification of germinal development extends into the next generation, and that thus an individual is born with the results of germinal stimulation without that stimulation, just as in parthenogenesis? It is also to be remembered that propagation by parthenogenesis and fission cannot go on to infinity, and that the cycle becomes exhausted, C |