tone of the venous system, are both related to a moderate amount of muscular exercise, and these are all largely facts in the hygiene of the brain.
5. Muscular contraction appears to be closely related to the genesis of all forms of psychic activity. Not only do the vaso-motor and muscular systems express the thinking, feeling, and willing of the individual, but the muscular apparatus itself appears to be a fundamental part of the apparatus for these psychical states. Without the muscular system, material for psychic activity can not be secured. All three of these processes—thinking, feeling, willing—are more or less remotely connected with a rehearsal in the body, both neural and muscular, of the acts by which the original material for the mental process came in. As President Hall puts it, we think in terms of muscular action, more or less remote, and all the parts that were concerned in the original activities are more or less active in the thought. Nerve currents are constantly going to muscles and coming from sense organs, all being a part of the thinking apparatus. If this is true, the fullness of the neuro-muscular experiences during early life would appear to be related to the opportunity of later psychic range. This is borne out by the fact that both in animals and in men, taken at large, the scale of intelligence corresponds to the scale of wideness of range in muscular co-ordinations. The more complicated the neuro-muscular apparatus, the higher the intelligence. It is true that in the individual life we profit mainly by our racial inheritance of all these complicated mechanisms, but even here we may expect to find that the individuals who live a rich psychic life have been, on the whole, those who during early life have had the rich and full experience in regard to muscular co-ordinations. It is not, however, merely in terms of intellect that the muscular system is important. The sensibilities, or feelings, or emotions, are definitely related both to muscular and to visceral states. We are accustomed to think of the expression of the body, particularly the expression of the face, as merely the outward manifestation of the inward state. The modern psychology, however, is telling us that this muscular contraction is a necessary part of the feeling itself, and that where the muscular expression of the feeling can be inhibited, the feeling itself is not the same. Rage is not rage until it expresses itself in muscular action of some form. It may be merely in the stiffening of the whole body, the clinching of the hands, or holding the jaws firmly together. Here, again, do we find the richness of feeling associated without exception in races with a fine development of the neuro-muscular and vaso-motor systems. This is related to muscular exercise. When we come to the regal faculty, the will, our modern psychology again tells us that will must express
