=Systematized Complexes.= In contrast with the limited group of fixed ideas, organized with one or more emotions (i.e., instincts) I have been describing, are the large _systems_ of complexes or associated experiences which become organized and fairly distinctly differentiated in the course of the development of every one’s personality. In many, at least, of these systems there will be found a predominant emotion and certain instinctive tendencies, and a predominant feeling tone—of pleasure or pain, of exaltation or depression, etc. It is quite possible that careful investigation would disclose that it is this conflicting affective force which is responsible for the differentiation of one system from another with opposing affects and tendencies. The differentiation of such systematized complexes is of considerable practical importance for normal and abnormal personality. Among such systems may here be mentioned those which are related to certain _subjects_ or departments of human experience, or are related in _time_, or to certain dispositions or _moods_ of the individual. The first may be called _subject_ systems, the second _chronological_ systems, and the last _mood_ systems. 1. _Subject systems_: I find myself interested, for instance, in several fields of human knowledge; (a) abnormal psychology; (b) public franchises; (c) yachting; (d) local politics; (e) business affairs. To each of these I give a large amount of thought, accumulate many data belonging to each, and devote a considerable amount of active work to carrying into effect my ideas in each field. Five large systems are thus formed, each consisting of facts, opinions, memories, experiences, etc., distinct from those belonging to the others. To each there is an emotion and a feeling tone which have more or less distinctive qualities; these coming from the intellectual interest of abnormal psychology differing qualitatively from those of the “joy of battle” excited by a public contest with a railroad corporation or gas company, as it does from that of the exhilarating sport of a yacht race, or from the annoying and rather depressing care of business interests; and so on.