• THE 
 
 ENGLISH AND FOREIGN 
 
 PHILOSOPHICAL LIBRARY. 
 
 VOLUME XIV.
 
 Los Angeles, Cal. 
 
 THE COLOUE-SENSE: 
 
 Its (25rtgtn anH aDeUelopment. 
 
 AN ESSAY IN COMPARATIVE PSYCHOLOGY. 
 
 BY 
 
 GKANT ALLEN, B.A. 
 
 AUTHOR OK "physiological AiSTHKTlCS." 
 
 BOSTON: 
 
 HOUGHTON, OSGOOD, & COMPANY. 
 
 1879.
 
 4tei 
 
 1^0 
 
 /<?71 
 
 PREFACE. 
 
 The materials which form the nucleus of the present 
 volume were originally collected as part of the basis for a 
 chapter on " the Genesis of Esthetics " in my little work 
 on " Physiological Esthetics," published some two years 
 since. I found, however, when I came to arrange them, 
 that the subject had grown under my hands, and that it 
 would be impossible fully to develop my ideas except in 
 the form of a separate treatise. The omission seemed all 
 the more desirable, because my former work dealt only 
 with Esthetics as an element of human psychology : 
 while the materials here collected refer rather to the 
 wider science which studies the phenomena of mind 
 throughout the whole animal world. Accordingly, I de- 
 ferred their publication for the time, only mentioning my 
 original intention in a footnote on p. 156 of "Physio- 
 logical Esthetics." But most of the critics who kindly 
 noticed that little work were so unanimous in calling at- 
 tention to the hints which I had thrown out with reference 
 to the Colour-Sense, and the love for colour which forms 
 such a striking characteristic of mankind, that I determined 
 
 on f olio win c^ up the subject on a wider basis, and eluci- 
 
 h
 
 vi PREFACE. ' 
 
 dating my view by full inductive generalisations. The 
 present volume is the result. 
 
 Meanwhile two works appeared, in Germany and in 
 England, which necessitated considerable divergences 
 from my original plan. The first was Dr. Hugo Magnus's 
 " Geschichtliche Entwickelung des Tarbensinnes ; " the 
 second Mr. A. K. Wallace's "Tropical JSTature." Put shortly, 
 the gist of my theory was this : that the taste for bright 
 colours has been derived by man from his frugivorous 
 ancestors, who acquired it by exercise of their sense of 
 vision upon bright-coloured food-stuffs ; that the same 
 taste was shared by all flower-feeding or fruit-eating 
 animals ; and that it was manifested in the sexual selection 
 of brilliant mates, as well as in other secondary modes, 
 such as the various human arts. The two volumes men- 
 tioned above came like utterly destructive criticisms of 
 any such belief. Dr. Magnus endeavoured to prove that 
 the Colour-Sense of mankind was a late historical acqui- 
 sition of the race, whose beginnings hardly dated back as 
 far as the Homeric and Vaidik periods. Mr. Wallace con- 
 troverted, with all his well-known vigour and ingenuity, 
 the theory of sexual selection, first announced by Mr. 
 Darwin, upon which rested almost the whole argument 
 for a love of pure colour among the lower animals. Thus 
 these two books between them cut away the whole ground 
 from under my feet. It became necessary to go back over 
 my materials afresh, and to seek for evidence against both 
 anticipatory assailants. I have tried, therefore, to show, 
 in opposition to Dr. Magnus, that the Colour-Sense of 
 mankind dates back to the earliest appearance of our race
 
 PREFACE. vii 
 
 upon earth ; and, in opposition to Mr. Wallace, that a 
 modified form of the sexual selection theory may still 
 survive his powerful attack. I am aware how ill prepared 
 I am to encounter so thorough a biologist as the joint dis- 
 coverer of Natural Selection on his own ground ; but I 
 have humbly offered such arguments as lay in my power, 
 trusting to the generosity of my opponent to forgive any 
 technical errors which may easily creep into a discussion 
 of the sort. 
 
 I should like to add that I enter the lists as a compara- 
 tive psychologist, not as a biological student. I do not 
 pretend to discover facts of botany or zoology at first 
 hand : I accept them as data from the lips of competent 
 specialists. Yet I hope my work may prove valuable in 
 its own peculiar sphere, which ought to be kept distinct 
 from the objective biological sciences whose conclusions 
 form its basis. Our great naturalists supply us with the 
 facts upon which to build our comparative psychology : 
 and I hope there is no presumption in employing them 
 sometimes to test the logical correctness of a few among 
 the naturalists' own conclusions. 
 
 One of the main necessities of science at the present 
 day is the existence of that organising class whose want 
 was pointed out by Comte, and has been further noted by 
 Mr. Herbert Spencer. To this class I would aspire, in a 
 humble capacity, to belong. But the organising student 
 cannot also himself be a specialist in all the sciences 
 whose results he endeavours to co-ordinate : and he must, 
 therefore, depend for his data upon the original work of 
 others. If specialists find technical errors in such co-
 
 viii PREFACE. 
 
 ordinated results, they should point them out frankly for 
 correction and improvement, but they should not regard 
 them as fit subjects for carping criticism. I shall feel 
 grateful to any biologists who can suggest alterations or 
 modifications in any part of what I cannot but feel a very 
 tentative and rudimentary work. But unless we make a 
 beginning in psychology we shall never reach the end : 
 and I send forth my speculations rather in the hope that 
 they may arouse comment and lead to further researches, 
 than because I consider them in any way final or com- 
 plete. 
 
 With regard to the authorities used or quoted, I have 
 followed the plan of making no references to original 
 works when dealing with the accepted common-places of 
 science ; but wherever I have occasion to note a particuW 
 fact, of comparatively modern ascertainment or specialist 
 knowledge, I give the authority in a footnote. For the 
 general groundwork of my theory, my acknowledgments 
 are mainly due to the works of Mr. Darwin and Mr. 
 Herbert Spencer, which I seldom quote by name, because 
 they now form part of the established body of scientific 
 doctrine. After these, I owe most to Mr. A. R Wallace, 
 Mr. Bates, and Mr. Belt. For personal assistance, by letter 
 or otherwise, I must thank Mr. Darwin, who supplied me 
 with corrections on the colours of flowers ; Mr. Wallace, 
 who kindly wrote to me with regard to the colours of 
 fruits; Mr. Galton, F.E.S., for an introduction to the 
 library of the Eoyal Society ; Mr. Gladstone, who called 
 my attention to notes in German periodicals ; the Eev. A. 
 H. Sayce, for reference to Assyrian and Babylonian works
 
 PREFACE, IX 
 
 of art ; the Eev. T. K. Cheyne, for aid on the question of 
 Hebrew colour-terms ; Mr. H. N. Moseley, naturalist to 
 the Challenger expedition, for references to papers on the 
 colouration of deep-sea organisms ; Sir John Lubbock and 
 Mr. B. T. Lowne, for copies of their original researches on 
 the eyes and optical perceptions of insects ; and the Eev. 
 S. J. Whitmee of Samoa, with a large number of other 
 missionaries or civil servants, for information with regard 
 to the Colour- Sense of savages. 
 
 In a more strictly personal sense, I owe my acknow- 
 ledgments to my friends, Mr. F. T. Eichards of Trinity 
 College, Oxford, Mr. G. J. Eomanes, F.L.S., and Professor 
 G- Croom Eobertson, for constant assistance in calling my 
 attention to passages in books or periodicals which bore 
 on the subject under investigation. 
 
 Finally, I should mention that, although most of the 
 matter contained in the present volume is entirely new, I 
 have incorporated into Chapters IV. and VI. the substance 
 of two papers on " The Origin of Flowers " and " The Origin 
 of Fruits," which appeared in the " Cornhill Magazine " 
 for May and August 1878. Part of the materials for 
 Chapter X. were also included in a note which I con- 
 tributed to " Mind " for January of the same year. 
 
 G. A.
 
 CONTENTS 
 
 CHAPTER I. I 
 
 1 
 
 INTRODUCTORY ...... I 1 
 
 CHAPTER n. : 
 
 I 
 
 ^THER-WAVES AND THEIR VARIETIES ... 7 \ 
 
 CHAPTER III. ; 
 
 THE ORGAN OF VISION ..... 23 I 
 
 1 
 
 CHAPTER IV. i 
 
 INSECTS AND FLOWERS . . . . • 33 | 
 
 CHAPTER V. 
 
 THE COLOUR-SENSE IN INSECTS . . . . 8 1 I 
 
 CHAPTER VI. ; 
 
 I 
 
 BIRDS OR MAMMALS AND FRUITS .... 97 j 
 
 ! 
 
 CHAPTER VII. - 
 
 THE COLOUR-SENSE IN VERTEBRATES . . • 117 
 
 CHAPTER VIII. ; 
 
 THE COMMUNITY OF TASTE BETWEEN FLOWER-FEEDING AND 
 
 FRUIT-EATING SPECIES . . . . I29 I
 
 CONTENTS. 
 
 CHAPTER IX. 
 
 THE DIRECT REACTION OF THE COLOUR-SENSE UPON THE 
 ANIMAL INTEGUMBNTS .... 
 
 [49 
 
 CHAPTER X. 
 
 THE INDIRECT REACTION OF THE COLOUR-SENSE UPON THE 
 
 ANIMAL INTEGUMENTS . . . . I95 
 
 CHAPTER XI. 
 
 THE COLOUR-SENSE IN MAN ..... 202 
 
 CHAPTER XII, 
 
 THE ^ESTHETIC VALUE OF COLOUR , . . .22'' 
 
 CHAPTER XIII. 
 
 THE GROWTH OF THE COLOUR- VOCABULARY . 
 
 CHAPTER XIV. 
 
 SUMMARY AND RECAPITULATION 
 
 !5o 
 
 79
 
 THE COLOUR-SENSE. 
 
 CHAPTER I. 
 
 I N T R O D U C T^O R Y. 
 
 There is no element of our sensuous nature wliicli yields 
 us greater or more varied pleasure than the perception 
 of colour. Whether we look at the larger physical wholes, 
 the azure heaven above us, the purple sea beneath us, 
 and the green meadows by our side ; — or at the smaller 
 organic bodies, the brilliant flowers, the crimson foliage of 
 autumn, the gaudily painted butterflies, the beetles clad 
 in burnished gold, the peacock adorned with all the hues 
 of the rainbow, and the humming-birds decked out in 
 ruby, sapphire, and amethyst ; — or again at the transient 
 effects of light in the spectrum, the soap-bubble, the 
 iridescent surface of the opal, the tints of eventide mir- 
 rored in the glassy lake ; — in each and every case we feel 
 a thrill of pure and unselfish enjoyment, which no other 
 mere sensuous stimulation is capable of arousing in our 
 breasts. '.The pleasure of colour is one which raises itself 
 above the common level of monopolist gratification, and 
 attains to the higher plane of aesthetic delightJ 
 
 ISTor is man the only creature who can appreciate and 
 enjoy the lavish store of beauty which nature pours forth 
 for his pleasure in the fields and the forest. We shall see 
 reason to conclude, from the facts collected in this volume, 
 
 A
 
 2 THE COLOUR-SENSE, 
 
 that many of our dumb relations can fully enter into the 
 love for exquisite colour, at least in its simplest and 
 earliest forms. We shall find good ground for believing 
 that the bird of paradise does not display its gorgeous 
 plumage to the careless eyes of an unobservant mate ; 
 that the gaily painted butterfly is not insensible to the 
 lovely tracery upon the wings of its fellow ; and even that 
 the tropical lizards or batrachians can duly admire the 
 glistening coats, crimson crests, or golden' pouches of their 
 lissome helpmates. We shall further note certain habits 
 which may lead us to suspect that birds and insects are 
 pleasurably affected, not only by the colour of their own 
 kind, but also by the delicate or brilliant tints of the 
 fruits and flowers upon which they feed. In short, our 
 object must be to trace back the pleasure which man 
 experiences from the deft combination of red and green 
 and violet, in painting or in decorative art, to a long 
 line of ante-human ancestry, stretching back indefinitely 
 through geological ages to the first progenitors of verte- 
 brate life. 
 
 More than this we must attempt to show. If we would 
 learn fully the whole history of the colour- sense, we 
 must track it backward through the generations of the 
 earlier earth, till we discover what were the circumstances 
 by which it was first produced. We must find out how 
 the various modes of sether-waves, which we now know 
 as colours, came originally to be distinguished from one 
 another by the nascent eyes of half-developed reptiles 
 and insects. We must see by what steps the hues of 
 flowers, and seeds, and fruits, and small animal prey 
 caused the growth of a distinctive colour-perception in 
 the creatures which fed upon them. And we shall pro- 
 bably conclude at the same time that the sense thus 
 developed became in turn a source of new pleasure to 
 its possessors, and a groundwork for more marvellous 
 developments in future. The taste which was formed by 
 the lilies and roses, the golden oranges and purple grapes,
 
 INTRODUCTORY. 3 
 
 ended by producing the metallic lustre of tlie sunbirds and 
 the daintily shaded ornamentation of the argus-pheasant. 
 We may hope to show, furthermore, that the existence 
 of bright colouring in the world at large is almost entirely 
 due to the influence of the colour-sense in the animal 
 kingdom. I do not mean, of course, that animals have 
 anything to do with the objective existence of those dif- 
 ferent aether-waves in the pencil of light which, when 
 decomposed or separated, we perceive as colours ; nor do 
 I mean to include in this category the shades of earth, 
 sea, sky, and other great inorganic masses. Obviously 
 the human or animal eye could have no influence upon 
 their origin or colouring. Even the green leaves of the 
 trees and grasses seem quite independent of man or beast. 
 But I still think that a vast mass of the coloured objects 
 with which we are most familiar owe their hues to the 
 perceptions of some insect, bird, or animal. If we look 
 briefly at a few of the best-known cases, the reader will 
 more clearly comprehend the line of argument which this 
 book proposes to itself. 
 
 In the drawing-room where we sit, every object has 
 obtained its colour entirely with reference to the likes 
 and fancies of humanity. Not only have the pictures 
 and ornaments been painted so as to please our eyes, but 
 the carpets, the wall-paper, the curtains, the table-covers, 
 the embroidery, the damask on the chairs and sofas, the 
 clothing of the women and children, have all been dyed 
 on purpose to stimulate and gratify the sense of sight. 
 Indeed, there is scarcely an article of human use and 
 manufacture, from the vermilion-stained earthenware of 
 the prehistoric savage and the woad adornment of the 
 Cymric warrior, to the Lambeth and Vallauris pottery, or 
 the cretonnes and crewel-work of modern aesthetic de- 
 signers, which has not received some special manipulation 
 to add pleasing colour by means of dyes or pigments. 
 The universal effect of the colour-sense on human pro- 
 ducts is too obvious to need further illustration.
 
 4 THE COLOUR-SENSE. 
 
 A step lower down, we reach the actual bodies of men 
 and animals themselves. It would seem at first sight as 
 thouo:h the colour-sense could have nothing to do with 
 the production of these. Yet the theory of sexual selec- 
 tion, into which we shall enter more fully hereafter, shows 
 us how the long-continued choice of beautiful mates may 
 have had the effect of encouraging the growth of bright- 
 hued individuals, and the obsolescence of their less 
 favoured fellows. I shall try to point out, also, an adjunct 
 to this theory, which seems to have escaped even the keen 
 eyes of Mr. Darwin, Mr. Wallace, and their German 
 allies. I shall endeavour to prove that only those animals 
 display beautiful colours, due to sexual selection, in whom 
 a taste for colour has already been aroused by the influ- 
 ence of flowers, fruits, or brilliant insects, their habitual 
 food. As the liking cannot have grown up without some 
 groundwork of advantage to be gained by it, we might 
 gather, even a priori, that such would be the case ; and I 
 hope, in the sequel, to adduce a sufficiently large array 
 of positive instances to justify an inductive conclusion 
 to the same effect. 
 
 Taking still another step backward, we arrive at the 
 brilliantly coloured fruits and flowers, upon which these 
 tastes were formed. And here we shall have reason to 
 believe that the agency of insects has been most powerful 
 in developing the hues of blossoms ; while the fruits, as 
 we shall see, are rather due to the selective action of birds 
 and mammals. Between them almost all the colours of 
 vegetal life, except the uniform green of the foliage, are 
 probably produced, being due to the colour-sense of one 
 or other of the great seeing classes, the vertebrate and the 
 articulate. 
 
 Many lesser cases may be alleged, where colours have 
 been acquired for purposes of protection or deception, and 
 of such an abundance will be forthcoming in their proper 
 place. But enough has doubtless been said to show the 
 immense importance of the colour-sense in man or animals,
 
 INTRODUCTORY. 5 
 
 and the conspicuous part which (as I believe) it has played 
 in the moulding of organic forms. If I put in two anti- 
 thetical paragraphs the various great classes of coloured 
 objects which we do or do not owe to its operation, the 
 reader will be able to see at a glance just how much influ- 
 ence I claim for it. 
 
 We do not owe to the colour-sense the existence in 
 nature of the rainbow, the sunset, or the other effects of 
 iridescent light ; the blue sky, the green or purple sea, the 
 red rocks, or the other great inanimate masses ; the foliage 
 of trees and shrubs, the hues of autumn, and the tints of 
 precious stones or minerals generally. 
 
 But we do owe to the colour -sense the beautiful flowers 
 of the meadow and the garden, — roses, lilies, carnations, 
 lilacs, laburnums, violets, primroses, cowslips, and daisies ; 
 the exquisite pink of the apple, the peach, the mango, and 
 the cherry, with all the diverse artistic wealth of oranges, 
 strawberries, plums, melons, brambleberries, and pome- 
 granates ; the yellow, blue, and melting green of tropical 
 butterflies; the magnificent plumage of the toucan, the 
 macaw, the cardinal-bird, the lory, and the honeysucker ; 
 the red breast of our homely robin ; the silver or ruddy fur 
 of the ermine, the wolverine, the fox, the squirrel, and 
 the chinchilla; the rosy cheeks and pink lips of English 
 maidens; the whole catalogue of dyes, paints, and pig- 
 ments ; and, last of all, the colours of art in every age and 
 nation, from the red cloth of the South Seas, the lively 
 frescoes of the Egyptian, and the subdued tones of Hel- 
 lenic painters, to the stained windows of Poitiers and the 
 Madonna of the Sistine Chapel. 
 
 The origin and rise of this powerful sense, and the means 
 by which it has effected all these marvellous reactions on 
 the external world, form the text upon which we must 
 string our discourse in the present volume. We shall 
 begin with the nature of colour, viewed as an external and 
 objective fact ; we shall next look at the steps by which 
 the various eyes of insects and animals became sensible to
 
 6 THE COLOUR-SENSE. 
 
 its diverse stimulations ; we shall then proceed to ask 
 what secondary effects the newly acquired sense produced 
 upon the surrounding existences; and we shall finally 
 examine its remote aesthetic results in the sphere of human 
 activity. We shall thus have traced the perception of 
 colour from its first faint beginnings in palaeozoic seas or 
 carboniferous forests down to its latest developments in 
 the palaces or galleries of civilised man.
 
 ( 7 ] 
 
 CHAPTER II. 
 
 ^THER-WAVES AND THEIR VARIETIES.^ 
 
 Befoee we can investigate any sensation in men or 
 animals, we must find out what is tlie external agency 
 to which it corresponds. Every feeling answers to some 
 outer fact, and in the development of life the fact must 
 necessarily have preceded the feeling. Unless there had 
 been matter there could never have been mind. Without 
 resistance we could not experience touch; without air 
 we could not possess hearing ; without aether we could 
 not have developed the wonderful faculty of sight. 
 Organic substances, acted upon by peculiar agencies in 
 the inorganic world, give rise to the phenomena of 
 sensation ; but we cannot understand the existence of 
 sensation unless we previously grant the existence of 
 an influence capable of developing it. Idealism, which 
 looks fallaciously plausible when applied to the fully 
 evolved intelligence, becomes meaningless and self-con- 
 tradictory when applied to the problem of its evolution. 
 
 1 In the short sketch of Physical mixture of pigments. Such questions 
 Optics which follows, I have en- are wholly foreign to our present 
 deavoured, not to give a resume of subject, and I merely note the omis- 
 all that is known upon so wide a sion to guard against possible criti- 
 subject, but merely to say as much cism. The reader who would go 
 as was absolutely necessary for the further into this department of the 
 proper comprehension of the sequel, subject will find full details in 
 Hence I have intentionally omitted Helmholtz's " Handbuch der Phy- 
 whatever might prove a stumbling- siologischen Optik," and a very read- 
 block to the general reader, such able abstract in Von Bezold's "Theory 
 as the difference between absorption of Colour," translated by S. R. Koeh- 
 colours and interference colours, or ler (Boston, U.S.A., L. Prang k Co., 
 that between mixture of lights and 1876).
 
 8 THE COLOUR-SENSE. 
 
 We must begin, then, by allowing that, previous to all 
 perception of colour by men or animals, colour itself 
 existed as an agency in the external universe. The 
 development of the colour-sense is equivalent to the 
 growth of a mechanism by which this agency became 
 capable of affecting organic matter. In the present 
 chapter we will consider the nature of the objective 
 agency, while in the next we shall have to look at the 
 first and rudest form of the percipient mechanism. 
 
 Throughout the whole vast ocean of space in which 
 suns, stars, and planets float like inconspicuous islets of 
 light, modern science has taught us that an all-pervading 
 element, known as sether, fills every available interstice. 
 From constellation to constellation of sidereal bodies the 
 sether spreads in wide expanses, which stretch uninter- 
 rupted over countless millions of miles. Between atom 
 and atom of terrestrial substances the sether penetrates 
 into ti^ intervals whose minuteness the boldest mathe- 
 maticians have only lately ventured to measure. Where- 
 ever matter is not, sether is. Every sun and every molecule 
 floats in a circumambient matrix of this unknown accent. 
 If we could view the most solid body with a microscopic 
 eye, magnifying some thousands of millions of diameters, 
 we should see that it was composed of innumerable little 
 masses, none of them in actual contact with its neighbours, 
 but all bound to one another, as the earth is to the sun, 
 by their mutual attractions extending over an intervening 
 space. This space would be filled, in the one case as in 
 the other, by the ubiquitous sether. And though we can 
 never succeed in knowing its existence directly, yet we 
 are every moment experiencing its effects in the most 
 obvious and unmistakable manner. Just as we believe 
 in air, which we never see, because we can feel it, so we 
 believe in aether, which we can never handle, because we 
 perpetually see by it and through it. 
 
 ^ther, though infinitely light and elastic, is naturally 
 a solid, or something very like one. But it shares the
 
 ^THER-WAVES AND THEIR VARIETIES. 9 
 
 common property of other solids in its ability to transmit 
 •undulations from a centre of disturbance. We all know 
 that if we set any body in motion, it imparts a portion of 
 its motion to all other bodies with which it comes in con- 
 tact. So, too, if we set up vibratory movements in a bell, 
 we know that its particles knock up against the air- 
 particles in their neighbourhood, and thereby send off into 
 surrounding space a Series of concentric air-waves, which, 
 when they strike the appropriate human organ, are known 
 to us in consciousness as sounds or tones. And in exactly 
 the same way, when disturbances of a peculiar kind affect 
 material particles of any sort, they set up a like series of 
 concentric waves in the circumambient sether, which, 
 falling in turn on their appropriate organs, are recognised 
 in consciousness as heat, light, or colour. What is the 
 exact nature of these waves and their differences we have 
 next to inquire. 
 
 Apparently every movement of a material body or 
 particle sets up more or less motion in the surrounding 
 aether. We know now that every sound, every moving 
 energy, every activity of any sort, as it dies away, is 
 transferred by minute friction to the setherial medium 
 which bathes us on every side. But the stronger class of 
 sether- waves, with which we have now to deal, is origin- 
 ated only in a single way. They all arise from the vibra- 
 tions of a material body in that state of rapid molecular or 
 atomic motion which we commonly know as red or white 
 heat. The waves thus set up may be reflected, refracted, 
 twisted about, and returned in varying proportions by 
 other surrounding objects, but they all owe their original 
 existence to a heated material mass, whether that mass be 
 the sun, the dog-star, the drawing-room fire, or the flame 
 of a candle. So we must look for a moment at the source 
 of such sether-waves before we can comprehend the nature 
 of the waves themselves. 
 
 Directly or indirectly, in every case, the vibration of the 
 original heated body is due to the rushing together of
 
 lo THE COLOUR-SENSE. 
 
 masses, molecules, or atoms which were previously in a 
 state of separation. In the heavenly bodies, the sun and 
 the fixed stars, the attraction of gravitation (which affects 
 masses) is drawing together their skirts; and under its 
 influence the outlying matter of their systems is clashing 
 with the central sphere and producing a terrific degree of 
 heat ; just as the continued clashing of hammers on an 
 anvil will heat a piece of iron red-hot here on our little 
 earth. In the grate and the candle, agrain, the attraction 
 of chemical affinity (which affects atoms) is drawing 
 together tiny particles of carbon and oxygen ; and as the 
 atoms clash against one another in the embers or the 
 flame, they are put into a similar state of rapid vibration 
 or heat. In physical language, the potential energy of 
 their previous separation has become kinetic in the act 
 of union, and is now being radiated off to surrounding 
 objects. As the quickly vibrating little bodies, either in 
 the sun or the flame, fly from side to side, they impart 
 each second a portion of their moving energy to the aether 
 about them; and each setherial molecule continues to 
 impart the communicated impulse to adjacent molecules, 
 so that a series of spherical waves is set up in every 
 direction from the central disturbance. If nothing inter- 
 venes to prevent them, these waves go on widening and 
 weakening through all space ad infinitum, at least as far 
 as human science or conjecture can follow them. 
 
 But all the sether-waves are not of exactly the same 
 size, nor do they follow one another with exactly the same 
 rapidity. When a material body vibrates with a com- 
 paratively slight motion (or, as we say in other words, is 
 only slightly heated), the waves to which it gives rise are 
 comparatively slow and voluminous : as the rate of vibra- 
 tion increases, more rapid waves succeed in the surround- 
 ing sether; and when the rapidity of vibration becomes 
 very great, the resulting waves follow one another with 
 an almost incredible speed. Three principal varieties of 
 slower or quicker sether-waves are commonly distinguished,
 
 ^THER-WAVES AND THEIR VARIETIES. ii 
 
 according to the effects wliich they produce upon the 
 human org^ans. 
 
 The slowest undulations are known as heat-waves ; those 
 of intermediate rapidity as light-waves ; and the quickest 
 of all as chemical waves. 
 
 All three classes of waves are produced together by a 
 body in a state of high molecular energy, such as the sun. 
 Fortunately, we are able to separate the various kinds from 
 one another, and to demonstrate their several properties, 
 by means of a simple piece of triangular glass, known as 
 a prism. 
 
 If we make a small slit in the shutter of a darkened 
 room, and allow a few of the sether-waves, generated by 
 the sun, to enter through this aperture, we can interpose 
 the prism across their path, and project them sideways on 
 to a screen. When we do so we find that the various 
 waves are all bent upward, but not all equally. They 
 occupy a broad space on the screen, the slowest waves 
 striking the lowest portion, and the quickest falling at the 
 top, while those of intermediate speed hit the middle 
 space.i If we put a thermometer of very delicate con- 
 struction (known as a thermopile) at the lowest point 
 where the waves surge against the screen, we shall find 
 that, in this portion of the wave-bundle, the undulations 
 possess great heating power. If we put a piece of speci- 
 ally prepared paper at the highest point where the waves 
 alight, we shall similarly find that the undulations of that 
 region possess high chemical power. And if we look at 
 the intermediate space, we shall see for ourselves that the 
 waves of that part produce the greatest amount of light 
 and colour. So here we learn that in every bundle of 
 solar aether-waves these three classes of undulations are 
 closely combined; but by the interposition of a proper 
 medium they can be sifted and separated each into a 
 place of its own. 
 
 1 As my purpose is here to explain careful to avoid any allusion to the 
 the objective nature of colour, I am subjective differences of perception.
 
 12 THE COLOUR-SENSE. 
 
 Fundamentally, then, light and radiant heat are iden- 
 tical. And not only so, but a third order of rays — the 
 chemical — is always bound up with them in the waves 
 which come to us from the sun. Yet though in their 
 objective nature these various agencies are so similar — 
 differing not at all in kind, but only in degree — there is 
 a very strange diversity in our subjective perception of 
 their effects. The slowest aether-waves we perceive with 
 every portion of our bodies, and know as heat ; the inter- 
 mediate sether- waves we perceive through a pair of small 
 and special organs — the eyes — and know as light ; while 
 the fastest sether- waves we do not perceive at all, except 
 by very rounda.bout and indirect means. 
 
 The reasons for this difference must surely be very 
 striking ones. It seems curious that such similar agen- 
 cies should be so diversely cognised, or should escape our 
 cognisance altogether. And it is for the purpose of bring- 
 ing into clear relief so strange a fact that I have chosen 
 what doubtless seemed at first sight an awkward and 
 unfamiliar mode of envisaging a well-known subject. 
 The question why we have two distinct methods for per- 
 ceiving two. closely allied forms of sether- waves, and no 
 method at all for perceiving the third, is a question which 
 evolutionism is bound to answer before it proceeds to the 
 minor discrimiDation of those lesser differences know^n as 
 colours. 
 
 For when we look at the matter objectively, we see at 
 once that each colour differs from its neighbour in just the 
 same manner as heat differs from light, though only to a 
 less degree. Accordingly, we must ask first, Whj are the 
 senses of animals so difi'erently affected by the extremes 
 and the mean of the solar undulations ? And when we 
 have answered that question we may go on to the next, 
 How did the various minor undulations of mean rapidity 
 come to have differential sensations attached to them in 
 consciousness ? 
 
 Fortunately, the answer is not a very difficult one. The
 
 ^THER-WAVES AND THEIR VARIETIES. 13 
 
 slower and more massive "undulations, which we know as 
 heat-waves, produce very marked results even upon inor- 
 ganic bodies, while their effects upon organic matter are 
 obvious and enormously important. To the animal, cold 
 is death and warmth is life. Hence it is not astonishing 
 that animals should very early have developed a sense 
 which informed them of the changes of temperature taking 
 place in their vicinity; and that this sense should have 
 been equally diffused over the whole organism, ^ther- 
 waves of slow vibration are capable of setting up motion 
 in the molecules of all bodies upon which they impinge, 
 as we know familiarly when we touch a stone on the 
 summer beach, or grasp a poker which has lain long in 
 front of the fire; and the motion so absorbed we call 
 warmth: while, on the other hand, molecules in rapid 
 motion give up their energy to the surrounding aether, as 
 we also know when a red-hot poker cools, or when we 
 expose our faces to the chilly wind of winter ; and the 
 loss of motion so induced we call cold. In either case, 
 the immediate effects are so highly important to animal 
 life, that we may well imagine the accompanying sensa- 
 tions to be amongst the earliest which evolution could 
 have produced. As soon as moving creatures began to 
 feel at all, they j)robably began to feel heat and cold. 
 
 The sether-waves of middle frequency, however, do not 
 produce such plain and universal results. If we interpose 
 a slab of rock-salt in the course of a solar beam, w^e can 
 sift out of it all the slower undulations (or heat-waves), 
 which are selected and absorbed by the salt itself. On 
 placing oi^r hands in the path of the remaining wavelets, 
 we do not experience any feeliog of heat whatsoever. 
 And if we put a piece of inorganic matter — say a pebble 
 — in the course of the sifted ray, we shall find that it is 
 similarly unaffected in temperature or structure. The 
 thermopile conclusively shows us that little or no imme- 
 diate mechanical power is left in the wavelets which pass 
 through the rock-salt. If we examine the results which
 
 14 THE COLOUR-SENSE. 
 
 these middle undulations produce upon the world at large, 
 we shall arrive at similar conclusions. While to the heat- 
 waves are due the conspicuous differences of summer and 
 winter, ice, snow, and rain, the poles and the tropics, 
 besides the great phenomena of ocean-currents, winds, 
 evaporation, clouds, rainfall, and atmospheric disturbances 
 generally ; their companions, the light-waves, scarcely pro- 
 duce any noticeable effects at all. Falling upon the mass 
 of the earth's surface, they are not, like the slower undula- 
 tions, absorbed and communicated through the substance 
 on which they impinge, but are reflected and twisted back 
 upon space in every possible direction. Even if they are 
 partially taken in by the matter on which they fall, yet 
 the greater portion of them are returned without effecting 
 any change in its arrangement ; and if, as in the case of 
 what we call a black surface, a large number or the whole 
 of them are absorbed and retained, they are yet degraded 
 by the process into the form of heat-waves, from which 
 they cannot be consciously discriminated except by in- 
 direct means. These middle waves could not, therefore, 
 prove of any great importance to animal life in its earliest 
 days; and we need not wonder that no sense for their 
 perception was at first developed. 
 
 There is one conspicuous exception, however, to this 
 comparative inertness of the light-waves — I mean the 
 case of plants. In their leaves, the middle and quickest 
 setherial undulations become the a^^^ents for efiecting; great 
 chemical and physical changes, upon which the whole 
 course of mundane life entirely depends. But these fat;ts, 
 all-important in themselves, do not directly affect our 
 present question. Light is essential to animal life, because 
 it is essential to the plants upon which, mediately or imme- 
 diately, animal life subsists. But a perception or discri- 
 mination of light is not at all necessary, except in a very 
 roundabout and derivative way. Why it has arisen at 
 all we may next briefly inquire. 
 
 The light-waves falling upon a body do not largely
 
 ^THER-WAVES AND THEIR VARIETIES. 15 
 
 affect it, as a rule, in any way. They may occasionally 
 be employed in bringing about slight changes of its super- 
 ficial molecules, but they do not penetrate deeply or 
 work conspicuous rearrangements of its whole substance. 
 Nevertheless, the power of discriminating them may in- 
 directly benefit an animal organism. If a jellyfish, swim- 
 ming at the water's top, has eyelets upon which the in- 
 cident light-waves produce distinct effects, it may be 
 warned of the approaching enemy, or informed of passing 
 prey, by having the path of the aether- waves cut off from 
 above. Still more valuable will the nascent sense become, 
 if, instead of being restricted to the full force of directly 
 incident undulations, it is capable of being impressed by 
 reflected waves. In this case, not only will the creature 
 be conscious of objects passing between it and the source 
 of light, but it will be able to receive varying stimulations 
 from aU surrounding objects upon which the light falls. 
 The more highly developed its sight becomes (for we may 
 now use the language of ordinary life without fear of 
 ambiguity), the more clearly will it be affected by the 
 beams which are twisted about and returned upon space 
 from every neighbouring body. Until at last that very 
 fact in the light- waves which made them originally so un- 
 important — the fact that they glance off every object they 
 hit like a ball reboundinf^ from a wall — chives them, in our 
 eyes, the greatest value, by enabling us to discriminate 
 from a distance the shape and texture of all we see, with- 
 out the trouble of actual examination by the hands and 
 fingers. 
 
 But this specialised sense is hardly likely to spread 
 itself over the whole body, like the sense of heat and cold. 
 Not only should we derive no advantage from being all 
 eye, but we should be positively incommoded rather than 
 benefited by such an arrangement. It will only be in 
 certain special spots or ocdli that the perception of light 
 will probably begin; and as the sense strengthens, we 
 shall find these spots becoming fewer and fewer, until in
 
 1 6 THE COLOUR-SENSE. 
 
 the approximately perfect organisms they are reduced to 
 the two conspicuous orbs which we commonly call eyes. 
 All such questions, however, must be left over for a while, 
 until we come to examine the development of the rudi- 
 mentary vision. At present we must hurry on to reach 
 our proper subject — the objective nature of colour. 
 
 As for the third class of setherial undulations, the 
 quickest or chemical waves, their effects are so slight and 
 inconspicuous that we have never had occasion to develop 
 any sense whatsoever for their perception. It is only quite 
 recently, and by quite indirect methods (chiefly through 
 the investigations of the earliest photographers), that we 
 have come to recognise their existence at all. Neither 
 upon inorganic substances nor upon animal bodies do 
 they produce any striking result; so that we need not 
 wonder at our inability to perceive them, either with our 
 whole organism or with any specialised organ. What- 
 ever has no influence upon our welfare as a species 
 can never have any effect upon the modification of our 
 senses. 
 
 We can dimly understand, then, why these three kinds 
 of sether-waves, differing from one another only in their 
 relative size and frequency, should be commonly thought 
 of as such utterly unlike agencies. The slowest waves 
 affect all material substances alike, and are consequently 
 cognised by our whole bodies as heat. The middle waves 
 are cast off- in varying proportions by almost every sub- 
 stance upon which they fall, but possess little power of 
 modifying their arrangement, and are consequently cog- 
 nised by a very special organ — the eye ; while the quickest 
 waves are almost inert, so far as our present purpose is 
 concerned, and are consequently not cognised by us at 
 all, except mediately and intellectually. 
 
 And now that we have seen the objective nature of 
 light in general, let us ask what is the objective nature of 
 colours in particular. 
 
 As I said above, each colour bears objectively the same
 
 ^THER-WAVES AND THEIR VARIETIES. 17 
 
 relation to light as light itself, heat, and chemical rays 
 bear to the whole set of setherial undulations. 
 
 If, once more, we have recourse to the prism and the 
 darkened room, we can throw a bundle of sether- waves as 
 before upon a white screen. Neglecting now the two ex- 
 tremes, the heat-rays and the chemical rays, which are of 
 course invisible, we need only concern ourselves with the 
 middle or light-rays, which form a bright band of colours, 
 ranging from red to violet. The lowest part of this band 
 or spectrum, next to the place where the thermopile 
 showed us the existence of the heat-rays, is occupied by 
 red. After it, in ascending order, come orange, yellow, 
 green, and blue ; while the highest place, next to the point 
 where the sensitised paper showed us the existence of the 
 chemical rays, is filled by a belt of violet. Each of these 
 colours answers to a set of aether- waves, whose frequency 
 is intermediate between that of heat-rays and chemical 
 rays in the order just given. Slowest of all visible rays 
 are the red, next come the green and blue, while the 
 violet are the quickest waves capable of producing any 
 direct effect upon the eye. 
 
 In the case of such a solar spectrum, we have sifted out 
 the various orders of sether-waves by means of their 
 varying ref Tangibility, that is to say, the extent to which 
 each is capable of being bent aside from its direct course 
 by means of the prism. But there are other ways in 
 which the same effect may be produced. Tor example, 
 we may intercept the whole bundle of compound undula- 
 tions with a piece of specially prepared glass, (red glass, as 
 we call it), which sifts out all the quicker waves, leaving 
 only the red, just as the rock-salt sifted out all the heat- 
 waves. Similarly, we may take a piece of green, blue, or 
 violet glass, which will cut off all but the proper kind of 
 waves which it is intended to let through. Neither of 
 these ways, however, is a common one in external nature. 
 The rainbow shows us the solar spectrum, and the green 
 light which has passed through a stratum of water gives
 
 1 8 THE COLOUR-SENSE. 
 
 lis an instance of selective absorption; but tbe way in 
 which ordinary colour is produced is a slightly different 
 one. 
 
 We saw above that every sether-wave has its origin in 
 an incandescent body, celestial or mundane. But most of 
 the objects which we see every day are not tjiemselves 
 incandescent; the light by which we perceive them is 
 reflected from the sun. Now when the light-waves from 
 the sun strike upon any terrestrial object, they may be 
 reflected in a great many different manners. If the sur- 
 face upon which they fall is perfectly smooth and quit^ 
 opaque (or incapable of transmitting the undulations 
 through its substance), the waves will be returned in their 
 entirety,^ as when we see an image of the sun in a mirror. 
 Here the waves are sent back as they came, exactly in 
 the same way as when a ball rebounds from the wall. If, 
 however, the surface is not quite smooth, but yet has 
 no special selective power for any one set of waves rather 
 than another, the light is then returned, not directly as it 
 came, but dispersedly in every direction. Such an object 
 is said to be white, and its mode of treating the light may 
 be compared to the case of a stone thrown against a wall, 
 and shivered in every direction into a thousand pieces. 
 Again, if the surface has such a molecular disposition that 
 it absorbs or neutralises one or more sets of waves, and 
 only returns one or more other sets, then it is said to be 
 coloured. If it absorbs all the green, blue, and violet 
 rays, returning only the red, then it is said to be a red 
 object, because the red rays alone strike our eyes when we 
 look at it. Similarly, if it absorbs all the red, orange, and 
 violet rays, returning only the green, it is said to be a 
 green object. And so on throughout. Lastly, if it absorbs 
 all the ?ether- waves, degrading their light into the form of 
 heat, and returning none, it is said to be black.^ 
 
 1 1 am speaking broadly, and pur- will forgive me for simplifying the 
 
 posely neglect minute and tedious question by omitting all reference to 
 
 details. inner reflexion and other minor 
 
 ^ I trust the critical scientific reader points.
 
