There are some very important phases of excitement that have not been given sufficient weight in most of the discussions. 1. In the very young, excitement is diffuse and spreads throughout the organism. An infant starts with a jump at a sudden sound and shivers at a bright light. A young child is unrestrained and general in his expression of excitement, no matter what emotional direction that excitement takes. Bring about any tension of expectation in a child--have him wait for your head to appear around the corner as you play peek-a-boo, or delay opening the box of candy, or pretend you are one thing or another--and the excitement of the child is manifested in what is known as eagerness. Attention in children is accompanied by excitement and is wearying as a natural result, since excitement, means a physical discharge of energy. A child laughs all over and weeps with his entire body; his anger involves every muscle of his body and his fear is an explosion. The young organism cannot inhibit excitement. As life goes on, the capacity for localizing or limiting excitement increases. We become better organized, and the disrupting force of a stimulus becomes less. Attention becomes less painful, less tense, i.e., there is less general muscular and emotional reaction. Expectation is less a physical matter--perhaps because we have been so often disappointed--and is more cerebral and the emotions are more reflective and introspective in their expression and less a physical outburst. Indeed, the process often enough goes too far, and we long for the excitement of anticipation and realization. We do not start at a noise, and though a great crowd will "stir our blood" (excitement popularly phrased and accurately), we still limit that excitement so that though we cheer or shout there is a core of us that is quiet. This is the case in health. In sickness, especially in that condition known as neurasthenia, where the main symptoms cluster around an abnormal liability to fatigue, and also in many other conditions, there is an increase in the diffusion of excitement so that one starts all over at a noise, instead of merely turning to see what it is, so that expectation and attention become painful and fatiguing. Crowds, though usually pleasurable, become too exciting, and there is a sort of confusion resulting because attention and comprehension are interfered with. The neurasthenic finds himself a prey to stimuli, his reaction is too great and he fatigues too readily. He finds sleep difficult because the little noises and discomforts make difficult the relaxation that is so important. The neurasthenic's voluntary attention is lowered because of the excitement he feels when his involuntary attention is aroused.