[3] `The Descent of Man,' 1870, vol. ii. p. 332. The words quoted are from Professor Owen. It has lately been shown that some quadrupeds much lower in the scale than monkeys, namely Rodents, are able to produce correct musical tones: see the account of a singing Hesperomys, by the Rev. S. Lockwood, in the `American Naturalist,' vol. v. December, 1871, p. 761.
That the pitch of the voice bears some relation to certain states of feeling is tolerably clear. A person gently complaining of ill-treatment, or slightly suffering, almost always speaks in a high-pitched voice. Dogs, when a little impatient, often make a high piping note through their noses, which at once strikes us as plaintive;[4] but how difficult it is to know whether the sound is essentially plaintive, or only appears so in this particular case, from our having learnt by experience what it means! Rengger, states[5] that the monkeys (_Cebus azaroe_), which he kept in Paraguay, expressed astonishment by a half-piping, half-snarling noise; anger or impatience, by repeating the sound _hu hu_ in a deeper, grunting voice; and fright or pain, by shrill screams. On the other hand, with mankind, deep groans and high piercing screams equally express an agony of pain. Laughter maybe either high or low; so that, with adult men, as Haller long ago remarked,[6] the sound partakes of the character of the vowels (as pronounced in German) _O_ and _A_; whilst with children and women, it has more of the character of _E_ and _I_; and these latter vowel-sounds naturally have, as Helmholtz has shown, a higher pitch than the former; yet both tones of laughter equally express enjoyment or amusement.
In considering the mode in which vocal utterances express emotion, we are naturally led to inquire into the cause of what is called "expression" in music. Upon this point Mr. Litchfield, who has long attended to the subject of music, has been so kind as to give me the following remarks:--"The question, what is the essence of musical `expression' involves a number of obscure points, which, so far as I am aware, are as yet unsolved enigmas. Up to a certain point, however, any law which is found to hold as to the expression of the emotions by simple sounds must apply to the more developed mode of expression in song, which may be taken as the primary type of all music. A great part of the emotional effect of a song depends on the character of the action by which the sounds are produced. In songs, for instance, which express great vehemence of passion, the effect often chiefly depends on the forcible utterance of some one or two characteristic passages which demand great exertion of vocal force; and it will be frequently noticed that a song of this character fails of its proper effect when sung by a voice of sufficient power and range to give the characteristic passages without much exertion. This is, no doubt, the secret of the loss of effect so often produced by the transposition of a song from one key to another. The effect is thus seen to depend not merely on the actual sounds, but also in part on the nature of the action which produces the sounds. Indeed it is obvious that whenever we feel the `expression' of a song to be due to its quickness or slowness of movement-- to smoothness of flow, loudness of utterance, and so on--we are, in fact, interpreting the muscular actions which produce sound, in the same way in which we interpret muscular action generally. But this leaves unexplained the more subtle and more specific effect which we call the MUSICAL expression of the song-- the delight given by its melody, or even by the separate sounds which make up the melody. This is an effect indefinable in language-- one which, so far as I am aware, no one has been able to analyse, and which the ingenious speculation of Mr. Herbert Spencer as to the origin of music leaves quite unexplained. For it is certain that the MELODIC effect of a series of sounds does not depend in the least on their loudness or softness, or on their ABSOLUTE pitch. A tune is always the same tune, whether it is sung loudly or softly, by a child or a man; whether it is played on a flute or on a trombone. The purely musical effect of any sound depends on its place in what is technically called a `scale;' the same sound producing absolutely different effects on the ear, according as it is heard in connection with one or another series of sounds.