 JETHER-WAVES AND THEIR VARIETIES. 19 
 
 Almost every object upon which the sunlight falls 
 possesses a power of selecting and returning various 
 aether- waves in varying proportions. Were it not so, the 
 sense of sight could never have been developed. If all 
 objects alike absorbed all the rays which fell upon them, 
 then the .whole earth would be one unbroken sheet of 
 black, and the only visible things would be the sun and 
 the fixed stars. If all objects alike reflected all the rays 
 which fell upon them, then the whole earth would be one 
 mass of dazzling white, without distinction of shape or 
 colour. But as each object reflects and disperses the light 
 in different ways from every point of its surface, the 
 discrimination of form, of light and shade, and of colour 
 becomes possible. The existence of the two first-named 
 faculties we must take for granted in this work, though 
 we shall have somewhat further to say about them in the 
 succeeding chapter. But the discrimination of colour, 
 the proper subject of our treatise, demands a little more 
 detailed treatment even at this preliminary stage. 
 
 By colour-perception, then, we shall understand in the 
 present work the power of discriminating hetiveen light- 
 ivaves having different rates of frequency. If any creature 
 shows by its actions that it is endowed with such a power, 
 we shall say that it possesses a colour- sense. Anything 
 more than this it is impossible to prove. Whether the 
 sensation or mental idea hhte, as perceived or thought by 
 a butterfly or a humming-bird, is the same in conscious- 
 ness with the sensation or mental idea hlue as perceived 
 or thought by you and me, we can never know. For, 
 observe, we can never even know, shifted with lan^^ua^e 
 as you and I are, whether my perception of blue is the 
 same as yours; far less then can we know this same 
 thing in the case of animals whose minds are so widely 
 diverse as man's and the butterfly's, and between whom 
 intercommunication is impossible. But we can know by 
 means of language that certain objective differences which 
 differentially affect me also differentially affect you. And
 
 20 THE COLOUR-SENSE. 
 
 so too we can know, by the testimony of voluntary or auto- 
 matic action, tliat these same objective differences which 
 differentially affect us two, in like manner differentially 
 affect birds, fishes, and insects. Such a power of being 
 differentially affected in the particular case of medium 
 sether-waves having quicker or slower rates of recurrence, 
 we call the colour-sense. 
 
 Moreover, just as, in spite of this logical and meta- 
 physical difticulty, no two human beings ever seriously 
 and really doubted the practical and essential identity of 
 their respective sensations, so too in the case before us, 
 I think we shall find such a general agreement in the 
 likes and dislikes of taste, smell, sound, and colour, 
 running through tw^o large groups of animals, whose 
 general habits of life coincide in the main, that we shall 
 not hesitate practically to assert the correspondence of 
 OUT idea of colour with that of beasts, birds, fishes, and 
 insects. That we can 'prove this correspondence no one 
 could for a moment maintain ; but that we should believe 
 it without strict proof, is not, it seems to me, a very 
 dangerous precedent. Eather should we hesitate to 
 introduce into our conception of the uniform order of 
 nature any supposed difference in kind without full and 
 weighty reason. 
 
 A few words more, before we close this unavoidably 
 tedious preliminary statement, as to the nature of the 
 colours objectively existent in nature. As a rule, the 
 bundles of sether- waves which fall upon terrestrial objects 
 are not directly reflected (in other words, the world is not 
 made up of innumerable mirrors) ; nor are they dispersed 
 in their integrity (in other words, the world is not a sheet 
 of snowy white) ; nor are they all wholly absorbed (in 
 other words, the world is not a pall of sombre black). A 
 few objects have sijch surfaces as to reflect totally, like 
 looking-glasses, mercury, or calm water; a few others 
 have such a molecular constitution as to disperse the 
 total beam, like snow-white paper and bleached linen ; a
 
 jETHER-VVAVES AND THEIR VARIETIES. 21 
 
 few more have such a different molecular arrangement as 
 to absorb entirely, like soot, lampblack, and broadcloth. 
 But most bodies have their molecules so set as to absorb 
 certain amounts or orders of gether- waves and to return, 
 certain other amounts or orders. It is these last of which 
 we generally speak as coloured objects. 
 
 Practically speaking, black, white, and grey only diffej? 
 in the amount of waves which they reflect and absorb, not 
 in their kinds. A black object absorbs nearly all ; a white 
 object disperses nearly all ; a grey object absorbs some and 
 disperses some, but in nearly equal proportions of the 
 various kinds. These varieties, then, yield us no sensa- 
 tions of colour proper, but rather of light and shade. 
 
 But many objects — the vast majority of objects, in 
 fact — do not reflect the various constituents of the total 
 wave-bundle in their entirety or in equal proportions. 
 They have such a molecular constitution that they select 
 from the waves which fall upon them certain special 
 waves, whose frequency is the same as their own natural 
 rate of oscillation, or else a multiple of the same. All 
 others they reject and reflect back upon the aether with- 
 out. It is these reflected waves which fall upon our eyes 
 and yield us the sensation of colour. 
 
 Very few natural objects, again, outside the organic 
 class, yield us pure colours. Most of them are of dull 
 mixed hues, like the various earths, sands, rocks, and 
 clays. A very small and highly prized class of inorganic 
 bodies do, indeed, reflect light of a single sort only, as in 
 the ruby, the topaz, the amethyst, and other precious 
 stones. But, as a rule, inorganic bodies, as found in 
 nature, are dull browns, dingy greys, or muddy whites. 
 When we turn to the organic world, however, we find 
 pure colours — that is to say, aether-waves of single or 
 slightly compounded orders — very prevalent. In the green 
 leaves of trees, the brilliant tints of flowers, the lovely 
 hues of fruits, the wings of butterflies, the feathers of 
 birds, we find colour constantly appearing in very pure
 
 22 THE COLOUR-SENSE. 
 
 forms. We shall see reason in the sequel to conclude 
 that these pure waves, rather than the mixed and con- 
 fused systems of inorganic nature, have given rise to the 
 perception of colour in animal organisms. 
 
 And now let me briefly sum up the points which I 
 have been endeavouring to italicise in this preamble. 
 Colour, objectively viewed, is nothing more or less than 
 the different rate of oscillation in different sether-waves. 
 The colour-sense, subjectively viewed, is an exaggerated 
 difference of perception attached to the effects of these 
 external agencies, which really differ so very little between 
 themselves. And the problem of its origin is this — How 
 did these slight differences in the frequencies of sether- 
 waves reflected from various organic or inorganic bodies 
 come to have such disproportionately diverse sensations 
 attached to them in consciousness ? In other words, 
 when red light differs from blue light only in degree, why 
 does red differ from blue, as we know them, in kind ? 
 
 The questions thus proposed our future chapters must 
 endeavour to answer.
 
 ( 23 ) 
 
 CHAPTER III. 
 
 THE ORGAN OF VISION. 
 
 The perception of light is not equally valuable to all 
 classes of animals. It seems to be specially connected 
 with the power of locomotion. Sessile or sedentary ani- 
 mals, as a rule, do not possess any form of visual organ ; 
 while very free and active animals, even of lower organisa- 
 tion, have well-marked eyes. The Echinodermata, for 
 example, are far more highly evolved creatures than the 
 Medusae, but their habits are comparatively sluggish, 
 while the Medusae lead a wandering, predatory life ; and 
 we find that the former class are apparently quite eyeless, 
 while the latter have distinct ocelli, which in some cases 
 reach a considerable complexity of structure. 
 
 Still more clearly is this connection made evident by 
 the metamorphoses of many creatures which pass from a 
 free to a fixed state. The young barnacles and halani are 
 active, locomotive animals, furnished with eyes, antennae, 
 and limbs ; but after a period of activity, they finally fix 
 themselves upon some solid object, and undergo a loss of 
 all their higher sense-organs. Similar changes take place 
 among the parasitic Entomostraca, the Tubicolar Annelids, 
 and many Mollusca. These must be regarded as cases of 
 degradation or retrogressive development. 
 
 Conversely, the Medusae are shown, by their peculiar 
 mode of development, to be the descendants of hydraform 
 polypes. During their sessile stage, when they exactly 
 resemble the true Hydroida, they are as destitute of eyes 
 as the other members of that order. But when they
 
 24 THE COLOUR-SENSE. 
 
 acquire their tentacles and assume the free mode of life, 
 the ocdli are produced together with the other mature 
 organs. This must be regarded as a case of progressive 
 development. 
 
 If we examine the various classes of animals in order, 
 the same general connection between free locomotion and 
 vision will be forced upon us once more. Passing over 
 the Protozoa, which of course are too humble in structure 
 to exhibit any such complex nervous organs as eyes, and 
 beginning with the Eadiata, we see that the only class in 
 that division which possesses high powers of locomotion 
 is the Discophora, or jellyfish, and this is also the only 
 class provided with visual organs. Among the ISTemato- 
 phora or Echinodermata, which are all very sedentary 
 animals, eyes are doubtfully present. The lower vermi- 
 form Articulata are mostly entozoic, and these of course 
 are quite blind ; but the few species which swim freely in 
 water by means of cilia have eyes with distinct lenses. 
 The free leeches have a ring of eyes around the sucking 
 disc. The highest of these vermiform creatures — the 
 Nereidse, Peripatidse, and Polyophthalmidse — are all very 
 locomotive, and all have very highly developed organs of 
 vision. So likewise have the active little Ptotifera. The 
 Arthropoda, or true articulates, yield like results. Thus, 
 among the Crustacea, the Cirrhopoda in their fixed state 
 and the parasitic Entomostraca are sightless ; but all the 
 higher free crustaceans are provided with eyes, which in 
 the active crab and lobster orders attain a high degree of 
 perfection. The flying insects show us eyes of great com- 
 plexity, inferior only to the same organs in vertebrates, if 
 even to those. Yet while most of the Hymenoptera (in- 
 cluding the wasps and bees) have very acute vision, it is 
 noteworthy that the ants, which have practically lost their 
 wings, are almost, and in some species quite, blind. It is 
 also a remarkable fact that the male and female ants 
 which are winged possess three ocdli, wanting in the 
 wingless neuters. Among the Mollusca, in like manner,
 
 THE ORGAN OF VISION. 25 
 
 the lower molluscoid animals, most of which are fixed, 
 have no organs of vision whatsoever; the bivalve mol- 
 lusks, leading very sedentary lives, are provided only with 
 doubtful ocelli ; the relatively active univalves have true 
 eyes, but of low organisation ; while the free-swimming 
 Cephalopods (cuttlefish and their allies) have eyes as 
 highly developed as those of many fishes. Lastly, the 
 vertebrates, the most active division of any, show us the 
 highest visual organs of all. 
 
 We shall have reason similarly to conclude hereafter 
 that the colour-sense, the most advanced mode of vision, 
 is specially strong amongst the flying insects, the fishes 
 (marine analogues of flying creatures), the birds, and the 
 very active forestine mammals. Its high development in 
 these classes is shown as well by the part they have borne 
 in the evolution of fruits, flowers, and coloured organisms, 
 as by their own brilliant hues, the probable result of 
 sexual selection. 
 
 Such a general connection between locomotion and 
 vision is exactly what we should have expected from the 
 nature of the case. A sessile animal, lying in wait for its 
 food, can derive little or no benefit from the possession of 
 visual organs. Even if it could see the approaching prey 
 or the nearing enemy, the knowledge of their vicinity 
 would be useless without the power of locomotion, whereby 
 it might seize the one or avoid the other. Accordingly, 
 most sessile animals are provided with very different 
 organs for the prehension of food, and very different means 
 for withdrawal from threateninfr danojer. Some of them 
 possess long floating arms or tentacles, spread out in every 
 direction to catch the passing prey, which they cannot 
 possibly secure unless it actually come within reach of 
 their grasp. These for the most part withdraw themselves 
 from attack into a solid tube, as in the case of the Sertu- 
 laridse, the Tubicolar Annelids, the Balani, and the Bryozoa; 
 or else curl themselves up into a contracted mass, as in 
 the Hydra, Sea-anemones, Crinoidea, and Eotifera. Others,
 
 26 THE COLOUR-SENSE, 
 
 again, like the bivalve MoUusca, are enclosed for protec- 
 tion in stout shells, and obtain their food by the creation 
 of currents in the surrounding water. A second group, 
 that of the Entozoa, live in the interior of larger animals, 
 often shut off from the access of light, and bathed by the 
 nutritive fluid of their hosts. These, also, apparently find 
 the possession of eyes no benefit to them. Accordingly, 
 animals originally leading a life of either sort here de- 
 scribed — sessile or parasitic — seldom or never acquire the 
 power of vision ; while animals originally possessing that 
 power, which afterwards adopt either of these modes of 
 life, usually or invariably lose their eyes, and become 
 degraded in many other ways, in accordance with the Law 
 of Parsimony, whereby all unnecessary organs become gra- 
 dually obsolescent. 
 
 On the other hand, any animal which has acquired 
 freedom of motion will naturally derive great advantage 
 from any premonition of food or enemies in his neighbour- 
 hood. Such indications will enable him to rush upon the 
 former or to dart away from the latter. There are various 
 modes by which information of the sort may be given, as 
 by those material particles which arouse the sense of 
 smell, or those undulations of the atmospheric or aqueous 
 medium which awaken the sense of hearing ; but the waves 
 of sether described in the last chapter form by far the most 
 certain premonition of all approaching or neighbouring 
 objects, and their reactions finally result in the sense of 
 sisjht. Of course such a sense cannot arise amon^^st 
 animals which live perpetually in the dark, like the cestoid 
 and nematoid worms, the lob-worm, and the common 
 earth-worm, all of whose freer relatives are provided with 
 more or less perfect eyes ; and even those animals which 
 originally possessed visual organs lose them partially or 
 entirely under like circumstances, as we see in the Bopy- 
 ridse, Acarina, and many other parasites, the blind moles, 
 and the well-known sightless fish and reptiles of the Ken- 
 tucky and Carinthian caverns. Similarly, most very deep-
 
 THE ORGAN OF VISION. 27 
 
 sea organisms are blind, though some remarkable excep- 
 tions occur. But amongst all the higher free locomotive 
 and open-air or shoal-water animals we find some form of 
 mechanism for the perception of light-waves, developed in 
 rough proportion to the perfection of the motor system. 
 
 There is good reason to believe that such a mechanism 
 has been independently evolved, time after time, by 
 several distinct leading orders in all the great classes of 
 animals. The eye of the bee, of the cuttlefish, and of the 
 eagle, have each apparently been separately developed 
 from unlike remote sightless ancestors. Accordingly, the 
 diversity of structure among these organs is so great, that 
 it would obviously be impossible to give even a brief 
 account of their leading morphological peculiarities in a 
 single introductory chapter. It must sufBce here to trace 
 out a few of the main steps in the evolution of such 
 organs, from the strictly psychological point of view. 
 
 Simple undifferentiated animal tissue, such as we see 
 in the Ehizopoda, is probably more or less affected by 
 incident sether-waves, like many other organic and inor- 
 ganic substances. But in order to produce even the most 
 vague and indeterminate sensation of light — or rather, 
 sensation having light for its exciting cause, since the sen- 
 sation itself (if any) is probably quite indefinite in quality 
 — certain portions of the external coat must apparently 
 be specialised by the collection of a relatively large 
 amount of matter unusually sensitive to light, and 
 directly connected with some simple or complex nervous 
 centre. Such spots are always marked by the presence of 
 pigmentary substances, which seem to play an important 
 part in the function of sight. The simplest form in which 
 they occur is that of the ocelli among naked-eyed Me- 
 dusse.^ These consist of small masses of pigment cells, 
 surrounding a minute silicious crystal; and they are 
 
 1 Certain more rudimentary ocdli are apparently degraded forms of 
 may perhaps be found amongst the higher organs, they may be left out 
 Mollusca and elsewhere, but as these of consideration here.
 
 28 THE COLOUR-SENSE. 
 
 iisiially placed on the under edge of the umbrella-like 
 disc. It may almost be doubted whether we can fairly 
 attach the idea of sensation in any form to these very 
 simple animals ; but at any rate, we now know with cer- 
 tainty that the ocdli are organs acted upon by light, and 
 responsive to its stimulation. Mr. G. J. Eomanes, how- 
 ever, the latest investigator of the subject, believes that 
 the eyes of Medusae are the simplest possible, because the 
 interval between the stimulus and the response is so 
 relatively great that, were it any greater, the animal could 
 hardly derive any advantage from the organs. 
 
 In such very rudimentary eyes, the only perception (or 
 affection) possible is that of light or its negation, the 
 latter being probably the most important. We may per- 
 haps dimly figure to ourselves its nature by shutting our 
 eyes and then passing one hand between them and the 
 light. Some such vague consciousness (if any) of a 
 change in the environment, is doubtless the utmost con- 
 jectural limit of discophorous vision. 
 
 The first step in progressive development from this 
 earliest form of_yisual organ would consist in a simple 
 increase in the power of distinguishing light from dark- 
 ness. This step appears to be the principal one taken by 
 the ordinary univalve MoUusca (Gasteropoda), whose eyes 
 probably only inform them of such wide distinctions. 
 
 But an eye, to be of any special use, must also give 
 more definite and particular information with regard to 
 surrounding objects, and this information can best be com- 
 municated by some mechanism for the perception of form. 
 A single percipient organ, every part of which is simul- 
 taneously and equally affected, cannot afford indications 
 of such a sort. In order to obtain definite information as 
 to the shape and disposition of neighbouring bodies, we 
 must have a number of separate sensitive elements, each 
 directed towards a point in the environing space, and sub- 
 tending a greater or less angle. Every one of these ele- 
 ments must be provided with a nerve-fibre of its own, and
 
 THE ORGAN OF VISION. 29 
 
 connected with some percipient centre. The minuteness 
 of discrimination must depend upon the number of such 
 sensitive elements and the angles which they respectively 
 subtend. 
 
 To trace out in detail the gradual steps by which such 
 structures were evolved would be both tedious and diffi- 
 cult, though certain materials exist for the purpose in the 
 simple and compound eyes of insects and their larvae, and 
 in the eyes of some lower vertebrates. But it will suffice 
 for our present object to describe, in rough generalisations, 
 the means adopted for the purpose in the most perfect 
 eyes, such as those of bees or of mammals. Here a large 
 number of separate nerve-terminals are arranged in a 
 more or less semicircular form, with single or numerous 
 lenses, which cast the aether-waves upon their percipient 
 surfaces. Each such terminal answers to a separate point 
 in the visual field, and the mechanism of the lens is so 
 arranged that sether-waves from that point alone fall 
 directly on its focal surface. Thus every point in the 
 visual field is represented to the mind by an excitation of 
 the corresponding terminal ; and the number and position 
 of the terminals affected gives the animal a clue to the 
 shape and place of tlie object. The interpretation of these 
 visual symbols into tactual and muscular terms becomes 
 apparently automatic or instinctive in many cases. 
 
 In the human eye, which may be taken as a fair 
 specimen of that found among mammals generally, the 
 main portions of the mechanism may be thus briefly 
 summarised. The external or optical-instrument portion 
 consists of a viscid lens, whose shape and focus may be 
 altered by muscular contraction, so as to converge at will 
 aether- waves from different sources at varying distances 
 upon a given point behind it. The internal or nervous 
 and percipient portion consists of the retina, essentially a 
 network of nerve-terminals, belonging to two different 
 orders, known as rods and cones. The excitation, in vary- 
 ing degrees, of these terminals, gives rise to the perception
 
 30 THE COLOUR-SENSE. 
 
 of the visual field. When no j^art is excited, we get the 
 blank form of visual consciousness known as darkness. 
 "When the whole is feebly excited, as through the eyelids, 
 we get a faint general consciousness of light. When the 
 whole is excited in the normal manner, the eyes being 
 open and turned toward an illuminated held, we get a 
 consciousness of mingled light and shade, yielding us 
 indications of form. Those parts of the visual field 
 which reflect large quantities of sether-waves yield us 
 the sensation of relative light ; those parts which re- 
 flect small quantities yield us the sensation of relative 
 _shade. 
 
 Were an eye so constituted to possess no further powers, 
 the whole visual field would appear to it monochromatic, 
 or rather strictly achromatic, and all objects would look as 
 we see them in a stereoscopic picture. But -the human 
 eye is also capable of distinguishing the quality of light as 
 well as its intensity. Not only can we discriminate be- 
 tween black, white, and grey, between much and little 
 illumination, but we can also discriminate between red, 
 blue, yellow, and green, between aether- waves of greater 
 or less frequency. This last mode of perception — the 
 colour-sense — is the only one with which we are concerned) 
 in the present volume ; and we shall therefore leave aside 
 all other questions of visual development as foreign to our 
 purpose. Moreover, as our point of view is psychological 
 rather than physiological or anatomical, we shall regard 
 the problem of its origin solely from the mental side, 
 without inquiring into the nature of the mechanism em- 
 ployed or the functions of its various parts. 
 
 Any other method of inquiry would at present be pre- 
 mature. Even in the human eye, where the existence of 
 a colour-sense is certain, we know little or nothing about 
 the mode of its production. There are good reasons, it is 
 true, for suspecting that colour-perception is the special 
 function of the cones, while the discrimination of light and 
 shade is set down to the rods ; both because we find colour-
 
 THE ORGAN OF VISION. 31 
 
 perception most pronounced in those parts of the retina 
 where the cones are most thickly massed, near the central 
 point, and less active in those parts where they are rela- 
 tively few, near the periphery;^ and because the cones 
 are wholly wanting in the eyes of nocturnal animals, 
 which only require to distinguish between light and shade. 
 But the physiology of the cones is much disputed, and the 
 accepted theories can only be regarded as provisional. 
 Moreover, in insects, where the colour-sense is most cer- 
 tain after the human species, we have not even a conjec- 
 tural hypothesis of the mode in which it acts. 
 
 It may, however, be worth while, before we pass on to 
 our proper subject — the origin and development of the 
 colour-sense, — briefly to state the current theory as to 
 the mechanism for the perception of colour in mankind. 
 This theory, first proposed by Young, and adopted by 
 Helmholtz and Schultze, supposes that each spot on the 
 retina contains a number of nerve-terminals, each of 
 which is capable of excitation by one colour only, or, in 
 other words, by aether- waves having a determinate rate of 
 rapidity, and no others. By these terminals, a compound 
 aether-wave would be decomposed into its constituent 
 elements, which would arouse sensation in the correspond- 
 ing nerve-fibres. It is usual to assume three such primary 
 percipient elements, adapted respectively to the stimula- 
 tion of red, green, and violet light. All other colours 
 would be represented in consciousness by combinations of 
 these in varying degrees of intensity. It is probable, 
 however, that the real number of separate kinds of terminal 
 is vastly greater. Moreover, considerable doubt hangs 
 over the mode of excitation in the cones themselves, each 
 of which is supplied with a large number of ultimate 
 nerve-fibres (axis cylinders), and is therefore in all pro- 
 
 1 See papers by Dr. Aug. Char- p. 924; and by Landolt and Char- 
 
 pentier, " De la Vision avec les Dif- pentier, Ooraptes Rendus, i8th Feb- 
 
 ferentes Parties de la Retine," in ruary 1878, p. 495. 
 Archives de Physiologic, No. 6, 1877,
 
 32 THE COLOUR-SENSE. 
 
 bability a compound, not a simple, percipient element. 
 It has lately been suggested that each cone may be pro- 
 vided with separate portions for the perception of the 
 various elementary colours; and these portions may be 
 divided either longitudinally or transversely. But the 
 whole subject is still wrapped in the greatest obscurity, 
 viewed from the physiological side; and it is only by 
 approaching it psychologically that we can hope to arrive 
 for the present at any decisive result.
 
 ( 33 ) 
 
 CHAPTER IV. 
 
 INSECTS AND FLOWERS. 
 
 Now that we have examined a few amongst the various 
 modes by which waves of aether, as a whole, may affect the 
 sensory system of animals, let us turn at last to our more 
 proper subject, and inquire by what steps the different 
 kinds of sether-waves came to be differentially cognised 
 in consciousness as red, green, yell.ow, or blue. We find 
 ourselves now face to face with the ultimate problem 
 which we have determined, if possible, to solve in the 
 present vol-ume. We must see what immediate advantage 
 animals could gain from the possession of a nervous 
 structure capable of that differential stimulation by the 
 diverse varieties of light which we know subjectively as 
 the colour-sense. 
 
 There are two f^reat classes of animals amoncjst which 
 the existence of a colour-sense is most certain, and its 
 reactions upon the external world most conspicuous. 
 These are the articulates and the vertebrates. The first 
 class affords us the beautiful butterflies, beetles, and 
 crustaceans ; the second gives us the golden coats of fish 
 and lizards, the exquisite plumage of tropical birds, and 
 the striped or dappled skins of the fur-bearing mammals. 
 To the first we owe the existence of flowers, to the second 
 we must refer the colours of all bright-hued seeds and 
 fruits. Accordingly, for every practical purpose, we may 
 narrow down our inquiry to the consideration of these two 
 great classes; and amongst the articulates, the division 
 which most obviously calls for special notice is that of 
 
 c
 
 34 THE COLOUR-SENSE, 
 
 insects. So our first task must be to account for tlie 
 existence of a colour-sense in the insect eye, and to 
 discover what were the objects for the sake of which this 
 mode of perception was developed ? 
 
 Clearly the inorganic world does not offer us any chance 
 of a satisfactory solution. The dull clay and grey-blue 
 rocks have none of the brilliancy and purity which is 
 needed as the groundwork for a first differential stimula- 
 tion. Such complex wave-systems as they reflect would 
 be too mixed, too confused, too indefinite, too variable to 
 afford any means of clear recognition by an early half- 
 developed sense. And even if it were otherwise, the 
 insect does not need to trouble itself about the chemical 
 or mineralogical character of the ground upon which it 
 crawls or alights. A few rare inorganic bodies do indeed 
 possess the requisite simplicity and richness for the sup- 
 posed first stimulus, as we see in the ruby, the emerald, 
 the sapphire, and the topaz ; nay, some much commoner 
 substances, such as red sandstone and blue granite, are 
 endowed with a moderately bright and pure colour. All 
 these bodies, however, lie open to the fatal objection that 
 they do not in any way contribute to the welfare of the 
 insect or animal which looks upon them. A sense highly 
 developed by other means may (as we see in the savage 
 or barbarous love for precious stones) be agreeably exercised 
 upon such objects ; but in order to give that sense its first 
 start, some direct advantage must be secured by the new 
 mode of discrimination, either in the pursuit of food, the 
 search for mates, or the avoidance of enemies. No faculty 
 can possibly be originally developed for the sake of mere 
 useless exercise upon unessential acts ; altliough, as we 
 shall see when we come to examine the aesthetic value of 
 colour, each faculty, when once fully established, admits 
 of immense pleasurable extension by being directed to- 
 wards such secondary ends. 
 
 The same line of argument applies to those occasional 
 displays of colour which are due to transient effects of
 
 INSECTS AND FLOWERS. 35 
 
 sunlight, tlirough the medium of a refractive vapour. 
 Long before the first insect vision learnt to discriminate 
 between red, yellow, and blue, the various rays which we 
 call by those names poured down unnoticed upon the 
 primeval world. Then, as now, the rainbow scattered 
 ten thousand colours upon the dull grey clouds, but no 
 eye drank in the diverse stimulation from its gorgeous 
 undertones of melting orange and exquisite green. Then, 
 as now, the sunset crimsoned the west with dying glory, 
 and bathed the horizon in floods of golden light, but 
 no living thing beheld its loveliness or revelled in its 
 changeful wealth. Such distant and exceptional displays 
 could have little or no effect upon the life of tiny creatures 
 that picked out in fear and trembling a precarious liveli- 
 hood amid palaeozoic forest shades. Even our own nearest 
 mammalian relatives seem totally unconcerned with regard 
 to the magnificent pictures which are spread nightly 
 before their eyes in tropical plains. Indeed, the savage 
 members of our own race, or even the stolid peasantry 
 of European countries, appear to notice such useless 
 phenomena with little curiosity or admiration. Part of 
 our business in this work will be to trace out the slow 
 steps by which the love of bright-coloured food led on to 
 the choice of bright- coloured mates ; and how this again 
 brought about a liking for bright colours in general, which 
 shows itself in the savage predilection for brilliant dyes 
 and glistening pebljles ; till at last the whole long series 
 culminates in that intense and unselfish enjoyment of rich 
 and pure tints which makes civilised man linger so lovingly 
 over the hues of sunset and the myriad shades of autumn. 
 But if even the lower types of humanity are little stirred 
 by such glowing sights, how could we expect the humble 
 insect to have developed a new sense for their perception? 
 Here, as elsewhere, the disinterested affection can only be 
 reached by many previous steps of utilitarian progress. 
 
 It is to the organic world, then, the insect's practical 
 world of food and prey, that we must look for the first
 
 36 THE COLOUR-SENSE. 
 
 development of the colour-sense. In the origin of flowers 
 we shall find also the origin of the insect's perception ; 
 and though the inquiry will seem at first to lead us rather 
 far afield from our proper path, I think we cannot do better 
 than steadily set to work at unravelling the tangled thread 
 of their mutual influence. In order to do so effectively 
 we must first glance at the condition of the world before 
 flowers, fruit, or colour-sense had yet begun the first stages 
 of their reciprocal existence. 
 
 Brongniart long ago pointed out that the periods of 
 jieolofrical vecretation fall into three main divisions, which 
 he called the reigns of acrogens, of gymnosperms, and of 
 angiosperms. Acrogens are plants like ferns and mosses, 
 which bear no fruits or fiowers, but produce their young 
 by means of spores, Gymnosperms are plants like pines 
 and firs, which have their blossoms and seeds in dry scaly 
 cones. Angiosperms are true flowering plants, often bear- 
 ing bright bells or brilliant clusters of bloom, and always 
 having their seeds enclosed in some more or less con- 
 spicuous form of enveloping fruit. These three kinds of 
 plants succeeded each other through the geological series 
 in the order here assigned to them — members of every 
 class still surviving on our earth, but outnumbered and 
 overlived, as a rule, by those of the newer and more suc- 
 cessful classes. 
 
 For our present purpose, however, we might say more 
 truly that the great epochs of vegetal life naturally fall under 
 three similar heads — the reign of flowerless plants, the reign 
 of wind-fertilised flowering plants, and the reign of insect- 
 fertilised flowering plants.^ These three heads correspond 
 in the main with Brongniart's divisions, but they serve to 
 bring more clearly into prominence the salient f anctional 
 facts with which we are here especially concerned. 
 
 Flowerless plants, or cryptogams, are those which have 
 
 1 See an excellent article on " The in the "Popular Science Review " for 
 Geological Antiquity of Insects and January 1878. 
 flowers," by Mr. J. E. Taylor, F.G.S,,
 
 INSECTS AND FLOWERS. 37 
 
 no conspicuous organs for the production of seeds or fruits. 
 Their chief varieties are known to all as fungi, sea- weeds, 
 mosses, and ferns. Floweriug plants, or phanerogams, are 
 those which possess more or less conspicuous organs for 
 the production of seeds and fruits. They may he divided, 
 not structurally but functionally, into two great sub- 
 classes — the anemophilons and the entomophilons. Ane- 
 mophilous plants include all species in which the pollen 
 of the male flower is wafted to the stigma of the female 
 flower by means of the wind. Entomophilous plants 
 include all species in which the pollen is carried to the 
 stigma upon the head, legs, or bodies of insects. Each of 
 these classes possesses numerous species in which various 
 modifications have been produced to aid fertilisation by 
 the appropriate means. Some of these modifications we 
 shall examine as we proceed ; for others, the inquirer must 
 be referred to special works upon the subject.^ 
 
 In the great forests of the Carboniferous era few or no 
 flowers diversified the unbroken green of the primeval 
 w^orld. Almost all the plants which raised their heads 
 above the dark mould of those forgotten deltas were acro- 
 gens or other cryptogams. Like the ferns and mosses of 
 our own epoch, they reproduced their kind, not by means 
 of flowers and seeds, but by inconspicuous little spores, each 
 of which rooted itself on the ground independently, and 
 grew into a young plant. Many of them resembled the 
 bristling horse-tails of modern waste lands, magnified a 
 hundred-fold, so as to present the appearance of huge 
 jointed trees, to which geologists have given the name of 
 calamites. Others were rather the gigantic analogues of 
 our creeping club-mosses, with monstrous tliickened stalks, 
 clad in a sort of plated armour, and known to science as 
 sigillarice, lepidodendra, and halonice. Yet others, again, 
 grew like the tree-ferns of our latter-day tropics, with 
 
 1 See, in particular, Mr. Darwin on Flowers in their Relation to Insects," 
 the "Fertilisation of Orchids," Sir and the works of Sprengel, Delpino, 
 John Lubbock on "British Wild and H. Miiller.
 
 38 THE COLOUR-SENSE. 
 
 graceful waving fronds, whose delicate outline is still 
 faithfully preserved on the flat surface of many a coal- 
 seam. But amongst them all not a single bright blossom 
 anywhere displayed its crimson petals or its golden bells ; 
 not a single fruit gleamed red or orange among the em- 
 bowering foliage. Green, and green, and green once more ; 
 wherever the eye of an imaginary visitor could turn, it 
 would have rested on one unbroken sea of glistening 
 verdure. 
 
 A few phanerogams there were, it is true, among this 
 mass of cryptogamic vegetation, but they belonged entirely 
 to the pine and cycad families, which grow their seed 
 in hard scaly cones, and would never be included amongst 
 the flowering plants by any but a technical botanist. 
 Moreover, as their blossoms are green when young and 
 brown when ripe, they would form little or no exception 
 to the prevailing tints of the palaeozoic world. Even if a 
 few primitive grasses of some archaic form intermingled, 
 as is possible, with the mosses and liverworts which car- 
 peted the ground beneath the conifers, the tree-ferns, and 
 the titanic lycopodites, yet these themselves would bear 
 their seed in green panicles on a waving stem, and would 
 still add no new element of colour to the one monotonous 
 field. ISTot a trace of any vegetal organism has yet been 
 discovered in the primary rocks to which we can even 
 conjecturally attribute a possible tinge of red or orange, 
 blue or yellow, in the form of flowers or fruit. 
 
 Equally unvaried, no doubt, was the hue of the articu- 
 late creatures which fed amid those green jungles of tangled 
 fern and club-moss. A few scorpion-like insects, an occa- 
 sional cockroach, beetle, or other uncanny creeping thing, 
 may still be detected in the dehris of a forgotten world ; 
 but no trace of a bee, a moth, or a joyous butterfly can be 
 discovered in these earliest ai^es of animal life. Scarlet 
 
 o 
 
 berry and crimson blossom, gorgeous bird and painted in- 
 sect, were all equally absent from the unvaried panorama 
 of careen overhead and brown beneath.
 
 INSECTS AND FLOWERS. 39 
 
 Such, we may suppose, was the general appearance of our 
 earth's surface before the colour-sense had given rise to all 
 the diverse wealth of hues which gladden the woodland 
 and the meadow for modern eyes. First to be developed 
 among the bright-coloured objects of the newer era were 
 the brilliant whorls of abortive leaves which ordinary 
 people know as flowers. Their origin affords us the key 
 to all the subsequent evolution both of coloured organisms 
 and of the sense whereby they are perceived. 
 
 Tlie transition from the wholly green and spore-bearing 
 cryptogams to the bright hues of entomophilous blossoms 
 was through the intermediate stage of anemophilous 
 plants. Already, in the Carboniferous era of the palaeozoic 
 world, we have seen that these org^anisms had bef]jun to 
 exist. The causes which led to their development throw 
 so much light upon the subsequent evolution of insect- 
 fertilised species, that we must pause for a moment to 
 examine the history of their first appearance. 
 
 Every individual cryptogamic plant' produces spores or 
 young individuals by its own unaided generative power. 
 It needs no co-operation from a partner of a different sex 
 to fertilise the embryo germs which it puts forth. True, 
 a male and a female element may always be discovered 
 within the plant itself ; but their occurrence does not mili- 
 tate against the general statement that cryptogamic repro- 
 duction is essentially hermaphrodite or non-sexual in its 
 character, For real sexual generation consists funda- 
 mentally in this, that two independent parents combine 
 to produce a brood of young, partaking equally, on the 
 average, of the idiosyncrasies of each. Now, Mr. Darwin 
 has shown 1 that whenever an organism is the result of 
 interaction between two anterior organisms, it possesses 
 a vigour, a plasticity, and a hardiness wdiich enable it to 
 thrive far more easily than any similar organism resulting 
 from the generative action of a single parent. Our great 
 teacher has proved that self-fertilised flowers produce 
 
 ^ On " Cross-Fertilisation," /jassm.
 
 40 THE COLOUR-SENSE, 
 
 relatively weak, puny, and unhealthy young ; while cross- 
 fertilised flowers produce relatively strong, hearty, and 
 vigorous young. The general principle upon which this 
 effect depends has been exposed, with his usual luminous 
 insight, by Mr. Herbert Spencer;^ but unfortunately its 
 explanation would involve too many wide questions of 
 biological theory for reproduction here. 
 
 If, then, by any special combination of circumstances, 
 it should happen at any time that certain plants acquired 
 the habit of fertilising the female element in one individual 
 by the male element of another, it would necessarily re- 
 sult that such plants would produce exceptionally healthy 
 yaung, and so gain unusual advantages for their descen- 
 dants in the struggle for life. And this is exactly the 
 case with flowering as opposed to flowerless plants. While 
 the latter still continue to fertilise themselves in every 
 instance, the former possess a special set of male and 
 female organs, often situated on different individuals, and 
 almost always so di&posed that the pollen of any particular 
 flower is specially prevented from quickening the ovules 
 of its own pistil. Indeed, the very effect which Mr. 
 Darwin's experiments show us on a small scale, nature 
 herself here shows us on a large scale \ for when once the 
 flowering plants had been introduced into the world, their 
 superior vitality gave them such an increased chance in 
 the struggle for life that they have now overrun the whole 
 earth, and almost lived down the very memory of their 
 cryptogamic predecessors, whose huge forms diversified the 
 landscape of a paleozoic wild. Step by step, throughout 
 the secondary and tertiary periods, we find the acrogens 
 decreasing in number of species, in frequency of indivi- 
 duals, in size and height ; while step by step we find the 
 flowering plants dispossessing them over the whole world, 
 and growing into more and more varied forms, with ever- 
 increasing numbers and ever-widening girth ; until at last 
 forest trees, and herbs, and grasses cover the face of hill, 
 
 1 Principles of Biology, vol. i. chap. x.
 
 INSECTS AND FLOWERS. 41 
 
 and plain, and valley ; while only in a few tropical jungles, 
 or a stray patch of neglected English warren, do we still 
 discover the degenerate descendants of those giant tree- 
 ferns and horse-tails which flourished without a rival over 
 vast continents during the earlier ages of vegetal life. 
 
 Among these flowering plants, which thus substituted 
 the sexual for the hermaphrodite method of reproduction, 
 the anemophilous or wind-fertilised division was the first 
 to appear. The ever-moving currents of air naturally 
 offer the earliest and simplest agency for the dispersion 
 and transference of pollen from the stamens of one blos- 
 som to the pistil of another. Accordingly, we find the 
 pines and cycads, both of which bear their flowers in the 
 form of cones or other unnoticeable bunches of floral 
 organs, as the earliest representatives of flowering plants. 
 After them, in geological order, come the monocotyledons, 
 represented by grasses, rushes, and other spiky species, 
 whose blossoms assume the shape of green panicles or 
 waving plumes ; while, last of all, come the dicotyledons, 
 whose anemophilous varieties are usually distinguished by 
 those pretty hanging clusters of stamens or pistils which 
 we know as catkins. Now, in all these cases, the mature 
 male organs, covered with the fertilising pollen, necessarily 
 protrude from the scales, sheathes, or glumes which guard 
 their younger stage, and offer large surfaces to the wind, 
 whose aid they require in the dispersion of their stores. 
 Similarly, the pistils or female organs must possess spread- 
 ing and feathery stigmatic processes, wherewith to catch 
 any stray grains of pollen which the unconscious wind 
 may waft to their neighbourhood. Hence these blossoms 
 consist usually of bundles or masses of male and female 
 organs, hanging out in* such a way as to secure the favour 
 of every passing breeze; but they never possess those 
 bright whorls of coloured leaves which make up the popular 
 idea of a flower. The latter notion is mainly based upon 
 the peculiar structure of entomophilous plants. 
 
