of a whole, which we may or may not fail to analyse, whereas in dissonance we are aware of a disconnected plurality which we cannot combine. Can this difference be explained?

Analytical psychology at all events seems to furnish no clue, but genetic psychology, based upon it, perhaps may do so. In the first place it is to be remembered that normal experience is and always has been confined to clangs or complex tones: the approximately simple tones that are now artificially produced in our laboratories and elsewhere lie altogether beyond it. We may, then, reasonably suspect the earlier and commoner experience that of the consonance or dissonance of complex tones-to be the clue we are seeking to this consonance or dissonance of simple tones, which is so nearly akin to an ideal. Suppose it were possible to cure a man born stonedeaf and to restrict his first experiences of sound to simple tones, would he distinguish between consonance and dissonance as we do? This crucial question we have no means of definitely answering. But, as Hensen has well said1, we should expect that he would have to learn to hear just as if born blind and cured he would have to learn to see. Bearing in mind the actual course of our auditory experience, we have, in the second place, to note the similarity in structure between a single harmonic clang and two consonant tones or clangs: the partial tones of the one may exhibit all the degrees of consonance possible to the other two; and the more perfect the consonance the closer the resemblance. Here then is an adequate basis for the assimilation of the latter, whether they be simple or complex, to the former. An inharmonic clang-which is characterized by its obtrusive beats-approximates more or less to a medley of tones; and so, here again a basis is provided for the assimilation of two dissonant clangs to such a complex tone. But if it be verily true that simple tones sounded together can be perceived not merely as diverse but as dissonant, even when beats are altogether excluded, it is difficult to see how genetic psychology can account for this. If however it be true that such dissonance is only detected by musical experts, it may be argued

1 Hensen, Physiologie des Gehörs, Hermann's Handbuch, III. ii. p. 27.

2 Cf. Max Meyer, Zeitschr. f. Psych. xvii. (1898), p. 413; Krueger, Meumann's Archiv f. d. gesammte Psych. ii. (1904), pp. 42 f.; Wundt's Psych. Studien, iv. (1909), pp. 226 ff.; C. S. Myers, Textbook of Experimental Psychology, 1911, p. 55.

that their judgment in this case is mediate or inferential, not immediate or sensory: the difficulty would then disappear. And on the whole facts seem to bear out this supposition'.

The psychological connexion between noises and tones has long been a keenly controverted topic. The physical relation of the two is clear enough: noises here, it is allowed, are complexes of pendular vibrations and so presuppose these. But to assume that the like holds good psychologically, that noises, like clangs, must be true complexes, is certainly a mistake. Fish and frogs have no 'ear for music' yet they are not deaf. The biological evidence for the differentiation of tones from sound is quite as conclusive as that for the differentiation of sounds from touch. In the higher vertebrates the auditory apparatus is more complicated, but certain elementary structures comparable to rattles and found even among the invertebrates, still persist. What function have these? Among others the perception of sound, it is maintained, but not the discrimination of tone, for which they are not adapted. If cases were forthcoming in which the discrimination of tones was lost while the perception of noise was retained, or vice versa, such positive evidence would be conclusive. Throughout an immense record, however, not a single clear case of this sort is to be found. But this negative evidence is not equally conclusive, especially not in view of repeated instances of serious defects on the one side without corresponding defects on the other2. And when the continuity of the organ of hearing is taken into account this is perhaps all that we ought to expect; save that a defective sense for tones might be looked for more frequently if such sense is later in development and correlated to a more complex and differentiated structure, as is here maintained. It is true that numerous gradations between noises and clangs are perceptible to human beings. This however is scarcely to the point, the physiologist could reply, for we have the requisite resonatory apparatus. But even a so-called 'momentary noise,' such as that of an electric spark or the thud of a steam hammer, still has some pitch: so it is said, but the statement is very questionable.

1 Cf. Helmholtz, Tonempfindungen, 4th edn., pp. 328 ff. Helmholtz's statements have been questioned, but it is doubtful whether they have been satisfactorily answered.

* Cf. Stumpf, Tonpsychologie, i. p. 402.

So far as the impression is verily momentary and single, so far the difference of 'high' or 'low' seems far more like a difference of extensity than a difference of pitch. Again the physiologist could reply that a single impulse could not, and in fact does not, give rise to a tone. If now it be objected that there simple noises, it is enough to

are no instantaneous, single, and remark that the nearer we approach to such a limit the more the explosive character predominates. That most of our auditory sensations are complexes of noises and tones is unquestioned'.

One such complex of special interest is human speech. In this the consonants are almost pure noises whereas the vowels approximate to tones, so much so indeed as to lead some recent writers to identify the two. In that case however the vowels should form a linear continuum as the tones do. On the contrary, as it is in many ways interesting to notice, the vowels are pretty definitely correlated only to certain fixed points in the tone-continuum, points moreover which together form a series of octaves-their order being u, o, a, e, i (as pronounced on the continent). This is exemplified in many onomatopoeic names for sounds or for the creatures producing them. It is also generally, perhaps always, true that the creatures voluntarily producing the most varied sounds have the most complicated organs of hearing—a fact which confirms the biological evidence for the differentiation of tonal sensations from noises3.

