rge and terrible as possible。 Rival males try to excel and challenge each other by their voices； and this leads to deadly contests。 Thus the use of the voice will have become associated with the emotion of anger； however it may be aroused。 We have also seen that intense pain； like rage； leads to violent outcries； and the exertion of screaming by itself gives some relief； and thus the use of the voice will have become associated with suffering of any kind。
The cause of widely different sounds being uttered under different emotions and sensations is a very obscure subject。 Nor does the rule always hold good that there is any marked difference。 For instance with the dog； the bark of anger and that of joy do not differ much； though they can be distinguished。 It is not probable that any precise explanation of the cause or source of each particular sound； under different states of the mind； will ever be given。 We now that some animals； after being domesticated； have acquired the habit of uttering sounds which were not natural to them。＇1＇ Thus domestic dogs； and even tamed jackals； have learnt to bark； which is a noise not proper to any species of the genus； with the exception of the _Canis latrans_ of North America； which is said to bark。 Some breeds； also； of the domestic pigeon have learnt to coo in a new and quite peculiar manner。
The character of the human voice； under the influence of various emotions； has been discussed by Mr。 Herbert Spencer＇2＇ in his interesting essay on Music。 He clearly shows that the voice alters much under different conditions； in loudness and in quality； that is； in resonance and _timbre_； in pitch and intervals。 No one can listen to an eloquent orator or preacher； or to a man calling angrily to another； or to one expressing astonishment； without being struck with the truth of Mr。 Spencer's remarks。 It is curious how early in life the modulation of the voice becomes expressive。 With one of my children； under the age of two years； I clearly perceived that his humph of assent was rendered by a slight modulation strongly emphatic； and that by a peculiar whine his negative expressed obstinate determination。 Mr。 Spencer further shows that emotional speech； in all the above respects is intimately related to vocal music； and consequently to instrumental music； and he attempts to explain the characteristic qualities of both on physiological groundsnamely； on 〃the general law that a feeling is a stimulus to muscular action。〃 It may be admitted that the voice is affected through this law； but the explanation appears to me too general and vague to throw much light on the various differences； with the exception of that of loudness； between ordinary speech and emotional speech； or singing。
＇1＇ See the evidence on this head in my ‘Variation of Animals and Plants under Domestication；' vol。 i。 p。 27。 On the cooing of pigeons； vol。 i。 pp。 154； 155。
＇2＇ ‘Essays； Scientific； Political； and Speculative；' 1858。 ‘The Origin and Function of Music；' p。 359。
This remark holds good； whether we believe that the various qualities of the voice originated in speaking under the excitement of strong feelings； and that these qualities have subsequently been transferred to vocal music； or whether we believe； as I maintain； that the habit of uttering musical sounds was first developed； as a means of courtship； in the early progenitors of man； and thus became associated with the strongest emotions of which they were capable；namely； ardent love； rivalry and triumph。 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 halftones； so that this monkey 〃alone of brute mammals may be said to sing。〃＇3＇ 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。 We can plainly perceive； with some of the lower animals； that the males employ their voices to please the females； and that they themselves take pleasure in their own vocal utterances； but why particular sounds are uttered； and why these give pleasure cannot at present be explained。
＇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 onwe 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。
＇4＇ Mr。 Tylor （‘Primitive Culture；' 1871； vol。 i。 p。 166）； in his discussion on this subject； alludes to the whining of the dog。
＇5＇ ‘Naturgeschichte der Saugethiere von Paraguay；' 1830； s。 46。
＇6＇ Quoted by Gratiolet； ‘De la Physionomie；' 1865； p。 115。
〃It is on this RELATIVE association of the sounds that all the essentially characteristic effects which are summed up in the phrase ‘musical expression；' depend。 But why certain associations of sounds have such…and…such effects； is a problem which yet remains to be solved。 These effects must indeed； in some way or other； be connected with the well…known arithmetical relations between the rates of vibration of the sounds which form a musical scale。 And it is possiblebut this is merely a suggestionthat the greater or less mechanical facility with which the vibrating apparatus of the human larynx passes from one state of vibration to another； may have been a primary cause of the greater or less pleasure produced by various sequences of sounds。〃
But leaving aside these complex questions and confining ourselves to the simpler sounds； we can； at least； see some reasons for the association of certain kinds of sounds with certain states of mind。 A scream； for instance； uttered by a young animal； or by one of the members of a community； as a call for assistance； will naturally be loud； prolonged； and high；