 As wind- fertilised flowers can only hope that a small
 
 42 THE COLOUR-SENSE. 
 
 fraction of their pollen will reach the stigmatic surface 
 of their brides, and there be drunk in to fertilise the em- 
 bryo within, they must needs produce enormous quan- 
 tities of useless material, to be dissipated by the storm in 
 every direction. The amount of pollen thus wasted is 
 often incredibly great. The floor of a pine forest during 
 the flowering season frequently lies thickly covered with 
 the rich yellow dust that cost so much useless energy to 
 the parent plant. Occasionally even showers of pollen 
 grains have been noted in the neighbourhood of great 
 forests or of fields thickly sown with anemophilous spe- 
 cies. At Mumbles, near Swansea, a yellow-coloured rain 
 fell in 1850, and left large spots of ochre-like matter, 
 which proved on close examination to consist of willow- 
 pollen.^ Similar showers, produced by the Canadian 
 conifers, have often been observed along the shore of the 
 great lakes, and others have taken place in Zurich, in 
 Brunswick, and in Inverness-shire. Of course, the loss 
 of energy which this waste expenditure involves for the 
 parent plant must necessarily be very great ; and any 
 change in its circumstances which produced a more econo- 
 mical mode of applying the pollen to the pistil would 
 naturally result in a saving of material, and so give 
 the plants in which it occurred a fresh advantage over 
 their less fortunate compeers. Such a change we see 
 in the utilisation of insect agency by the entomophilous 
 plants. 
 
 Even as early as the Carboniferous period we find traces 
 of terrestrial articulates which might have sought their 
 food among the few coniferous blossoms of that mainly 
 flowerless world. Most of the plants about them were 
 hard, scaly, innutritions acrogens, whose stem and leaves 
 contained large quantities of silica, as we still see to be 
 the case in the horse-tail family, their nearest modern 
 allies. But the stray flowering species which grew at 
 rare intervals in the midst of the calamites and lepido- 
 
 ^ Balfour's Class-Book of Botany, p. 562.
 
 INSECTS AND FLOWERS. 43 
 
 dendra must have offered special] attractions to insects 
 (or their undifferentiated ancestors) in the shape of soft, 
 edible, nutritious pollen. And as the insects travelled 
 from one flower to another, carrying on their legs or heads 
 the fertilising powder, they would supply the plant with 
 a cheaper and more certain means of impregnation than 
 that afforded by the wasteful wind. Accordingly, any 
 plants which offered special advantages to insects, in the 
 shape of pollen, sweet juices, or soft edible matter, would 
 thus obtain an extra chance in the general competition 
 for a share of the earth's surface, and hand down the 
 peculiarity to an ever-increasing brood of descendants. 
 So, when once the entomophilous flora began to exist, it 
 gained ground rapidly on the anemophilous division, as 
 the anemophilous flora had previously gained ground on 
 the fiowerless plants, until in our own day the two divi- 
 sions divide the world between them ; while in the future, 
 doubtless, the balance will be still further disturbed in 
 favour of the younger and more vigorous races.^ 
 
 Of course, the change from fertilisation by wind to 
 fertilisation by insects could not be accomplished without 
 many structural modifications, whereby the flower became 
 adapted to the new and more specialised agency thus 
 afforded it. Some of these modifications were concerned 
 with the food offered by the flower to the fertilising 
 insect. At first this food doubtless consisted of pollen 
 alone, but after a time there was added that sweet matter 
 known as sugar or honey, wdiich is contained more or less 
 in most plants, and which is especially developed during 
 the two processes of flowering and fruiting. Now sugar, 
 by its crystalline condition, so rare amongst energy-yield- 
 
 1 The botanical critic need hardly adaptive accident. The general reader 
 
 be told that I am here intentionally would only be confused by constant 
 
 neglecting the more deep-seated references to the cross-division of 
 
 structural differences, which depend monocotyledons and dicotyledons, 
 
 upon the line of descent, and con- especially when complicated by the 
 
 sidering only the superficial func- peculiar geological position of the 
 
 fi07ia^ differences, which depend upon gymnosperms.
 
 44 THE COLOUR-SENSE. 
 
 ing organic products, seems specially adapted for afford- 
 ing pleasurable stimulation to the gustatory nerves of 
 animals ; ^ and it has therefore been stored up by plants 
 in all those cases where the attraction of some animal 
 ally is desirable for their protection or the continuance of 
 their species. Certain plants lay it by in glands upon 
 their stems to allure the harmless ants who protect them 
 from the ravages of their leaf-cutting congeners.^ Others, 
 again, as we shall see in a later chapter, collect it in the 
 pulpy covering of their seed-vessels, and thus induce 
 parrots, pigeons, or monkeys to devour and distribute the 
 undigested kernel. Yet others distil it in the recesses of 
 their blossoms, and so tempt the bee, the butterfly, or the 
 humming-bird to rifle their labyrinthine storehouses, and 
 unconsciously aid in the impregnation of their embryos. 
 The honey thus elaborated by the flower has become at 
 last the main ultimate attraction for all fertilising insects, 
 whose most specialised forms we find in the common hive- 
 bees of domestic economy. 
 
 A second class of modifications is connected with the 
 shape of the flower. Most entomophilous blossoms pos- 
 sess, in addition to the pistil and the stamens, two other 
 whorls of floral leaves — the corolla and the calyx. In the 
 simplest form of flower, these whorls consist of separate 
 leaves (petals and sepals), as we see in the buttercup or the 
 dog-rose. But in certain more specialised flowers the long- 
 continued action of the insect-fertilisers has unconsciously 
 selected those blossoms which most easily suited them- 
 selves to the form of their visitor, and has thus produced 
 a united corolla, all whose petals are joined into a regular 
 tube or cup, as we see in the Canterbury bell, the con- 
 volvulus, and the lily of the valley. A number of these 
 tubular flowers united form the head of the daisy, the 
 marigold, and the sunflower. In still more specialised 
 cases the cup becomes irregularly lobed, so as to suit still 
 
 1 See my "Physiological JSstlie- ^ F. Miiller in " Nature," June 7, 
 
 tics," p. 68. 1877.
 
 INSECTS AND FLOWERS. 45 
 
 more closely the shape of its insect friend — a change 
 whose first steps we see in honeysuckle and foxglove, 
 while its completed stage is shown in mint, dead-nettle, 
 snapdragon, lobelia, and orchids. All these varieties of 
 entomophilons flowers we shall have to examine at greater 
 length hereafter. 
 
 But the third class of modifications, the important class 
 for our present subject, is that which refers to the colouring 
 of flowers. By far the most conspicuous difference between 
 entomophilous and anemophilous blossoms is the difference 
 of colour. While wind-fertilised plants have seldom more 
 than a few brownish scales or tiny green sepals around 
 their fructifying organs, insect-fertilised plants are almost 
 always distinguished by the growth of large, brilliantly- 
 coloured petals outside the essential whorls, which act as 
 guides and allurements to the eyes of bees or butter- 
 flies. These wide, expanded, and costly structures have 
 absolutely no other purpose in the vegetal economy than 
 that of attracting the fertilising agents ; and they afford 
 by themselves a strong presumption of developed colour- 
 sense in the creatures for whose guidance they have been 
 slowly evolved. Let us see by what steps they can gradu- 
 ally have reached their present conspicuous dimensions. 
 
 We will suppose that some of the flowering plants in 
 the early ages of the world showed some slight tendency 
 to develop the various attractive structures which we 
 now observe in their completed form. They offered to 
 insects the soft and nourishing pollen, and perhaps, too, 
 small quantities of stimulating saccharine matter. Such 
 saccharine matter we know is always evolved during the 
 opening of flowers, at least in small amounts, for the 
 nurture of the blossom itself; and there is nothing extra- 
 vagant in the supposition that occasional individuals might 
 produce it in more than the average quantity, and so might 
 attract more than the average share of insect attention. 
 In like manner they may possibly have shown a tendency 
 to develop bright-coloured leaves around their essential
 
 46 THE COLOUR-SENSE. 
 
 organs ; and if the eyes of insects were capable of distin- 
 guishing these bright colours, in however imperfect a 
 degree, it would naturally follow that the hues would go 
 on deepening from generation to generation among the 
 plants, while the perception would go on sharpening itself 
 from generation to generation among the insects. For 
 while the flowers which thus become more and more 
 readily distinguishable by their fertilisers would thereby 
 better secure the chance of descendants, the insects which 
 most readily distinguished flowers would thereby secure 
 for themselves the greatest amount of the available food- 
 stores. So that, supposing such a tendency once set up 
 on either side, we can see every reason why it should 
 ultimately develop to its present noticeable extent. 
 
 This, however, is mere a 'priori hypothesis. The experi- 
 mental philosopher will ask at once whether we have any 
 grounds for believing that the tendency in point would 
 ever be set up. I think we have such grounds in abun- 
 dance, and although the question involves a little closer 
 application and more technical considerations than any we 
 have yet encountered, I shall ask the reader patiently to 
 follow me through the exposition, because it really encloses 
 the whole fundamental basis of the developed colour-sense 
 in every terrestrial animal. The point which we have first 
 to consider is this : Did flowers show an original tendency 
 to the production of coloured adjuncts prior to the selec- 
 tive action of insects ? And when we have answered that 
 question we must proceed to the second one : Did insects 
 possess any tendency vaguely to discriminate colours 
 apart from the reactive influence of entomophilous 
 flowers ? 
 
 The solar radiations, falling upon the green portions 
 of plants, are the sole ultimate source of all the energy 
 existing in the animal or vegetal organism. Under their 
 influence, the plant separates carbon and hydrogen from 
 the oxygen with which they were originally combined, 
 stores them up in some part of its own tissues, and turns
 
 Los Angeles, Cal. 
 
 INSECTS AND FLOWERS. 47 
 
 the free oxygen adrift iipoii the atmosphere around. In 
 this process, the kinetic or active energy of the solar 
 undulations has assumed the potential or dormant form. 
 The potential energy thus laid up is associated with the 
 carbon and hydrogen of the plant on the one hand, and 
 with the free oxygen of the atmosphere on the other. 
 Whenever they may recombine, the dormant energy will 
 assume once more the active form, and be yielded up in 
 the shape of mechanical motion, heat, or light. 
 
 This reconversion of contained energy into its mobile 
 mode may be brought about in many ways. Sometimes 
 the plant may be cut down and burnt, as we all see in 
 wood-fires, and then the energy will be given out rapidly 
 as heat and light, while part of it will also go off as motion 
 of the surrounding air. Sometimes the plant may fall as 
 it lies, be changed into peat or coal, and finally burnt, like 
 the w^ood, in a human grate, with the same concomitant 
 phenomena as in the first case. Sometimes, too, these 
 same materials — w^ood, coal, peat — may be used to feed a 
 steam-engine, and mainly converted into visible move- 
 ments of the locomotive or its parts, which are finally 
 dissipated by friction into the circumambient aether. In 
 yet other cases, the plant may be eaten by an animal, and 
 then its elements will recombine within his body with 
 the free oxygen supplied by his lungs or gills, and will 
 give off heat and motion, less conspicuously perhaps, but 
 quite as truly as in the engine. There remains, however, 
 another instance, fully as common as these, yet far less 
 generally observed — the instance in which the elements 
 recombine in the tissues of the living plant, and yield up 
 their dormant energies in producing growth, development, 
 and rearrangement of its parts. This metamorphosis of 
 energy (known as Stoffcuechsel or Metastasis) actually takes 
 place in every active portion of a plant which does not 
 itself assimilate nutritive material from the surrounding 
 air. And all such parts of plants may be considered as 
 carrying on essentially animal functions — that is to say,
 
 48 THE COLOUR-SENSE. 
 
 functions by which potential energy becomes kinetic, 
 oxygen unites with carbon to form carbonic anhydride, 
 heat is evolved, and motion is given out. 
 
 The most noticeable eases of such quasi-animal processes 
 may be seen in the germination of s^eds, the growth of 
 bulbs and tubers, the unfolding of flowers, and the ripening 
 of fruits. In fact, every growing and active part of a 
 plant, unless it be itself assimilating kinetic energy from 
 solar undulations, must necessarily be using up energies 
 assimilated elsewhere. Otherwise, it would be manufac- 
 turing new energies for itself out of nothing, which we 
 know to be impossible, and inconceivable as a direct con- 
 travention of all physical and mental laws. 
 
 Now, the active agent of deoxidation in ordinary plants 
 is that peculiar compound substance known as chlorophyll, 
 the pigment which gives a green ■colour to healthy leaves. 
 Hence all the active organs of plants are usually green in 
 hue, because the chlorophyll is seen through the transparent 
 cell-walls of the epidermis. But there are reasons for 
 believing that wherever the reverse process of metastasis 
 is taking place, other bodies are frequently formed, which 
 reflect the light in slightly different manners, and so give 
 rise to tints of red, orange, yellow, pink, mauve, purple, or 
 blue. We will examine the evidence in order, and see 
 whether we can gather from it any inference as to the 
 origin of coloured flowers.^ 
 
 In the first place, even in active leaves, the presence of 
 green chlorophyll is often masked by the occurrence of 
 other pigments, which give the foliage a tinge of brown, 
 russet, scarlet, or golden yellow. Cases of this sort are 
 
 1 In the succeeding argument I have 636), "becaTise the results hitherto 
 
 neglected for a while the difficult eh em- reached are still somewhat indefinite, 
 
 ical question of the relations between and becaiise the consideration of the 
 
 chlorophyll, xanthophyll,erythrophyll, chemical changes involved is better 
 
 and the other colouring matters of relegated to the end of the physical 
 
 plants (see Sorby in Proc. Royal and physiological inquiry, upon wliich 
 
 Soc, vol. XV. p. 433, and vol. xxi. we must now enter. A fuller state- 
 
 p. 442 ; also in the English version ment on this point will be found on 
 
 of Sach's Teit-Book of Botany, p. a later page.
 
 INSECTS AND FLOWERS. 49 
 
 commonly known in the copper beech, the red cabbage, 
 and the various species of purple coleus, crimson-hearted 
 caladium, pink dracsena, or pale mauve begonia. Here 
 the colouring matter doubtless belongs to some one among 
 the many by-products of vegetal physiology, which must 
 necessarily occur from time to time in one part or another 
 as the results of assimilative or metastatic changes. But 
 in the more noticeable cases of coloured juices or pig- 
 ments, other than green, we shall find that the special 
 colouring matter is almost always more or less connected 
 with those portions of the plant where energy is being 
 liberated, and where accordingly oxidation is necessarily 
 taking place. ^ 
 
 The only class of plants in which green rarely — we 
 might almost say never — occurs, is that of fungi. But 
 fungi differ from all other plants (except a few parasites 
 and saprophytes) and agree with animals in this, that 
 they derive their energies not directly from solar undula- 
 tions, but from organised matter already contained in the 
 soil or matrix on which they grow. And there is some- 
 thing in the vivid orange, yellow, lilac, and crimson of 
 their hues, as well as in the pasty whiteness of their 
 common tissues, which strikingly recalls the possibly 
 adventitious colouring of the lower animal forms, such as 
 sea-anemones, starfish, and medusee. This analogy, as we 
 shall note hereafter, is not without a deep significance for 
 our present purpose.^ 
 
 When, however, we go on to those plants which have 
 normally green leaves, we see a like result. In the first 
 place, dying leaves, as we all know, assume the most bril- 
 
 ^ See on the whole process of metas- &c. A botanical work "which should 
 
 tasis, Sach's "Text-Book of Botany," extend to the plant organism the 
 
 p. 626, seq. It is to be regretted same strictly physical treatment as 
 
 that the author of this otherwise Hermann's "Physiology" applies to 
 
 lucid and valuable book has not the animal organism is still a desider- 
 
 brought more prominently into atum. 
 
 notice the question of the energies ^ See also Sorby, in Proc. Eoy. 
 
 involved, and the transformations Soc, vol. xxi. pp. 475-480. 
 which they undergo, by oxidation,
 
 so THE COLOUR-SENSE. 
 
 liant tints of red, yellow, orange, and brown. Even in 
 our own damp and uncertain climate, the Virginia creeper 
 dows with the richest crimson, while the forest trees 
 shade off into delicate tones of golden gloss and occasional 
 flashes of deep scarlet light. But in American wood- 
 lands these displays assume grander dimensions and more 
 glorious beauties, forming perhaps the most magnificent 
 fields of gorgeous colour in the whole organic world. 
 Now, Macaire-Princep has shown,^ that as leaves begin to 
 turn yellow they give up the function of deoxidation, 
 while a reverse process at once sets in. Mr. Sorby traces 
 the gradual loss of vitality in the fading leaf from bright 
 i^reen throuc^h crreenish-brown, red, scarlet, and orange- 
 brown to the final dull and dingy hue of the dry leaf.^ 
 That this change results from some degradation of energy, 
 in whatever component of the leaf it may take place, is 
 beyond all doubt.^ 
 
 Any injury to leaves causes similar -effects, whether due 
 to disease, external impact, or the attacks of insects. Gall- 
 nuts and rose-blights have generally an outer coating of 
 small reddish excrescences, while feeble plants produce 
 yellow-spotted or pink-speckled leaves. Here, too, oxida- 
 tion, or some other de-energising action, is most probably 
 the cause of the change observed. 
 
 Leaves which have given up their natural functions 
 frequently assume bright hues. Thus the pitchers of the 
 side-saddle flower {Sarracenia rubra) have purple tips.* 
 Those of the pitcher-plant {Nepenthe) are "tinted and 
 mottled with red and purple."^ The leaves of the curious 
 insectivorous plants, with whose habits Mr. Darwin has 
 made us so familiar, are apt to be speckled with similar 
 hues, especially in the active portions, which show, by 
 
 1 Mem. de la Societe Phys. et •* See the figure in Sir W. Hookers 
 d'Hist. Xat. de Geneve, iv. 43. " Flora Exotica,'' pi. 13. 
 
 - Ubi supra, and "Nature," Jaim- ^ Wallace, "Malay Archipelago," 
 ary 19, 1871. -p. 81. 
 
 2 Quarterly Journal of Science, 
 1871, p. 64, and 1873, p. 451.
 
 INSECTS AND FLOWERS. 51 
 
 tlieir movements and secretions, some approach to animal 
 functions. The common English sundew {Drosera rotun- 
 difolia), which may be found in all boggy or peaty places, 
 has bright red glands scattered over its leaves. The 
 Venus fly-trap {Dioncea muscipula) is "thickly covered 
 with minute glands of a reddish or purplish colour/' while 
 the spikes which close upon the insect prey have small 
 projections described as '' reddish-brown or orange." Like 
 organs in Drosophyllum lusitanicum are bright pink, and 
 in Finguicula lusitanica purple.^ Our own common 
 butterwort and saxifrage, which share to a less extent the 
 same peculiarity, have also slightly reddish or yellowish 
 foliage. 
 
 Parasites which live upon the energetic matter stored 
 up by other plants fall obviously under the same class. 
 Their whole existence consists in a continuous metastasis, 
 that is to say, in the expenditure and liberation of pre- 
 viously accumulated nutriment, under the influeuce of 
 oxidation. The common European broom-rapes {Oro- 
 hanchc) have no green leaves, but merely pink, purple, 
 brown, yellow, blue, or rose-coloured scales and flowers. 
 Ci/tinus hypocistis, which grows parasitically on the roots 
 of the Cistus, has a bright orange stem and leaves. The 
 common English dodder is noticeable for its pretty twining 
 red filaments, while its Indian congeners display brilliant 
 hanging masses of golden threads.^ In fact, almost all 
 true and perfect parasites are remarkable for the absence 
 of green and the presence of other bright hues. Of course, 
 many plants usually included under that name, like the 
 mistletoe family, have foliage of the ordinary colour ; but 
 these are in reality only half-parasitical, a kind of step- 
 ping-stone between the epiphytic plants (orchids and 
 bromelias) and the thorough-going parasites, such as 
 RaJJicsia. To the very end, indeed, the degraded leaves 
 
 1 For Drosera, see Darwin, "In- Drosophyllum, p. S33 ', and for Pin- 
 sectivorous Plants, ' or any English guicula. p. 391. 
 moor; for Dioncea, ibid., p. 287; for - Hooker, Himalayan Journal, pp. 
 
 28, 38.
 
 52 
 
 THE COLOUR-SENSE. 
 
 or scales of flowering plants contain some traces of cliloro- 
 phyll/ which, however, like the leaves themselves, must 
 be reo-arded as mere obsolescent relics of their earlier 
 state. It should also be noticed in passing, that many 
 parasites, like Rafflesia and Hydnora, have exceptionally 
 larse and brilliant flowers. The blossom of R. Arnoldi 
 sometimes measures three feet in diameter. 
 
 Still more noticeable in hue are the plants known as 
 saprophytes, which live like fungi on the decaying matter 
 contained in dead foliage or other organic remains. These, 
 too, haA^e no real assimilative leaves, while their functions 
 are purely animal, consisting in the absorption of oxygen 
 and the expenditure of previously accumulated energies. 
 The Indian-pipe plant of Canada (Monotropa wiiflora) 
 has a pure w^hite scaly stem and flower,^ exactly re- 
 sembling a fungus to the untrained eye ; it grows under 
 the shade of pine forests, amid the rich dShris of their 
 pollen and their fallen foliage. The beautiful Neottia 
 speciosa has a scape and rudimentary leaves of bright 
 scarlet. CoraUorhiza and many other saprophytes are 
 equally remarkable for their exquisitely coloured scales. 
 It is true that several, if not all, of these plants contain 
 small quantities of chlorophyll or xanthophyll ; ^ but here 
 again, we must regard the pigment as a mere remnant 
 of earlier ancestors ; while the plant, as a whole, mainly 
 consists of metastatic materials, or, in other words, of 
 oxidation products. 
 
 The resemblance which both parasites and saprophytes 
 bear to fungi is certainly remarkable when we remember 
 their close community of nature and function. All alike 
 live upon previously organised material, and all have the 
 same flabby, succulent, pulpy appearance. The Indian- 
 pipe plant is always described by Canadian farmers as " a 
 kind of toadstool ; " the Rafflesia is noted for its fungoid 
 
 1 "Wiesner, Botan. Zeitting, 1871, as differing from green, must, of 
 p. 37, quoted in Sachs, 643. course, be accounted a colour. 
 
 2 For our present purpose, white, ^ Oscar Drude, "Biologie von Mo- 
 
 notropa,"&c., Gottingen, 1873.
 
 INSECTS AND FLOWERS. 53 
 
 look and animal odour; tlie Cytinus exhales a meaty 
 flavour ; and the Cynomormm coccineum is known to 
 druggists by the technical name of Fungus melitensis or 
 Malta mushroom. Putting these facts by the side of 
 their very similar colouration, we are not unnaturally led 
 to expect some causal connection such as that of which 
 we are now in search. Let us pass on to other coloured 
 portions of ordinary plants, which may throw a little more 
 light upon the question at issue. 
 
 Buds contain energetic material, stored up by the plant 
 during the preceding season, and expended, presumably, 
 by union with oxygen, during the spring. The sprouting 
 buds of the hawthorn and of many other plants present 
 exquisite tints of pink and mauve. The bulbils of the 
 tiger-lily are covered by purple scales. The various 
 devices by which plants lay by nutriment during one 
 season for their growth in the next are known as bulbs, 
 tubers, corms, or rhizomes. All of these are apt to produce 
 young sprouts of dainty colouring and bright hue. The 
 growing sprays of the potato, when kept carefully from 
 the light, exhibit distinct tinges of pink, blue, violet, and 
 yellow. Asparagus shoots and blanched sea-kale have 
 scales or leaves of mauve, lilac, and greenish brown. 
 Almost all bulbs, on first producing leaves, show very 
 decided colours, which change to green under the action 
 of light. Beet-root, permitted to sprout in the dark, sends 
 up beautiful bunches of deep crimson foliage. Carrots, 
 under like circumstances, put forth golden sprays, varying 
 from light primrose to bright orange. Sprouting peonies 
 are of a full dark red. Ehubarb has rosy stems and pink 
 or yellow leaves. In many of these cases, the colour is 
 most conspicuous in the thin laminated portion of the 
 young leaves, which offer the best medium for the display 
 of delicate pigments. In every case, exposure to the 
 sunlight brings about reversion to the original assimilative 
 function, and results in the final triumph of green chloro- 
 phyll.
 
 54 THE COLOUR-SENSE. 
 
 The young shoots at the end of branches are in the 
 same position, as regards energy, with the sprouts which 
 arise from bulbs or tubers. They cannot yet feed them- 
 selves, but they are nourished by energetic materials from 
 the older leaves, whose carbon combines with oxygen in 
 their tissues to yield the energy whereby their growth is 
 carried on. Kow the bright tints of these young shoots 
 are very noticeable (as may be especially observed in the 
 fuchsia, the hawthorn, and the rose-apple), and they can 
 be skilfully arranged in such combinations as to produce 
 a visible effect not at all unlike that of flowers. 
 
 If we compare these various cases with those of bright- 
 hued entomophilous blossoms and brilliant fruits, we 
 shall find that they have all one quality in common — 
 they occur in parts which are expenders, not accumulators, 
 of energy. Hence we are led to suppose that those por- 
 tions of plants which subsist upon previous accumulations 
 are apt to assume bright hues of different sorts. To what 
 can we attribute the tendency which we thus observe ? 
 Can we give any causal formula for the empirical general- 
 isation at which we have now arrived ? I think we can, 
 and in the f olio win cr manner : — 
 
 o 
 
 Chlorophyll, the active deoxidising principle, has a 
 definite composition, which enables it to carry on its 
 proper functions, and a definite mode of reflecting light, 
 which we call green. How far its greenness is bound up 
 with its other physical properties we cannot say. Perhaps, 
 as has been objected, it might equally well perform its 
 physiological purpose were it red or yellow. But more 
 probably its special reaction upon light is intimately con- 
 nected with its special reaction upon carbonic anhydride 
 under the influence of light. However this may be, at 
 least we know that active chlorophyll is ahvays green ; 
 and the more active, the brighter its hue, as Mr. Sorby 
 has abundantly shown. Hence, every part of a plant 
 which performs deoxidising functions has necessarily a 
 green pigment for its foundation. The greenness may
 
 INSE CTS A ND FL WERS. 5 5 
 
 indeed be masked "by other dyes (perhaps themselves the 
 products of oxidation), as in cell-sap or epidermis, but in 
 the actual active principle itself, greenness is apparently 
 always present as an essential and inherent property. 
 
 So leaves as a rule, where exposed to sunlight, are 
 green, but the remaining portions of the plant do not 
 seem to be bound by such a stringent law of colouration. 
 There is no reason why other colours should not appear 
 in them from time to time, and, if they prove useful, be 
 perpetuated through the action of natural selection. How^, 
 then, do they arise ? 
 
 Colour, we have seen already, is merely the mode in 
 which various bodies react upon light, reflecting or ab- 
 sorbing its constituent elements in varying proportions 
 of their several rays. But there is no property of different 
 bodies more variable in its nature than this particular 
 mode of reaction. The slightest change in the molecular 
 constitution of a substance is apt to be accompanied by 
 considerable changes in its hue. Materials which appear 
 chemically almost identical pass through strange varieties 
 of tint with the greatest readiness. And this is particu- 
 larly the case with organic matter, which differs from all 
 other matter in the striking effects produced upon its 
 physical constitution by apparently trifling causes. Hence 
 we might naturally expect that very small changes in the 
 constituents or contents of plant tissues would be likely 
 to produce great alterations in their colour. And we find 
 accordingly in all non-active parts of a plant that by- 
 products of various tints do actually occur wdth consider- 
 able frequency : take, for example, the bright hues of many 
 stems, barks, and juices, the red under-side of the Victoria 
 regia leaf, the amber nether foliage of the star-apple, and 
 the beautiful scales of the gold and silver ferns. 
 
 Whether such colours are ahcays due to oxidation, 
 it would be difficult to say ; but in a large number of 
 instances it is quite clear that oxidation is going on in 
 the tissues where the colours appear. Obviously, in all
 
 S6 THE COLOUR-SENSE. 
 
 cases of metastasis, the recombination of oxygen with 
 the accumulated hydrocarbons is the only source of the 
 energy whereby growth is carried on. Sometimes as much 
 as 40 or even 50 per cent, by weight of the organic matter 
 contained in seeds which germinate in the dark is lost by 
 conversion into carbonic anhydride and water ; 1 and 
 somewhat the same change must take place in bulbs, 
 tubers, corms, and rhizomes. Almost all the above- 
 quoted cases fall apparently under a like generalisation. 
 The red colouring matter of persistent winter leaves, as 
 seen in Sempervwum, MaJionia, Vaccinium, and Sedum, is 
 due to a substance mainly consisting of tannin.^ Mr. Sorby 
 does not absolutely say that the colours of autumn foliage 
 are due to oxidation, but he refers them on the whole to 
 decreased vitality, absorption of chlorophyll, and similar 
 causes, which bring into prominence various minor prin- 
 ciples otherwise unnoticed. Of the lychnoxanthine series 
 he says expressly, " They are probably only products of the 
 oxidisation of chlorophyll, from which they may be pre- 
 pared artificially." Of the erythrophyll series, on the 
 other hand, he merely observes, " They are usually indica- 
 tive of low constructive energy." The chrysotannin group, 
 again, " when oxidised, give rise to various brown sub- 
 stances, which are the cause of many of the characteristic 
 tints of autumnal foliage." But with regard to the pig- 
 ments of entomophilous flowers his language is much 
 more decided in tone. " The coloured substances in the 
 petals are in many cases exactly the same as those in the 
 foliage from which chlorophyll has disappeared ; so that 
 the petals are often exactly like leaves which have turned 
 yellow or red in autumn, or the very yellow or red leaves 
 of early spring. , . . The colour of many crimson, pink, 
 and red flowers is due to the development of substances 
 belonging to the erythrophyll group, and not unfrequently 
 to exactly the same kind as that so often found in leaves 
 . . . The facts seem to indicate that these various sub- 
 
 1 Sachs, uU supra. 2 gaclis, 657.
 
 INSECTS AND FLOWERS. 57 
 
 stances may be due to an alteration of the normal con- 
 stituents of leaves, some being probably formed from 
 chloropliyll, others from the xanthophylls, and perhaps 
 some from other constituents. So far as I have been able 
 to ascertain, their development seems as if related to extra 
 oxidisation, modified by light and other varying conditions 
 not yet understood." ^ In like manner Lory found that 
 parasites, as exemplified by broom-rapes, absorbed oxygen 
 and exhaled carbonic anhydride in all stages of growth, 
 whether exposed to the sun or not.^ So, also, Morot 
 showed that in etiolated plants the coloured portion of 
 the tissues gave out carbonic anhydride, while the green 
 portion gave out oxygen.^ In short, without going into 
 the lengthy ultimate question — scarcely soluble at present 
 — whether all bright vegetal pigments (except chloro- 
 phyll) are themselves actually oxidation products, we 
 may at least affirm that they occur with exceptional 
 frequency in those plants or parts of plants where oxida- 
 tion is largely taking place. They may be always directly 
 due to the absorption of oxygen, or they may be merely 
 secondary results of that action ; but they certainly show 
 a great tendency to present themselves wherever energy 
 is being expended ; and that conclusion is quite sufficient 
 for our immediate object. 
 
 Here, to guard against an obvious criticism, it should be 
 added that only a tendency, not a universal law, in such 
 a direction is believed to exist. For example, the leaves 
 of the sensitive plant and the Desmodiicm, which exhibit 
 movements far more marked than those of the insectivo- 
 rous species already noticed, are perfectly green.* But the 
 
 1 Proc, Koy. Soc, vol. xxi. p. 478. the materials for this chapter when 
 
 2 Annales des Sciences Nat., 3ine in manuscript. Professor Thiselton 
 Ser. Botanique, viii. 158. Dyer also supplied me with many use- 
 
 3 Balfour, Class-Book of Botany, ful notes in connection with this sub- 
 p. 473. ject, of which I have gladly availed 
 
 ^ My thanks for calling attention to myself. At the same time, I ought 
 
 this exception are due to Mr. Darwin, to mention that although I. have al- 
 
 who kindly favoured me with several tered much of my original matter in 
 
 valuable critical observations upon accordance with objections raised by
 
 58 THE COLOUR-SENSE. 
 
 Avliole conclusion here suggested amounts in brief to the 
 following principle : Wherever considerable changes occur 
 in the nature of the vegetal tissues or their contents, they 
 are apt to be accompanied by similar changes in the re- 
 action of the tissues upon the incident sunbeams. 
 
 Yet it is a noteworthy fact of great importance, as shed- 
 ding light upon the origin of the colour-sense, that such 
 brilliant tints are everywhere exceptionally common in 
 the organic world. Besides the green of chlorophyll, the 
 orange and scarlet of autumn leaves, or the varied hues of 
 flowers and fruits, we find unusually bright colouring in 
 many parts of animals, especially the very simplest, such 
 as jellyfish and sea-anemones. Although, as we shall 
 observe hereafter, many of these are doubtless due to the 
 selective action of sexual preference, acting through the 
 colour-sense itself, yet in the lowest organisms there is 
 some reason to believe that the purity and splendour of 
 the prevailing hues are only due to the adventitious com- 
 position of their molecules. And when we further notice 
 the brightness of mammalian blood, besides the numerous 
 changeful hues of sundry viscera or their contents, we shall 
 probably be willing to allow that organic bodies habitually 
 display pure and gorgeous tints, which the mineral w^orld 
 only shows us in a few rare and exceptional jewels. 
 
 Before we proceed, however, to apply these general 
 principles to the genesis of entomophilous flowers, it will 
 be well to glance briefly at a distinction of considerable 
 importance, already hinted at in the preceding paragraph. 
 Colour, as such, cannot of itself subserve any special func- 
 tion except in connection with the animal eye. The hues 
 of all inorganic and of most organic bodies depend entirely 
 upon the fortuitous molecular constitution of the parti- 
 cular body. But when a colour so reflected happens to 
 produce some specific effect upon the eyes of any animal, 
 
 tliese distinguislied naturalists, they many of which Professor Dyer, at 
 are not in anyway responsible for any least, would dissent in the most uu- 
 of the statements here made, from equivocal manner.
 
 INSECTS AND FLOWERS. 59 
 
 ■whose interference is either useful or noxious to the ani- 
 mal or plant reflecting it, then the principle of natural 
 selection will come into play, and the colour, as such, may 
 be said to subserve the special function of attraction or 
 protection, as the case may be. Henceforward, in the 
 present w^ork, a colour which seems simply to depend upon 
 molecular constitution, apart from function to be subserved, 
 will be described as adventitious ; w^hile a colour which 
 also subserves a special function will be described as 
 'piiT'posive: 
 
 Now all the coloured objects with which we have so far 
 dealt — green leaves, autumn foliage, young shoots, sprout- 
 ing buds — are purely adventitious in their tints. Flowers, 
 however, which we next approach, are purposive; but, 
 like all other purposive adaptations, they must neces- 
 sarily have taken their rise in some adventitious circum- 
 stance, after^vards increased and developed by selective 
 action. 
 
 With such data before us, then, let us proceed to inquire 
 what was the genesis of those bright entomophilous 
 flowers, which present brilliant tints in specialised thin 
 leaves or petals, admirably adapted alike for rapid 
 oxidation, and for the ostentatious display of delicate 
 pigments. 
 
 The flower is one of the purely expensive structures 
 which we noticed above as seats of oxidation and liberated 
 energy. The well-known experiments of Saussure, Du- 
 trochet, Vrolik, and De Vriese, detailed in all handbooks 
 of physiological botany, sufficiently prove that during the 
 act of flowering oxygen is consumed, carbonic anhydride 
 evolved, and heat liberated. These experiments have been 
 generally conducted upon various species of Arum, which 
 are insect-fertilised flowers ; but similar phenomena have 
 also been observed in the cones of cycads, whose blossoms 
 are strictly anemophilous. Indeed, as the absorption of 
 oxygen is chiefly concerned with the maturation of the 
 pollen, and, to a less extent, of the pistil, it is clear
 
 6o THE COLOUR-SENSE. 
 
 that it can be but little influenced by the nature of tlie 
 surroundiiiGf structures. 
 
 o 
 
 Hence we would naturally expect that all floral organs, 
 wind-fertilised or insect-fertilised alike, would show a 
 tendency to the production of bright colours, in accord- 
 ance with the general princii)le here laid down. This a 
 ^priori expectation is fully justified by the actual facts. 
 
 In the first place, even among flowerless plants, the 
 purely expensive structures employed in the elaboration 
 of young spores are almost always tinged with some other 
 hue than that of the green pigment which distinguishes 
 the active and assimilating leaves. In mosses the grace- 
 ful little spore-cases, which rise like miniature fruits at 
 the extremity of the tall spiky stems, are usually pink or 
 reddish brown in colour. The beautiful SplacJmum ruhrum 
 of the Canadian forests has a cup of brilliant scarlet, which 
 has led the children who pick it to give it the pretty 
 popular name of red-cap moss. Many lycopodiums pro- 
 duce bright golden fructifications, very conspicuous in the 
 lovely exotic L. dendroideum. Ferns generally bear their 
 spores on the under surface of the frond, where their 
 brown or russet colour makes them very noticeable and 
 pretty objects. So that, in spite of their ill-chosen name, 
 the cryptogams themselves exhibit the universal tendency 
 to varied colouration in the reproductive organs. 
 
 I^ext, when we examine the phanerogamous division of 
 plants, we see at once that the actual floral structures 
 themselves are always more or less marked by distinctive 
 colours. The pollen is generally of a rich golden yellow, 
 while the surrounding scales show tints of silvery grey or 
 faint pink. Even among the wind-fertilised blossoms, not 
 a few are thus rendered conspicuous when they hang 
 thickly together in large close-set masses. Many catkins, 
 several grasses, the larch and other conifers, the dock and 
 its congeners, all display blossoms of considerable distinc- 
 ness, quite uninfluenced by the selection of insects. The 
 inner bracts of the unopened artichoke head are often a
 
 INSECTS AND FLOWERS. 6i 
 
 brilKant mauve, not less beautiful than that of many 
 flowers. The glumes which surround the floral organs of 
 grasses are ruddy purple. The female flowers of the com- 
 mon hazel are a fine red, as Mr. Darwin reminds me. 
 Evidently we have here a groundwork of differential 
 colouring upon which selection might set to work, and 
 ultimately produce the striking results that we see to-day 
 in every flower-garden. 
 
 These, then, are the ultimate elements of our problem, 
 riowers consist essentially of male and female organs, 
 which really represent aborted leaves, greatly modified for 
 their special function, as Wolff and Goethe long since 
 pointed out. These reproductive organs are situated at 
 the ends of axes, where growth is failing ; and Mr. Herbert 
 Spencer observes that such points are just the ones where 
 coloured leaves, as noted above, frequently make their 
 appearance.^ In anemophilous flowers, as a rule, we find 
 only the two whorls of essential floral organs ; but in 
 entomophilous flowers, as a rule, we find two additional 
 whorls, the petals and the sepals, one or both of which are 
 brilliantly coloured, the colouration apparently subserving 
 no other purpose than the attraction of insects who aid in 
 fertilising the flowers. We can hardly resist the inference 
 that the coloured whorls represent an intensification of 
 the natural tint in growing shoots and floral organs, slowly 
 modified by the selective action of the insect eye. 
 
 When we look more closely at the nature of showy 
 entomophilous flowers, this conviction becomes greatly 
 strengthened. If colouration depends wholly or in part 
 upon oxidation of previously stored material, it will follow 
 that very large and massive blossoms can only be produced 
 by the aid of considerable prior accumulations in some 
 portion of the parent plant. Now this is exactly what 
 we find to be the case in nature. Most very big flowers 
 
 1 Principles of Biology, ii. 249, but vigorously sketched out in a few 
 ■where the whole question treated in pages, 
 detail in this chapter has been rapidly
 
 62 . THE COLOUR-SENSE. 
 
 depend for their support upon bulbs, corms, tubers, or other 
 like bulky reservoirs of energetic material. It will be 
 sufficient to mention the cases of the waterlilies, the 
 lotus, the dahlias, the orchids, the iris, the crocus, the 
 gladiolus, the narcissus, the snowdrop, the daffodil, the 
 tulip, the various lilies, the tuberose, the hyacinth, and the 
 meadow-saffron. In many of these plants the handsomest 
 heads of bloom are secured by cutting off the flower-buds 
 for several successive years, and so preventing the expen- 
 diture of material until enough has been accumulated for 
 a gorgeous display of blossom. Certain other flowers, 
 again, depend for support upon starch or other nutriment 
 laid by in the fleshy receptacle from which they spring. 
 This is the case with the artichoke, the dandelion, and 
 many of their sister composites. A third class lives upon 
 materials stored up in the woody branches, as in the 
 almonds, flowering cherries, and other trees, which bloom 
 in the spring before the fresh leaves make their appear- 
 ance. Yet a fourth sort maintain themselves cheaply 
 upon the manufactured juices of other plants, like the 
 leafless parasite, Eafflesia, whose flower measures three 
 feet in diameter, or the pretty little English dodder, whose 
 suckers fasten themselves tightly upon the growing stems 
 of gorse. A great number of the most beautiful exotics 
 are saprophytes, which live entirely upon the decaying 
 vegetable mould in which they are embedded. Indeed, 
 whenever showy flowers, like poppies and convolvulus, 
 grow without the aid of some such accumulated nutri- 
 ment, it will generally be found that their petals are thin 
 and papery, so that the total cubical content of the flower- 
 bud is really quite inconsiderable. Such plants, in fact, 
 have learnt to make a very great display at very little 
 actual expense. 
 