The Lower Senses.

§ 7. Unlike the higher senses of sight and hearing, the lower senses of touch, taste, smell, warmth, &c., do not constitute qualitative continua. 'Temperatures' may indeed be represented as

1 Cf. v. Hensen, Arch. f. Ohrenheilk. xiii. (1886), pp. 69 ff.; Stumpf, Tonpsychol. ii. § 28.

2 Cf. the investigations carried out in Stumpf's laboratory by Köhler, Zeitschr. f. Psych. liv. (1910), pp. 241 ff., lviii. (1911), pp. 59 ff.

3 À propos of this connexion between the production and the perception of tone a suggestion of Külpe's is worth mentioning. Notwithstanding the greater difference in pitch between the two tones of a given interval in a higher octave as compared with a lower one, musical people-unlike the unmusical-regard the equality of both cases as a matter of course, and that it by no means is. It becomes however more comprehensible if we suppose that difference in the adjustment of the vocal chords in singing the said interval is in both cases the same. Cf. Külpe, Grundriss der Psychologie, 1893, p. 110; also Stumpf, Tonpsychologie, i. pp. 339 ff.

ranging in opposite directions between a zero of no sensation and the organic sensations due to the destructive action at both extremes of heat and cold alike. But the continuity in each direction in this case is intensive rather than qualitative. Tastes fall into the four distinct qualities known as sweet, sour, bitter, saline; but smells hardly admit of classification at all.

Unlike the higher senses again, these lower senses frequently yield sensation-complexes from two or more of them: in a draught of mulled claret, for example, we can discriminate various 'flavours' as well as 'aroma,' astringence, and warmth. Their treatment in detail, however, is for the most part mainly of interest to the physiologist; though there are one or two points calling for our notice in the case of touch and 'temperature.' Noteworthy first of all is their close connexion with, we might almost say their primary inclusion within, the general sensibility—as we have already remarked à propos of the ambiguity of the term 'feeling1. So when differentiated as specific senses, even in perception they are still beset with a certain ambiguity because of the peculiar share of the body itself in 'the physical basis' of their stimuli. Thus when I say I feel warm or cold, I refer to a certain state of my body, with which I so far identify myself. But when we talk of specific sensations of temperature such language has not the passable accuracy there is in talking of a specific sensation of red. What is meant is neither a state of the body alone nor a state of the environment alone, but a varying relation between the two. As Locke and Berkeley remarked-and indeed the ancient sceptics long before them-water of a given temperature 'sensed' as warm by one hand may be 'sensed' as cool by the other. For the stimulus is not a temperature at all but a loss or gain of heat, and the intensity of the sensation depends on the rate of such loss or gain. But there is a further relativity still. The zero or indifference point at which there is neither loss nor gain of heat, or-to be more accurate-where the temperature is steady, varies considerably for different parts of the body. A like local

1 Cf. above, ch. ii, § 3, p. 41.

2 The temperature of exposed parts of the body is usually considerably lower than that of the rest, but there is still no sense of heat or cold unless it is raised or lowered; and after a fall of temperature there is a sensation of cold till the indifference point is regained though all the while the temperature is rising, and vice versa after a rise of

relativity, as we might call it, pertains in a far higher degree to the sense of touch and is peculiar to these two senses, since they alone have an organ, the skin, coextensive with the whole superficies of the body: we shall have presently to consider it further under the title of 'local signs.' Again the imperfect differentiation that makes it inaccurate to describe the one sense as presenting temperature also makes it inaccurate to speak of the other as presenting pressure. The 'adequate stimulus,' to put the matter physiologically and here most simply, is not necessarily mechanical pressure: the same sensation may be the concomitant of either pressure or tension1.

Still less sharply differentiated from the general sensibility or coenaesthesis are the many very various sensations which are classed together as 'organic,' because we come later to refer most of them to states of one or other of the internal organs, as with hunger, thirst, dyspnoea, for example; though some, as exhilaration or depression, are referred rather to the bodily state as a whole. But the two are in fact inseparable, in so far as the healthy working or otherwise of any organ tends to increase or decrease the general sense of bodily comfort. In other respects too these so-called organic sensations are extremely complex and difficult to analyse: they seem usually to be not only complexes of simpler sensations but to involve reflex actions as well. They are nevertheless very important, and we shall have to deal with them again in other connexions later on.

Movement.

§ 8. Closely allied to organic sensations are the sensations that we at first normally experience only when we react to such sensations as are given: they belong to the active as distinct from the passive or receptive side of experience, but are none the less in themselves sensory. Like organic sensations they are usually complexes, but are more readily analysed-so to temperature. But, if the change persists, a new indifference point ensues in consequence of adaptation. The 'subjective' relativity is thus altogether very great.

1 Cf. T. Thunberg's article, Nagel's Handbuch der Physiologie, 1907, iii. p. 658. 2 Experimental psychology has already begun to throw some light on this intricate subject. The following are worth consulting:-Articles by E. Meumann, Archiv f. die ges. Psychol. ix. (1907), pp. 26 ff.; xiv. (1909), pp. 279 ff.; and by F. E. O. Schultze, xi. (1908), pp. 147 ff.