This also fits in with the not as yet understood fact that the concurrence of fear with mechanical shaking produces the severest hysterical forms of traumatic neurosis.  It may at least be assumed that inasmuch as even a slight intensity of these influences becomes a source of sexual excitement, the action of an excessive amount of the same will produce a profound disorder in the sexual mechanism.

Muscular Activity.—­It is well known that the child has need for strong muscular activity, from the gratification of which it draws extraordinary pleasure.  Whether this pleasure has anything to do with sexuality, whether it includes in itself sexual satisfaction? or can be the occasion of sexual excitement; all this may be refuted by critical consideration, which will probably be directed also to the position taken above that the pleasure in the sensations of passive movement are of sexual character or that they are sexually exciting.  The fact remains, however, that a number of persons report that they experienced the first signs of excitement in their genitals during fighting or wrestling with playmates, in which situation, besides the general muscular exertion, there is an intensive contact with the opponent’s skin which also becomes effective.  The desire for muscular contest with a definite person, like the desire for word contest in later years, is a good sign that the object selection has been directed toward this person.  “Was sich liebt, das neckt sich."[21] In the promotion of sexual excitement through muscular activity we might recognize one of the sources of the sadistic impulse.  The infantile connection between fighting and sexual excitement acts in many persons as a determinant for the future preferred course of their sexual impulse.[22]

Affective Processes.—­The other sources of sexual excitement in the child are open to less doubt.  Through contemporary observations, as well as through later investigations, it is easy to ascertain that all more intensive affective processes, even excitements of a terrifying nature, encroach upon sexuality; this can at all events furnish us with a contribution to the understanding of the pathogenic action of such emotions.  In the school child, fear of a coming examination or exertion expended in the solution of a difficult task can become significant for the breaking through of sexual manifestations as well as for his relations to the school, inasmuch as under such excitements a sensation often occurs urging him to touch the genitals, or leading to a pollution-like process with all its disagreeable consequences.  The behavior of children at school, which is so often mysterious to the teacher, ought surely to be considered in relation with their germinating sexuality.  The sexually-exciting influence of some painful affects, such as fear, shuddering, and horror, is felt by a great many people throughout life and readily explains why so many seek opportunities to experience such sensations, provided that certain accessory circumstances (as under imaginary circumstances in reading, or in the theater) suppress the earnestness of the painful feeling.