Those associations which have physical expression are of importance only in particular cases. For example, the feeling of ants all over the body when you think that you have been near an anthill, or the feeling of physical pain on hearing the description of wounds. It is exceedingly funny to see how, during the lectures of dermatologists, the whole audience scratches that part of the body which is troubling the patient who is being described.
Such associations may be legally valuable in so far as the accused who plead innocence make unconscious movements which imply the denied wounds. In any event, it is necessary to be cautious because frequently the merely accurate description of a wound may bring about the same effect in nervous persons as the sight of that wound. If, however, the wound is not described and even its place not mentioned, and only the general harm is spoken of, then if the accused reaches for that part of his body in which the wound of his victim is located, you have a clew, and your attention should be directed upon it. Such an index is worth no more, but even as a clew it has some value.
All in all, we may say that the legally significant direction of association falls in the same class with “getting an idea.” We need association for the purpose of constructing an image and an explanation of the event in question; something must “occur to us.” We must “get an idea,” if we are to know how something happened. We need association, moreover, in order to discover that something has occurred to the witness.
“Getting an idea” or “occurrence” is essentially one and the same in all its forms. We have only to study its several manifestations:
1. “Constructive occurrence,” by means of which the correct thing may possibly be discovered in the way of combining, inferring, comparing and testing. Here the association must be intentional and such ideas must be brought to a fixed image, which may be in such wise associated with them as to make a result possible. Suppose, e.g., that the case is one of arson, and the criminal is unknown. Then we will require the plaintiff to make local, temporal, identifying, and contrasting associations with the idea of all and each of his enemies, or of discharged servants, beggars, etc. In this wise we can attain to other ideas, which may help us to approach some definite theory.