1. For emotions we shall accept a modified James-Lange theory, supplementing it by the developments of science since their day. When a thing is seen or heard (or smelled or tasted or thought), it arouses an emotion; that emotion consists of at least three parts. First, the arousal of memories and experiences that give it a value to the individual, make it a desired object or a dreaded, distasteful object. Second, at the same time, or shortly preceding or succeeding this, a great variety of changes takes place in the organism, changes that we shall call the vaso-visceral-motor changes. This means merely that there is a series of reactions set up in the sympathetic nervous system, in the blood vessels and bodily structures they control and in the glands of internal secretion,--changes which include the blush or the pallor, the rapid heartbeat, the quickened or labored breathing, the changes in the digestive tract which include the vomiting of disgust and the diarrhoea of fear; the changes that passion brings in the male and the female and many other alterations to be discussed again. Third, there is then the feeling of these coenaesthetic changes,--a feeling of pleasantness, unpleasantness mingled with the basic feeling of excitement, and from then on that situation is linked in memory with the feeling that we usually call the emotion but which is only a part of it. Nevertheless, it becomes the part longed for or thereafter avoided; it is the value of the emotion to us, as conscious personalities, although it may be a false, disastrous, dangerous value. Excitement is the generalized mood change that results in consciousness in consequence of the vaso-visceral-motor changes of emotion; it is therefore based on bodily changes as is the feeling, pleasant or unpleasant, that also occurs. William James said that we laugh and are therefore happy; we weep and are therefore sad; the bodily changes are primary and the feeling secondary. We do not accept this dictum entirely, but we say that the organism reacts in a complicated way and that the feeling--sadness, disgust, anger, joy--springs from the memories and past experiences aroused by a situation as well as from the widespread bodily excitement also so aroused. For the neurologist both the cerebral and the sympathetic- endocrinal components of emotion are important. For the moment we turn to instinct and instinctive reactions.