 Furthermore, flowers often exhibit different colours 
 according to the state of oxygenation which their juices 
 have reached, and these differences, as I shall endeavour 
 to show hereafter, bear a definite relation to the various
 
 INSECTS AND FLOWERS. 63 
 
 periods of maturity, and tlie particular insect whose 
 assistance is required. Almost all blossoms in their early 
 stages contain green pigments and perform foliar func- 
 tions ; but as they mature, they gradually assume their 
 proper hues of yellow, blue, or red. " The endochrome of 
 the rudimentary petals," says Mr. Sorby,^ " approximates 
 in character to that of the leaves ; and, during their 
 development, their leaf-like character is gradually lost, 
 and often new colouring matters are formed." The series 
 of changes may be easily followed in a hyacinth, a tulip, 
 or a daffodil ; but perhaps the garden hydrangea {H. hor- 
 tensis) offers the best opportunity for watching this inte- 
 resting phenomenon, because the structures in which the 
 mauve or pink pigment finally appears are exposed to 
 view during the whole process of maturation. Other 
 changes also frequently take place after the flower is fully 
 developed. " CheirantJius chamcdeo has at first a whitish 
 flower, then a citron-yellow, then red or slightly violet ; 
 the petals of StylicUum friiticosum are pale yellow at first, 
 then lightish rose-coloured ; the flowers of CEiiotliera tetra- 
 ptera are first whitish, than rose-coloured or nearly red ; 
 the corolla of Cobcca scanclens is greenish-white the first 
 day, and violet the day following ; the flowers of Hibiscus 
 mutahilis appear in the morning of a white colour, towards 
 midday they become flesh-coloured, and at night they 
 are red." ^ F. MuUer has observed a Lantana at Sta. 
 Catherina in Brazil, the flowers of which last three days, 
 " being yellow on the first, orange on the second, purple 
 on the third day ; " ^ and his interesting explanation of 
 this peculiarity will find further mention when we come 
 to treat of the parallel adaptation whereby insects have 
 accommodated themselves to the colours of flowers. In- 
 deed, Delpino believes that all such changes of hue are 
 specially intended to inform the fertilising insects of the 
 proper moment for efi'ecting impregnation. 
 
 1 Quarterly Journal of Science, " Balfour, p. 541. 
 1873, p. 463. 3 "Nature," November 29, 1877.
 
 64 THE COLOUR-SENSE. 
 
 We conclude, tlien, with much probability, that the 
 bright pigments of entomophilous plants are due origin- 
 ally to the natural oxidation taking place in all purely 
 expensive structures, aided by the selective action of 
 insects. It is noteworthy, as proving the functional 
 origin of these pigments, that both great divisions of 
 flowering plants, the monocotyledons and the dicotyledons, 
 have independently hit upon the very same device of 
 coloured leaves for attracting their insect allies. But 
 this could hardly have happened had not some original 
 groundwork existed in the mere fact of oxidation, upon 
 which selective action might be successfully exerted. 
 Still more clear does this argument become when we 
 recollect that in almost every family under these two 
 great divisions, anemophilous and entomophilous genera 
 may be found side by side, thus proving that the device 
 of colour has been independently adopted by different 
 plants, not twice alone, but a thousand times over. When- 
 ever brilliant leaves showed any tendency to appear in 
 the neighbourhood of the floral organs, no matter what 
 the species, genus, family, or class, it would seem that the 
 plant thereby derived such an advantage as to perpe- 
 tuate the habit in future, under the constant stimulus of 
 over-population and natural selection, resulting in survival 
 of the fittest. 
 
 When we pass on to examine the various parts of the 
 flower which may thus become devoted to the attractive 
 function, we find still plainer evidence to the same eftect. 
 The essential floral organs themselves, already so conspi- 
 cuous in the various catkins, may be specially modified 
 for the sake of displaying brilliant pigments. The com- 
 mon meadow rue depends almost entirely for attraction 
 upon these organs. In the family of Mesembryanthe- 
 mums, the outer stamens become flattened and petaloid, 
 so as to resemble the corolla of ordinary flowers. In the 
 waterlilies, the tendency towards a similar change is 
 always noticeable. Indeed, if one may hazard a guess in
 
 INSECTS AND FLOWERS. 65 
 
 SO uncertain a question, analogy would rather lead us to 
 suppose that all petals are modified stamens than that 
 the transition has taken place in the opposite direction. 
 However this may he, the corolla, or petaline whorl, forms 
 in most flowers the main attractive orc^an. Eoses, butter- 
 cups, violets, bluebells, and primroses may stand as suffi- 
 cient examples. Next in order comes the calyx, or 
 sepaline whorl, usually a protective organ, but often so 
 modified as to aid in the function of alluring the insect 
 guests. In the fuchsia, the bright sepals make the most 
 striking part of the whole blossom; while in the tulip, 
 crocus, and other brilliant monocotyledonous plants, both 
 sepals and petals are coloured alike, so as to be usually 
 lumped together under the common name of perianth 
 pieces. In the marsh marigold, the marvel of Peru, the 
 purple clematis, and the crimson Aristolocliia cordata, the 
 petals are wholly wanting, and the calyx alone performs 
 the task of ostentatious chromatic display. 
 
 Nor does the process of colouration stop short at the 
 regular floral whorls. The bracts and other secondary 
 adjuncts often aid in the attractive effect. Several 
 euphorbias have separately inconspicuous flowers, enclosed 
 in a common involucre of the most beautiful scarlet hue. 
 Foinsettia pulcherrima bears tiny yellow blossoms, which 
 would doubtless fail by themselves to catch even the 
 microscopic eye of a tropical butterfly; but they are sur- 
 rounded by a thick mass of gorgeous crimson bracts, so 
 strikingly lovely as to ensure for the plant a place in all 
 our great conservatories. The various arums bear their 
 minute flowers on a yellow spadix, about which grows a 
 huge white or purply-green sheath, known as a spathe, 
 whose large size and bright colour makes up for the rela- 
 tive inconspicuousness of the essential organs. In short, 
 whatever part happened to display a tendency towards 
 bright colouration, and thereby attracted the attention of 
 insects, would naturally grow more and more prominent
 
 66 THE COLOUR-SENSE. 
 
 from generation to generation, till it readied the furthest 
 limit of useful expenditure.^ 
 
 That the colour of the flower is a mere intensification 
 of that prevailing in the stem has long since been recog- 
 nised by painters. In some cases, as in Peperomia, the 
 hue of the stem becomes itself very noticeable. In 
 others, as in Echeveria, the stalk and bracts are pinkish, 
 gradually growing deeper till we reach the calyx, while 
 the petals themselves appear simply as an intensified form 
 of the surrounding tint. In Epiphyllums, the end of the 
 leaf -like peduncle is often bright red like the blossom 
 itself. Amongst English plants, Ecliium, Sedum, Chryso- 
 splenmm, Rumex, and many other genera, show like pheno- 
 mena. And when, as in the parasites and saprophytes, 
 the stem and scales have no special reason for greenness, 
 we find such brilliant examples as Lastrma, Monotropa, 
 Neottia, and Corallorhiza, whose rudimentary leaves are 
 quite as beautifully coloured as the flowers themselves. 
 
 From whatever point of view we regard the question, 
 then, it seems equally probable that even before insect 
 selection had come into play certain flowers would show 
 a considerable tendency to the production of adventitious 
 colours. Wherever such patches of red or blue shone out 
 among the prevailing green of primitive forests, we may 
 be sure they would act as beacons to the rudimentary eyes 
 of unspecialised insects. At first their colours would 
 doubtless be arranged in very indefinite patches ; but as 
 they were gradually selected by their insect visitors, the 
 effects of cross-fertilisation, by weeding out individual 
 peculiarities, would make their shape and hue more and 
 more definite with .each new generation. For such defi- 
 niteness, as we shall observe abundantly hereafter, is a 
 
 ^ I was once given a pine-apple in liarity had proved \iseful to the 
 
 Jamaica by a negro cottager, the plant, instead of hurtful, as it really 
 
 crest or empty bracts of which liad was, it might have originated a per- 
 
 assumed a bright scarlet hue, like manent variety, Tlie garden cocks- 
 
 thtit oi so many Bromelice, while the comb {Ceiosia cristata) is an instance 
 
 succulent mass beneath had become of such a monstrosity carefully pre- 
 
 dry and shrivelled. If this pecu- served by artificial selection.
 
 INSECTS AND FLOWERS. 67 
 
 mark of contradistinction between adventitious and 
 purposive colouration. Wherever we find a plant, like 
 the common West Indian Bromelia pinguin, in which the 
 spathes are coloured brightly but irregularly, the crimson 
 fading off into white or green, we may fairly conclude 
 that the selective process has not yet proceeded very far. 
 But when we get a definite bunch of crimson bracts, as in 
 Poinsettia 'pulchciTima, standing apart as a regular mass 
 from the green foliage below, we may be sure that the 
 selective process has continued for a considerable period 
 of time ; while in the three constant coloured leaves which 
 surround the little blossoms of the Bougainvillea, we see a 
 still further progress in numerical definiteness. So, too, 
 if we compare the English cuckoo-pint with the Ethio- 
 pian lily {Richardia africana), or the apple with the 
 orange, we shall see reason to believe that the former cases 
 represent a relatively incomplete, and the latter cases a 
 relatively complete, stage of the differentiating action. And 
 we shall observe hereafter, when we come to examine the 
 origin of bright-coloured fruits, that these structures, 
 which have been developed to suit the eyes of birds and 
 mammals, and are therefore comparatively late in geolo- 
 gical time, possess on the whole much less definite colours 
 than entomophilous flowers, which have been developed 
 to suit the eyes of insects, and date far back in geological 
 time. 
 
 The first step towards definiteness in colouration is 
 gained by that dwarfing of the internodes which gives the 
 floral whorls their circular appearance. The earliest ento- 
 mophilous flowers probably belonged to the dicotyledonous 
 group, which now exhibits the highest differentiation of 
 any ; but they consisted of separate petals, like the com- 
 mon dog-rose, instead of being tubular or bell-shaped, like 
 the honeysuckle or the campanula.^ Gradually, however, 
 
 1 J. E.Taylor, F.G.S., " Geologi- ary 1878. I cannot agree witli Mr. 
 cal Antiquity of Insects anil Flowers," Taylor, however, in supposing that 
 in "Popular Science Review," Janu- entomophilous monocotyledons pre-
 
 68 THE COLOUR-SENSE. 
 
 the various petals in certain cases became adnate, that is 
 to say, developed together, so as to form a single indented 
 corolla. The former class of flowers are known as ipoly- 
 petalous, the other as ganwpdalous. At a still later date 
 came the irregular flowers, like the labiates and orchids, 
 which are specially adapted to the shapes of insects; 
 while the differentiating process is doubtless still going 
 on under our very eyes whenever a bee visits a blossom in 
 the meadows around us. 
 
 Side by side with this differentiation of various flowers 
 went the differentiation of flower-haunting insects. Even 
 in the Carboniferous w^orld some vagrant species of that 
 great class already lived in the hard siliceous underbrush ; 
 but Sir John Lubbock believes that Hym.enoptera, Hemip- 
 tera, and Diptera first came into being during the Cre- 
 taceous era; while Lepidoptera, or butterflies, did not 
 appear until the Tertiary times. Beetles first exhibit 
 evident marks of flower-feeding during the Miocene epoch. 
 As for honey-bees, they probably represent the very latest 
 and most highly differentiated members of the whole class, 
 and they could hardly have reached their present form till 
 a very late period. In short, if we look at the correlation 
 of the flowers and the insects, we shall see reason to be- 
 lieve, what is already suspected on purely palseontological 
 grounds, that gamopetalous flowers could not be developed 
 before the rise of specialised insects having a proper pro- 
 boscis fitted for fertilising their bloom. 
 
 Again, the entomophilous monocotyledons are probably 
 far more modern in date than the bright-coloured dicoty- 
 ledons, and they are also on the wdiole far more leaflike 
 and less definite. Most of them consist of six perianth 
 pieces, shaped very much like the ordinary leaves, and 
 seldom having any specialised features. Yet, as they 
 found the field already occupied by bright-hued dicotyle- 
 
 ceded similar dicotyledoas. All the plants counts for very little, as their 
 
 structural indications point in the earliest species may very well have 
 
 opposite direction ; and the mere fact been anemophilous. 
 cf the early appearance of liliaceous
 
 INSECTS AND FLOWERS, 69 
 
 dons, it was necessary, if they would secure the attention 
 of insects, to bid for their favour by very large and showy 
 blossoms. Accordingly, these newest comers amongst the 
 insect-fertilised plants form a large proportion of our 
 choicest garden species. It will suffice merely to enume- 
 rate the iris, crocus, narcissus, daffodil, snowdrop, ama- 
 ryllis, aloe, tulip, tiger -lily, fritillary, crown -imperial, 
 tuberose, hyacinth, star of Bethlehem, meadow-saffron, 
 hellebore, arum, and Ethiopian lily, to show how many 
 of the most brilliant flowers belong to this class. Even 
 here, however, a large number of species have advanced 
 to a high degree of differentiation, due to the agency of 
 insects. While many lilies have six separate perianth 
 pieces, as we see in the tulip and the fritillary, others, like 
 the lily of the valley, have become quite gamopetalous, or, 
 to speak more correctly, the petaline and sepaline whorls 
 have coalesced into a bell-shaped cup. But the orchid 
 family display the most curious adaptations of all, being 
 modified in an infinite variety of ways to suit the insects 
 of their several countries, and presenting the most mar- 
 vellous tricks of mimicry, mechanical device, and sportive 
 cunning, which at first sight almost compel us to imagine 
 an inherent consciousness guiding the blind course of their 
 strange developments.^ 
 
 It has been remarked, too, that, as a rule, flowers whose 
 forms are highly modified, so as to admit of fertilisation 
 with considerable certaint}^ by a single insect visitor, do 
 not need the same large display of showy corollas as those 
 which trust almost to chance for the conveyance of their 
 pollen to the proper receptacle. Thus Sprengel contrasts 
 the great size and numerous petals of the water lily, whose 
 shape has no special reference to the organs of the ferti- 
 lising insect, with the little labiates, whose form ensures 
 the due application of the pollen at every visit.^ So, too, 
 we may compare the common orchid with the fritillary, 
 
 1 See Darwin, ''Fertilisation of Or- ^ Lubbock, "British Wildflowers, 
 chids," passim. in tbeir Kelation to Insects," p. 55.
 
 70 THE COLOUR-SENSE. 
 
 tlie lily of the valley with the tulip, and the composites 
 with the rose family. Of course many interfering causes 
 must be understood as putting a limitation upon the truth 
 of this roughly generalised statement. For example, 
 the great tropical butterflies, the larger bees, and the hum- 
 ming-birds, form fertilising agents who naturally demand 
 large masses of colour as an attraction; or, again, the 
 presence of scent, honey, or other special allurements, may 
 make up in particular cases for the lack of bright corollas. 
 Yet, on the whole, it may be said that, other things equal, 
 high modification in form is accompanied by a decreased 
 expenditure on coloured adjuncts. 
 
 Nor is it only in the shape and colour of individual 
 flowers that plants vie with one another for the favours of 
 their insect guests. Like varieties are also to be found in 
 the mode of massing the blossoms so as to attract from a 
 great distance the eyes of passing bees or butterflies. We 
 must remember that the facets of the articulate visual 
 organ are not adapted for perceiving small objects except 
 at a comparatively close range.^ Hence those plants 
 which can group their several blossoms into large and 
 conspicuous bunches may derive special advantages from 
 the extra attractiveness thus attained. Such species a^ 
 the peony or the tulip bear a single terminal blossom at 
 the end of their stalk. Others, like the pimpernel or 
 the veronica, have a few tiny flowers half hidden at the 
 axes of the leaves. But the hyacinth, the laburnum, and 
 the lilac, group their bloom into large upright or hang- 
 ing masses ; while the cowslip, the carrot, and the cal- 
 ceolaria produce flattened heads which strike the eye 
 from a considerable distance. The dog-rose, with its 
 scattered flowers, does not catch our passing glance so 
 readily as the apple-tree or the may ; and the great 
 tropical flowering forest trees may often be discerned by 
 
 ^ See Mr. Lowne's paper "On the fore the Eoyal Society, March 28, 
 Modifications of the Simple and Com- 1878. 
 pound Eyes of Insects," read be-
 
 jy SECTS AND FLOWERS. 71 
 
 human sight at almost incredible distances for the stay- 
 at-home European. 
 
 But the composite plants offer by far the most instruc- 
 tive example of the effect produced after many genera- 
 tions of unconscious selection by the visits of insects. 
 The first approach toward their mode of aggregation 
 may be seen in the head of clover, where a number of 
 separate little pea-blossoms are collected into a compact 
 assemblage by the shortening of their several stalks. In 
 the scabious we find the like tendency carried still 
 further by the addition of a broad receptacle and a bunch 
 of surrounding leaves, known as an involucre, which 
 fulfils the protective functions of a calyx for the com- 
 pound group. The real calyx, however, on each single 
 blossom, still retains its original form, and doubtless 
 assists in the performance of its proper office. But in the 
 true composites, like daisies or dandelions, the separate 
 flowers have almost mersjed their distinct individualities 
 in that of the complex whole. The calyx has become 
 degraded into a mere bundle of hairs (known as a pajjpns), 
 which serves as a float for the mature seed, and forms the 
 " clock," blown away by village children from the withered 
 dandelion head, as well as the gossamer-like wings that 
 carry the thistle seeds among the farmer's corn. The in- 
 volucre here usurps the whole protective function : and 
 the head of flowers is mistaken by the ordinary human 
 observer for a single blossom. But if we look close into 
 the daisy, we see that its centre comprises a whole mass 
 of little yellow bells, each of which consists of corolla, 
 stamens, and pistil. The insect who alights on the head 
 can take his fill in a leisurely way without moving from 
 his standing-place ; and meanwhile he is proving himself 
 a good ally to the plant by fertilising one after another of 
 its numerous ovaries. Each tiny bell by itself would prove 
 too inconspicuous to attract much attention from the 
 passing bee ; but union is strength for the daisy as for 
 the state, and the little composites have found their
 
 72 THE COLOUR-SENSE. 
 
 co-operative system answer so well, that late as was 
 their appearance upon the earth, they are generally 
 considered at the present day to be the most numerous 
 family both in species and individuals of all flowering 
 plants. 
 
 Nor has the process of differentiation stopped even here. 
 Amongst the composites themselves great variety may be 
 observed in the means adopted for the attraction of insects. 
 The simplest form of composite head, wdiich we see in the 
 thistle and the artichoke, consists of uniform flowers, none 
 differing in shape or colour from their neighbours. The 
 common English centaury shows an intermediate stage, in 
 which the outer florets are longer and larger than those 
 in the centre of the head. The sunflower and the ragwort 
 advance a step farther in the same direction, their outer 
 florets having become ray-shaped or ligulate, but still 
 preserving the yellow hue of the central mass. The ray 
 florets, in these cases, practically fulfil the functions of 
 petals, while the inner blossoms continue to act as true 
 floral organs. Finally, in the daisy and in many chry- 
 santhemums, the outer florets, besides being prolonged 
 into petal-like rays, are coloured white, pink, mauve, or 
 blue, while the central mass retains its original colouration. 
 Here we find the external row of flowers quite diverted 
 from its true purpose, and devoted almost exclusively to 
 the attractive function. 
 
 Even now we have not yet arrived at the last stages of 
 the differentiating process. The complex heads of flowers 
 thus formed again unite into still more complex masses. 
 The daisy and the sunflower bear only one composite head 
 on each stalk, but the common thistle produces a whole 
 mass of heads in a kind of umbel, and the ragwort has 
 bunches of such umbels growing together side by side. 
 In the groundsel, each head of flowers looks like a single 
 blossom ; in milfoil, the umbellate form is almost exactly 
 reproduced in still wilder profusion; while the pretty 
 waving golden-rod caps the climax by collecting compound
 
 INSECTS AND FLOWERS. 73 
 
 "bandies of heads into a many-branched and multitudinous 
 plume. Flowers too small to succeed individually thus 
 succeed in serried masses ; and masses, again, too small 
 for success in single complexity, achieve attention in their 
 turn by reuniting into yet more complex groups. 
 
 As to the special colouring matter employed in each 
 case, but little can be said as yet about its determining 
 causes. In a few cases, indeed, we can conclude with 
 some probability that the existing hue has been developed 
 because it subserved, as such, some special function. 
 Thus night-flowering plants are usually pure white or 
 pale yellow, the very colours best adapted for scattering 
 the scanty moonbeams or the dying twilight, and so 
 attracting the eyes of moths and other crepuscular insects. 
 Again, Rafflesia, Hydnora, Stapdia, and many other fetid 
 flowers, which obtain fertilisation by deceiving flies 
 through their resemblance to putrid meat, imitate the 
 lurid appearance as well as the noisome smell of carrion. 
 Many orchids are believed to be coloured in mimicry of 
 insects, either for the sake of attraction or of protection 
 from hurtful creatures. Other flowers appear to cater 
 specially for the peculiar tastes of certain insects, which 
 exhibit a preference for red, blue, yellow, or orange, as 
 the case may be, and these will receive more extended 
 treatment in the succeeding chapter. Sir John Lubbock 
 thinks that the lines or spots on many flowers act as 
 guides for the bees, pointing out the exact spot where 
 the honey may be found ; and Fritz Miiller suggests that 
 their changing hues serve as timepieces to show the right 
 moment for effecting fertilisation.! But in the majority 
 of cases we cannot point to any such special determining 
 cause for the particular hue which we find in nature. It 
 is known that the colouring matters of flowers may be 
 divided into two classes, the xanthic and the cyanic, whose 
 types are respectively yellow and blue ; and these two 
 classes do not readily pass into one another. Thus, we 
 
 ^ " Nature," November 29, 1S77.
 
 74 THE COLOUR-SENSE. 
 
 cannot liavG a blue rose or a blue dahlia, tliougli we may 
 vary the hues of either blossom by proper treatment 
 almost indefinitely within the prescribed limit. Hence, 
 it might appear that each flower produced as a rule those 
 colours which most readily result from the chemical 
 properties of its constituents, varying the tint, so far as 
 possible, under the influence of insect selection, in accord- 
 ance with the nature of the percipient eye, of the sur- 
 rounding foliage, and of other adventitious circumstances 
 in the environment. It might well happen, however, in 
 the majority of cases, that any bright colour would equally 
 answer the attractive purpose, supposing only it contrasted 
 sufficiently with the green leaves or other objects in the 
 natural background. Such, at least, we know to be the 
 fact with the eye of man, who is struck indifferently by 
 the golden orange, the ruddy strawberry, the rosy-cheeked 
 mango, or the purple grape. 
 
 With regard to the infinite variety of tints which we 
 find in various flowers, it is sufficient to remember that 
 very slight alterations in the physical conditions or in 
 the particular stock suffice artificially to produce such 
 varieties among cultivated plants. Any one who looks 
 at the multitudinous shades of garden hyacinths, dahlias, 
 fuchsias, chrysanthemums, tulips, and pansies, need not 
 wonder at the great profusion of colour in wild plants. 
 Almost any shade seems easily procurable from another, 
 provided only it does not overstep the natural limitation 
 set down above. In all probability, the ordinary colouring 
 matters of flowers differ from one another only in the 
 minutest particulars of chemical composition. 
 
 So far we have been engaged in answering, to the best 
 of our knowledge, the first question proposed above : Did 
 flowers show an original tendency to the production of 
 coloured adjuncts even prior to the selective action of 
 insects ? We have settled to our own satisfaction — I hope 
 also to the satisfaction of the critical reader — that such an 
 original and adventitious tendency did really exist ; and
 
 INSECTS AND FLOWERS. 75 
 
 we have traced it up through its various stages, as it 
 became, from generation to generation, more and more 
 purposive, until at last we have seen it culminate in the 
 gorgeous peonies, tulips, lilies, and rhododendrons of our 
 modern flower-s^ardens. But all this time we have been 
 putting off the consideration of our second question : Did 
 insects possess any tendency vaguely to discriminate the 
 various colours apart from the reactive influence of ento- 
 mophilous Howers ? To this further inquiry we must now 
 address ourselves for a few short minutes. 
 
 The answer must be a somewhat dubious one — in a 
 certain sense negative, in another sense affirmative. There 
 is no reason to think that insects could be definitely 
 affected by various colours before the rise of bright-hued 
 flowers had developed their colour-sense. But we must 
 remember that while colours differ qualitatively for us, 
 they also differ quantitatively in an absolute manner. 
 Now, " to be affected more or less," as Professor Bain well 
 puts it, " is a consequence of being affected at all ; " and 
 therefore every animal which has any organ for the per- 
 ception of light must be capable of quantitatively differ- 
 ential stimulation by its greater or less intensity. Herein 
 we have a slight original groundwork through which white 
 might be distinguished by the primitive eye from green, 
 brown, or black. But the growth of a distinctive mode of 
 consciousness, or, to put it objectively, of distinct nerve- 
 oroans for the various waves of sether, must needs have 
 been the result of long ages, during which those insects 
 who best discriminated colour lived down on the average 
 their less gifted compeers. How this result was brought 
 about we cannot even guess, for here we rind ourselves on 
 the threshold of an ultimate metaphysical problem, un- 
 fathomable as yet — perhaps unfathomable for ever ! Why 
 the sensations of the auditory central organs should differ 
 from those of the optical central organs ; ivliy the stimula- 
 tion of a certain fibre and its connected ganglia should 
 yield the feeling of blue, while the stimulation of its
 
 76 THE COLOUR-SENSE. 
 
 neigiibour yields that of red — these final questions we 
 cannot even pretend to guess. How the differentiation 
 began, how it continued, how it acts to-day, we do not 
 know, and very probably we may never know. But we 
 do know this, that in a developed sensorium a differential 
 sensation is attached to the differential stimulation of each 
 among several very like nervous bodies ; and that if it were 
 not so, consciousness itself would be impossible. 
 
 Passing over this ultimate problem, however, it is not 
 difficult to see how a substance so unstable and so 
 modifiable as nerve-matter might easily present various 
 modifications which answered to the various varieties of 
 sether-wave falling upon it. If once such differentiated 
 nerve-terminals began to exist, all experience and analogy 
 show us that they would be followed by the differentiation 
 of their connected nerve-centres, to each of which, in this 
 mysterious way, a differentiated mode of consciousness 
 would come to be attached. And this is what we mean 
 by colour-sense. 
 
 Vague and symbolical as such a sketch confessedly 
 must be, it would be foolish and premature to fill in any 
 further conjectural details in the present state of our 
 knowledge. We must accept it as a bare skeleton of the 
 possible truth which fuller acquaintance with the nature 
 of nerve-substance may some day flesh out for us in all its 
 minor aspects. But we are not wholly without analogies 
 which allow us faintly to foreshadow in our minds some 
 indefinite hypothesis of its evolution. We know that a 
 single material, such as glass, may be so moulded into globes 
 that each globe will not only yield, when struck, a single 
 constant note, but will also answer sympathetically to that 
 note alone when sounded on another instrument. Now if 
 we suppose that the nerve-terminals of the insect eye were 
 similarly tuned at first, but so badly as to vibrate sympa- 
 thetically with the whole gamut of separate sether-waves, 
 we shall have a symbolical picture of an eye without a 
 colour-sense. But if we further suppose that, under the
 
 INSECTS AND FLOWERS. 77 
 
 influence of sundry incident causes unknown, certain 
 amonc^ these nerve-terminals became restricted in the 
 range of their sympatliies, so as onlv to vibrate in unison 
 with ?ether-waves having a limited range of frequency, 
 then we shall have a symbolical picture of an eye with a 
 rudimentary colour-sense. And if natural selection, pick- 
 ing out, as we know it would, from the whole number of 
 variations in either direction those which varied most on 
 the side of a still more limited range, at last produced 
 terminals which were affected only by waves lying within 
 an extremely small compass, we should then have the 
 symbolical picture of an eye with a highly developed 
 colour-sense. Eude as this representation of the possible 
 course of evolution must obviously be, it may still answer 
 the purpose of enabling the reader diagrammatically to 
 grasp the idea which would otherwise float vaguely through 
 his mind and elude every attempt to fix and crystallise it 
 into thouoht. More than this humble service our rough 
 and materialistic metaphor cannot pretend to perform. 
 
 And now, to recapitulate the chief points of this lengthy 
 chapter, let us look back in imagination over the whole 
 complex process here so imperfectly sketched out, and 
 state our hypothetical conclusions, for clearness' sake, in 
 the lancTuai^e of established fact. Amid the earliest forests 
 of our earth, green cryptogamic vegetation formed the 
 whole flora. But as time went on, the advantages of 
 cross-fertilisation produced, through some unknown com- 
 bination of circumstances, the earliest flowering plants. 
 These, strengthened by the constant infusion of fresh 
 blood (to use the familiar phrase), lived down the con- 
 sanguineous offspring of the great ferns and horse-tails 
 amongst which they grew. But such primeval flowering 
 species were all fertilised by the aid of the wind, and 
 possessed no bright corollas or other coloured adjuncts. 
 The aspect of a palceozoic forest presented an almost un- 
 broken sheet of monotonous verdure. Even then, how- 
 ever, a tendency towards the production of red or yellow
 
 78 THE COLOUR-SENSE, 
 
 juices and other colouring matters might have been noticed 
 in certain portions of the different plants. The tendency 
 was especially displayed in those parts of the organism 
 where energies were being used up in the performance of 
 physiological functions ; this effect being due, perhaps, to 
 the process of oxidation. Such phenomena might be 
 noticed both in the dying leaves and in the youngest 
 shoots ; but they were also to be found in the floral organs 
 and their neighbourhood. As yet, however, no eye could 
 distinguish them as colours : they had only an objective 
 existence as sether-waves of unusual simplicity and purity. 
 But among these flowers a few undeveloped and unspe- 
 cialised insects sought their food. Some of the blossoms 
 thus obtained fertilisation more easily than before; and 
 those among them which offered special attractions to the 
 insects were able to effect a great economy of pollen, 
 besides being impregnated with immensely greater cer- 
 tainty than their anemophilous competitors. Thus certain 
 plants became permanently and regularly entomophilous. 
 Thenceforward those entomophilous plants which pro- 
 duced the greatest quantities of insect food, as honey or 
 pollen, were most often visited, and so most regularly 
 fertilised. Again, out of this number, whatever indivi- 
 duals most conspicuously displayed the original tendency 
 toward bright and distinctive colouration were most 
 likely to strike the eyes of insects. Conversely, whatever 
 insects most readily discriminated the nascent patches of 
 colour were best able (other things equal) to secure their 
 food. So the production of coloured floral whorls, and the 
 perfectioning of the insect colour-sense, went on pro- 
 gressing side by side. The various flowers entered into 
 unconscious competition with one another for the visits 
 of their fertilisers ; and those which could specially lay 
 themselves out for the attention of a single species there'by 
 procured impregnation with greater ease and certainty. 
 Thus arose the quaintly-shaped bells, labiates, snap- 
 dragons, orchids, and other irregular flowers, whose forms
 
 INSECTS AND FLOWERS. 79 
 
 are definitely correlated to those of their insect allies. 
 Similarly, an insect with a specially long proboscis, and 
 with certain hairy appendages on his legs or forehead, 
 might at once abstract honey from flowers which no other 
 insect could reach, and fertilise deeply-seated organs 
 which no other insect would affect. Thus arose the 
 specialised flower-feeders like bees and butterflies. Again, 
 other flowers which separately failed to attract the proper 
 insects might prove very alluring when massed in large 
 bunches. The result is seen in the development of com- 
 pound blooms like clover, lilac, horse-chestnut, and the 
 various composites, which last undergo still further selec- 
 tions, ultimately producing yet more compound forms. 
 At length the colour-sense of insects, thus aroused, 
 strengthened, and fully developed, is employed for other 
 purposes, of defence, protection, the chase after prey, the 
 search for mates, or similar life-serving actions ; and these 
 activities once more react on the growing sense, so as to 
 increase its definiteness and its worth. Last of all, the 
 colour-sense is employed by the insects themselves, as we 
 shall see in a future chapter, as an sesthetic instrument 
 in the choice of mates, and so indirectly produces, throuo-h 
 sexual selection, the brilliant hues of butterflies, beetles, 
 and all the other exquisite winged or creeping articulates 
 which fill the gorgeous cabinets of our museums. 
 
 In this list of what the colour-sense owes to the hues 
 of blossoms, we might further include many facts with 
 regard to humming-birds, sunbirds, and other flower- 
 feeding vertebrates. But these belong properly to a later 
 stage in our inquiry ; and enough has already been said 
 or hinted, I believe, to show how fundamental a fact in 
 the history of the colour-sense and its reactions is the 
 primitive tendency towards the display of bright hues 
 around the floral reproductive organs. Already we have 
 here, indeed, the origin of many among those brilliant 
 objects which we noted as wanting in the Carboniferous 
 world — the world without a colour-sense. We must here-
 
 8o THE COLOUR-SENSE. 
 
 after go on to inquire what was the development of the 
 remainder ; and w^e shall find, when we search the records 
 of evolution, that no small proportion of these, too, may 
 be ultimately traced back, through some remote and in- 
 direct pedigree, to the lovely and varied tints of tropical 
 or woodland flowers.
 
 ( 8i ) 
 
 CHAPTER V. 
 
 THE COLOUR-SENSE IN INSECTS. 
 
 Throughout the \yliole of the preceding chapter we have 
 taken for granted the existence of a developed colour- 
 sense in some at least amongst the insects of modern 
 times. We have tried to show what were the circum- 
 stances which gave it origin, and what the steps by which 
 it reached its present supposed perfection. But now a 
 deeper question arises, a question due to a destructive 
 criticism which might seek to overthrow our whole super- 
 structure by denying that modern insects do, as a matter 
 of fact, possess any colour-sense whatsoever. In the face 
 of such a possible criticism we must review all the various 
 proofs of colour-perception in articulate animals which 
 experiment or observation may reveal to our patient 
 search. 
 
 This course is rendered the more necessary because 
 within the last few years the existence of a faculty for 
 the discrimination of different hues, even in primitive 
 man himself, has been gravely called in question, both 
 in this country and in Germany, by competent authorities 
 in various walks of science or criticism. Mr. Gladstone 
 first suggested that the Homeric poems contained no 
 evidence of a colour-sense amongst the Akhaians of that 
 early date.i Many years later. Dr. Lazar Geiger noticed 
 that the colour-words employed in the Bible, the Vedas, 
 the Zend-Avesta, and other early works, were very vague 
 
 1 Gladstone, "Studies on Homer," vol. iii. § 4.
 
 82 THE COLOUR-SENSE. 
 
 and indeterminate. 1 Dr. Magnus, a distinguislied German 
 oculist, next followed up the hint thus thrown out, and 
 endeavoured to prove, in two learned pamphlets,- that the 
 colour-perception of civilised man was a faculty of quite 
 recent development, and that so lately as some 3000 years 
 ago mankind was utterly incapable of distinguishing 
 between violet, green, blue, and yellow. These views 
 were further popularised by Mr. Gladstone in a later 
 paper,^ and have been partially adopted by several 
 scientific authorities, including even that staunch evolu- 
 tionist, Mr. A. E. Wallace, the joint-discoverer of natural 
 selection.^ Indeed, although the allegations of Dr. 
 Magnus and his friends have not gone entirely un- 
 answered,^ yet it would seem as though the scientific 
 world generally, in Germany at least, was prepared to 
 accept them as representing the approximate truth. 
 
 To the evolutionist, however, this crude and ill-digested 
 theory can hardly seriously reconmiend itself.*^ The sup- 
 position that any mode of perception so distinct and so 
 varied as our colour-sense could be developed in the 
 short space of time intervening between the Homeric 
 Akhaians and our own epoch seems little short of in- 
 credible. The few centuries which have rolled past 
 during that interval form but a single pulse of the pen- 
 dulum whose seconds make up the epochs of geological 
 evolution. To me, it appears rather that the colour-sense 
 
 ^ Zur Entwickelungsgeschichte der 264, 423; by an anonymous critic in the 
 
 Menschheit, chap, iii., passim, Stutt- Allgemeine Zeitung, IMarch 8, 1878; 
 
 gart, 1871. by Prof. Blackie, read before the 
 
 2 Die Geschichtliche Entwickelung Royal Society of Edinburgh, January 
 
 des Farbensinnes, Leipzig, 1877, and 1878; by Prof. Robertson Smith in 
 
 in Preyer's Physiologischer Abhand- "Nature," December 6, 1877; by 
 
 lungen, I. ix. 515, Dr. Pole in "Nature," October 24 
 
 2 "The Colour-Sense" in "Nine- and 31, 1878; and by myself in 
 
 teenth Century," October 1877. "Mind," January 1878. 
 
 ■* "Colour in Animals and Plants," ^ I learn by a private letter from 
 
 " Macmillan's Magazine," October Mr. Wallace that, on fuller considera- 
 
 1877. tion, he cannot endorse Dr. Magnus's 
 
 5 Readers desirous of following up views so implicitly as he was at 
 
 the whole discussion will find papers first inclined to do, and he has since 
 
 on this question by Mr. Darwin and partially retracted his adhesion in 
 
 Dr. Krause in "Kosmos," 1877, pp. " Tropical Nature," p. 246.
 
 THE COLOUR-SENSE IN INSECTS, Z^ 
 
 of man is derived, through his mammalian ancestry, from 
 a long line of anterior generations, and that its origin 
 must be sought for in ages before a solitary quadrumanous 
 animal had appeared upon the face of the earth. Holding 
 this view, it becomes incumbent on me to propose a 
 counter-theory to that of Dr. Magnus and Mr. Gladstone ; 
 a theory which will trace back our colour-sense to its 
 ultimate sources in the bright hues of vegetal products 
 like fruits and flowers. And it becomes necessary also to 
 seek for every possible fact which goes to prove the 
 existence of a similar faculty throughout the whole 
 animal world. For if even man himself, " the head and 
 crown of things," did not possess any such power until a 
 few hundred years since, how can we suppose that the 
 lower animals, including the humble little insects, have 
 been for ages in enjoyment of this highest sensuous gift ? 
 It may be asked, however, " Why take the trouble to 
 search for recondite proofs on such a plain and straight- 
 forward subject ? Why not try at once a few simple and 
 direct experiments upon the colour-perception of various 
 insects, beasts, and birds ? " The suggestion is a natural 
 one, and yet it is not so easy to act upon as would at first 
 appear to be the case. Experiments of the sort are 
 difficult to devise, and still more difficult to carry out 
 successfully to any definite result. We cannot ask the 
 animals to detail their sensations, and we find it hard to 
 invent decisive or crucial tests of an objective character. 
 A few lucky exceptions will be described in the following 
 pages, but they are mere oases amongst a desert of lament- 
 able failures. As a rule, animals refuse in the most 
 provoking manner to take any notice of the psychological 
 traps which you have carefully baited as tests of their 
 sensations. For the most part, we must rely upon the 
 less satisfactory method of observation, and upon various 
 indirect conclusions, each of which has separately very 
 little weight. In short, the evidence in favour of a colour- 
 sense amongst the lower animals is purely cumulative. Each
 
 84 THE COLOUR-SENSE. 
 
 link in the argument is but a slender support ; yet I hope 
 to show as we proceed that the whole strand, formed of 
 variously twisted chains, is collectively strong enough and 
 sure enough to support the burden of a weighty conclusion. 
 Happily, as regards the higher insects, we can start fair 
 with a set of decisive experiments tried by Sir John 
 Lubbock. That patient and minute observer saw grounds 
 for believing that bees were attracted by the hues of 
 flowers. However, to make assurance doubly sure, he 
 placed slips of glass smeared with honey on paper of 
 various colours, black, white, yellow, orange, blue, and 
 red. The general results may be given in the original 
 words. " A bee which was placed on the orange returned 
 twenty times to that slip of glass, only once or twice 
 visiting the others, though I moved the position and also 
 the honey. The next morning again two or three bees 
 paid twenty-one visits to the orange and yellow, and only 
 four to all the other slips of glass. I then moved the 
 glass, after which, out of thirty-two visits, twenty-two 
 were to the orange and yellow." ^ However, this prefer- 
 ence did not depend upon an inability to discern the blue, 
 for on another occasion, says the author, " I had ranged 
 my colours in a line, with the blue at one end. It was 
 a cold morning, and only one bee came. She had 
 been several times the preceding day, generally to the 
 honey which was on the blue paper. This day also she 
 came to the blue. I moved the blue gradually along the 
 line one stage every half hour, during which time she 
 paid fifteen visits to the honey, in every case going to 
 that which was on the blue paper." Sir John Lubbock, 
 however, never relies upon single or few experiments. 
 Accordingly, he tried once more at a later date with 
 greater variation in the circumstances. " On the 1 2th of 
 July," he says, " I brought a bee to some honey which I 
 placed on blue paper, and about three feet off I placed a 
 
 ^ Journal of the Linnean Society, ing me copies of all his papers 
 vol. xii. p. 129. I have to thank Sir and lectures on this interesting 
 John Lubbock for kindly forward- question.
 
