It is a well-known fact that if an ant be removed from a nest and afterward put back it will not be attacked, while almost invariably an ant belonging to another nest will be attacked. It has been customary to use the words memory, enmity, friendship, in describing this fact. Now Bethe made the following experiment. An ant was placed in the liquids (blood and lymph) squeezed out from the bodies of nest companions and was then put back into its nest; it was not attacked. It was then put in the juice taken from the inmates of a “hostile” nest, and was at once attacked and killed.[14] A further instance of the manner in which ants communicate will illustrate how simple and automatic communication may become on the instinctive level. An ant, when taking a new direction from the nest for the first time, always returns by the same path. This shows that some trace must be left behind which serves as a guide back to the nest. If an ant returning by this path bears no spoils, Bethe found that no other ants try this direction. But if it bring back honey or sugar, other ants are sure to try the path. Hence something of the substances carried over this path by the ants must remain on the path. These substances must be strong enough to affect the ants chemically.[15] The important fact is that by means of this comparatively simple device corporate action is made possible. Individuals not only react upon one another in this reflex way, but they inevitably communicate their sentiments, attitudes, and organic excitements, and in doing so they necessarily react, not merely to what each individual actually does, but to what he intends, desires, or hopes to do. The fact that individuals often betray sentiments and attitudes to others of which they are themselves only dimly conscious makes it possible for individual A, for example, to act upon motives and tensions in B as soon, or even before, B is able to do so. Furthermore, A may act upon the suggestions that emanate from B without himself being clearly conscious of the source from which his motives spring. So subtle and intimate may the reactions be which control individuals who are bound together in a social-psychological process. It is upon the basis of this sort of instinctive and spontaneous control that every more formal sort of control must be based in order to be effective. Changes in the form of social control may for the purposes of investigation be grouped under the general heads: 1. The substitution of positive law for custom, and the extension of municipal control to activities that were formerly left to individual initiative and discretion.