An idea may become the starting point of a host of associations. The word "Rome" can call up a hundred. Why is one called up rather than another, and at such a moment rather than at another? There are some associations based on contiguity and on resemblance which one may foresee, but how about the rest? Here is an idea _A_; it is the center of a network; it can radiate in all directions--_B, C, D, E, F, etc._ Why does it call up now _B_, later _F_? It is because every image is comparable to a force, which may pass from the latent to the active condition, and in this process may be reinforced or checked by other images. There are simultaneous and inhibitory tendencies. _B_ is in a state of tension and _C_ is not; or it may be that _D_ exerts an arresting influence on _C_. Consequently _C_ cannot prevail. But an hour later conditions have changed and victory rests with _C_. This phenomenon rests on a physiological basis: the existence of several currents diffusing themselves through the brain and the possibility of receiving simultaneous excitations.[24] A few examples will make plainer this phenomenon of reinforcement, in consequence of which an association prevails. Wahle reports that the Gothic _Hotel de Ville_, near his house, had never suggested to him the idea of the Doges' Palace at Venice, in spite of certain architectural likenesses, until a certain day when this idea broke upon him with much clearness. He then recalled that two hours before he had observed a lady wearing a beautiful brooch in the form of a gondola. Sully rightly remarks that it is much easier to recall the words of a foreign language when we return from the country where it is spoken than when we have lived a long time in our own, because the tendency toward recollection is reinforced by the recent experience of the words heard, spoken, read, and a whole array of latent dispositions that work in the same direction. In my opinion we would find the finest examples of "constellation," regarded as a creative element, in studying the formation and development of myths. Everywhere and always man has had for material scarcely anything save natural phenomena--the sky, land, water, stars, storms, wind, seasons, life, death, etc. On each of these themes he builds thousands of explanatory stories, which vary from the grandly imposing to the laughably childish. Every myth is the work of a human group which has worked according to the tendencies of its special genius under the influence of various stages of intellectual culture. No process is richer in resources, of freer turn, or more apt to give what every inventor promises--the novel and unexpected.