 THE COLOUR-SENSE IN INSECTS, 85 
 
 similar quantity of lioney on orange paper. After she 
 had returned twice, I transposed the papers ; but she 
 returned to the honey on the blue paper. After she had 
 made three more visits, always to the blue paper, I trans- 
 posed them again, and she again followed the colour, 
 though the honey was left in the same place." A series 
 of careful observations followed, which are detailed in a 
 tabular form ; but my readers will probably be satisfied 
 with a general summary, to the effect that thirty conse- 
 cutive visits were all made to the same colour, in spite of 
 four separate transpositions. On one of these occasions, 
 says Sir John, "At 8.5 she returned to the old place, 
 and was just going to alight ; but observing the change of 
 colour, without a moment's hesitation darted off to the 
 blue. No one who saw her at that moment could have 
 entertained any further doubt about her perceiving the 
 difference between the two colours." ^ 
 
 Similar results were obtained with wasps. At 6 A.M. 
 on September 13, 1875, Sir John observes, ''I put a wasp 
 to some honey on green paper and about a foot off I put 
 some more honey on orange paper. The wasp kept re- 
 turning to the honey at the usual intervals. At 8.30 I trans- 
 posed the papers ; but the wasp followed the colour. At 
 9 o'clock I transposed the papers again, but not the honey ; 
 she returned again to the green, from which it would ap- 
 pear that she was following the colour, not the honey. 
 At 10.20 I again transposed them, with the same result." 2 
 
 It should be mentioned, however, that later experi- 
 ments led Sir John Lubbock to the conclusion that bees do 
 not so easily discriminate between blue and green as be- 
 tween other colours — a very natural fact, considering how 
 slight is the objective difference between these shades. It 
 would also appear that though wasps can distinguish 
 colours, they are less guided by them than is the case 
 with bees.^ This we might have expected a priori from 
 
 ^ Journal of the Linnean Society, ^ See part iv. of Sir John Lubbock's 
 vol. xii. p. 232. investigations in Journ. Linn. Soc, 
 
 - Ibid., p. 237. vol. xii. p. 312 seq.
 
 86 THE COLOUR-SENSE. 
 
 the diversity of habits of the two insects, and we shall see 
 hereafter that the difference has important bearings on 
 the question of relative tastes. 
 
 With respect to ants, Sir John Lubbock's experiments, 
 though read before the Linnean Society, have not at the 
 date of writing yet been published in its Transactions. It 
 must suffice, therefore, without anticipating the author's 
 statement, to notice here, that though these insects are 
 very defective in the sense of vision, depending much more 
 largely upon touch and smell, they are evidently affected 
 in a distinctive manner by the red and violet ends of the 
 spectrum. Of course the habits of ants would not lead us 
 to credit them with the necessary circumstances for giving 
 rise to a developed colour-sense ; nor are their reactions 
 on external nature of the same startling character as those 
 which we observe in the case of the fully-winged insects, 
 like bees and butterflies. Nevertheless, it is interesting 
 to observe that even here a groundwork of faint discri- 
 mination evidently exists, which might possibly have been 
 developed into a perfect sense had the circumstances of 
 ant-life so determined its evolution. 
 
 Observation in many ways confirms the results thus 
 obtained by experiment. Let us look first at the evidence 
 on this head which can be derived from the visits of bees 
 and butterflies to flowers. 
 
 We have seen already that one main difference between 
 anemophilous and entomophilous flowers consists in the 
 fact that while the former are usually small, greenish, and 
 inconspicuous, the latter are usually large, brilliant, and 
 deeply coloured with white, red, blue, or yellow. We 
 have the high authority of Mr. Darwin for the statement, 
 as an invariable rule, " That when a flower is fertilised by 
 the wind it never has a gaily-coloured corolla." ^ And 
 though the converse proposition is not strictly true in 
 every case, yet a large proportion of those blossoms which 
 
 ^ Origin of Species, p. 127.
 
 THE COLOUR-SENSE IN INSECTS. 87 
 
 depend for fertilisation upon insects are noticeable for 
 their bright and flaunting hues. 
 
 Xow, the structures in which the brilliant pigments 
 reside have absolutely no function except that of attract- 
 ing the insect agents for fertilisation. But these struc- 
 tures, as we have already seen, are produced by the plant 
 at an enormous physiological cost, often so as to engage 
 by far the greater portion of all its energies. Unless we 
 allow, then, that roses, tulips, lilies, and rhododendrons 
 have developed their large and showy corollas for the sake 
 of allurinsj their insect allies, we shall be reduced to believe 
 that they have produced these expensive and useless ad- 
 juncts for no other purpose than that of wasting their 
 substance in riotous living. Such a supposition involves 
 a simple physical absurdity. If any plant could, by any 
 accidental combination of circumstances, once acquire so 
 bad a habit, it must necessarily stand at a disadvantage in 
 comparison with all other plants, and so be quickly extin- 
 guished in the ceaseless struggle and competition of ter- 
 restrial life. We cannot for a moment believe that any 
 structure could exist at all, far less spread itself through 
 all the most successful species of a dominant class, unless 
 it subserved some function of great utility to the organism 
 in which it is found. 
 
 Nor are we left here entirely to such a 'priori reasoning. 
 It happens that a few aberrant plants possess two forms of 
 flowers — the one entomophilous, and often appearing in the 
 spring ; the other self-fertilised, and often appearing in the 
 autumn. Of this phenomenon the common violet offers a 
 well-known example. The entomophilous blossoms, which 
 seem to be frequently sterile, and to answer the purpose 
 of such occasional cross-fertilisation as may keep up the 
 vigour of the stock, are distinguished by the usual coloured 
 corolla, as well as by a sweet and attractive perfume in 
 certain species. But the self-fertilised or clcistogamous 
 blossoms, which in many ways recall the spore-cases of 
 cryptogams, are quite green and inconspicuous, so much
 
 88 THE COLOUR-SENSE. 
 
 so, that no ordinary observer would call tliem flowers at 
 all, but would set them down as fruits or seed-vessels. 
 These latter blossoms do most of the effective reproductive 
 work ; but as they do not aim at cross-fertilisation, and so 
 do not require the aid of insects, they have entirely lost 
 all semblance of coloured floral whorls, and consist merely 
 of hidden fructifying elements. Thus nature herself, as it 
 were, makes an experiment for us which clearly demon- 
 strates, by the Method of Difference, the real function of 
 the pigmented corolla. 
 
 Like results are shown in the case of many plants be- 
 longing to mainly entomophilous families. True anemo- 
 philous flowers, whose ancestors have been anemophilous 
 for all past generations, and have never learnt to depend 
 upon insects at all, possess only the two effective sexual 
 whorls, with at most some appendage having more or less 
 the nature of a calyx. But certain plants, which appar- 
 ently belong by descent to mainly entomophilous tribes, 
 seem to have dropped the habit of insect-fertilisation, and 
 to have reverted once more to wind-fertilisation. In all 
 (or almost all) these cases, where the corolla still exists at 
 all in a rudimentary form, bearing witness to their ances- 
 tral habit, the petals have grown quite small and dwarfed 
 (because their original function is gone), and have once 
 more resumed the green appearance of ordinary leaves. 
 In short, we see that where flowers require the aid of 
 insects they almost always bid for it by assuming bright 
 hues ; but that those flowers, anemophilous or cleistoga- 
 mous, which do not need their aid, are normally destitute 
 of such hues, while those plants which once required their 
 aid, but have ceased to do so, rapidly lose their coloured 
 adjuncts, in accordance with that Law of Parsimony where- 
 by all structures whose functions are no longer necessary 
 become finally obsolescent. How these facts can be ac- 
 counted for if we suppose insects to be destitute of a 
 colour-sense it would baffle the cleverest theorist to say. 
 
 In some few instances we even possess actual proof that
 
 THE COLOUR-SENSE IN INSECTS. 89 
 
 insects are attracted by the bright hues of petals. Thus 
 Mr. Anderson noticed that when the corolla of certain 
 blossoms, so constructed as to favour or almost ensure 
 cross-fertilisation, had been cut away, the insects never 
 discovered or visited the flowers.^ " I proved the import- 
 ance of the gaily coloured corolla," says Mr. Darwin, " by 
 cutting off the large lower petals of several flowers of 
 Lobelia erinus, and these flowers were neglected by the 
 hive-bees, which were incessantly visiting the other 
 flowers." ^ 
 
 Descending to particular instances, we find that while 
 most bright-coloured blossoms ofi'er the visiting insect 
 some real advantage in the shape of honey, other unprin- 
 cipled plants, trading upon the general faith in a connec- 
 tion between colour and food, delude insects into visiting 
 them by their hue alone.^ Again, certain insects, as Mliller 
 has observed, visit certain flowers only ; and in other 
 cases, a particular insect, during a single day, confines 
 himself, for some reason of his own, to some one chosen 
 species. Numerous naturalists have put on record the 
 preferences which individual insects have shown on special 
 occasions for one kind of blossom alone. A single case 
 must suffice for all. That careful observer, Mr. H. O. 
 Forbes, saw " by the roadside, near Kew Bridge Station, 
 several species of Hymenoptera, of the genus Bomlus 
 principally; one visited thirty flowers of Lamium pur- 
 jpureum in succession, passing over without notice all the 
 other plants on the same bank — species of Convolvulus, 
 Ruhus, Solarium. Two other species of JBomhus and a 
 Pieris rapce also patronised the Lamium, seeking it out 
 deep in the thicket, thrusting their probosces even into 
 withered cups, although the Ruhus flowers were far more 
 accessible, and seemed much more attractive, beins^ fresh 
 and well-expanded." ^ The pages of scientific journals 
 
 1 Darwin, "Cross and Self-Fertili- ^ Lubbock, " British Wildflowers," 
 sation of Plants," p. 87, p. 11. 
 
 ^ Ibid., p. 176. ^ "Nature,"' Xovember 22, 1877.
 
 90 THE COLOUR-SENSE. 
 
 during the last few years have positively teemed with 
 similar instances from all parts of the world. 
 
 Furthermore, the varying colours of flowers seem 
 adapted, as we saw in the last chapter, to attract parti- 
 cular insects at particular periods of inflorescence. I 
 have already mentioned the case of a Lantana described 
 by F. MuUer as altering in hue at different times during 
 its maturation, being yellow on the first, orange on the 
 second, and purple on the third day. " This plant," says 
 Mliller, " is visited by various butterflies. As far as I have 
 seen, the purple flowers are never touched. Some species 
 inserted their proboscis both into yellow and into orange 
 flowers (JDanais erippus, Pieris aripa) ; others, as far as I 
 have hitherto observed, exclusively into the yellow flowers 
 of the first day {Heliconius apseiides, Coloenis julia, Eurema 
 leucc). ... If the flowers fell off at the end of the first 
 day, the inflorescence would be much less conspicuous : 
 if they did not change their colour, much time would be 
 lost by the butterflies inserting their proboscis in already 
 fertilised flowers."^ In another species of the same genus 
 the flowers are lilac, but the entrance of the tube is 
 marked with yellow, surrounded by a white circle. These 
 yellow and white markings, which probably serve as guides 
 for the insect allies, disappear entirely on the second day. 
 
 And now, from the evidence supplied by flowers, we 
 may pass on to the evidence supplied by the colours of 
 insects themselves. I do not here propose to enter upon 
 the consideration of those hues which depend for their 
 origin upon sexual selection ; that part of our cumulative 
 argument must be delayed to a later chapter. But we 
 may fittingly consider at the present point the proofs of a 
 colour-sense in insects afforded by the curious phenomenon 
 of mimicry, so fully illustrated by Mr. Wallace and Mr. 
 Bates. 
 
 It is now an established fact that certain animals have 
 
 1 "Nature," Xov ember 29, 1877.
 
 THE COLOUR-SENSE IN INSECTS. 91 
 
 survived in the struggle for existence by means of some 
 special resemblance to other species or to objects in the 
 environment which gives them a special chance of deceiv- 
 ing prey, escaping the notice of enemies, or adopting some 
 similar protective device. Colour enters largely into the 
 special adaptations thus produced, and many insects 
 have been largely modified in their colouration by the 
 action of such mimetic selection. But, as a rule, the 
 particular hues or lines have reference less to the eyes of 
 insects themselves than to the eyes of the reptiles, birds, 
 or mammals which prey upon them ; and these cases will 
 therefore be more fully considered when we come to treat 
 of the colour-sense in vertebrates. In a few instances, 
 however, protective imitation seems to have been pro- 
 duced in certain insects with reference to the eyes of other 
 species in their own class ; and these latter cases may 
 properly be treated under the present heading. 
 
 First of all, we may take the instance of those flies 
 which live in a sort of social parasitism among the hives 
 or nests of bees. These flies have acquired belts of colour 
 and other imitative appendages closely resembling those 
 of the host upon whose stores they commit their depreda- 
 tions, while their larvse actually live by devouring the 
 larvae of the bees themselves. Obviously, any fly which 
 entered a beehive could only escape detection and ex- 
 termination at the hands of its inhabitants, provided it so 
 far resembled them as to be mistaken at a first glance by 
 the community for one of their fellows. Thus any fly 
 which showed the slightest superficial resemblance to a 
 bee miohfc at first be enabled to rob their storehouses 
 with impunity, while such flies would escape continued 
 detection from generation to generation just in proportion 
 as they more and more closely approximated to the ap- 
 pearance of their unwilling hosts. For, as Mr. Belt has 
 well pointed out, while the mimicking species would 
 become naturally more numerous from age to age, the 
 senses of the mimicked species would become naturally
 
 92 THE COLOUR-SENSE. 
 
 sharpened by the habit of detecting flimsy pretences ; and 
 so at last very close resemblance might be expected to 
 arise.^ In the particular instance now under notice, I 
 learn from Mr. Lowne, who has carefully measured the 
 curvature of the facets in the compound eyes of insects 
 (upon which, of course, depends the minimal size of ap- 
 prehensible objects), that the mimicry has proceeded just 
 so far as the structure of the bee's eye would lead him to 
 expect, and no further. In other words, Mr. Lowne is 
 inclined to suppose, if measurements of angular distance 
 subtended can guide him, that such a fly is indistinguish- 
 able by a bee from one of his own species within the 
 limits of ordinary vision.^ 
 
 Mr. Bates mentions a still more interesting case of some 
 showy coloured Brazilian spiders (which, of course, are not 
 themselves insects in the scientific sense), "who double 
 themselves up at the base of leaf-stalks, so as to resemble 
 flower-buds, and thus deceive the insects upon which 
 they prey."^ Sir Joseph Hooker believes that an Indian 
 Mantis, or praying-insect, similarly deludes the little 
 creatures which form its food by its extraordinary like- 
 ness to a leaf.'^ Another rapacious example of the same 
 genus exactly mimics the white ants, whom it devours 
 quietly and unsuspected.^ But all these curious facts are 
 thrown into the shade by a third Mantis, for which Sir 
 Charles Dilke stands as voucher — a bloodthirsty wretch, 
 whose head and fang^s have been moulded into the ima^e 
 of an orchid, with a deceptive blossom which closes upon 
 the insect who seeks for food in its treacherous arms. 
 
 Sometimes even higher animals seem to have acquired 
 
 ^ The aSTaturalist in Nicaragua, p. was a Syrian Laphria, and the crea- 
 
 383. ture mimicked a wasp. 
 
 - For a very perfect instance of '^ The Naturalist on the Amazons, 
 
 such mimetic resemblance, where the p. 54. 
 
 colour is especially noticed in great •* Himalayan Journal, vol. ii. p. 
 
 detail, see an interesting paper b}" JNIr. 306. 
 
 Neville Goodman in "Proc. Camb. ^ Wallace, "Contributions to the 
 
 Phil. Soc," vol. iii, part 2, March Theory of Natural Selection," p. 98. 
 1878, p. 25. In this case the mimicker
 
 THE COLOUR-SENSE IN INSECTS. 93 
 
 similar disguises in order to deceive the insects for which 
 they lie in wait. Thus Mr. Belt notices a green ISTicara- 
 guan lizard, looking like the herbage by which it is sur- 
 rounded, and decked with leaf-like expansions, which 
 serve to conceal its predacious nature from passing beetles 
 or flies. 1 How far the greenness of lizards and forestine 
 birds in general, or the sandy hue of those which frequent 
 deserts, may serve them as aids in escaping the notice of 
 prey upon which they creep, is too uncertain a question 
 to be urged in evidence as to the colour-sense of insects, 
 and yet too interesting to be passed by without at least 
 an allusion. 
 
 In all these instances, various predatory species have 
 acquired mimetic resemblances for the sake of deceiving 
 their quarry ; but in other cases the defenceless booty 
 turns the tables upon the tyrants, and is accordingly 
 enabled to elude their hungry quest. Thus Mr. Wallace 
 tells us of a cricket w^hich exactly reproduces the features 
 of its foe the sandwasp ; ^ while Mr. Belt saw a green leaf- 
 like locust, overrun by foraging ants, yet remaining as 
 motionless as the leaves, whose colour and texture it so 
 faithfully mimicked. This latter creature appeared to 
 have some dim instinctive knowledge of the fact that its 
 safety depended upon its absolute immobility, for even 
 when lifted by the hand from the ground, it continued 
 strenuously to preserve its rigid attitude.^ 
 
 But indeed, to any mind unbiassed by preconceptions 
 derived from another sphere of thought, the grand evi- 
 dence in favour of an insect colour-sense is to be found, 
 not in isolated instances, but in the broad expanse of 
 meadow and hillside around us. The million hues of 
 spring or summer flowers have no meaning and no ex- 
 planation on any other hypothesis. The colour-sense of 
 bees and butterflies has metamorphosed the world ; and 
 
 ^ Naturalist in Nicaragua, p. 12. 
 
 2 Contributions to the Theory of Natural Selection, p. 99. 
 
 2 Naturalist in Nicaragua, p. 19.
 
 94 THE COLOUR-SENSE. 
 
 we must seek for its indications on every plain and moun- 
 tain of every country in the earth. 
 
 A human analogy will make clear the magnitude of the 
 changes in the face of nature due to the reactive effects 
 of the insect colour-sense. Man has wrought many altera- 
 tions in the aspect of the fauna and flora of all coun- 
 tries which he has brought under his sway. He has cut 
 down the forests, cleared the jungle, irrigated the desert, 
 reclaimed the stony waste. Whatever plants or animals 
 served him for food, clothing, or other useful purposes, 
 he has selected, propagated, and carried with him in his 
 wanderings from shore to shore. Whatever others proved 
 useless or positively noxious, he has extirpated from their 
 native haunts. His fields glow with golden corn or dark- 
 green maize ; with millet, barley, oats, or rice ; with vines, 
 hops, or sugar-cane ; w^ith yams, potatoes, plantain, or 
 bananas ; with flax, hemp, cotton, oil-seeds, or fibres. His 
 orchards are laden with apples, plums, peaches, pears, 
 oranges, olives, mangoes, and papaws. His meadows are 
 stocked with the clover, lucerne, vetches, and grass which 
 feed his flocks and herds. The woodland itself is spared 
 only to supply him with timber for firewood or building. 
 In like manner, the wild beasts of the forest have given 
 place to his cattle, his horses, and his sheep. Camels, 
 elephants, and llamas bear his burdens on their patient 
 backs. Alpacas and merinos, the goats of Kashmir and 
 the yaks of Tibet, supply his woven fabrics. Even insects 
 are not exempt ; silkworms fatten on his mulberry trees, 
 and nopaleries, specially planted for that purpose, afford 
 sustenance to his cochineal flies. The wolves, bears, 
 foxes, tigers, and venomous snakes retire before his face, 
 and he wages a perpetual warfare with the intrusive weeds 
 which seek to find a root-hold among his growing crops. 
 Such are the changes which man has impressed upon the 
 lands where he has made his settled home. 
 
 But all these alterations are mere surface scratches 
 compared with the immense revolution wrought in the
 
 THE COLOUR-SENSE IN INSECTS. 95 
 
 features of nature by the unobtrusive insect. Half tlie 
 flora of the earth has taken the imprint of his likes and 
 his necessities. While man has only tilled a few level 
 plains, a few great river valleys, a few peninsular moun- 
 tain slopes, leaving the vast mass of earth untouched by 
 his hand, the insect has spread himself over every land in 
 a thousand shapes, and has made the whole flowering 
 creation subservient to his daily wants. His buttercup, 
 his dandelion, and his meadow-sweet grow thick in every 
 English field. His mint clothes the hillside ; his heather 
 purples the bleak grey moorland. High up among the 
 Alpine heights his gentian spreads its lakes of blue; 
 amid the snows of the Himalayas his rhododendrons 
 gleam with crimson light. Even the wayside pond yields 
 him the crowfoot and the arrowhead, while the broad 
 expanses of Brazilian streams are beautified by his gor- 
 geous waterlilies. The insect has thus turned the whole 
 surface of the earth into a boundless flower-garden, which 
 supplies him from year to year with pollen or honey, and 
 itself in turn gains perpetuation by the baits that it offers 
 for his allurement. 
 
 If any man can seriously doubt that these changes are 
 really due to a colour-sense in the little creatures which 
 live upon the beautiful flowers, if he can imagine that the 
 plant has produced its gorgeous petals for no other pur- 
 pose than that of suicidal wastefulness ; that the Mantis 
 has grown into the perfect semblance of a leaf from pure 
 wanton causeless mimicry ; that the lurid red of fly-ferti- 
 lised blossoms bears its likeness to the mangled flesh of 
 animals by a simple freak of creative power; then the 
 whole science and philosophy of the last hundred years 
 have been thrown away upon him, and he may return at 
 leisure to the blind and hopeless chance of the eighteenth- 
 century atheists. Even if we could allow the strangely 
 gratuitous hypothesis of a distinguished naturalist,^ that 
 
 1 Mr. A. R. "Wallace, " On the Colours of Plants and Animals," " Mac- 
 millan's Magazine," September 1877, ad init.
 
 96 THE COLOUR-SENSE. 
 
 tlie colours of organic beings were originally developed 
 by natural causes, with a sort of divine aftertliought re- 
 garding the pleasure which man might derive from their 
 contemplation, yet we cannot blind ourselves to the abso- 
 lute necessity of their performing from the very first some 
 special utilitarian function. Not even the watchmaker 
 deity of Paley himself, one may suppose, would have 
 invented flowers in the Secondary age for the sole gratifi- 
 cation of man in the Post-tertiary. To put it briefly, if 
 insects have not a colour-sense, then the whole universe 
 must be nothing more than a singularly happy concourse 
 of fortuitous atoms. The theist and the evolutionist are 
 equally ready to disclaim with all their might this gro- 
 tesque and monstrous supposition.
 
 ( 97 ) 
 
 CHAPTER VI. 
 
 BIRDS OR MAMMALS AND FRUITS. 
 
 What insects are to bright-hued flowers, birds and mam- 
 mals are to bright-hued fruits. And we might almost say, 
 though with more reservation, what flowers are to the 
 colour-sense in insects, fruits are to the colour-sense in 
 birds and mammals. 
 
 Accordingly, we may fairly conclude that bright-coloured 
 fruits belong to a much later geological age than entomo- 
 philous blossoms.^ We need not here transport ourselves 
 in imagination to the green expanse of palceozoic jungles, 
 unenlivened by scarlet flowers or gaudy insects ; we have 
 only to place ourselves amid the comparatively modern 
 flora of the Tertiary age, surrounded by forest trees of 
 familiar aspect, and tenanted by animals whose shape 
 differs but little from those of our own historical epoch. 
 Already the ground spreads a carpet of soft grass beneath 
 our feet; already simple forms of insect-fertilised blos- 
 soms stand out in profusion as brilliant points of colour 
 among the green foliage around. It is true we see no 
 highly-differentiated daisies or thistles, with their clus- 
 tered heads of tubular bells ; no strangely-shaped orchids 
 or snapdragons, with their forms nicely adjusted to those 
 of the fertilisincr bees ; but we find a fair abundance of 
 unspecialised flowers, with a regular corolla of separate 
 pieces, such as we know so well in the buttercup, the 
 poppy, or the geranium. Moreover, we may see among 
 them, not merely the little dingy creeping insects of the 
 
 See Wallace's " Tropical Nature," p. 228. 
 
 G
 
 98 THE COLOUR-SENSE. 
 
 Carboniferons deltas, but flitting butterflies with coloured 
 wings, and flower-haunting beetles of exquisite metallic 
 slieen. These brij^hter forms of insect life have been de- 
 veloped in the vast cycles of that immeasurable interim 
 by the selective action of sexual preference, working 
 through a taste for brilliant hues which has been origi- 
 nally formed in the search for food ; but this portion of 
 our subject we must remove from its proper historical 
 place, owing to the exigencies of logical treatment, and 
 relegate it to a- later chapter, where we may consider the 
 question of sexual selection in its ensemble, as exhibited 
 throughout all departments of the animal kingdom. For 
 the present, we must content ourselves by taking for 
 granted the existence among the Tertiary forests of gaily- 
 tinted insects and gorgeous lizards, as well as that of 
 crimson leaves and orange blossoms. Nay, more, we may 
 probably allow that the higher vertebrate types which 
 lived in those primitive modern wilds possessed some 
 more or less distinct form of colour-perception, derived 
 perhaps from their earlier marine ancestors, and kept alive 
 l-y exercise upon these varied objects in their actual envi- 
 ronment. Yet, in spite of such facts and probabilities, it 
 will be well worth while briefly to trace the origin of 
 bright-hued fruits, as we have already traced the origin of 
 bright-hued flowers, both because the colour-sense of the 
 highest vertebrates probably owes much to the reaction of 
 these brilliant food-stuffs, and because the taste for colour 
 in man himself may be plausibly referred to the arboreal 
 habits of his ante-human progenitors, Furthermore, we 
 shall see reason to conclude hereafter that the plumage of 
 the most beautiful birds and the fur or skin of the most 
 highly-coloured mammals are due to the love for bright 
 hues originally developed in connection with the pulpy 
 fruits ; and this conclusion affords another reason why we 
 should first inquire into the history of their evolution. 
 
 The ultimate object of flowering is the production of 
 seeds, that is to say, of embryo plants^ destined to replace
 
 ■ BIRDS OR MAMMALS AND FRUITS. 99 
 
 their parents, and continue the life of the species to future 
 generations. The vessel which includes one or more such 
 seeds, the produce of a single flower, is known in botanical 
 parlance as a fruit. But as it often happens that the ripe 
 pistils of more than one blossom become united together 
 into a single mass, instances of which habit may be seen 
 in the fig and the mulberry, it becomes convenient to 
 describe these aggregate seed-vessels also as compound 
 fruits. In the language of ordinary life, however, a fruit 
 means something very different from such hard and dry 
 seed-vessels as those of poppies, beans, or thistles. We 
 understand by the word, in daily usage, some sweet, soft, 
 pulpy object, more or less connected with the seeds, and 
 usually possessing some bright-coloured portion. To these 
 latter structures we shall generally give the designation of 
 fruits-proper, to distinguish them from such among their 
 like as are merely fruits by botanical courtesy. Fruits- 
 proper, then, in this restricted sense, form the special object 
 of our present investigation. 
 
 The botanical fruit consists of a covering or pericarp, 
 often extremely thin and almost papery, enclosing one or 
 more ripe seeds. But other connected portions of the plant, 
 for example, the swollen flower-stalk and the receptacle, 
 frequently coalesce so thoroughly with these essential 
 organs that it becomes impossible to distinguish them, 
 even for technical purposes. This is especially the case 
 with fruits-proper, where the edible portion quite as often 
 consists of some irregular adjunct as of the juicy pericarp 
 itself. Accordingly, in the following account, I shall take 
 the liberty of dealing a little broadly with the technical 
 terms of botany, suppressing all unnecessary detail, and 
 only dwelling upon the simplest and most salient points. 
 
 The ideal form of fruit would consist of a plain peri- 
 carp enclosing a single seed ; and though such fruits are 
 comparatively rare, one may reasonably suppose that the 
 earliest flowering plants would in all probability produce 
 seed-vessels of a very simple kind, in which the separate
 
 loo THE COLOUR-SENSE. 
 
 seeds were small and inconspicuous, thougli relatively 
 numerous. Indeed, the gymnosperms, or pine and cycad 
 group, which appeared upon the earth before any other 
 phanerogamous plants, cannot be said to possess any fruit 
 at all in the proper sense of the term. Moreover, there is 
 reason to believe that early plants produced large quan- 
 tities of seeds which were relatively ill provided with 
 coverings or nutriment, and which depended rather upon 
 their number than upon any special adaptation for their 
 chance of survival. But as time went on, slight adventi- 
 tious variations in the nature of the seeds or their cover- 
 ings might prove useful in protecting them from some 
 one or other amonsf the numerous dans^ers to which their 
 fellows were exposed, and so might give them an extra 
 advantage in the struggle for existence. The most notice- 
 able among these variations is, that which consists in 
 the extra supply of energetic material for the sprouting 
 plantlet. 
 
 A young plant consists of an embryo whose growth 
 depends upon the liberation of energy contained in its 
 hydro-carbonaceous or albuminoid materials, by union 
 with the free oxygen of the air. The energetic substances 
 upon which it feeds were laid up for it by the parent 
 plant, either in the growing seed-leaves (cotyledons), as 
 in the case of the pea and bean, or in a separate albu- 
 minous mass, as in the case of the wheat tribe. But such 
 energetic materials are exactly the portions of plants 
 which form the best food-stuffs for animals ; and accord- 
 ingly, as birds and mammals multiplied upon the face of 
 the earth, it must happen that those very seeds which 
 possessed the best chance of survival through their stores 
 of nutriment would also be the ones which lay most ex- 
 posed to the ravages of animal foes. Hence plants are 
 compelled to adopt many devices whereby they may secure 
 themselves against such depredations. 
 
 One common plan is that by which some underground 
 structure, such as a bulb, tuber, corm, or root, is made to
 
 BIRDS OR MAMMALS AND FRUITS. loi 
 
 supplement, or in many cases almost to supersede, the 
 natural mode of reproduction by seeds. This is seen in 
 numerous plants, such as potatoes, onions, beets, and many 
 grasses. But perhaps the most interesting case is that of 
 the ground-nuts, whose " hypogean " fruit is buried deep 
 in the earth, so as to escape the notice of all but burrow- 
 ing animals. Yet even these species, which try to conceal 
 their stores of food by hiding them under the soil, fall a 
 prey at last to the snouts of rodents or swine. In fact, it 
 must naturally happen that, as young plants and animals 
 feed on exactly the same energetic substances, every 
 device on the part of the plant will soon be met by a 
 counter-device on the part of the hungry animal.^ 
 
 Each species of plant must, of course, solve for itself 
 the problem, during the course of its development, whether 
 its energies will be best employed by hoarding nutriment 
 for its own future use in bulbs and tubers, or by produc- 
 ing richly-endowed seeds which will give its offspring a 
 better chance of rooting themselves comfortably, and so 
 surviving in safety amid the ceaseless competition of rival 
 species. The various cereals, such as wheat, barley, rye, 
 and oats, have found it most convenient to grow afresh 
 with each season, and to supply their embryos with an 
 abundant store of food for their sustenance during the 
 infant stage of plant life. Their example has been fol- 
 lowed by peas and other pulses, by the wide class of nuts, 
 and by the majority of garden fruits. On the other hand, 
 the onion and the tiger-lily store nutriment for themselves 
 in the underground stem, surrounded by a mass of over- 
 lapping or closely-wound leaves, which we call a bulb ; 
 the iris and the crocus lay by their stock of food in a 
 woody or fleshy stalk ; the potato makes a rich deposit 
 of starch in its subterraneous branches or tubers; the 
 turnip, carrot, radish, and beet use their root as the store- 
 house for their hoarded food-stufl's ; while the orchis 
 
 1 See an article on " The Origin of August 1S78, a large part of wbicli I 
 Fruits " in the Cornhill Magazine for have transferred to this chapter.
 
 I02 THE COLOUR-SENSE, 
 
 produces each year a new tubercle by the side of its 
 existing root, and this second tubercle becomes in turn 
 the parent of its next year's flowering stem. Perhaps, 
 however, the common colchicum or meadow-saffron affords 
 the most instructive instance of all; for during the summer 
 it sends up green leaves alone, which devote their entire 
 time to the accumulation of food-stuffs in a corm at their 
 side \ and when the autumn comes round, this corm pro- 
 duces, not leaves, but a naked flower-stalk, which pushes 
 its way through the moist earth, and stands solitary before 
 the October winds, depending wholly upon the stock of 
 nutriment laid up for it in the corm. 
 
 Now, if we look at the materials used as food by man 
 or other frugivorous creatures, we shall see that they con- 
 sist almost universally of these reservoirs of energetic 
 material, laid up by the plant for itself or its descendants. 
 It is true that the graminivorous animals, like deer, sheep, 
 cows, and horses, live mainly off the green leaves of grasses 
 and creeping plants. But we know how small an amount 
 of food they manage to extract from these fibrous masses, 
 and how constantly their whole existence is devoted to 
 the monotonous and imperative task of grazing for very 
 life. Those animals, however, who have learnt to live at 
 the least cost to themselves always choose the portions of 
 a plant which it has stored with nourishment for itself or 
 its offspring. Men and monkeys feed naturally off fruits, 
 seeds, and bulbs. Wheat, maize, rye, barley, oats, rice, 
 millet, pease, vetches, and other grains or pulses, form the 
 staple sustenance of half mankind. Other fruits largely 
 employed for food are plantains, bananas, bread-fruit, 
 dates, cocoa-nuts, chestnuts, mangoes, mangostines, and 
 papaws. Among roots, tubers, and bulbs stored with 
 edible materials may be mentioned beet, carrot, radishes, 
 turnips, swedes, ginger, potatoes, yam, cassava, onions, and 
 Jerusalem artichokes. But if we look at the other vege- 
 tables used as food, we shall observe at once that they are 
 few in number and unimportant in economical value. In
 
 BIRDS OR MAMMALS AND FRUITS. 103 
 
 cabbage, Brussels sprouts, lettuce, succory, spinach, and 
 watercress, we eat the green leaves; yet nobody would 
 ever dream of making a meal off any of these poor food- 
 stuffs. The stalk or young sprout forms the culinary por- 
 tion of asparagus, celery, seakale, rhubarb, and angelica, 
 none of which vegetables are remarkable for their nutri- 
 tious properties. In all the remaining food-plants some 
 part of the flowering apparatus supplies the table, as in 
 tme artichokes, where we eat the receptacle, richly stocked 
 with nutriment for the opening florets ; or in cauliflower, 
 wliere we choose the aborted flower-buds themselves. In 
 short, we find that men and the higher animals generally 
 support themselves upon those parts of plants in which 
 energy has been accumulated either for the future growth 
 and unfolding of the plant itself, or for the sustenance of 
 its tender offspring. 
 
 Doubtless the earliest seeds differed but little from the 
 spores of cryptogams in the amount of nourishment with 
 which they were provided, and the mode in which they 
 were dropped upon the nursing soil beneath. But during 
 the great secondary and tertiary ages of geology, through- 
 out whose loncj course first the conifers and then the true 
 flowering plants slowly superseded the gigantic horse-tails 
 and tree-ferns of the coal-measures, many new devices for 
 the dispersion and nutrition of seeds were gradually 
 developed by the pressure of natural selection.^ Those 
 plants which merely cast their naked embryos adrift upon 
 the world to shift for themselves in the fierce struggle of 
 stout and hardy competitors must necessarily waste their 
 energies in the production of an immense number of seeds. 
 In fact, calculations have been made which show that a 
 single scarlet corn-poppy produces in one year no less than 
 50,000 embryos ; and some other species actually exceed 
 
 1 I trust that in the sequel the and fruits. Some little simplifica- 
 critical botanist will excuse me for tiou is absolutely necessjiry for gen- 
 having neglected the strict termi- eral readers in this the most involved 
 nology of carpological science, and department of structural botany, 
 made no distinction between seeds
 
 I04 THE COLOUR-SENSE. 
 
 this enormous figure. If, then, any plant happens, by a 
 favourable combination of circumstances, to modify the 
 shape of its seed in such a manner that it can be more 
 readily conveyed to open or unoccupied spots, it will be 
 able in future to economise its strength, and thus to give 
 both itself and its offspring a better chance in the struggle 
 for life. There are many ways in which natuj-al selectioa 
 has effected this desirable consummation. 
 
 The thistle, the dandelion, and the cotton-bush provide 
 their seeds with long tufts of light hair, thin and airy as 
 gossamer, by which they are carried on the wings of Ihe 
 wind to bare spaces, away from the shadow of tlieir 
 mother-plant, where they may root themselves successfully 
 in the vacant soil. The maple, the ash, and the pine sup- 
 ply their embryos with flattened wings, which serve them 
 in like manner not less effectually. Both these we may 
 classify as wind-dispersed seeds. A second set of plants 
 have seed-vessels which burst open explosively when ripe, 
 and scatter their contents to a considerable distance. The 
 balsam forms the commonest example in our European 
 gardens; but a well-known tropical tree, the sandbox, 
 displays the same peculiarity in a form which is almost 
 alarming, as its large, hard, dry capsules fly apart with the 
 report of a small pistol, and drive out the disc-shaped nuts 
 within so forcibly as to make a blow on the cheek decidedly 
 unpleasant. These we may designate as self-dispersed seeds. 
 Yet a third class may be conveniently described as animal- 
 dispersed, divisible once more into two sub-classes, the 
 involuntarily and the voluntarily aided. Of the former 
 kind we have examples in those seeds which, like burrs 
 and cleavers, are covered with little hooks, by whose 
 assistance they attach themselves to the fur or wool of 
 passers-by. The latter or voluntarily aided sort are exem- 
 plified in fruits-proper, the subject of our present inves- 
 tigation, such as apples, plums, peaches, cherries, haws, 
 and brambleberries. Every one of these plants is provided 
 with hard and indigestible seeds, coated or surrounded by
 
 BIRDS OR MAMMALS AND FRUITS. 105 
 
 a soft, sweet, pulpy, perfumed, bright-coloured, and nutri- 
 tious covering known as fruit. By all these means the 
 plant allures birds or mammals to swallow and disperse 
 • its undigested seed, giving in, as it were, the pulpy cover- 
 ing as a reward for the services thus conferred. 
 
 But before we go on to inquire into the mode of their 
 development we must glance briefly at a second important 
 difference in the constitution of seeds. 
 
 If we plant a grain of mustard-seed in moist earth, and 
 allow it to germinate, we shall see that its young leaves 
 begin from the very first to grow green and assimilate 
 energetic matter from the air around them. They are, 
 indeed, compelled to do so, because they have no large 
 store of nutriment laid up in the seed-leaves for their 
 future use by the mother-plant. But if we treat a pea in 
 the same manner, we shall find that it long continues to 
 derive nourishment from the abundant stock of food trea- 
 sured up in its big round seed-leaves. ISTow of course any 
 plant which thus learns to lay by in time for the wants of 
 its offspring gives its embryo a far better chance of surviv- 
 in"" and leaving^ descendants in its turn than one which 
 abandons its infant plants to their own unaided resources 
 in a stern battle with the unkindly world. Exactly the 
 same difference exists between the two cases as that which 
 exists between the wealthy merchant's son, launched on 
 life with abundant capital accumulated by his father, and 
 the street Arab, turned adrift as soon as he can walk alone, 
 to shift or starve for himself in the lanes and alleys of a 
 great city. 
 
