ABSTRACT
Struggle, either by defence or attack, for self-preservation from aggression is as old as man, or, indeed, as life. In biology the term Struggle means resistance to all sorts of factors that menace the existence-struggle against the forces of Nature, against storms, sickness, etc.; in a narrower sense the term indicates a reaction against more or less sudden dangers from living beings. In association with other excitations, especially visual ones, but also sonorous or tactile, it takes a form which is translated into our language by the term Menace. The phenomena involved are known in biology as fascination and mimicry for terrorization. The emotion of fear, which may be defined with precision from the physiological point of view, and of which the characteristics may be objectively registered, and may be produced at will, is a necessary element of struggle and especially of menace.
