Now this exciting gesticulation can be very easily observed, but the observation must not come too late. If the witness is once quite lost in it and sufficiently excited by the concomitant speeches he will make his gestures well and naturally and the artificial and untrue will not be discoverable. But this is not the case in the beginning; then his gestures are actually not skilful, and at that point a definite force of will and rather notable exaggerations are observable; the gestures go further than the words, and that is a matter not difficult to recognize. As soon as the recognition is made it becomes necessary to examine whether a certain congruity invariably manifests itself between word and gesture, inasmuch as with many people the above-mentioned lack of congruity is habitual and honest. This is particularly the case with people who are somewhat theatrical and hence gesticulate too much. But if word and gesture soon conform one to another, especially after a rather lively presentation, you may be certain that the subject has skilfully worked himself into his alarm or whatever it is he wanted to manifest. Quite apart from the importance of seeing such a matter clearly the interest of the work is a rich reward for the labor involved. In close relation to these phenomena is the change of color to which unfortunately great importance is often assigned.[77] In this regard paling has received less general attention because it is more rare and less suspicious. That it can not be simulated, as is frequently asserted in discussions of simulation (especially of epilepsy), is not true, inasmuch as there exists an especial physiological process which succeeds in causing pallor artificially. In that experiment the chest is very forcibly contracted, the glottis is closed and the muscles used in inspiration are contracted. This matter has no practical value for us, on the one hand, because the trick is always involved with lively and obvious efforts, and on the other, because cases are hardly thinkable in which a man will produce artificial pallor in the court where it can not be of any use to him. The one possibility of use is in the simulation of epilepsy, and in such a case the trick can not be played because of the necessary falling to the ground. Paling depends, as is well known, on the cramp of the muscles of the veins, which contract and so cause a narrowing of their bore which hinders the flow of blood. But such cramps happen only in cases of considerable anger, fear, pain, trepidation, rage; in short, in cases of excitement that nobody ever has reason to simulate. Paling has no value in differentiation inasmuch as a man might grow pale in the face through fear of being unmasked or in rage at unjust suspicion.