 So then as plants went on varying and improving under 
 the stress of over-population, it would naturally result that 
 many species must hit independently upon this device of 
 laying by granaries of nutriment for the use of their de- 
 scendants. But side by side with the advancing develop- 
 ment of vegetable life, animal life was also developing in 
 complexity and perfect adaptation to its circumstances. 
 And herein lay a difficult dilemma for the plant. On the
 
 io6 THE COLOUR-SENSE. 
 
 one hand, in order to compete with its neighbours, it must 
 lay up stores of starch and oil and albumen for the good 
 of its embryos ; while, on the other hand, the more indus- 
 triously it accumulated these expensive substances, the 
 more temptingly did it lay itself open to the depredations 
 of the squirrels, mice, bats, monkeys, and other clever 
 thieves, whose number was daily increasing in the forests 
 round about. The plant becomes, in short, like a merchant 
 in a land exposed to the inroads of powerful robbers. If 
 he does not keep up his shop with its tempting display of 
 wares, he must die for want of custom ; if he shows them 
 too readily and unguardedly, he will lay himself open to 
 be plundered of his whole stock-in-trade. In such a case 
 the plant and the merchant have recourse to the self-same 
 devices. Sometimes they surround themselves with means 
 of defence against the depredators ; sometimes they buy 
 themselves off by sacrificing a portion of their wealth to 
 secure the safety of the remainder. Those seeds which 
 adopt the former plan we call nuts, while to those which 
 depend upon the latter means of security we give the name 
 of fruits. 
 
 A nut is a hard-coated seed, which deliberately lays 
 itself out to escape the notice and baffie the efforts of 
 monkeys and other frugivorous animals. Instead of bid- 
 ding for attention by its bright hues, like the flower and 
 fruit, the nut is purposely clad in a quiet coat of uniform 
 green, indistinguishable from the surrounding leaves during 
 its earlier existence, while afterwards it assumes a dull 
 brown colour as it lies upon the dusky soil beneath. Nuts 
 are rich in oils and other useful food-stuffs ; but to eat 
 these is destructive to the life of the embryo, and therefore 
 the nut commonly surrounds itself with a hard and stony 
 shell, which defies the stoutest teeth to pierce its thickened 
 walls. Outside this sohd coating it often spreads a softer 
 covering with a nauseous, bitter taste, so familiar to us all 
 in the walnut, which at once warns off the enemy from 
 attacking the unsavoury morsel. ISTot content with all
 
 BIRDS OR MAMMALS AND FRUITS. 107 
 
 these protective devices of colour, taste, and hardness, the 
 nut in many cases contains poisonous juices, and is thickly 
 clad in hooked and pointed mail, which wounds the hands 
 or lips of the would-be robber.^ In brief, a nut is a seed 
 which has survived in the struggle for life by means of 
 multiplied protections against the attacks of enemies. We 
 cannot have a better instance of these precautions than the 
 common cocoa-nut palm. Its seed hangs at a great height 
 from the ground on a tall and slender stem, unprovided 
 with branches which might aid the climber, and almost 
 inaccessible to any animal except the persevering monkey. 
 Its shell is very thick and hard, so extremely impermeable 
 that a small passage has to be left by which the germinat- 
 ing shoot may push its way out of the stronghold where it 
 is born. Outside this shell, again, lies a thick matting of 
 hairy fibres, whose elasticity breaks its fall from the giddy 
 height at which it hangs. Yet, in spite of all these cun- 
 ning precautions, even the cocoa-nut is not quite safe from 
 the depredations of monkeys, or, stranger still, of tree- 
 climbing crabs. The common Brazil-nuts of our fruiterers' 
 shops are almost equally interesting, their queer, shapeless 
 forms being closely packed together, as they hang from 
 their native boughs, in a hard outer shell, not unlike that 
 of the cocoa-nut. It must be very annoying to the un- 
 suspecting monkey, who has succeeded after violent efforts 
 in breaking the external coat, to find that he must still 
 deal with a mass of hard, angular, and uncanny nuts, which 
 sadly cut his tender gums and threaten the stability of his 
 precious teeth — those invaluable tools, which serve him 
 well in the place of knives, hammers, scissors, and all other 
 human implements. 
 
 A fruit-proper, on the other hand, lays itself open in 
 every way to attract the attention of animals, and so to be 
 dispersed by their aid, often amid the nourishing refuse 
 
 ^ See Wallace's "Tropical Nature," sage is extracted was in proof before 
 
 p. 225 seq. I may perhaps be allowed the appearance of Mr. Wallace's book, 
 
 to add that the article in the "Corn- though not published till some months 
 
 hill Magazine " from which this pas- later.
 
 loS THE COLOUR-SENSE. 
 
 of their meals. It is true that, with the fruit, as with 
 the nut, to digest the actual seed itself would be fatal 
 to the life of the young plant. But fruits get OA^er this 
 difficulty by coating their seeds first with a hard, indiges- 
 tible shell, and then with a soft, sweet, pulpy, and nutri- 
 tious outer layer. The purely accidental or functional 
 origin of this covering is testified by the immense variety 
 of ways in which it has been developed. Sometimes a 
 single seed has shown a slight tendency to succulence in 
 its outer coat, and forthwith it has gone on laying up juices 
 from generation to generation, until it has developed into 
 a one-seeded berry. Sometimes a whole head of seeds has 
 been surrounded by a fleshy stem, and the attention of 
 animals has thenceforward encouraged its new habit by 
 ensuring the dispersion of its embryos. A few of the 
 various methods by which fruits attain tlieir object we 
 shall examine in detail further on : it will suffice for the 
 present to point out that any property which secured for 
 the seed dispersion by animal agency would at once give 
 it an advantage over its fellows, and thus tend to be 
 increased in all future sjenerations. 
 
 So, then, as birds, squirrels, bats, monkeys, and the 
 higher animals generally increased on the face of the 
 earth, every seed which showed a tendency to surround 
 itself with succulent pulp would obviously gain a point 
 thereby in its rivalry with other species. Accordingly, as 
 we might naturally expect, fruits which have been deve- 
 loped to suit the taste of birds and mammals are of much 
 more recent geological origin than flowers, which have 
 been developed to suit the taste of insects. For example, 
 there is no family of plants which contains a greater num- 
 ber of fruity seeds than the rose tribe, in which are com- 
 prised the apple, pear, plum, cherry, blackberry, raspberry, 
 strawberry, quince, medlar, loquat, peach, apricot, and 
 nectarine, besides the humbler hips, haws, sloes, and com- 
 mon hedge-fruits, which, though despised by lordly man, 
 form the chief winter sustenance of such among our Bri-
 
 BIRDS OR MAMMALS AND FRUITS. 109 
 
 tisli birds as do not migrate to warmer climates during our 
 chilly December days' IS'ow, no trace of tlie rose tribe 
 can be discovered until Miocene times ; in other words, no 
 fruit-bearers appear before the evolution of the fruit-eaters 
 who called them into existence ; while, on the other hand, 
 the rapid development and variation of the tribe in the 
 succeeding epoch shows how great an advantage it derived 
 from its tendency to produce edible seed-coverings. 
 
 But not only must these coverings be succulent and 
 nutritious ; tliey must also be conspicuous and alluring. 
 For the attainment of these objects the fruit has recourse 
 to just the same devices which had already been so suc- 
 cessfully initiated by the insect-fertilised flowers. It 
 collects into its pulpy substance a quantity of that com- 
 monly-diffused vegetable principle which we call sugar. 
 Now sugar, from its crystalline composition, is peculiarly 
 adapted for acting upon the exposed nerves of taste in the 
 tongues of vertebrates; and the stimulation which it affords, 
 like all healthy and normal ones, when not excessive in 
 amount, is naturally pleasurable to the excited sense. Of 
 course, in our own case, the long habituation of our frugi- 
 vorous ancestors to this particular stimulant has rendered 
 us peculiarly sensitive to its effects. But even from the 
 first, there can be little doubt that a body so specially 
 fitted to arouse sensation in the gustatory nerve must have 
 afforded pleasure to the unspecialised palates of birds and 
 rodents ; for we know that even in the case of naturally 
 carnivorous animals, like dogs, a taste for sugar is ex- 
 tremely noticeable. So then the sweet juices of the fruit 
 were early added to its soft and nutritive pulp as an extra 
 attraction for the animal senses. 
 
 But the greatest need of all, if the plant would succeed 
 in enticing the friendly parrot or the obsequious lemur to 
 disperse its seed, is that of conspicuousness. Let the fruit 
 be ever so luscious and ever so laden with sweet syrups, it 
 can never secure the suffrages of the higher animals if it 
 lies hidden beneath a mas i of green foliage, or clothes itself
 
 no THE COLOUR-SENSE. 
 
 in the quiet garb of the retiring nut. To attract from a 
 distance the eyes of wandering birds or mammals, it must 
 dress itself up in a gorgeous livery of crimson, scarlet, and 
 orange. The contrast between nuts and fruits is exactly 
 parallel to the contrast between the wind-fertilised and 
 the insect-fertilised flowers. An apple-tree laden with its 
 red-cheeked burden, an orange bough weighed down with 
 its golden spheres, a rowan or a holly bush displaying 
 ostentatiously its brilliant berries to the birds of the air, is 
 a second edition of the roses, the rhododendrons, and the 
 maythorns, which spread their bright petals in the spring 
 before the fascinated eyes of bees and butterflies. Some 
 gay and striking tint, which may contrast strongly with 
 the green foliage around, is needed by the developing fruit, 
 or else its pulpiness, its sweetness, and its fragrance will 
 stand it in poor stead beside its bright-hued compeers. 
 
 How fruits began to acquire these brilliant tints is not 
 difficult to see. We found already, in the case of flowers, 
 that all external portions of a plant, except such green 
 parts as are actually engaged in assimilating carbon under 
 the influence of solar energies, show a tendency to assume 
 tints other than green. This tendency would, of course, 
 be checked by natural selection in those seeds which, like 
 nuts, are destroyed by animals, and so endeavour to escape 
 their notice ; while it would be increased by natural selec- 
 tion in those seeds which, like fruits-proper, derive benefit 
 from the observation of animals, and so endeavour to 
 attract their attention. But it is noticeable that fruits 
 themselves are sour, green, and hard during their unripe 
 stage, that is to say, before the seeds are ready to be 
 severed from the mother-plant ; and that they only acquire 
 their sweet taste, brilliant colour, and soft pulp just at the 
 time when their mature seeds become capable of a separate 
 existence. 
 
 The connection of these changes with the process of 
 oxidation is far more certain and more marked in the case 
 of fruits than in that of flowers. During their early state,
 
 BIRDS OR MAMMALS AND FRUITS. iii 
 
 pulpy fruits have the structure and chemical composition 
 of leaves. But as they mature, they gradually pass through 
 the acid stage, and finally reach that of ripening, when their 
 gum, their cellulose, and their acids are partially converted 
 into sugar. These alterations are accompanied by " a loss 
 of watery fluid, a slight increase of temperature, and an 
 evolution of carbonic acid." " Saussure and Couverchel 
 state that grapes, apples, and pears, when separated from 
 their respective plants, and kept at a temperature of about 
 60° F., gave out carbonic acid. Fremy found that ripe 
 fleshy fruits gave out a large quantity of carbonic acid 
 when boiled in a saline solution.^ Berard thinks that 
 these changes in fruits depend essentially on the action of 
 the oxygen of the air. Fleshy fruits, he says, may be pre- 
 served with little alteration for many weeks in vacuo, in 
 nitrogen, and in hydrogen gas ; peaches, plums, and apri- 
 cots may be kept from twenty to thirty days, and pears 
 and apples for three months, in a sealed bottle containing 
 a little sulphate of iron, lime, and water, which remove 
 the oxygen of the air. Fremy found that the ripening of 
 the fruit was arrested by covering it with varnish, which 
 he supposes to act partly by preventing the access of air, 
 and partly by stopping the transpiration, and thus check- 
 ing the flow of sap into the fruit." ^ 
 
 It may also be added that here, as in the case of flowers, 
 an original tendency towards colouration in seed-coverings, 
 quite apart from any selective action, may be distinctly 
 noted. Not only are the spore-cases of many mosses 
 prettily tinted with pink or yellow, but the fruits of many 
 flowering plants which have no succulent pulp yet ex- 
 hibit a decided turn for coloured juices. Instances may 
 be found in the dock, and less markedly in almost all 
 capsuled fruits. But with fruits, as with flowers, we may 
 say roughly that all the bright-coloured species depend 
 
 1 Fremy, "Recherches Chimiques 2 Balfour's Class-Book of Botany, 
 sur la Maturation des Fruits, " in pp. 604, 606. 
 "Comptes Rendus," xix. 784.
 
 112 THE COLOUR-SENSE. 
 
 for tlieir diffusion upon animals, while all tho^e wliich do 
 not depend upon animals are dull. " The smaller plants," 
 says Mr. Wallace, "whose seeds simply drop upon the 
 ground, as in the grasses, sedges, composites, umbelliferee, 
 &c., always have dry and obscurely-coloured capsules, 
 and small brown seeds. Others, whose seeds are ejected 
 by the bursting open of their capsules, as with the 
 oxalis and many of the caryophyllacese, scrophularia- 
 ceae, &c., have their seeds small, and rarely or never 
 edible." ^ 
 
 In the case of the attractively coloured fruits, however, 
 Mr. Wallace points out that the actual seeds are of such 
 a nature as to escape destruction when the fruit itself is 
 eaten. " They are generally very small and comparatively 
 hard, as in the strawberry, gooseberry, and fig ; if a little 
 larger, as in the grape, they are still harder and less 
 eatable ; in the fruit of the rose (or hip), they are dis- 
 agreeably hairy; in the orange tribe, excessively bitter. 
 When the seeds are larger, softer, and more edible, they 
 are protected by an excessively hard and stony covering, 
 as in the plum and peach tribe ; or they are enclosed in a 
 tough horny core, as with crabs and apples. . . . These 
 fruits may also be sw^allowed by some of the larger fru- 
 givorous birds ; just as nutmegs are swallowed by pigeons 
 for the sake of the mace which encloses the nut, and 
 which, by its brilliant red colour, is an attraction as 
 soon as the fruit has split open, which it does upon the 
 tree." 2 
 
 But exactly as we saw that some flowers attract insects 
 by a delusive hope of honey where no honey is really to be 
 had, so do some fruits hold out attractions of colour to 
 birds or mammals where little or no food is to be had 
 in return. Thus many beans have beautiful coverings, 
 wdiich must be purely deceptive in their nature for 
 though some animals may perhaps be able to eat them, 
 yet these can be of no benefit to the plant, and it cannot 
 
 ^ Tropical Nature, p. 227. ' Ibid., p. 226.
 
 BIRDS OR MAMMALS AND FRUITS, 113 
 
 be for their sake, therefore, that the bright integument lias 
 been developed. An extreme case is that of the hard 
 little rosary bean (Ahrus jy^^ecatoria), so well known as 
 the seed from which the prisoners in Cayenne manufac- 
 ture their pretty ornaments. "It may be/' says Mr. 
 Wallace, " that birds, attracted by the bright colour of the 
 seeds, swallow them, and that they pass through their 
 bodies undigested, and so get dispersed." If so, the in- 
 genious naturalist suggests that the device may only 
 succeed with " young and inexperienced birds." I am 
 myself inclined to think, however, that some plants, such 
 as our English cuckoo-pint and the famous AYest Indian 
 manchineel, actually derive a benefit from their poisonous 
 properties ; because if eaten by birds or small mammals, 
 they might destroy their host, and the seeds would thus 
 have an opportunity of germinating in the midst of a rich 
 manure-heap, consisting of its decomposing body. 
 
 Another analogy with entomophilous flowers may be 
 found in the very variable nature of the pulpy and 
 coloured substance. It does not matter at all what por- 
 tion of the seed-covering or its adjacent parts happens 
 first to show the tendency towards succulence, sweetness, 
 fragrance, and brilliancy. It serves the attractive purpose 
 equally well whether it be calyx, or stalk, or skin, or re- 
 ceptacle. Just as in the case of flowers, we found that 
 the coloured portion might equally well consist of stamens, 
 petals, sepals, bracts, or spathe, so, but even more conspi- 
 cuously in the case of fruits, the attractive pulp may be 
 formed of any organ whatsoever which exhibits the least 
 tendency towards a pulpy habit, and an accumulation of 
 saccharine deposits. 
 
 Thus, in the pomegranate, each separate seed is enclosed 
 in a juicy testa or altered shell ; in the nutmeg and the 
 spindle-tree, an aril, or purely gratuitous coloured mass, 
 spreads gradually over the whole inner nut ; in the plum 
 and cherry, a single part, the pericarp, divides itself into 
 two membranes, whereof the inner or protective coat is 
 
 H
 
 114 THE COLOUR-SENSE. 
 
 hard and stony, while the outer or attractive coat is soft^ 
 sweet, and bright coloured ; in the strawberry, the recep- 
 tacle, which should naturally be a mere green bed for the 
 various seed-vessels, grows high, round, pulpy, sweet, and 
 ruddy ; in the rose, the fruit-stem expands into a scarlet 
 berry, containing the seed-vessels within, which also hap- 
 pens in a slightly different manner with the apple, pear, 
 and quince ; while in the fig a similar stem encloses the 
 innumerable seeds belonging to a whole colony of tiny 
 blossoms, which thus form a compound fruit, just as the 
 daisy head, with its mass of clustered florets, forms a 
 composite flower. Strangest of all, the common South 
 American cashew tree produces its nut (which is the true 
 fruit) at the end of a swollen, pulpy, coloured stalk, and 
 so preserves its embryo by the vicarious sacrifice of a 
 fallacious substitute. These are only a few out of the 
 many ways in which the selective power of animals has 
 varied the surroundings of different seeds to serve a single 
 ultimate purpose. 
 
 Nor is any plan too extravagant for adoption by some 
 aberrant species. What seed-organ could seem less adapted 
 for the attraction of animals than a cone like that of pines 
 and fir-trees ? Yet even this hard, scaly covering has 
 been modified, in the course of ages, so as to form a fruit. 
 In the cypress, with its soft young cones, we can see dimly 
 the first step in the process ; in the juniper, the cone has 
 become quite succulent and berry-like ; and finally, in the 
 red fruit of the yew, all resemblance to the original type 
 is entirely overlaid by its acquired traits. 
 
 Equally significant is the fact that closely allied species 
 often choose totally different means for attracting or 
 escaping observation. Thus, within the limits of the rose 
 tribe itself we get such remarkable variations as the straw- 
 berry, where the receptacle forms the fruit ; the apple, 
 which depends on the peduncle, or swollen stalk, for its 
 allurement ; the raspberry, where each seed-vessel of the 
 compound group has a juicy coating of its own, and so
 
 BIRDS OR MAMMALS AND FRUITS. 115 
 
 forth; while, on the other hand, the potentilla has no 
 fruit at all, in the popular sense of the word ; and the 
 almond actually diverges so far from the ordinary habits 
 of the tribe as to adopt the protective tactics of a nut. 
 Similarly, in the palm tribe, while most species fortify 
 themselves against monkeys by extravagant hardness, as 
 w^e see in the vegetable ivory, and the solid coquilla nuts 
 from which door-handles are manufactured, a few kinds, 
 like the date and the doom-palm, trust rather to the soft- 
 ness and sweetness of their pulp as aids to dispersion. 
 The truth which we learn from these diverse eases may 
 be shortly summed up thus : Whatever peculiarities tend 
 to preserve the life of a species, in whatever apposite 
 ways, equally aid it in the struggle for life, and may be 
 indifferently produced in the most closely related types. 
 
 I have given this large amount of space to the con- 
 sideration of fruits, because I believe we can hardly over- 
 estimate their importance in quickening the colour-sense 
 of the higher animals, and, above all, in settling the 
 aesthetic tastes of birds, quadrumana, and men. We are 
 apt to forget how considerable an element in the total 
 coloured environment of forestine animals is formed by 
 brilliant fruits. The utilitarian connection of fruits 
 generally has made us cultivate them more for tlieir 
 pulp and sweetness than for their beauty, and in many 
 cases they have actually lost in colour under cultivation ; 
 while flowers, being selected entirely for their visual 
 attractiveness, have gone on developing more and more 
 expanded masses of bright petals.^ But if we look at 
 a few strikinc^ instances, we shall find that fruits almost 
 equal in native beauty their earlier rivals, the entomophilous 
 blossoms. Among cultivated varieties commonly grown 
 in Britain, we may take apples, plums, peaches, cherries, 
 grapes, strawberries, raspberries, currants, and pumpkins ; 
 while it may be worth while to remind the reader that 
 
 1 See tins point further elucidated in Chapter XII., on the ^Esthetic Value 
 of Colour.
 
 li6 THE COLOUR-SENSE. 
 
 certain otiier fruits or seeds, which usually appear on our 
 tables in a green state, like cucumbers and scarlet-runner 
 beans, have brilliant coats in their mature forms. Amongst 
 English wild fruits, sufficient examples will be found in 
 the hips, haws, hoUyberries, mistletoe, sloe, mountain ash, 
 barberry, yew, juniper, ivy, spindle-tree, arum, blackberry, 
 iris, saffron, elder, and sea-buckthorn. The tropics and 
 sub-tropical climates, however, supply us with far more 
 gorgeous examples in their oranges, shaddocks, lemons, 
 mangoes, star-apples, pomegranates, capsicums, bananas, 
 nutmegs, achees, egg-fruits, prickly pears, tomatoes, winter 
 cherries, solanums, dates, and passion-flower berries. In 
 fact, we may say that fruits-proper exhibit larger amounts 
 of brilliant colouration than any other class of organic 
 objects except entomophilous flowers.
 
 ( 117 ) 
 
 CHAPTER VII. 
 
 THE COLOUR-SENSE IN VERTEBRATES. 
 
 Although the perception of colour by birds and mammals 
 has been taken for granted in the preceding chapter, and 
 although it is practically all but incontestable that the 
 higher vertebrates are quite as fully endowed in this 
 respect as ourselves, yet the positive proofs which can be 
 advanced in favour of the belief are very meagre and in- 
 sufficient. The only real evidence is that supplied by our 
 every-day observation, but no person familiarly acquainted 
 with the habits of birds and mammals ever doubts for a 
 moment their essential agreement with ourselves so far as 
 concerns the visual faculties. Nevertheless, it may be 
 well to point out the few positive facts which are forth- 
 coming on the subject, connecting them at the s^me time 
 with the probable genesis of the developed sense. 
 
 Apparently the perception of colour is inherited by the 
 whole vertebrate series from some earlier common ancestor. 
 At any rate, considerable traces of the colour-sense may 
 be detected among many marine invertebrates. The best 
 known instance is that of the chameleon shrimp (Mi/sis 
 chaiiiceleo), which has the power of altering its own colour 
 in correspondence with the material among which it is 
 found. When lying on a sandy bottom it appears grey ; 
 but when lurking among seaweed, it is green or reddish 
 brown, according to the nature of the background. This 
 change is produced by means of a reflex action connected 
 with the eye, for when the animal is blinded it no longer 
 occurs. In other words, we must suppose that when the
 
 ii8 THE COLOUR-SENSE. 
 
 optic nerve of the shrimp is affected by the green light 
 from a piece of seaweed, certain muscles are set in action, 
 voluntarily or automatically, which cause a corresponding 
 change in the arrangement of the pigment cells, so that 
 the animal appears green itself. It may be added, too, 
 that this peculiarity affords an indirect proof of a colour- 
 sense in the enemies of the chameleon shrimp (which 
 cannot be more highly developed animals than fishes, 
 and may perhaps by other crustaceans) ; because ^the 
 creature can only possess this power for the sake of 
 escaping the observation of its foes. If we believe it 
 to be so provided for the purpose of deceiving its prey, 
 then we must allow the existence of colour-perception 
 even in more lowly forms on the average than fishes or 
 Crustacea. 
 
 Indeed, the brilliant nature of many marine animals 
 and plants affords an excellent opportunity for the de- 
 velopment of a colour-sense. Instead of the uniform 
 green of the forest, with the dingy black or brown of soil 
 and rocks, we have here the exquisite colours of sea- 
 anemones, starfish, corals, serpulae, jellyfish, callianiridse, 
 aphroditida3, ascidians, sea-slugs, and shell-covered mollusca, 
 which browse amid groves of variegated algae, whose hues 
 are far more diversified than those of terrestrial veo-eta- 
 
 o 
 
 tion. Amongst such surroundings it would almost be 
 impossible that a colour-sense should not take its rise : 
 and many indirect proofs conspire to show that in the 
 class of fishes at least it exists in high perfection. 
 
 The most striking evidence is that afforded by certain 
 flat-fish, which, like the chameleon shrimp, possess the 
 power of changing their colour, so as to suit the bottom 
 upon which they lie. Here again the peculiarity not only 
 shows that the fish themselves are differentially affected 
 by the various colours, but also that their enemies or 
 prey are conscious of similar differences, or else the dis- 
 guise would be useless. 
 
 Equally significant is the colouration of the common
 
 THE COLOUR-SEXSE IN VERTEBRATES. 119 
 
 sole, brill, dab, and flounder. Any person who has seen 
 these fishes lying on a natural bottom or in an aquarium 
 must have been struck by the perfection of the imitation, 
 which often baffles even human eyes, in spite of the 
 actual knowledge that a fish is somewhere to be found 
 upon the spot. 
 
 In like manner, the fishes, mollusca, and crustaceans 
 which inhabit the sargasso weed, are all protectively 
 coloured of exactly the same pale buff hue as the sargasso 
 itself. One may often closely examine a piece of the 
 weed, freshly brought up in a bucket of sea- water, and 
 yet fail to detect any sign of life, until the attempt to 
 raise the weed from the water reveals the fact that some 
 small crabs or tiny fishes are lurking unseen among its 
 waving branches. In all such cases, the existence of the 
 imitative colouring is fair proof that it subserves the good 
 of the species by protecting its members against enemies, 
 or enabling them more readily to secure their prey. 
 
 Perhaps the only direct evidence, however, is that of 
 the baits used by fishermen. Mackerel and other fish are 
 often taken by means of red rags. A spoon painted bright 
 scarlet forms a capital trolling bait. All anglers are 
 agreed that trout can discriminate between the various 
 imitation flies offered to their notice, and that the original 
 colours must be carefully copied. Indeed, the facts 
 rather tend to show, not only that fishes can discriminate 
 colours, but also that they are attracted by metals or other 
 brilliant objects, and by pure or intense hues. A taste 
 for colour as w^ell as a mere neutral perception seems to 
 be implied by these observations. 
 
 Those who have given the greatest attention to the 
 subject are inclined to credit fish with a very high degree 
 of colour sensibility ; and their opinion may be set down 
 here as having some weight in so uncertain a subject. 
 Mr. H. iST. Mosely, the accomplished naturalist of the 
 Challenger expedition, believes that almost all the colours 
 of marine animals have been acquired for purposes of
 
 120 THE COLOUR-SENSE. 
 
 warning, protection, or attraction of pre}^, and that tliey 
 have special reference to the eyes of fishes and higher 
 crustaceans.^ The whole colouration of the lower aquatic 
 organisms is exactly what we should expect it to be if the 
 more highly evolved marine creatures were possessed of 
 a colour-sense ; and it is quite inexplicable and gratui- 
 tously complex if we suppose them to be destitute of such 
 a faculty. Mr. Darwin is farther of opinion that the 
 colours of many fishes have been produced by the action 
 of sexual selection ; and though I do not mean to treat 
 this part of our subject in detail till a later chapter, I 
 think the conclusion of so careful and masterly an ob- 
 server has considerable substantive value as corroborative 
 of the positive facts. 
 
 When we proceed to examine the amphibia, much better 
 evidence is available. The two colours green and blue 
 are the least markedly different of all hues ; and if they 
 can be discriminated from one another by any species, we 
 may be sure that that species possesses a very perfect 
 form of colour-sense. Kiihne of Heidelberg, in the course 
 of certain researches on the nature and functions of retinal 
 purple, discovered that if a number of frogs, Rana esculenta 
 and R. temporaria, are confined in a shallow dish, one half 
 of which is covered with oreen c^lass and the other half 
 with blue, they will shortly all collect under the green 
 portion. Great care was taken to eliminate all disturbing 
 elements, such as unequal transparency to heat (diather- 
 mancy), or unequal intensity of illumination, and it was 
 conclusively ascertained that an enormous majority of the 
 frogs exhibited a distinct preference for the colour green 
 over the colour blue. Blind frogs introduced into the 
 same vessel showed no preference for one part over 
 another.^ In this case, again, it is interesting to note 
 that a special emotional taste, as well as an intellectual 
 
 ^ Quarterly Journal of Microsco- - Uutersuch. aus dem Physiol. In- 
 pical Science, New Series, vol. xvii. stitut iu Heidelberg, Band i. Heft 2. 
 pp. 19, 22.
 
 THE COLOUR-SENSE IN VERTEBRATES. 121 
 
 discrimination, is proved by the facts ; and tliis taste 
 becomes particularly interesting from the point of view 
 of sexual selection, when we remember that green forms a 
 very common colour amongst the Ranidce, 
 
 Frogs likewise possess the power of changing their 
 colour in correspondence with the environment, in the 
 same manner as already noted in Mysis} 
 
 Eeptiles also show some distinct marks of colour- 
 perception. The most familiar instance is that of the 
 chameleon, whose natural hue is a muddy white, changing 
 with the nature of the background to yellow, brown, 
 green, or bluish grey. The mechanism by wliich this 
 change is effected has met with full treatment at the 
 hands of Von Wittich.^ Two layers of pigment cells are 
 deeply seated under the skin, consisting of blue and 
 yellow colouring matter respectively ; and by forcing up 
 one or other of these layers through muscular pressure, 
 the animal assumes a bluish or yellowish tint, while the 
 green is produced by simultaneous pressure upon both 
 layers. In this manner the chameleon is able to simulate 
 the appearance of the branches or leaves on which it 
 stands, and so, perhaps, both to escape enemies and de- 
 ceive prey. As before, the power of changing colour 
 implies impressibility both in the animal itself and in 
 certain other species for whose deception the habit has 
 been acquired. The action is undoubtedly reflex, and 
 ceases if the eyes be covered. 
 
 Many of the insects which mimic leaves or other like 
 objects in the environment have probably gained this 
 means of protection to escape the notice of lizards and 
 other reptiles. But as the mimetic resemblance is oftener 
 useful for deceiving birds, we may more fitly consider 
 these cases when we pass on to examine the colour-sense 
 in the higher vertebrates. There are one or two instances 
 
 ^ Pouchet, Comptes Rendus, xxvi. 2 Proc. Vienna Imperial Acad. Nat. 
 575, and Lister, Phil. Trans., 148, p_ Sci., vol. iv., and Miiller's Archiv., 
 627. 1854.
 
 122 THE COLOUR-SENSE. 
 
 of protective colouring, however, which evidently have 
 reference to the reptilian eye alone. Mr. Bates mentions 
 a South American snake {Dryopliis fulgida), whose pale 
 green body exactly resembles the stem of a liana, and even 
 imposed upon the keen-eyed naturalist himself at first 
 sight. The prey for which this living branch lies in wait 
 consists of tree-frogs and lizards.^ These, themselves, 
 in turn, may perhaps escape it by their own prevailing 
 greenness, which makes them so difficult of detection 
 amongst the foliage on which they rest. Again, Sir 
 Joseph Hooker found three ticks on an Indian lizard, 
 each of which was coloured in imitation of that part of its 
 host's body on which it preyed. One from the yellow 
 belly was yellow ; one from the brown head was brown ; 
 and one from the parti-coloured scales was parti- coloured, 
 " the hues corresponding with the individual scales which 
 they covered." ^ Here we can hardly suppose that the 
 imitation could be of any use except as a protection 
 against the lizard himself and the other members of his 
 family. 
 
 It may be worth while to mention in passing that many 
 lizards besides the chameleons possess the power of chang- 
 ing their colour by inflating their lungs, which compresses 
 or spreads the layers of pigment cells.^ The sexual col- 
 ours of the beautiful Draco and other reptiles have been 
 fully described by Mr. Darwin. " The shining appendages 
 of the throat," says Dr. Giinther, " are merely folds of the 
 skin, ornamental and sexual. Such appendages always 
 betray an excitable temper," or, in other words, co-exist 
 with strong sexual jealousies. The significance of these 
 facts will become more apparent when we pass on to 
 the general question of selective preference for decorated 
 mates. 
 
 Among birds, the perception or colour is shown by a 
 
 ^ The Naturalist on the Amazons, ' Giinther, Eeptiles of British In- 
 P- 99- r'ia, p. 56. 
 
 2 Himalayan Journal, vol. i. p. 37.
 
 THE COLOUR-SENSE IN VERTEBRATES. 123 
 
 large number of facts, collected by Mr. Darwin.^ A tame 
 partridge described by Mr. Hussey " seemed fond ' of gay 
 colours, and no new gown or cap could be put on without 
 catching his attention.' " ^ Lord Lilford notices that the 
 ruff " will dart down to a bright-coloured handkerchief, 
 regardless of rej)eated shots." ^ The well-known bower-bird 
 " collects gaily coloured articles, such as the blue tail- 
 feathers of parrakeets, bleached bones, and shells." Mr. 
 Gould " found in one bower a neatly worked stone toma- 
 hawk and a slip of blue cotton." " The regent-bird, as 
 described by Mr. Eamsay, ornaments its short bower with 
 bleached land-shells belonging to five or six species, and 
 with berries of various colours, blue, red, and black, which 
 give it when fresh a very pretty appearance. Besides 
 these, there were several newly picked leaves and young 
 shoots of a pinkish colour, the whole showing a decided 
 taste for the beautiful." * 
 
 To these facts, which bear evidence to taste as well as 
 perception, we may add the antipathy of the turkey-cock 
 to scarlet, which is probably an effect of sexual jealousy, 
 as the red would be ancestrally associated in his mind 
 with the wattles of a rival. " The recognition of colour 
 by small birds generally," says a late writer,^ '' is indis- 
 putable. Every one must have observed with varied feel- 
 ings the discrimination with which they select the ' sunny 
 side ' of a pear, a plum, or a peach. It is also an esta- 
 blished fact that they will attack the red currant in 
 preference to the white variety, though the latter is much 
 the sweeter of the two. Many observers during the last 
 few years have pointed out how the yellow crocus is torn 
 to pieces by sparrows and other birds, while the white and 
 other varieties are unmolested." I have myself often 
 
 ^ The Descent of Man, vol. ii. p. Australia, 1865, vol. i. pp. 444-461 ; 
 
 no. and Ramsay, in "Tlie Ibis," 1867, p. 
 
 2 The Zoologist, 1847-48, p. 1602, 456, quoted in Darwin, uhi sujora. 
 
 quoted in Darwin, w6i sw/>ra. ^ " The Senses of the Lower 
 
 2 "The Ibis," vol. ii. p. 344, i860. Animals," in the Quarterly Journal 
 
 ^ Gould, Handbook to the Birds of of Science, July 1878.
 
 124 THE COLOUR-SENSE. 
 
 noticed in Jamaica the unerring certainty Vvith wliich 
 chickens darted from blossom to blossom of a yellow 
 potentilla, for which they have a particular fancy, and 
 which they always snapped up as though they supposed 
 it to be alive. 
 
 These instances lead us on to those of the fruits, whose 
 development we examined in our last chapter. " Eed," 
 says Mr. Wallace, " being a very common colour of ripe 
 fruits which attract birds to devour them and thus dis- 
 tribute their seeds, we may be sure that the contrast of 
 red and green is to them very marked."^ But this seems 
 to me a somewhat inadequate expression of the real evi- 
 dence on the point. We have seen that almost all those 
 seeds or fruits which would be injured by the interference 
 of birds are protectively coloured green or brown, while 
 almost all those seeds or fruits which would be aided by 
 the interference of birds are attractively coloured red, 
 pink, orange, yellow, purple, blue, lilac, or black. I think 
 these facts fully justify us in concluding that birds are 
 able to distinguish every one of these colours from green, 
 and most likely from one another. Otherwise there would 
 be no reason why succulent fruits should differ in colour 
 from nuts. The single case of the almond and the plum 
 will bring the question at issue into strong relief. As in 
 the case of entomophilous flowers, so in the case of succu- 
 lent fruits, unless we believe that the seemingly attractive 
 organs were developed for the purpose of enticing animals, 
 we must believe that they are a positive waste of energy 
 to the parent plant. 
 
 The evolution of bright flowers themselves shows that 
 birds as well as insects are attracted by their beautiful 
 petals. Mr. Darwin has collected many instances in 
 which blossoms are fertilised by birds ; and Fritz MuUer 
 notes several species of Ahutilon in Brazil, which he 
 believes depend entirely on humming-birds for the disper- 
 sion of their pollen.^ Mr. Wallace observes that brilliant 
 
 1 Tropical Nature, p. 246. 2 Cross-Fertilisation, p. 371.
 
 THE COLOUR-SENSE IN VERTEBRATES. 125 
 
 flowers witli handsome corollas exist in many Oceanic 
 islands, such as Juan Fernandez, where flying insects are 
 almost unknown ; but their place is supplied by humming- 
 birds, which Mr. Mosely mentions as being " extraordinarily 
 abundant." ^ Mr. Belt believes that a climbing plant of 
 Central America, 3f«'7-c9'ra via nepentlioides, has been specially 
 adapted to the same birds ; while Mr. Wallace thinks that 
 many Australian and Malayan flowers have been similarly 
 specialised for the visits of honey-eaters, lories, and sun- 
 birds. "Only large flowers," says Mr. J. E. Taylor, "can 
 be visited by these birds, or those whose polypetalous 
 corollas allow of the head being thrust into the centre. 
 Hence we have, in some measure, a reason afforded us for 
 the laro^er size of the flowers in resjions where such birds 
 are abundant. The large bushes and trees of such countries 
 usually bear very fine showy flowers in order to attract 
 the birds ; and it is found that the brush-tongued parra- 
 keets are particularly fond of the flowers which grow at a 
 height above the ground." ^ Any one who has watched a 
 humming-bird darting with lightning speed from blossom 
 to blossom could "hardly have a doubt of his acute colour- 
 perception. 
 
 The proofs afforded by imitation and mimicry are 
 stronger in the case of birds than of any other class. One 
 may say generally that almost all insects which display 
 protective or imitative colouring do so for the sake of 
 escaping birds or lizards. A few cases must suffice to 
 show the general tendency of the evidence. The leaf and 
 stick insects (Phylliidoe and Phasmidse) closely imitate the 
 colours and shapes of leaves and sticks. One in particular, 
 the Ceroxylus laceratus, is apparently overgrown by moss 
 or jungermaunia.^ Sir Emerson Tennent describes the 
 
 1 Tropical Nature, p. 273. ^'^^ the omission would have been a 
 
 2 Flowers, their Origin, &c., p. serious defect; sol have here departed 
 294. This is the only instance in from my usual rule, and taken most 
 which I have availed myself of new of the above cases from Mr. Taylor's 
 matter from this interesting little pages. 
 
 volume, which appeared while I was ' Wallace, Contributions to the 
 \n course of revising my manuscript ; Theory of Natural Selection, p. 64.
 
 126 THE COLOUR-SENSE. 
 
 leaf-insects as possessing " all varieties of hue, from the 
 pale yellow of an opening bud to the rich green of the 
 full-blown leaf and the withered tint of decay." ^ The 
 Kallima paraleJcta, a leaf-like butterfly of the Malay 
 Archipelago, always rests among dead or dry leaves, which 
 it resembles in all their varying hues, even appearing to 
 be spotted with small fungi. Canon Tristram has noted 
 that almost every insect, bird, or reptile inhabiting the 
 desert of Sahara is coloured exactly like sand,- and Lord 
 George Campbell mentions a butterfly similarly imitative 
 of its background which frequented the sea-shore at Am- 
 boyna.^ A South American Zeptalis so closely resembles 
 an uneatable Ithomia "in every shade and stripe of colour," 
 that Mr. Bates could hardly distinguish them, even with 
 the aid of his minute entomological knowledge. *' One of 
 the Hemiptera (Spiniger luteicornis)," says Mr. Belt, " had 
 every part coloured like the hornet {Priocnemis) that it 
 resembled. In its vibrating coloured wing-cases it departed 
 greatly from the normal character of the Hemiptera and 
 assumed that of the hornets." * The same careful observer 
 gives many similar instances of mimetic resemblance in 
 the Coleoptera,^ and Lepidoptera.^ But perhaps the most 
 astonishing of these imitative forms is that of a moss-like 
 insect, the larva of a Phasma, which is prolonged into 
 curious green filaments, to mimic the moss in which it 
 lives.'^ Of course these creatures could derive no advantage 
 from their minute reproduction of spots, lines, and hues, 
 unless the enemies against which they required protection 
 were capable of distinguishing their colours. 
 
 Mimicry or imitative devices of this sort are not confined 
 to insects. Many lizards, such as the geckos, have colours 
 like those of the walls on which they creep ; while the 
 
 1 Ceylon, j). 251. authority, lie may be confidently relied 
 
 2 See also Gurney, Kambles of a on for any question of fact. 
 Naturalist, p. 56. ^ The Naturalist in Nicaragua, p. 
 
 ^ Log-letters from the Challenger, 319. 
 p. 208. Although this amusing writer ^ Ibid., p. 317. ^ P. 382. 
 
 can hardly be considered a scientific ' Figured in Belt, ubi supra, p. 
 
