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.
That animals utter musical notes is familiar to every one, as we may daily hear in the singing of birds. It is a more remarkable fact that an ape, one of the Gibbons, produces an exact octave of musical sounds, ascending and descending the scale by half-tones; so that this monkey, “alone of brute mammals, may be said to sing.” From this fact, and from the analogy of other animals, I have been led to infer that the progenitors of man probably uttered musical tones before they had acquired the power of articulate speech; and that, consequently, when the voice is used under any strong emotion, it tends to assume, through the principle of association, a musical character.