Institutio Oratoria

One of the commonest of all the gestures consists in placing the middle finger against the thumb and extending the remaining three: it is suitable to the exordum, the hand being moved forward with an easy motion a little distance both to right and left, while the head and shoulders gradually follow the direction of the gesture. It is also useful in the statement of facts, but in that case the hand must be moved with firmness and a little further forward, while, if we are reproaching or refuting our adversary, the same movement may be employed with some vehemence and energy, since such passages permit of greater freedom of extension.

On the other hand, this same gesture is often directed sideways towards the left shoulder: this is a mistake, although it is a still worse fault to thrust the arm across the chest and gesticulate with the elbow. The middle and third fingers are also sometimes turned under the thumb, producing a still more forcible effect than the gesture previously described, but not well adapted for use in the exordium or state-