 382.
 
 THE COLOUR-SENSE IN VERTEBRATES. 127 
 
 protective green hue of the tree-frogs has already been 
 noticed. Even birds occasionally mimic one another in 
 the same manner. For example, two species of Mimeta 
 (a sort of oriole), in Bouru and Ceram, imitate two Tropi- 
 dorhynclii (honeysuckers) in minute details of colour, 
 thus escaping small birds of prey, as the Tropidorhynchi 
 are strong and pugnacious creatures.-^ For other cases 
 the reader must be referred to Mr. "Wallace's admirable 
 essay on " Mimicry and other Protective Eesemblances 
 among Animals." 
 
 These various proofs, though indirect, can leave us in 
 little doubt with regard to the general existence of a 
 colour-sense among birds. 
 
 "When we come to the highest class of vertebrates — the 
 mammalia — strangely enough the evidence of a colour- 
 sense almost entirely fails us. The antipathy of male 
 ruminants for scarlet, and the curiosity which certain 
 monkeys display with regard to bright-coloured objects, 
 are the only facts in point which come under ordinary 
 observation. This result, so contrary to what we might 
 have expected, appears really quite natural when we exa- 
 mine more closely the circumstances of the case. By far 
 the larger part of the mammalia are either herbivorous 
 like the ruminants and pachyderms, or carnivorous like 
 the technical carnivores, insectivores, and whales. Only 
 a small portion of the class subsists upon fruits, w^hile 
 none of them are very specially connected with flowers. 
 Hence a large set of possible tests which we can employ 
 in the case of insects and birds are wholly inapplicable to 
 mammals. Moreover, the want of close relations with the 
 coloured parts of plants has probably resulted in a want 
 of any peculiar love for bright colour, such as we see 
 reason to suspect in the butterflies, humming-birds, and 
 parrots. This absence of a taste for brilliancy is probably 
 marked by the absence of brilliant hues in the animals 
 themselves, the result of sexual selection ; for these hues, 
 
 •■ Wallace, Malay Archipelago, p. 401.
 
 128 THE COLOUR-SENSE. 
 
 as we shall see hereafter, only appear among the mam- 
 malia in a few higher arboreal and frugivorous species, 
 such as the mandrill and certain squirrels. For the most 
 part, throughout the mammalian series sexual selection 
 seems only to have exerted itself, if at all, in the produc- 
 tion of elegant shapes, protuberances like horns and dew- 
 laps, and marked contrasts of light and shade, as in the 
 zebra, giraffe, and hysena. 
 
 Nevertheless we can hardly doubt that mammals do 
 possess a considerable colour-sense, though, owing to the 
 circumstances of their practical environment, their taste 
 for any special hue is probably far from strong. 
 
 Here once more I must remind the reader that the 
 proofs of a colour-sense throughout the whole infra-human 
 world are necessarily very derivative, and that they owe 
 their chief strength to their cumulative character. The 
 fragmentary evidence collected in this chapter will be 
 much corroborated and supplemented by that which will 
 be detailed in the sequel. Enough will have been done if 
 we succeed in showing that the hypothesis of a general 
 colour-sense is consonant with all the facts of nature, and 
 helps us to understand those facts in a way which no other 
 hypothesis can do. ' For the present it will be sufficient if 
 we bear in mind the one great point hitherto settled — that 
 wherever any part of a plant, be it flower or fruit, will 
 derive any benefit from attracting the eye of an animal, be 
 it insect, bird, or mammal, that part is almost invariably 
 coloured with some pure and brilliant hue, be it blue, red, 
 yellow, pink, orange, violet, or lilac, quite distinctive from 
 the green of ordinary vegetation. This one fact is the 
 great pivot upon which turns our whole knowledge of the 
 animal colour-sense.
 
 ( 129 ) 
 
 CHAPTER VIII. 
 
 THE COMMUNITY OF TASTE BETWEEN FLOWER- 
 FEEDING AND FRUIT-EATING SPECIES. 
 
 Before we proceed to consider the secondary reactions of 
 the colour- sense in insects and vertebrates upon their own 
 external appearance, we must glance for a moment at one 
 of the determining causes which give approximate unifor- 
 mity to the general results of such reactions in the animals 
 with which we are most specially concerned. In the next 
 chapter we shall have to examine the production of bright 
 hues in the wings of butterflies, the skins of lizards, the 
 feathers of birds, and the fur of mammals, due to the 
 selective action of sexual preferences. But, as a necessary 
 preliminary to that inquiry, we must first set ourselves to 
 determine the principles which govern the formation of 
 tastes generally among the flower-feeding and fruit-eating 
 animals. Before we can trace to its final effects the action 
 of a sexual preference for bright colouring, we must pre- 
 viously find out with certainty the reasons why a taste 
 for such colouring should exist at all in the animal con- 
 sciousness. 
 
 People are generally too apt to accept as ultimate and 
 obvious every fact with which they have always been 
 familiar. Seeing that bright colours as a rule attract chil- 
 dren and savages, dogs, birds, fish, and insects, they do not 
 trouble themselves to seek a reason for this preference, 
 but take it for granted as an inherent and natural pro- 
 perty of the animal organism, or, more often and more 
 absurdly still, of the colours themselves. If, however, we 
 
 I
 
 I30 THE COLOUR-SENSE. 
 
 reflect upon the subject for a moment, we shall see that 
 there is no primitive and self-sufficing reason in the nature 
 of things why anj^ one colour should be more beautiful to 
 us than another. Dull and dingy hues might conceivably 
 have been just as pleasant to our sense, under slightly 
 different conditions of our development, as we know bright 
 and pungent hues to be, under the actual circumstances of 
 humanity. We must get a little deeper into the ground- 
 work of our likes and dislikes if we would really under- 
 stand the origin of our native preference for brilliant tints 
 over mixed or unstimulating colours. 
 
 Now, after this preamble, most readers will imagine 
 that I mean to explain the liking of flower-feeders and 
 fruit- eaters for bright hues by means of that grand but 
 somewhat vaguely employed shibboleth, the Association 
 Theory. I know that to the mass of loose thinkers associa- 
 tion is a sort of psychological dms ex 7nachinawh.ic]i satisfac- 
 torily accounts for every ill-defined mental problem, just as 
 electricity is a sort of physical deus ex machina which simi- 
 larly gets over every ill-comprehended material problem. 
 Such persons say to themselves at once, " Oh, of course, 
 birds and butterflies feed off bright-coloured objects ; so 
 bridit colours f^et associations with their food, and are 
 consequently pleasant to them." Having thus satisfied 
 their nascent critical doubts by the easy application of an 
 accepted formula, they never pause to translate their vague 
 speculation into thinkable terms, but leave it as they took 
 it up, a mere algebraical expression, incapable of rational 
 statement in a concrete form. For how can association 
 with food make a colour or anything else pleasant in itself ? 
 This is the true crux of the Association Theory, a crux 
 which, as I humbly believe, few of its adherents have ever 
 perceived in its full significance. Until it has been solved, 
 the theory remains a mere verbal explanation, adding no- 
 thing to our real knowledge of the subject, yet deluding 
 us by its specious resemblance to an explanatory truth. 
 
 The mode of exposition here adopted will be a very
 
 COMMUNITY OF TASTE. 131 
 
 different one, based upon the known psyclio-pliysical law 
 of pleasure and pain. According to that law, pleasure is 
 the psychical aspect of an ultimate physiological fact, 
 which in its physical aspect may be summed up as the 
 unimpeded activity of a fully nurtured and not over- 
 worked nervous structure in unbroken connection with 
 the cerebro-spinal or other central sentient system. Con- 
 versely, or nearly so, pain is the psychical aspect of an 
 ultimate physiological fact, which in its physical aspect 
 may be summed up as the disintegration, insufficient nutri- 
 tion, or excessive activity of a nervous structure, similarly 
 connected with the sentient organism.^ With the latter 
 half of this important law we have here little or nothing 
 to do ; but the former half so intimately concerns our 
 subject that I shall make no apology for endeavouring 
 briefly to explain its meaning in simpler language than 
 that of the above abstract formula. 
 
 A pleasure, then, is the feeling which results when any 
 sentient nervous centre receives a stimulation not exces- 
 sive in quantity, nor beyond the existing power of the 
 structures concerned. Every centre undergoes at each 
 stimulation a certain amount of disintegration ; and if that 
 disintegration pass beyond the easy repairing-point of the 
 system, pain sets in. But, on the other hand, so long as 
 the stimulation is moderate, by exercising the structures it 
 promotes their general efficiency, and hence it is accom- 
 panied by a feeling of pleasure. Or to translate our law 
 into still more concrete and ordinary language, we may 
 say that whenever an organ which can feel at all is exer- 
 cised not beyond the due amount, pleasure is the result. 
 Hence the pleasurableness of any activity may be ac- 
 cepted as a rough gauge of its general desirability for the 
 organism as a whole, while conversely its painfulness 
 
 1 For a full explanation of the form wards), see my "Physiological ^Es- 
 
 here given to this law (originally due thetics," chap, ii., "Pleasure and 
 
 to Mr. Herbert Spencer and Professor Pain," where the grounds upon which 
 
 Bain, working on the basis of previ- the conclusion is based have been de- 
 
 OU3 inquirers, from Aristotle down- tailed at length.
 
 132 THE COLOUR-SENSE. 
 
 may be regarded as a certain proof of its general unde- 
 sirability. 
 
 ]^ow the more fully-nurtured an organ mayj be, tlie 
 higher is its functional efficiency, and the greater the plea- 
 sure to be derived from its exercise. We all know that 
 the fresher our limbs, our muscles, our nerves, and our 
 eyes, the greater the enjoyment we derive from a country 
 walk or a game of cricket. After long fasting we eat our 
 food with greater relish ; after long confinement we use our 
 less and arms with redoubled delio-ht. But we also know 
 that in order to keep up a state of high efficiency in any 
 organ, frequent exercise is necessary. Only by running, 
 jumping, rowing, and gymnastics can we bring our muscles 
 into a proper condition for hard athletic work. Only by 
 constant practice can we retain any accomplishment which 
 we have learnt by dint of serious effi)rt. And just the 
 same is true of nerves. Their existing structure has been 
 acquired by continuous function in past generations, and 
 continuous function is necessary still if we would prevent 
 them from rusting into obsolescence. 
 
 Accordingly, whenever we find that any activity is pro- 
 ductive of immediate pleasure in ourselves, we may be sure 
 that the activity in question is one which has long been 
 practised by our human or ante-human ancestors. The 
 greater the pleasure, as I have elsewhere endeavoured to 
 show, the greater the intimacy of connection between the 
 activity and the life of the species. Let us, for example, 
 take the case of colour itself, with which we are here so 
 fully engaged. If in any species the need for distinguish- 
 ing different colours ever arose, and if by its side there also 
 arose a nascent structure for so distinguishing them, then 
 those individuals in which that structure was most fully 
 developed would survive from generation to generation, in 
 virtue of their superior adaptation to the needs of their 
 environment above their less highly endowed compeers. 
 But with each such increment in the structure there would 
 go increased pleasure in the function. Conversely, the
 
 COMMUNITY OF TASTE. 133 
 
 more fully the function was indulged the more would the 
 structure increase and strengthen by exercise. So from 
 generation to generation, as the power of distinguishing 
 colours became more and more developed, the pleasure 
 arising from their perception would grow more and more 
 acute. Such pleasure forms the first groundwork for that 
 differential preference in individuals or species which we 
 Know as taste. 
 
 But every colour would not probably prove equally 
 pleasurable. Some, like the ordinary greys, greens, and 
 browns, occur too often in the surrounding world to allow 
 of any marked gratification, derivable only from the in- 
 termittent stimulation of little-worked nerves. Moreover, 
 these common colours would have no special reference to 
 the life of the race, and so would have few structural con- 
 nections with other portions of the central nervous system. 
 But in the case of fruit-eating and flower-feeding species, 
 we may well suppose that the special nerves devoted to 
 the perception of red, yellow, orange, and purple would 
 naturally be much strengthened by constant hereditary 
 use ; while the comparatively intermittent nature of the 
 stimulation would render the accompanying feeling far 
 more pleasurable than in the more familiar instances of 
 green or brown. Furthermore, the close relation of these 
 colours with the food of the species would doubtless give 
 rise to numerous nervous connections in the central sys- 
 tem, whereby the sight of such coloured objects might set 
 up the necessary movements for obtaining the booty. In 
 this manner the central organs of special colour-percep- 
 tion for the brilliant hues of fruits and flowers would in 
 all probability assume unusually large dimensions, and 
 would certainly possess large numbers of concurrent fibres 
 along which waves of discharge might readily travel, thus 
 giving free vent for a considerable volume of pleasure- 
 yielding energy. Such species might fairly be said to 
 possess a taste for red, yellow, and other like pungent 
 hues ; and we might accordingly give a rough definition
 
 134 THE COLOUR-SENSE. 
 
 of taste as a special preference, in an individual or a race, 
 for one or more out of several similar objective stimuli, 
 depending ultimately upon special variations of nervous 
 development. 
 
 Of course this hasty definition leaves out of considera- 
 tion the other half of the subject, which we might perhaps 
 sum up as distaste, — the special repugnance to one or 
 more among such stimuli, ultimately due to like diversi- 
 ties of individual or generic organisation. In this case, 
 however, we must distinguish between two widely dif- 
 ferent forms of feeling, which are apt at first to be men- 
 tally confused, — mere neutral indifference, which results 
 from a stimulation too languid or too common to produce 
 pleasure, and positive dislike or disgust, which arises 
 from some actually painful and disintegrative action. 
 Thus, in sight, an ugly colour, like that of mud, is simply 
 neutral and unstimulating ; but in taste, a bitter or acrid 
 substance probably sets up material disintegration, and so 
 of course produces a positively painful sensation. This 
 distinction will become more obvious and more important 
 as we proceed. 
 
 In this way only, then, as it seems to me, can associa- 
 tion have anything to do with the intrinsic pleasurable- 
 ness of any sensation, namely, by affording outlets for 
 the overflowing nervous energy. But the main pleasure 
 of the sensation itself, as I understand the question, must 
 be due to inherited cahbre of the nerves and nervous 
 centres employed, that calibre being due itself to ances- 
 tral function throughout many previous generations. To 
 put once more the concrete case, fruit-eaters and flower- 
 feeders derive pleasure from brilliant colours (postulating 
 the fact for the time being, argumenti gratia), not because 
 those colours have mental associations with their food, 
 but because the structures which perceive them have been 
 continually exercised and strengthened by hereditary use. 
 The connection with food has given numerous outlets for 
 the nervous energy, and has been the ultimate cause for
 
 COMMUNITY OF TASTE. 135 
 
 the extra development of colour-perceiving structures, 
 but it has had no direct effect, as I believe, upon the 
 immediate pleasure of sensation. 
 
 It is true that in highly evolved animals, with whom 
 the emotions have attained an immense and preponderant 
 influence, associations do largely enter into all pleasur- 
 able feelings. But even here the ultimate explanation 
 is equally simple and straightforward. These emotions 
 have their own proper nervous seats, as Terrier's experi- 
 ments sufficiently show ; and we must suppose that the 
 actual sensation, being located in a centre which has con- 
 nections with the seats of such emotions, rouses action in 
 the emotional centres, more or less conspicuously, and so 
 adds a more or less distinct factor to the total resulting 
 consciousness. But it would be very foolish to transfer 
 similar ideas into the simple nervous organisation of 
 birds, and still more into that of bees and butterflies. 
 Taste in these animals must be almost entirely a matter 
 of direct sensation, dependent upon the calibre of the 
 nerves employed, and little influenced by the few possible 
 associated feelings.^ 
 
 Having premised these few considerations as to the 
 nature of taste in general, let us now go on to examine 
 the special tastes of fruit-eating and flower-feeding ani- 
 mals. We shall find on investigation that these appear to 
 be approximately identical throughout the whole animal 
 series ; while they are more or less strongly marked off' 
 from the opposite tastes of carnivores and carrion-eaters. 
 The very same sweet and sugary substances, the very 
 same etherial and delicate perfumes, the very same bright 
 
 1 Lest any reader should imagine that I begin to dissent ; and even 
 
 that I mean by these remarks to cast here my dissent, as will be seen 
 
 some doubt upon the whole body of from the above paragraph, extends 
 
 Associationist Psychology, I hasten only to the very simplest elements of 
 
 to add, parenthetically, that I fully feeling. I do not for a moment 
 
 accept that system so long as it con- doubt that the a3sthetic pleasures of 
 
 fines itself to the relation between cultivated Aryan man depend largely, 
 
 the senses aud the intellect. It is or even mainly, upon associated emo- 
 
 only when it is brought forward as a tion. 
 verbal explanation of emotional facts
 
 136 THE COLOUR-SENSE. 
 
 and dainty colours, seem pleasing in the very same way to 
 butterflies, and humming-birds, and parrots, and apes, and 
 men. The similarity of nervous impressibility which we 
 thus perceive to hold throughout the whole heterogene- 
 ous collection of fruit and flower haunters casts much light 
 upon the nature of sexual selection, and upon the identity 
 of taste between man and so many lower animals. It 
 enables us to see why the flowers which the bee de- 
 veloped for his own delight and guidance should be the 
 joy of children and the envy of artists ; why the hues of 
 the orange and the mango should be as beautiful to man 
 as to the toucans and macaws which gave them origin ; 
 why the wing of the butterfly, the tail of the peacock, 
 and the burnished throat of the sun-bird should be exqui- 
 site to our eyes as they were to those of their fastidious 
 mates ; and why human beings should dye their bodies 
 with the woad of Britain and the ochre of Papua, or tinge 
 their garments with the purple of Tyre and the thou- 
 sand hues of Lyon, to vie with the gorgeous tints of bird 
 and insect in the very self-same profusion of refulgent 
 colours. 
 
 First, then, let us begin with the sense of tasU. It is 
 a most noteworthy fact that wherever any part of a plant 
 can gain any advantage by attracting the notice of 
 animals, it always effects its purpose by the secretion of 
 sugar, or, as we oftener though more incorrectly call it in 
 this connection, honey. Now sugar, as I have already 
 pointed out, has a special power of acting upon the 
 gustatory nerves of animals, through the great solubility, 
 diffusibility, and crystalline texture of its particles. Ac- 
 cordingly, we find that almost all classes of fruit-eaters 
 and flower-feeders show a decided partiality for this 
 pleasant stimulant — a partiality due, doubtless, to the 
 long habits of their ancestors, which have developed cor- 
 respondingly differentiated structures for the perception 
 of the particular body in question. In flowers, sugar is 
 secreted to attract bees and other insects ; while in fruits,
 
 COMMUNITY OF TASTE. 137 
 
 it acts as an allurement to birds and mammals. Further- 
 more, certain plants possess organs for the secretion of 
 sugar on their stems or at the base of their leaf-stalks, of 
 which Sir John Lubbock gives the following account : — 
 " Belt and Delpino have, I think, suggested the true func- 
 tion of these extra-floral nectaries. The former of these 
 excellent observers describes a South American species 
 of Acacia, which, if unprotected, is apt to be stripped of 
 its leaves by a leaf-cutting ant, which uses the leaves not 
 directly for food, but, according to Mr. Belt, to grow 
 mushrooms on. The Acacia, however, bears hollow 
 thorns, and each leaflet produces honey in a centre-formed 
 gland at the base, and a small sweet pear-shaped body at 
 the tip. In consequence, it is inhabited by myriads of a 
 small ant which nests in the hollow thorns, and thus finds 
 meat, drink, and lodging all provided for it. These ants 
 are continually roaming over the plant, and constitute a 
 most efficient bodyguard, not only driving off the leaf- 
 cutting ants, but even, in Mr. Belt's opinion, rendering 
 the leaves less liable to be eaten by herbivorous 
 mammalia." ^ Indeed, so universal is the taste for suo'ar 
 among insects, that certain small animal creatures, like 
 the Aphides and Cocci, have themselves acquired the 
 habit of developing nectaries, and so gaining the protection 
 of ants, which may be seen " assiduously running up the 
 stems of plants to milk these curious little cattle." And 
 if we want further proof of the general love for sweet food- 
 stuffs, we need only bethink us how the insects flock about 
 a barrel of treacle in our streets, how the birds cono-re^-ate 
 in fruit-gardens, and how our own children gather around 
 the windows of the confectioner's shop to stare at the 
 tempting wares within — rendered all the more enticing, 
 be it observed, through the very same addition of red, blue, 
 and yellow, which had already been invented by the fruit 
 and the flower. 
 
 1 " On Certain Eelations between Plants and Insects," a lecture delivered 
 at Glasgow, January 24, 1878, p. 6.
 
 138 THE COLOUR-SENSE. 
 
 Equally significant are the changes in habit or mode of 
 life between fruit-eating and flower-feeding classes. Thus, 
 a large number of hymenopterous insects live upon honey 
 extracted from flowers ; but the omnivorous wasps, as we 
 all know, have taken to surreptitious feasting upon the 
 sugary juices of peaches, pears, and nectarines. In like 
 manner, I have often noted lepidopterous species, whose 
 natural food consists of the nectar in summer blossoms, 
 feeding greedily upon fallen fruit. Mr. W. M. Gabb 
 captured the lovely Morplios of Nicaragua by baiting with 
 a piece of over-ripe banana ; ^ and the Eev. J. G. Wood, a 
 most trustworthy recorder in all that concerns the habits 
 of animals, notices on one occasion having seen whole 
 hordes of the Eed Admiral butterfly ( Vanessa atalanta) 
 darkening the ground wdiere a number of egg-plums lay 
 beneath their parent tree.^ So, too, amongst birds ; while 
 most of them take their sugary food in the form of fruit 
 or seeds, a few kinds, like humming-birds and sun-birds, 
 live largely off the nectar of flowers, mixed with the insects 
 which frequent them.^ Mr. Webber, an American natura- 
 list, tried the experiment of taming the pretty little 
 ruby-throats, which he fed on syrup alone, and though 
 he found that they could not thrive without a fair pro- 
 portion of insects as well, he also discovered that they 
 showed a decided partiality for the taste of sugar. 
 " Some which had been thus tamed and set free returned 
 the following year, and at once flew straight to the re- 
 membered little cup of sweets." ^ In certain instances, we 
 find the interchange of habit taking place within the 
 limits of a single tribe. Thus, the true parrots live al- 
 most entirely off sweet fruits, but their congeners the lories 
 are nectar-eaters. These facts, once more, we may cor- 
 relate with well-known human habits ; as when we see 
 children, whose taste for sweets is derived from frugi- 
 
 ^ " Nature," February 7, 1878. see Wallace, " Tropical Nature," p. 
 
 2 "Insects at Home," p. 401. 235. 
 
 2 Ou the food of humming-birds, ■^ Ibid., p. 137.
 
 COMMUNITY OF TASTE. 139 
 
 vorous ancestors, sucking the juices of honeysuckle and 
 clover, or stealing the honey-bag from our domesticated 
 hive-bees. Indeed, we could have no more simificant 
 symbol of the community of nature here pointed out 
 than the fact that we keep these same bees to gather 
 honey for us from the nectaries of flowers. 
 
 Conversely, whatever parts of a plant would be injured 
 by the interference of animals, secrete a bitter or acrid 
 juice, which acts deleteriously upon the nerves of taste. 
 Thus, as I have already pointed out, the pericarp, which 
 in fruits-proper is provided with sugary secretions, in 
 nuts is commonly stored with a nauseous principle as a 
 deterrent to animal foes. Again, those fruits which have 
 a sweet pulp generally guard against the loss of their 
 actual seeds by filling them with a bitter substance, of 
 which prussic acid often forms a leading constituent : 
 cases occur in the peach-stone, the apple-pip, and the 
 seeds of oranges or mangoes. That animals as a rule dis- 
 like bitter substances is a matter of common observation ; 
 and experiments which I have conducted on a small 
 number of insects and birds have always resulted in 
 marks either of indifference or of positive distaste. Thus 
 we see that both in their likes and dislikes a oreat com- 
 munity of taste runs through all the flower-feeding and 
 fruit-eating animals. 
 
 If, now, we turn to the carnivores and carrion-feeders, 
 we shall find a totally different set of sympathies and 
 antipathies. It is true that many dogs and flesh-eating 
 flies love sugar ; but they also love numerous other bodies 
 which several of the former class of creatures would never 
 touch. Fresh meat, or still worse, putrid flesh, does not 
 appeal at all to the senses of bees and parrots. Man, of 
 course, forms an intermediate link, a fruGjivorous animal 
 who has partially adopted carnivorous tastes. Hence we 
 have a certain liking for the flavour of roast beef and 
 turkey; some of us eat high game and caviare; and 
 savages even prefer meat in an advanced stage of decom-
 
 I40 THE COLOUR-SENSE. 
 
 position. But these are mere surface-tastes, while the 
 deeper-seated ancestral habits come out strongly in our 
 children and our unsophisticated adults. The liking for 
 strong-tasted meats and half -putrid preparations has to 
 be slowly acquired ; whereas the love for sugar, for honey, 
 for fruits, for all sweet things, is born with us into the 
 world, and taken in with our first draught of mother's 
 milk. And in this connection it is worth while to note 
 that the natural food of the human infant contains 62.3 
 parts of sugar in 1000, while that of a herbivorous calf 
 possesses only 45.6,^ so that it becomes necessary in 
 giving cow's milk to babies to sweeten it considerably up 
 to the proper point. 
 
 Secondly, let us look at the sense of smell. Here again 
 we notice that wherever any part of a plant wishes to 
 attract animals, it adds to its sweetness the extra allure- 
 ment of perfume ; and the same perfumes are, as a rule, 
 pleasant to all flow^er-feeders and fruit-eaters alike. The 
 delicate odour of a peach, a pine-apple, or a strawberry 
 scarcely differs in kind from that of a lily, a hyacinth, or 
 a violet. Mankind, whose tastes in this matter are de- 
 rived from the tropical fruits, have equal pleasure with 
 bees or butterflies in the dainty scent of clover and 
 meadow-sweet. Only, as might naturally be expected, 
 the perfumes of fruits (which we have already seen reason 
 to believe are comparatively modern structures) are not 
 so highly developed as the perfumes of flowers ; whence 
 arises the seeming anomaly that our olfactory nerves are 
 more pleasurably stimulated by the stephanotis or the 
 jasmine, which is relatively remote from our practical 
 life, than by the apple or the pear, which is relatively 
 essential. Of course, the explanation here is that the 
 more powerful stimulant naturally affords the greater 
 volume of pleasure, irrespective of its ulterior useful- 
 ness. 
 
 In this case, too, we see the essential agreement 
 
 1 Hermann, Human Physiology, English translation, p. 121.
 
 COMMUNITY OF TASTE. 141 
 
 between the higher and the lower forms of vegetal- 
 feeders. For just as our taste for sweets corresponds to 
 the insect's taste for honey, so our love for the perfume of 
 flowers is absolutely identical with the pleasure which 
 draws the butterfly towards the luscious blossoms in our 
 English meadows. And it is w^orth while to observe that 
 most of the sweet-smelling flowers appear to be quite late 
 developments of vegetal life; a fact which harmonises 
 well with the correspondingly late development of the 
 bees and other highly-adapted honey-suckers. There is 
 no tribe of plants, for example, more noticeable for their 
 perfume than the family of Labiates, which includes the 
 various species of mint, thyme, balm, sage, marjoram, 
 lavender, rosemary, horehound, calamint, patchouli, hyssop, 
 and basil. The flowers of these plants are almost all 
 very peculiarly shaped and highly scented, and their 
 attractiveness for bees has become proverbial — the honey 
 of poetry is commonly " redolent of thyme." Now the 
 Labiates, so far as known, are tertiary plants of rather 
 late date, which did not make their appearance on the 
 earth until bees and other specialised honey-seekers had 
 reached a high point of evolution. Nor should we omit 
 to notice the fact that many of these plants are now cul- 
 tivated by man for the sake of this very property ; 
 lavender to dry and use for scent, patchouli to extract an 
 essence for the handkerchief, and mint, thyme, or sage 
 to flavour various preparations for the table. The exactly 
 similar cases of nutmeg, cloves, and other spices, whose 
 perfume is famous for its diffusibility, while the mode of 
 their dispersion by nutmeg-pigeons has become classical 
 in the pages of Darwin and Wallace, do not need further 
 comment. 
 
 In some few instances the pleasure of perfume has been 
 turned into a sexual allurement, as with certain butter- 
 flies, where the two sexes exhibit a different arrangement 
 in the nervures of the wings. "In all cases which I 
 know," says Fritz MuUer, " this difference in neuration is
 
 142 THE COLOUR-SENSE. 
 
 connected with, and probably caused by, the development 
 in the males of spots of peculiarly formed scales, pencils, 
 or other contrivances, which exhale odours agreeable no 
 doubt to their females. This is the case in the genera 
 Mechanitis, Dircenna, in some species of Thecla, &c." ^ 
 Similar instances occur in the musk-deer and other mam- 
 mals, whose perfumes are used by human beings as 
 pleasurable stimulants. Indeed, I do not think it would 
 be too much to say that almost every substance which we 
 employ as a native scent is derived either from a vegetal 
 product whose natural function is the attraction of ani- 
 mals, or from an animal product whose natural function 
 is the attraction of the opposite sex. 
 
 On the other hand, we find amongst the carnivores and 
 carrion-feeders a totally different form of olfactory plea- 
 sure. Dogs, wolves, and other predatory mammals, track 
 their prey by scent, while the smell of raw meat renders 
 the larger cats wild with excitement. Vultures and sopi- 
 lotes revel in the hideous smell of putrid animal matter, 
 and flies collect around dung or decaying meat. Curi- 
 ously enough, too, some plants have availed themselves 
 of this special taste, and have laid themselves out, as 
 already noticed, to deceive carrion insects by their like- 
 ness in appearance and smell to putrescent flesh. The 
 Sumatran Rafflcsia and the South African Hydnora have 
 large and lurid blossoms, which thus cunningly induce 
 flies to visit them for the purpose of laying their eggs, and 
 are accordingly fertilised by means of an organised de- 
 ception. To naturally frugivorous man, the scent is, of 
 course, simply disgusting. Yet it is worth notice that many 
 savages, who have acquired for generations the habit of 
 eating half-decomposed meat, positively enjoy those odours 
 which are most distasteful to the nostrils of civilised huma- 
 nity. As Kolben quaintly phrases it, in his old-fashioned 
 style, "Wliat you take for a stink, a Hottentot, if you 
 
 ^ In "Nature," November 29, 1877.
 
 COMMUNITY OF TASTE. 143 
 
 will believe him, receives as the most agreeable per- 
 fume." 1 
 
 Hence one may see how futile is the argument of 
 Geii:^er, who remarks, as illustratinGr the sensuous in- 
 feriority of the lower animals, that it would be -useless to 
 offer a dog a bouquet to sniff at.^ Of course the dog has 
 no reason for being pleased with a perfume which has 
 no special relation to himself or his ancestors in any way ; 
 but if we offer him a piece of meat, or set him to hunt 
 down game, we shall find how keenly he has been pro- 
 vided by nature with senses to aid him in his ow^n mode 
 of life. In fact, we can only expect pleasure to be felt 
 where ancestral habit has produced a corresponding 
 sensory system. The transference of feeling whereby we 
 are enabled to enjoy the perfume of flowers does not con- 
 tradict this general principle, for it is really analogous to 
 the transference whereby the humming-bird sipped the 
 syrup which resembled the native nectar, or whereby we 
 ourselves enjoy sweetmeats and cakes through our here- 
 ditary liking for fruits and berries. Honey is a more 
 concentrated form of sugar than that which we get in 
 strawberries or oranges, and frangipanni is a more con- 
 centrated form of perfume than that which we get in 
 peaches and pine-apples ; but they probably act in just 
 the same way, though to a greater extent, upon the nerves 
 involved as do the original stimulants, and consequently 
 they need no special explanation. Very different, how- 
 ever, would be the case if a dog or any other animal were 
 to feel pleasure in a stimulation derived from some object 
 which had no kind of relation to his ancestral habits. 
 Such an instance, one might venture to say, would be 
 wholly inexplicable, and opposed to all the known prin- 
 ciples of scientific psychology. 
 
 The sense of hearing, though interesting in itself through 
 
 1 Kolben, "Cape of Good Hope," 2 ''Zur Entwickelungsgeschichte 
 vol. i. p. 231. der Menschheit, iii. p. 50.
 
 144 THE COLOUR-SENSE. 
 
 its connection with song-birds and the sexual allurements 
 of sound amongst sundry insects, has so little relation 
 with our present subject, that I must reluctantly pass it 
 over here. 
 
 Lastly, then, we arrive at the sense of siglit, which we 
 must only examine with special reference to the taste for 
 colour. And here, as before, we note at once that those 
 portions of plants which lay themselves out to attract 
 animals are almost without exception conspicuous for 
 their bright colours. Entomophilous flowers, as we have 
 already abundantly observed, have a monopoly of brilliant 
 corollas, while fruits - proper differ from nuts in the 
 startling vividness of their hues. These facts would go by 
 themselves to prove that flower-feeding and fruit-eating 
 animals find an allurement in colour. It is certainly 
 a noticeable fact that just as the sweetness of fruits 
 answers to the sweetness of honey, and just as the scent 
 of fruits answers to the scent of flowers, so do the colours 
 of fruits answer exactly to the colours of flowers. It would 
 seem as though, in every case, nature found a single mode 
 of modifying the nervous substance was amply sufficient 
 (because simplest and easiest) alike for insect and reptile, 
 for bird and ape and human being. 
 
 Some special facts help to point in the same direction. 
 Thus we find within the limits of a single family, the 
 Eosacese, a large number of fruits -proper, the plum, the 
 apple, the hip, the haw, the strawberry, the raspberry, and 
 the bramble, in which the pericarp or other succulent 
 portion, besides being sweet and scented, is more or less 
 brilliantly coloured ; and again, we also find an aberrant 
 member, the almond, whose seed is enclosed in a nut, and 
 whose pericarp accordingly is hard, dry, and green or 
 brownish, after the usual fashion of nuts. Or once more, 
 we know that in most Oceanic islands there are few flying 
 insects, and that most of the flowers are destitute of bright 
 corollas ; but Mr. Wallace has pointed out that in a few, 
 cases, where honey-sucking birds frequent such islands
 
 COMMUNITY OF TASTE. 145 
 
 the flowers are extremely large and handsome.^ This fact 
 clearly shows that the birds in question find colour quite 
 as attractive as do bees or butterflies. 
 
 I do not propose to enter very fully into this question 
 until w^e have seen w^hat light may be cast upon it by the 
 examples collected and the inferences drawn in the suc- 
 ceeding chapter. But I should like to point out here 
 that if our general theory of pleasure be well-founded, 
 it must necessarily result that flower-feeding and fruit- 
 eating animals should derive agreeable sensations from 
 coloured objects. So soon as the eyes of insects or birds 
 have become sufficiently differentiated to discriminate the 
 pinkish or ruddy flower-cases and fruit-vessels from the 
 green leaves around them, and to employ their nascent 
 sense in the quest for food, so soon must the special 
 nerves exercised and strengthened in this process receive 
 some faint pleasure from their due stimulation. And 
 the more developed the nerves become, the more intense 
 must be the resulting enjoyment, till at last an ever-in- 
 creasing gratification would grow up side by side with the 
 growth of entomophilous blossoms and coloured fruit, be- 
 coming stronger and stronger day by day as the structures 
 increased by practice in calibre and power. 
 
 Two short passages from the works of two leading 
 evolutionists will serve to bring out in strong relief the 
 position here assumed. Mr. A. E. Wallace thus sums up 
 his view with regard to the nature of colour-perception 
 in the lower animals : — " The fact that the higher verte- 
 brates, and even some insects, distinguish what are to 
 us diversities of colour, by no means proves that their 
 sensations of colour bear any resemblance whatever to 
 ours. An insect's capacity to distinguish red from blue 
 or yellow may be (and probably is) due to perceptions of 
 a totally distinct nature, and quite unaccompanied by any 
 of that sense of enjoyment or even of radical distinctness 
 which pure colours excite in us. Mammalia and birds, 
 
 1 Tropical Nature, p. 238.
 
 146 THE COLOUR-SENSE. 
 
 whose structure and emotions are so similar to our own, 
 do probably receive somewhat similar impressions of 
 colour ; but we have no evidence to show that they ex- 
 perience pleasurable emotions from colour itself, when 
 not associated with the satisfaction of their wants or the 
 gratification of their passions." ^ From the whole of this 
 passage, with all due deference to ]\Ir. AVallace (for most 
 of whose work I entertain the deepest respect), I must 
 take leave to differ toto codo. Each of its three sentences 
 appears to me to contain a fallacious position. For the 
 first, the burden of proof lies distinctly with Mr. Wallace, 
 not with his opponents; because, where the external 
 stimulus is the same, and where a general continuity of 
 structure exists, we are not justified in assuming a dif- 
 ference of sensation without some special reason; nor do 
 I believe that so clear a thinker as the author of the 
 *' Malay Archipelago " would have assumed such a differ- 
 ence, were it not for that predisposition to find some 
 eff'ective distinction between man and the lower animals 
 which has so often led him into questionable conclusions. 
 For the second, it seems to me that, since the insect's need 
 for discriminating colour is far greater than our own, 
 analogy would lead us to suppose that his enjoyment 
 would be even deeper, and his sense of distinctness more 
 marked, than in the human subject. For the third, the 
 single instance of the oft-quoted bower-birds, who collect 
 coloured objects to decorate their meeting places, shows 
 that some vertebrates at least possess a liking for brilliant 
 hues in themselves, of a truly aesthetic sort : and the be- 
 haviour of monkeys with regard to flowers and birds, or 
 to red shawls and other strikingly-dyed articles, would 
 seem to point in the same direction. For the rest, Mr. 
 Darwin has gathered together a few isolated instances of 
 disinterested love for colour in a well-known section of 
 his " Descent of Man." ^ It is true that the evidence on 
 this head is still far from satisfactory; but it must be 
 
 ^ Tropical Nature, p. 243. 2 Yo\. ii. p. no.
 
 COMMUNITY OF TASTE. 147 
 
 remembered tliat without the assistance of language de- 
 finite information as to tastes cannot be procured except 
 with great difficulty, and that human infants only dis- 
 play the love for colour in the same simple ways as mon- 
 keys or bower-birds. 
 
 The second passage to which I would refer is one from 
 our great naturahst himself. " How the sense of beauty in 
 its simplest form," says Mr. Darwin, — " that is, the recep- 
 tion of a peculiar kind of pleasure from certain colours, 
 forms, and sounds, — was first developed in the mind of 
 man and of the lower animals, is a very obscure subject. 
 The same sort of difficulty is presented if we inquire how 
 it is that certain flavours and odours give pleasure, and 
 others displeasure. Habit in all these cases appears to 
 have come to a certain extent into play ; but there must 
 be some fundamental cause in the constitution of the ner- 
 vous system in each species."^ Now this fundamental 
 cause I believe to reside in the general law that pleasure 
 accompanies normal stimulation when not excessive in 
 amount; while the influence of ancestral habit, joined 
 with natural selection, has so modified the nervous system 
 in each case that it finds itself normally stimulated by 
 those external agents whicli conduce to the general wel- 
 fare of the organism, and excessively or destructively 
 stimulated by those which conduce to its general detri- 
 ment.2 Accordingly, I infer that in all fruit-eating and 
 flower-feeding species, a taste for sweet flavours, delicate 
 perfumes, and bright colours will have been slowly deve- 
 loped by the hereditary mode of life ; and that the taste 
 so developed will have opportunities for exerting itself in 
 the sexual selection of bright-coloured mates. 
 
 If this be so, then it must follow that flower-feeding 
 and fruit-eating insects or vertebrates will be specially 
 distinguished from other animals by the exceptional bril- 
 liancy of their colouration. In the next chapter we will 
 
 1 Origin of species, 6th edit., p. 162. tics," pas«u7i, where this main prin- 
 
 2 See my "Physiological Ji^sthe- cii)le is worked out in detail.
 
 148 THE COLOUR-SENSE, 
 
 submit our general conclusion to the test tliTis suggested to 
 us, and if we find that bright hues are, as a matter of fact, 
 unusually common amongst those species in which we have 
 inferred a 'priori that a taste for brilliancy would have 
 been evolved by the circumstances of their life, then we 
 shall have added another item to our cumulative proof 
 of the existence and influence of a colour-sense among 
 the lower animals. Just as we saw that the taste for 
 sweets, formed upon flowers and fruits, could be trans- 
 ferred to syrup, sugar, honey, bonbons, cakes, and pud- 
 dings ; just as we saw that the human liking for dainty 
 perfumes, formed upon strawberries and oranges, could be 
 transferred to hyacinths and heliotropes : so, I believe, 
 the love for colour, formed upon the natural food of the 
 various species, can be transferred to the choice of beauti- 
 ful mates, and, strengthened by this transference, can be 
 handed down by heredity to mankind till it results at last 
 in the disinterested delight in the sunset and the autumn 
 hues, in the flowers of our gardens, the varying tints of 
 our landscapes, and the exquisite harmony of our Guides 
 and our Eossettis. Let us see, then, how far the facts of 
 nature will bear out the theory on this subject which we 
 have framed from the analogy of our other senses.
 
