* * * * * [Page 75.] The heart will be all the more readily affected through habitual associations, as it is not under the control of the will. A man when moderately angry, or even when enraged, may command the movements of his body, but he can not prevent his heart from beating rapidly. His chest will, perhaps, give a few heaves, and his nostrils just quiver, for the movements of respiration are only in part voluntary. In like manner, those muscles of the face which are least obedient to the will will sometimes alone betray a slight and passing emotion. The glands, again, are wholly independent of the will, and a man suffering from grief may command his features, but can not always prevent the tears from coming into his eyes. A hungry man, if tempting food is placed before him, may not show his hunger by any outward gesture, but he can not check the secretion of saliva. * * * * * [Page 77.] With all, or almost all, animals, even with birds, terror causes the body to tremble. The skin becomes pale, sweat breaks out, and the hair bristles. * * * * * [Page 79.] A physician once remarked to me, as a proof of the exciting nature of anger, that a man when excessively jaded will sometimes invent imaginary offenses, and put himself into a passion, unconsciously, for the sake of reinvigorating himself; and, since hearing this remark, I have occasionally recognized its full truth. * * * * * [Page 81.] Exertion stimulates the heart, and this reacts on the brain, and aids the mind to bear its heavy load. XIII. MEANS OF THE EXPRESSION OF THE EMOTIONS. VOCAL ORGANS. [Expression of the Emotions, page 83.] With many kinds of animals, man included, the vocal organs are efficient in the highest degree as a means of expression. We have seen in the last chapter that, when the sensorium is strongly excited, the muscles of the body are generally thrown into violent action; and, as a consequence, loud sounds are uttered, however silent the animal may generally be, and although the sounds may be of no use. Hares and rabbits, for instance, never, I believe, use their vocal organs, except in the extremity of suffering; as, when a wounded hare is killed by the sportsman, or when a young rabbit is caught by a stoat. Cattle and horses suffer great pain in silence, but when this is excessive, and especially when associated with terror, they utter fearful sounds. * * * * * [Page 87.]