Finally, in certain cases the emotional development is completely detached from the other, and even in advance of it; this is direct evolution. Feeling, as has been said, is the pioneer of knowledge—_i.e._, it sometimes involves a confused knowledge; it is the anticipation of an ideal. In this case it is not an idea which excites a feeling, but the development of a feeling which ends by taking concrete form in an idea; its source is in the temperament and the character. The theory of evolution has familiarised us with the notion of spontaneous variations in animals and plants. This phenomenon is also found in psychology—in the intellectual order, in the emotional order, in the order of action. We are too much inclined to believe that inventors, revealers, initiators, exist only in the region of knowledge or activity; but in the region of feeling, too, there are spontaneous variations, both serviceable and injurious. If there are original ways of thinking, there are also original ways of feeling, which impose themselves on others, create a contagion. We shall find examples of this in abundance, for these “variations” have played a great part, especially in the evolution of the moral sentiment. These remarks are of too general a character, but will be supplemented later on, when we come to study each form of emotion in its turn. Such is the object of our second part. It will consist of a series of monographs of varying length. Except for a general survey of the law which seems to govern the dissolution of the feelings, their pathology will not be treated in a special section, but will be distributed throughout the work, terminating the study of each normal form, but only in such measure as will serve to render their nature more comprehensible, in which case it partakes of the character of psychology. II. Before setting out on our journey we must map out our route. At the beginning of this work I presented the reader with a general survey of the emotional life; it will be necessary to return to this subject in a briefer, more precise, and more limited manner. Since complex emotions are derived from simple emotions, and the latter from needs and instincts, whether satisfied or thwarted, from tendencies which are the direct and immediate expression of our physical and mental constitution; since the irreducible element is a motor phenomenon, actual or virtual, realised or in a nascent condition, it is indispensable to draw up a list of those primitive tendencies or instincts which are the roots of emotion.