THE object of this paper is, to examine the physical accompaniments of mental action, and, chiefly, to discuss the nature of the feelings or emotions which accompany the various conditions of body and mind; in fact, to lay down the theory that feeling (or emotion, which is another name for high and complex feeling) is the state which accompanies the excitation of a nerve centre or centres, being pleasant or painful according to the condition of the centre, or the intensity of the excitation.
Supposing this view to be correct, there is no need to allot one place in the brain to the intellectual and another to the emotional portion of the mind, neither can we discuss them apart. The intellectual or idea function, the thinking and working function of the mind, may be supposed to depend on the intercommunication of the nerve cells or centres of the entire hemispheres, carried on by means of the nerve- fibres, this interaction being accompanied by a feeling or emotion peculiar to the centres acting, but which varies according to their physical state at the moment of excitation, or that produced by the excitation itself.
That the cells, which in their aggregation make up what we call nerve-centres, vary immensely in their endowments and qualities, is a fact which probably few will dispute. We have centres of vision, centres of hearing, centres of taste and smell: the nerve-cells which form the intellectual centres of one who comes of a Ions: line of educated and cultivated forefathers will differ from those of a descendant of Bushmen, even before they have been submitted to the influence of education. But, besides the special quality or endowment which each cell possesses, that quality which constitutes one a cell and centre of vision, as distinguished from another which is a centre of hearing, there is in each a varying state or condition on which depends its efficiency, its power of perceiving more or less accurately that which is presented to it, or of communicating with other centres of idea or motion. This condition will be influenced by a number of circumstances—by due nutrition, by heat or cold, rest or fatigue; but, according to it will be the efficiency or non-efficiency of the cell-function: by it, moreover, will be regulated, as I conceive, the pleasure or pain experienced when the cells are called into action. When the condition is sound and healthy, the function of the cells will be duly performed, and, in the due performance, pleasure, not pain, will be experienced. In other words, the supply of nerve-force being ample, the cells will energize pleasantly: when the nerve-force is insufficiently produced, or