 ( 149 ) 
 
 CHAPTER IX. 
 
 THE DIRECT REACTION OF THE COLOUR-SENSE UPON 
 THE ANIMAL INTEGUMENTS. 
 
 If any unscientific person were asked to name tlie two most 
 beautiful classes of animals in the world, he would unhe- 
 sitatingly answer, '' Butterflies and humming-birds." It 
 is a significant fact that these are perhaps the most exclu- 
 sively flower-haunting of all invertebrate or vertebrate 
 creatures respectively. And if he were asked to name any 
 other birds, besides the single family above mentioned, 
 which are specially conspicuous for their brilliant colour- 
 ation, he would probably reply, '' Parrots and their allies." 
 It is an equally significant fact that these birds are fruit- 
 eaters. Following up the hint thus given us, we may run 
 through the chief instances of brilliant species in both 
 great divisions of articulates and vertebrates, in order to 
 discover whether there is any constancy of connection 
 between the nature of the food and the colouration. 
 
 As before, we may narrow down our consideration of the 
 articulates to the great group of insects, because we know 
 too little about the habits of their marine congeners to 
 argue with any certainty as to their traits ; while the other 
 land-articulates are relatively unimportant for our present 
 purpose. Now amongst the insects, the most brilliant 
 order are the Lepidoptera, including both the butterflies 
 and moths, which, it need hardly be said, feed upon flowers. 
 Of course, it may be readily objected that the amount of 
 food eaten by the perfect winged insects is relatively small, 
 and that the caterpillars live for the most part upon the
 
 I50 THE COLOUR-SENSE. 
 
 green portions of plants. Indeed, some butterflies possess 
 no mouths at all, and pass the whole of their short lives 
 by the expenditure of energy laid up in the larval condi- 
 tion. Yet this objection does not really invalidate the 
 general conclusion ; for the eyes of the perfect insects have 
 been evidently adapted to the colours of flowers, and the 
 main object of their winged state is the perpetuation of 
 the species ; so that we can easily understand how the 
 tastes ancestrally formed in their last stage should domi- 
 nate the selection of their mates. Hence we find that the 
 colours of caterpillars are mostly protective, being due to 
 natural -selection alone, while those of butterflies are mostly 
 attractive, being largely due to sexual selection. 
 
 Furthermore, if we examine the Lepidoptera in detail, we 
 shall find similar conclusions thrust upon us. They may 
 be divided into two great sections, — the moths and the 
 butterflies, — of which the former are mainly nocturnal or 
 crepuscular, while the latter are mainly diurnal. Now 
 there can be no comparison as to brilliancy between the vast 
 majority of these two groups. The moths vary for the 
 most part from dingy grey to dusky black, while the but- 
 terflies revel in every shade of golden yellow, splendid 
 crimson, and metallic blue. Again, the eyes of these two 
 divisions differ in structure in a manner which suggests 
 the inference that the diurnal insects are much better pro- 
 vided with optical discrimination than their nocturnal 
 allies,^ especially when the facts are compared with cer- 
 tain exactly similar or corresponding peculiarities in the 
 nerve-terminals in the eyes of owls and bats.^ 
 
 Nor does the argument stop here. Certain species or 
 families of moths fly by day, and these [e.g., the crimson- 
 speckled Deiopeia pulcliella, Callimorplia dominula, the 
 Agaristidce, ^gcriidm, Zygmnidm, &c.) are as brightly tinted 
 as any butterflies. Mr. Bates mentions a Brazilian Urania, 
 
 ^ See a paper by Mr. B. T. Lowne, F.L.S., in Proc. Roy. Soc, No. clxxxvi. 
 p. 26 r, 1878. 
 ^ See below.
 
 DIRECT RE A CTION. x 5 1 
 
 " a beautiful tailed and gilded moth, whose habits are those 
 of a butterfly ; " ^ and I know by personal experience the 
 Jamaican species of similar tastes, whose wings are exqui- 
 sitely dappled with black, green, and gold. Indeed, it 
 may be stated generally that most brilliant insects are 
 fond of displaying themselves in the open sunlight ; while 
 conversely most insects which frequent dark places or fly 
 by night alone are dusky and ugly. By the side of these 
 facts it is well to remember that diurnal flowers, which 
 appeal to bees and butterflies, have corollas in every 
 variety of red, blue, orange, and purple ; while nocturnal 
 flowers, which appeal to moths, are generally white or 
 pale yellow in hue. 
 
 If we compare the carrion-feeding and omnivorous flies 
 with the flower-haunting Lepidoptera, we see at once the 
 difference of taste, as exhibited in the presence or absence 
 of sexual selection. The flies are generally dark and 
 inconspicuous, with thin transparent wings; and what- 
 ever beauty they possess is due to mere surface-play of 
 interference-colours, not to the existence of distinct pig- 
 ments. Nothing in the nature or appearance of their 
 ordinary food-stuffs would lead us to credit them with any 
 ancestral love for pure and beautiful hues. 
 
 There are, however, some striking exceptions amongst 
 the dipterous insects, which fully bear out our general 
 conclusion. The tribe of Brachystomatidce are " large flies, 
 adorned with brilliant colours, which for the most part 
 haunt flowers, living upon honey." ^ The Xotacanthte 
 " are also frequently brilliantly coloured. They generally 
 frequent flowers." The Conopidse, too, " are elegantly 
 variegated in their colours. They may be found in great 
 abundance during the summer, hovering upon their power- 
 ful wings over flowers in gardens and elsewhere." The 
 invariability of this conjunction will hardly allow us to 
 recrard it as accidental. 
 
 o 
 
 1 The Naturalist on the Amazons, ^ Dallas, The Animal Kin^dum, 
 p. 105. p. 191.
 
 152 THE COLOUR-SENSE. 
 
 Beetles or Coleoptera show us like results. The car- 
 rion-feeders are for the most part black and unattractive, 
 as are also the nocturnal species and those which live in 
 water. But the brilliant species are often flower-feeders, 
 and fly much in the sunlight, exhibiting their exquisite 
 metallic sheen, and displaying their beauty to their 
 mates. If we take the Lamellicorn beetles in particular, 
 we shall find a very instructive difference between two 
 of their closely-allied families. The cockchafers feed on 
 leaves, and they are some of the dingiest creatures of their 
 class ; but the Cetoiiiadcc feed upon flowers, as their English 
 name of " rose-beetles " implies, and they are conspicuous 
 for the beauty of their colouring, including " a vast num- 
 ber of the most brilliant exotic species." " It is a signifi- 
 cant fact, too, that their mandibles have been specially 
 modified, so as to enable them to lick up honey, which 
 clearly shows a long persistence in flower-haunting habits, 
 quite sufi&cient to account for the formation of a definite 
 taste for colour. " Those species," says Latreille, speak- 
 ing of Lamellicorns generally, " which live in the perfect 
 state upon vegetable substances, are remarkable for the 
 brilliancy of the metallic colours with which they are 
 adorned. But the majority of the other species, which 
 subsist on decomposing vegetation, manure, tan, or excre- 
 mentitious matter, are generally of a uniform black or 
 brown hue." The magnificent Buprestidse are also, in many 
 cases at least, flower-haunters. The tetramerous beetles, 
 including the gorgeous Longicorns, may be regarded as 
 mainly flower-feeding or plant-haunting insects, and their 
 colours, as a rule, are very brilliant. Similarly, among 
 heteromerous beetles, the Trachelia of Professor West- 
 wood are active diurnal animals, most of which live upon 
 the leaves or suck the honey of flowers, and they are 
 often adorned with beautiful colours ; but the Atrachelia, 
 nocturnal in their habits and foul feeders, are generally 
 black and dingy in hue. Altogether, though it would be 
 difficult to sum up so very varied a group as the Coleop-
 
 DIRECT RE A CTION. 153 
 
 tera in a single sentence, I think a careful examination 
 will convince the inquirer that here, too, a general con- 
 nection exists between brilliancy of hue and flower-feed- 
 ing or fruit-eating habits. 
 
 When we turn to the Hymenoptera, or bee and wasp 
 tribe, a great difficulty at first sight arises in our way. It 
 would seem as though some of these insects ought to be 
 of all others the most gorgeously arrayed, and yet for the 
 most part they are but plain and inconspicuous creatures. 
 However, a closer view dispels the doubt. Only one tribe 
 of the Hymenoptera, that of the Anthophila, or bees, is 
 specially adapted for feeding on flowers. Now these fall 
 into two classes, the social and the solitary ; and the habits 
 of the former class, of course, place them almost entirely 
 outside the sphere of sexual selection. The queen or 
 mother-bee, a prisoner for life, does not herself seek honey 
 among flowers, and those bees which do so have no power 
 of transmitting their tastes or habits to descendants. 
 Indeed, the whole question of heredity in these interest- 
 ing animals remains involved in so much mystery, that it 
 would be useless to base any arguments upon it in either 
 direction. 
 
 On the other hand, the solitary bees are often beauti- 
 fully coloured, as in the well-known case of the carpenter- 
 bee. The Nomadae, or cuckoo-bees, are also very brilliant 
 insects. The omnivorous wasps do not exhibit equal 
 beauty ; and the almost wingless, highly social, and mainly 
 carnivorous ants are quite inconspicuous animals, pro- 
 bably possessing colour-perception in a very sight degree. 
 But the Chrysidse, a family of lower Hymenoptera, are 
 also solitary flower-haunters, and " in the richness of their 
 colours they vie with humming-birds." 
 
 Of course, it cannot be denied that a few less notable 
 classes of insects which do not haunt flowers are never- 
 theless more or less brilliant in their colouring. But this 
 does not interfere with the general truth of our inference 
 that flower-feeders are specially noticeable for their bright
 
 154 THE COLOUR-SENSE. 
 
 lilies. If we can find ground for believing that those spe- 
 cies which habitually seek their food in gay blossoms have 
 developed a peculiar love for colour, which is shown in 
 their choice of mates, we shall have done quite as much as 
 is needful. Besides, other sources exist from which a love 
 for colour may be derived as well as from flowers. For 
 example, the Orthopterous family of Mantidse, or praying- 
 insects, are noticeable in many instances for their bright 
 tints ; but as they live by devouring other insects, a taste 
 of the sort may have been generated indirectly in their 
 case from the nature of their food. Still, most of the 
 Mantidse seem rather to be deceptively coloured like their 
 surroundings, so as to escape the notice both of their prey 
 and of their enemies among birds. A similar explanation 
 must be given in the case of the Phasmidae, or leaf and 
 stick insects, whose colouring, though sometimes compara- 
 tively striking when seen in a cabinet, is purely imitative 
 of the foliage or fallen sticks around them. Many flower- 
 haunting spiders, too (to travel for a moment outside the 
 limits of the true insects), are " exquisite gems " of ruby 
 or sapphire colouration ; yet we must rather attribute their 
 magnificent hues to the need for imitating the petals on 
 which they creep than to sexual selection. Such instances, 
 however, in no way militate against our main conclusion ; 
 they only show that other causes at work have sometimes 
 produced similar results to those which we are contem- 
 plating, though in a different manner. Thus it is quite 
 possible that the beauty of the tiger-beetles may be due 
 to their habit of huntincf other brio^ht- coloured insects in 
 the open sunlight. 
 
 There still remains a margin of inexplicable cases, 
 as might naturally be expected, for the study of these 
 questions is yet in its infancy, and only a few isolated 
 endeavours have hitherto been made to account at all for 
 the external appearance of animals. Among such may 
 be mentioned the gorgeous tropical locusts, the dragon- 
 flies (which, however, prey upon many brilliant species),
 
 DIRECT RE A CTION. 155 
 
 and several of the Longicorn beetles. But all these in- 
 stances cannot blind us to the fact that if we look at the 
 flower-haunting insects in the mass they are by far the 
 most conspicuous for beauty of their kind. It is not 
 necessary to explain in detail the colouring of every in- 
 dividual species — an endless task, which would demand 
 far more competent treatment than I could give : it is 
 quite sufficient if we find a general coincidence between 
 bright food and bright hues in the feeder, without 
 pretending at once to account for every apparent ex- 
 ception. 
 
 And now, before we pass on to examine the vertebrate 
 world in the same manner as we have here examined the 
 articulate, we must pause a moment to meet, or rather 
 to touch lightly, a powerful objection which has been 
 urged against the whole theory of sexual selection by no 
 less a writer than Mr. A. E. Wallace. In his work on 
 " Tropical Nature," that ingenious evolutionist endeavours 
 entirely to overthrow Mr. Darwin's laborious superstruc- 
 ture, raised with so much toil and skill in the " Descent of 
 Man," and to substitute for the doctrine of A'oluntary 
 choice, which the older naturalist there advanced, a number 
 of minor principles, whose joint action may be supposed 
 to have produced the existing colours of the animal world. 
 Mr. Wallace has urged his objections with even more 
 than his usual ingenuity ; and I may frankly confess that 
 he has attacked the theory of sexual selection with such 
 judicious vigour that I felt inclined on first reading his 
 essays to abandon entirely all that part of the present 
 work which was based on the orio-inal doctrine enunciated 
 by Mr. Darwin. On fuller consideration, however, I have 
 determined, though with much hesitation, to retain it, in 
 hopes that the few suggestions which I have to make 
 upon the question may possibly contribute to a clearer 
 comprehension of its issues, and to its ultimate settle- 
 ment in one direction or the other. I cannot for a 
 moment pretend to meet a distinguished specialist like
 
 156 THE COLOUR-SENSE. 
 
 Mr. "Wallace on liis own ground ; nor do I wish to dis- 
 pute the force and accuracy of many among his criticisms ; 
 yet I trust I may be able to add my small quotum of facts 
 and inferences to the whole data for a final opinion, and 
 I believe that the very generalisation which it is the 
 object of the present chapter roughly to establish, may be 
 useful in showing some additional basis for the theory of 
 sexual selection. For if we find that ^fruit-eating and 
 flower-feeding animals do really exhibit unusually beauti- 
 ful colours, then we shall have some further ground for 
 believing that they do exert some vague sort of choice or 
 preference in the search for mates. 
 
 Accordingly, I shall jot down in passing, under each 
 head, such points as occur in relation to this vexed ques- 
 tion. 
 
 In the first place, it is well to remember that sexual 
 selection does not necessarily imply a deliberate exercise 
 of will, or comparison between the rival charms of various 
 possible mates, which seems hardly probable in the case 
 of insects at least. We must guard against the error of 
 transferring our own highly-developed notions of beauty 
 to the simple half- conscious minds of beetles or butter- 
 flies. With us, beauty is a very complex idea, compounded 
 of numerous presentative, representative, and re-represen- 
 tative elements ; and our choice of mates is a conscious 
 selection, guided more or less deliberately by many com- 
 plicated considerations, often too numerous for analysis 
 even in our own minds. But, without attributing to the 
 butterfly any such highly-evolved feelings, w^e may well 
 believe that certain individuals, whose brilliant colours 
 contrasted strikingly with the green foliage about them, 
 might more readily succeed in attracting the attention of 
 mates than their dingier compeers. We know that the eyes 
 of insects are allured by the colours of flowers, which have 
 been developed for this very purpose : and there is there- 
 fore nothing improbable in the supposition that they are 
 also allured by bright hues in their fellows. In short, I am
 
 DIRECT RE A CTION. 1 57 
 
 inclined to suggest that conspicuousncss rather than leauty 
 in our human sense is aimed at by the butterfly's wing. 
 To some this will doubtless appear equivalent to a sur- 
 render of the whole position ; but a little reflection will 
 probably remove such an apprehension. For the sense of 
 beauty in its simplest form, as Mr. Darwin rightly puts it, 
 is nothing more than " the reception of a peculiar kind of 
 pleasure from certain colours, forms, and sounds." ^ Now 
 we have seen reason to believe that the insect feels some 
 slight pleasure in the perception of colour in flowers ; and 
 we may also conclude that the pleasure is equally felt 
 from the similar stimulation of a brilliant mate. In either 
 case, it seems probable that a semi-automatic action is set 
 up by the sight of the bright hue, which leads on the insect 
 instinctively to the blossom or the opposite sex alike. 
 Such a selective process does not seem to me at all to 
 transcend the narrow faculties of a beetle or a butterfly. 
 Mates on this theory are not chosen on account of their 
 brilliancy, but their brilliancy renders them the most 
 natural objects to choose. 
 
 The familiar instance of the moth and the candle shows 
 us this automatic tendency in its fullest form. In that case 
 it w^ould seem as though the intensity of the visual stim- 
 ulus set up a motor activity of the wings, which w^ould 
 become more and more powerful the more directly the eyes 
 of the insect were turned towards the light. Accordingly, 
 any random movements in that direction would be fol- 
 lowed by more and more rapid gyrations, ending, as we 
 know, in the central flame, whenever the eyes both pointed 
 straight toward that quarter. We must conclude here that 
 in the natural circumstances of moths few bright objects 
 would occur around them, except flowers, and so the eye 
 has probably been connected with the motor system in 
 such a manner that the reception of a light- stimulus acts 
 immediately upon the wings. In the presence of such a 
 rare and unpremeditated object as a candle, the hereditary 
 
 ^ Origin of SiJecies, sixth edition, p. 162.
 
 158 THE COLOUR-SENSE. 
 
 instinct or organised habit becomes a bad guide, finds itself 
 at fault, and finally results in the insect's death. But the 
 case is very much like that of a human child, who knowing 
 that bright red berries are usually sweet and innocuous, 
 poisons itself with those of the cuckoo-pint or the yam. 
 The instinctive pleasure can only have been adapted to the 
 usual environment of the race, not to special and excep- 
 tional circumstances like artificial lights and poisonous 
 berries. 
 
 It is possible that the light of fire-flies and glow-worms 
 may be similarly of use for the guidance of the sexes, 
 though Mr. Belt believes it to be a warning mark of inedi- 
 bility. However this may be, it is certain that butterflies 
 and insects generally are so constituted that they can dis- 
 tinguish their own mates unerringly from all others, even 
 though the difference between the species be almost 
 microscopical. Whether this discrimination be due to 
 sight, or, as some authors maintain, to smell, it shows 
 equally that a minute correspondence exists between the 
 senses of the insect and its habits of life. And as this 
 correspondence, so far as each separate species is con- 
 cerned, must have had a beginning at some time or other, 
 and consequently a cause, there seems no sufficient ground 
 for doubting that conspicuousness of colour formed one of 
 the determining conditions. Indeed, I cannot myself see 
 why Mr. Wallace, who allows the attractive nature of 
 colouring in flowers, should deny its attractive nature in 
 the question of sex. 
 
 It is allowed on all hands, I believe, that the special 
 odours of insects,! as well as their stridulatingj noises,^ are 
 guides to the sexes in their search for one another. It 
 does not appear that colour stands on any different footing 
 in this respect. 
 
 Furthermore, many insects have two sets of colours, 
 apparently for different purposes, the one set protective 
 
 1 See r. Miiller in " Nature," November 29, 1877. 
 
 2 Darwin, Descent of Man, passim.
 
 DIRECT RE A CTIOX. 1 59 
 
 from tlie attacks of enemies, the other set attractive for 
 the opposite sex. Thus several butterflies have the lower 
 sides of their wings protectively coloured, so as to preserve 
 them from the notice of birds or lizards, while they sit 
 with folded wings on a flower or leaf ; whereas the upper 
 sides are attractively coloured, and displayed in the open 
 sunlight as they flit about in search of mates. Moths, 
 again, whose habits of folding the wings are exactly 
 opposite, often have their upper surfaces imitative or pro- 
 tective, while tlie under sides are bright and beautiful 
 Sometimes the union of protective and attractive features 
 in the same insect is very striking. Thus Mr. WaEace 
 himself mentions a leaflike butterfly, Kallima jparalekta, 
 whose w4ngs are purple and orange above, but exactly 
 mimic dead foliage when closed ;^ this insect always rests 
 among dead or dry leaves, and imitates every stage of 
 decay, being even apparently spotted with small fungi. 
 So, too, Mr. Bates tells us of a grasshopper, Pterochroza, 
 whose sheath-like fore-wings similarly resemble a green 
 leaf, while its hind-wings, usually covered except during 
 flight, are " decorated with gaily-coloured eyelike spots." ^ 
 Again, Mr. Belt observes that the males of some butterflies 
 which mimic the Heliconidae are coloured with black and 
 white, quite unlike the mimicking females,^ while some 
 South African species show perfectly marvellous differ- 
 ences in this respect. In all these cases, one cannot but 
 believe that while the one form of colouring has been 
 acquired for the sake of protection, the other must differ 
 from it for some sufficient functional purpose. 
 
 Once more, there seems to be a pretty constant connec- 
 tion between the general beauty of the flora in any 
 particular district and the general beauty of its insect 
 
 1 Malay Archipelago, p. 131. vious truth that white and pale yel- 
 
 2 The Naturalist ou the Amazons, low are really very brilliant colours 
 r- 145- when comi)ared with the green or 
 
 3 Mr. Wallace seems to me to have brown of ordinary life. See " Tropi- 
 quite perverted the simple explana- cal Nature," p. 204. 
 
 tion of this fact by neglecting the ob-
 
 i6o THE COLOUR-SENSE. 
 
 inhabitants. Of course, it lias long been noted that where 
 few or no flying insects exist, few or no bright-coloured 
 flowers are found. But what I wish to point out here is 
 the converse fact that where bright blossoms are common, 
 insects are brilliant, while where most blossoms are 
 inconspicuous, most insects are dingy. On this head 
 the mass of evidence, though difficult to quote, is over- 
 whelming. A few of the more striking instances may, 
 however, be briefly given here. On the whole, the brightest 
 flowers grow among the tropics, and on the whole, tropical 
 insects are unusually beautiful. The flora and the minor 
 fauna of Madagascar are equally remarkable for their 
 splendid hues. Sir Joseph Hooker notices the extreme 
 magnificence of the Himalayan flora; and he also 
 mentions the singular loveliness of the butterflies.^ Sir 
 Emerson Tennant speaks continually of the beauty of the 
 " brilliant flowering shrubs " in Ceylon,^ and he likewise 
 speaks of the beauty of its butterflies in large numbers.^ 
 In Mr. Bates's work on Brazil, I notice almost on every 
 page the conjunction of pretty insects with striking 
 flowers, or the absence of both together.* Especially does 
 he note the beauty of the Longicorn beetles found on 
 flowers^ at Caripi, while a few pages before he remarks 
 upon the abundance of exquisite blossoms at the same 
 place.^ I cannot help interpolating here, though out of 
 proper order, the remark that, just in like manner, he seldom 
 mentions the capture of a handsome bird without adding 
 that it was shot in a fruit-tree. Almost the only bright 
 butterfly which I ever observed in large numbers in 
 Jamaica was the Calliclryas eubule, feeding on the abundant 
 yellow cactus blossom, whose hue it exactly resembled, and 
 which is the only common and conspicuous large entomo- 
 philous flower in the colony. Both Mr. Wallace himself 
 
 1 Himalayan Journal, i. 152, and ^ See the Naturalist on the Ama- 
 ii. 98. zons, pp. 20, 274, 
 
 2 Ceylon, pp. 87, 88, 92. ^ Ibid, p, no. 
 2 Ibid, pp. 247, 248. 6 Ibid, p. loi.
 
 DIRECT RE A CTION. 1 6 1 
 
 and Lord George Campbell,^ an excellent non-scientific 
 observer, remark upon the beauty of the insects and 
 flowers of the Ke Islands. Similarly, the flowers of 
 Amboyna are paralleled by its gorgeous beetles, butterflies, 
 and birds.^ On the other hand, in ISTew Zealand " there 
 are scarcely any gay flowers and blossoms ; but few her- 
 baceous plants, nothing but shrubs and trees; shrubs 
 with obscure green flowers ; " ^ while at the same time " the 
 butterflies are distinguished neither by size nor by richness 
 of colour." * Oceanic islands, which have few or no bright 
 flowers, are remarkable for the absence of bright insects ; 
 and Mr. Darwin mentions of the Galapagos group both 
 the fact that he " did not see one beautiful flower," and 
 also the universal dinginess of the whole fauna. But this 
 question is one on which it is difficult to quote positive 
 authorities : it must rather suffice to mention that a con- 
 siderable search into the general impressions of travellers 
 — the best evidence, after all, on so indefinite a point — has 
 convinced me that such a general relation does actually 
 obtain. It is no answer to say that the insects are neces- 
 sary for the production of the flowers : the real point at 
 issue is this — why are insects bright where bright flowers 
 exist in numbers, and dull where flowers are rare or in- 
 conspicuous ? We can hardly explain this wide coinci- 
 dence otherwise than by supposing that a taste for colour 
 is produced through the constant search for food among 
 entomophilous blossoms, and that this taste has reacted 
 upon its possessors through the action of unconscious 
 sexual selection. 
 
 Finally, it would seem that Mr. Wallace's own theory 
 of " typical colours " really allows all that is here required. 
 For Mr. Wallace speaks distinctly of the " need of recog- 
 nition and identification by others of the same species " ^ 
 
 1 Log-Letters from the Challenger, 133. See also Six- Joseph Hooker's 
 p. 187. "Flora of New Zealand," p. 28. 
 
 2 Ibid., p. 208. "* Hochstetter, p. 170. 
 
 2 Hochstetter's New Zealand, p. ^ Tropical Nature, p. 215. 
 
 L
 
 i62 THE COLOUR-SENSE. 
 
 as one among the determining causes of sucli colours, not 
 only in the case of birds, but also in that of butterflies, 
 four families of which he specifies by name. ISTow, con- 
 spicuousness of hue is certainly a very simple means of 
 identification : and I think we must allow that it acts as 
 an allurement to the eye in the case of flower-feeding 
 species. I am quite disposed to accept Mr. Wallace's 
 belief that the actual disposition of the stripes, spots, and 
 lines, is a matter of special typical arrangement ; but even 
 here one would naturally suppose that some minute cause 
 must at first have led to the preference for one arrange- 
 ment over another. Briefly, to sum up the whole question, 
 after making full allowance for warning colours and for 
 mimetic or other protective colours, there seems to remain 
 a large margin of cases in which brilliancy exists for 
 purely attractive purposes : while often the attractive 
 function is combined with more or less of protective 
 device. Anybody who watches our own English butter- 
 flies on a sunny day can hardly doubt that display forms 
 a part of the object for which their yellow, orange, or 
 crimson-spotted wings have been developed, and that such 
 display makes them an easier mark for their scattered 
 mates. Above all, it is necessary to remember that the 
 winged condition in these insects is hardly more itself 
 than a sexual device for the perpetuation of the various 
 species. 
 
 And now let us pass on to consider the fuller evidence 
 afforded us by vertebrates. 
 
 To begin with fishes, it must be allowed that our present 
 knowledge of their habits scarcely justifies us in making 
 any distinct inferences from their colouring. ISTevertheless, 
 a few facts may perhaps be gleaned even here. The mass 
 of lower marine animals are brilliantly coloured with what 
 seem to be purely adventitious or protective colours ; and 
 we had occasion already to remark upon the similarity 
 between their hues and those of fungi, saprophytes, and 
 other like vegetal organisms. As a few examples may
 
 DIRECT RE A CTION. 163 
 
 be mentioned sea-anemones, star-fisli, ecliini, medusae, 
 ascidians, sea-slugs, and corals. When we reach the 
 moUusca, the colouring begins to assume a different type, 
 but it would be difficult to assign any sufficient cause ibr 
 its occurrence. Amongst the marine articulata, and espe- 
 cially the crustaceans, many species exhibit a regularity 
 of hue, and minute arrangement of spots and lines, which 
 seems to bespeak a certain amount of sexual selection. 
 These doubtful instances, however, we must pass over, not 
 because they are less interesting, but because they are so 
 very uncertain ; and in a brief examination like the present, 
 we must necessarily confine our attention to the most 
 salient points. Now, the abundance of coloured organisms, 
 both animal and vegetal, in the sea, affords a fair ground 
 for belief that fishes may have acquired o^colour-sense, and 
 a taste for bright hues. We know that they (as well as 
 the crustaceans) can be attracted by crimson or scarlet 
 rags, and that glistening objects like rnetals or artificial 
 baits rapidly seize upon their attention. As to the 
 brilliancy, beauty, and regularity of their colouring, the 
 reader must be referred to Mr. Darwin's description in 
 the " Descent of Man," where he will find a full account of 
 the principal facts which go to prove the existence among 
 them of sexual selection. I must content myself here by 
 saying that for gorgeous colouring and variety of patterns 
 they are nowhere surpassed in the whole animal kingdom; 
 and that metallic sheen is especially conspicuous among 
 the devices whereby they insure the attention of their 
 mates. 
 
 As regards the special question upon which we are now 
 engaged, a few facts may be shortly set down. In the first 
 place, the lower animals of tropical seas are on the whole 
 much more brilliantly coloured than those of temperate 
 climates, and the same remark holds good of the fishes. 
 Mr. Darwin has noticed the extreme beauty of the shoals 
 which played in and out among the brilliant organisms of 
 the coral lagoons; and though Mr. Wallace objects that
 
 1 64 THE COLOUR-SENSE. 
 
 tliis may be due to protective causes, in order tliat they 
 may escape notice among the bright creatures about them, 
 y^et as Mr. Darwin pertinently replies, he was struck by 
 the obvious conspicuousness of their appearance rather 
 than by their resemblance to environing objects. I have 
 myself observed the same point frequently in the West 
 Indian harbours, where the fish and the neioiibourincj 
 creatures, seen through clear still water, all appeared 
 equally beautiful and noticeable. But I cannot do better 
 than quote Mr. Wallace's own description of the harbour 
 of Amboyna. " The bottom," he says, " was absolutely 
 hidden by a continuous series of corals, sponges, actiniae, 
 and other marine productions of magnificent dimensions, 
 varied forms, and brilliant colours. ... In and out among 
 them moved numbers of blue and red and yellow fishes, 
 spotted and banded and striped in the most striking 
 manner, while great orange or rosy transparent medusa3 
 floated along near the surface." ^ And elsewhere he ob- 
 serves, " The fishes (of Amboyna) are perhaps unrivalled 
 for variety and beauty by those of any one spot on the 
 earth." These facts at least tend to show that our theory 
 does not receive any active contradiction from the condi- 
 tions of marine existence ; and they are confirmed by 
 numerous other like passages in several authors whom I 
 think it superfluous to quote. 
 
 On the other hand, the larger predatory species, such as 
 sharks and pikes, together with the majority of temperate 
 fishes, are decidedly wanting in brilliant hues. Mr. Wallace 
 observes that river fish, even of the tropics, rarely if ever 
 have gay or conspicuous markings ; ^ and this is just what 
 we would expect from the nature of their food, consisting 
 as it does of worms, small flies, and other inconspicuous 
 objects. However, we must allow that in this case Mr. 
 Wallace has witnessed against himself with excessive 
 fervour ; for many river fish undoubtedly liave very 
 
 1 Malay Archipelago, p. 295. 
 " Contributions to the Theory of Natural Selection, p. 55.
 
 DIRECT REACTION. 165 
 
 brilliant colours, as I can especially testify from having 
 caught in my youth numbers of the Canadian sun-fish, 
 perhaps the most exquisite creature of its class which I 
 have ever seen. But this particular species lives in shallow 
 marshy water, and maij have derived its tastes from butter- 
 flies and dragon-flies. Professor Agassiz speaks much, 
 too, concerning the beauty of the Amazonian fishes,^ which 
 he describes as having a quasi-marine character ; ^ and in 
 spite of a possible accusation for grotesqueness, I would 
 venture to suggest that their colouring may perhaps be 
 due to those numerous butterflies which Mr. Bates so often 
 describes as flitting in numbers along the banks of that 
 mighty river. However this may be, we must leave these 
 somewhat inconclusive cases, and hurry on to the terrestrial 
 vertebrates. 
 
 The amphibia yield little evidence in either direction. 
 The beautiful colouring of tree-frogs, when compared with 
 toads and common frogs, is more probably protective than 
 attractive. Still, the newts show us very unmistakable 
 signs of sexual selection in their crests ; and we cannot 
 say that the habits of amphibia may not have generated a 
 love for colour. 
 
 Among the reptiles, however, a good many facts may 
 be quoted to our purpose. In the first place, the large 
 water-haunting crocodiles and alligators are peculiarly 
 dull and unsightly objects; while the whole order of 
 Chelonia, including the turtles and tortoises, are as incon- 
 spicuous for colour as they well can be. On the other 
 hand, the smaller saurians, many of which lead an ar- 
 boreal life, and feed off varied food, sometimes fruit, some- 
 times insects and other small animals, are often noticeable 
 for their beauty. Most iguanas, great jungle lizards, con- 
 trast strongly in hue with the crocodiles ; but one species, 
 AmUyrlujnclius cristatus, which inhabits the dull-coloured 
 Galapagos Islands, and has taken to a strangely abnormal 
 marine life, is remarkable for the same sombre tints 
 
 ^ A Journey in Brazil, p. 184. - Ibid., p. 238.
 
 1 66 THE COLOUR-SENSE. 
 
 wliicli characterise the other animals of that singular 
 archipelago, being described by Mr. Darwin as of " a dirty- 
 black colour." The lesser lizards give unmistakable 
 proofs of sexual selection in the brilliant pouches which 
 they protrude when sunning themselves, and whose exqui- 
 site colours have struck every observer. Their mechanism 
 for changing the hue of their skin, by compressing or 
 spreading the layers of pigment cells, has already been 
 noticed ; and it seems to betray a considerable sensitive- 
 ness to colour. Dr. Giinther also sees reason to believe 
 that the frugivorous lizards have the tongue as an organ 
 of taste, while in the insectivorous species he considers it 
 merely an organ for the prehension of prey.^ Now, a 
 large number of all lizards are noticeable for their exqui- 
 site hues. Green, as might naturally be supposed, from 
 protective reasons, forms the general groundwork of their 
 colouring; but, as often happens under similar circum- 
 stances, many other shades are intermingled, apparently 
 to perform the attractive function. Especially is this 
 noticeable in the Anolis and other like genera, whose 
 beautiful orange pouches consist of folds of the skin, 
 which are concealed under ordinary circumstances, but 
 protruded for display when the animal feels himself 
 secure, and can sun himself at leisure on a dead branch. 
 The family of Agamidm include many of the most bril- 
 liant species, especially the exquisite Draco, whose beauty 
 Mr. Darwin extols so highly ;2 and these, says Dr. 
 Giinther, are arboreal in their mode of life, while the dull- 
 coloured genera inhabit rocks or plains.^ It is true that 
 Draco feeds on insects; but when we remember the 
 beauty of many among these little tropical creatures, we 
 see fair grounds for believing that its habits may have led 
 it to form a taste for colour. The Geckos also eat moths ; * 
 
 ^ Eeptiles of British India, p. 56. amongst butterflies, birds, these liz- 
 
 - I shiill note hereafter the singular ards, and even the flying squirrels, 
 
 coincidence betM^een the possession of &c. 
 
 a flying apparatus and general bril- ^ Reptiles of British India, p. 120. 
 
 liancy of hue, which seems to obtain ■* Giinther, p. 100.
 
 DIRECT REACTION. 167 
 
 while Mr. Gosse found on dissection many pretty insects 
 in the stomach of the lovely Yenus lizard of the West 
 Indies.^ Here, too, we may even see the indirect effect 
 of flowers and fruits ; for Mr. Wallace, after noticing the 
 " abundance and varied colours of the little jumping spiders 
 w^hich abound on flowers and foliage (in the Aru Islands), 
 and are often perfect gems of beauty," 2 goes on to say 
 about the lizards in the same place, " Every rotten trunk 
 or dead branch served as a station for some of these 
 active little insect-hunters, who, I fear, to satisfy their 
 gross appetites, destroy many gems of the insect world, 
 which would feast the eyes and delight the heart of our 
 more discriminatincj entomoloofists." ^ 
 
 Among snakes we find somewhat similar facts. W^hile 
 the arboreal species, still having green for their ground- 
 work, " are characterised by their vivid colouration," ^ the 
 ground-snakes, burrowing-snakes, and water-snakes are 
 mostly dull and inconspicuous. Of the ground-colubrides, 
 in particular. Dr. Glinther says, " They live on the ground, 
 and are generally of not brilliant colouration ; only a few, 
 which frequent grassy plains, are of a bright green 
 colour."^ The Dendrophidse eat lizards and like prey, 
 and are usually very bright ; their colours sometimes, as 
 in the magnificent Chrysopelea ornata, being decidedly not 
 protective. Of course, almost all arboreal snakes feed 
 upon various foods, such as birds, smaller reptiles, or 
 other brilliant animals, whose colours may have served to 
 give them a taste in that direction. I confess I attach 
 little importance to any of these cases ; still I think it 
 worth while prominently to call attention to the fact that 
 most arboreal creatures are conspicuous for their excep- 
 tional brilliancy. 
 
 Doubtless much of the bridit colouration in all these 
 
 o 
 
 animals is more or less warning or protective. Thus, one 
 
 1 The Naturalist in Jamaica, p, 145. ■* Gimtber, p. 166. 
 - Malay Archipelago, \). 432. 5 ibid., p. 221. 
 
 3 Ibid., p. 433.
 
 i68 THE COLOUR-SENSE. 
 
 may mention Mr. Belt's "little frog that hops about in 
 
 the daytime, dressed in a bright livery of red and blue." ^ 
 
 Mr. Belt suspected this species to be inedible, from the 
 
 staring nature of its hues ; accordingly, he offered one to 
 
 some ducks, but only succeeded in making one young duck 
 
 bite it amongst some meat ; and the bird " instantly threw it 
 
 out of its mouth, and went about jerking its head as if 
 
 trying to throw off some unpleasant taste." Then, again, 
 
 there are the coral-snakes of South America, for which 
 
 Mr. Darwin has fully accounted. Once more Mr. "Wallace, 
 
 in his " Contributions to the Theory of Natural Selection," 
 
 has pointed out that green lizards frequent trees, while 
 
 many Geckos are so marbled as to resemble the bark on 
 
 which they crawl.^ Mr. Belt speaks also of a green 
 
 Mcaraguan species, which looks exactly like- the herbage 
 
 among which it lurks, and has actually acquired leaf-like 
 
 expansions to deceive its prey.^ Mr. Bates, too, notices a 
 
 pale-green snake {Dryopliis fulgida) so perfectly imitating 
 
 the stem of a liana that it deceived even his practised eye 
 
 at first sight ; ^ and we must, doubtless, refer to the same 
 
 cause the verdant colour of the grass-snakes mentioned by 
 
 Dr. Gtinther. But the noticeable point here, as in the case 
 
 of the butterflies, is thi.s, that while we find a prevailing 
 
 imitative greenness, apparently for protective purposes, we 
 
 so often find a mixture of crimson, blue, yellow, orange, or 
 
 metallic iridescence, whose function seems to me purely 
 
 attractive. We shall notice similarly, when we come to 
 
 look at the parrots, that their prevailing ground-tint is 
 
 likewise green, but that they indulge in every variety of 
 
 brighter pigments in a decidedly conspicuous manner. 
 
 My own observation of West Indian lizards would certainly 
 
 lead me to say that their colours were far more likely to 
 
 betray them than to protect them, even in their native 
 
 haunts. 
 
 ^ Naturalist in Nicaragua, p. 321. ^ Naturalist in Nicaragua, p. 12. 
 
 2 See also Tropical Nature, p. iii, ^ Naturalist on the Amazons, p. 
 seq. 99.
 
 DIRECT REACTION. 169 
 
 Birds, however, offer the best evidence of alh It will 
 be desirable to mark briefly the most conspicuous instances, 
 and then to give the minor cases in detail. 
 
 The birds of prey — eagles, hawks, and falcons — and the 
 carrion birds — vultures, condors, and (since we are speak- 
 ing of habits only) ravens or adjutant storks — are all dull 
 greyish or blackish birds,^ and their colouring may be com- 
 pared to that of the flies and crocodiles. Nocturnal birds, 
 again, such as owls and goat-suckers, show considerable 
 analogies to moths and other night-flying insects.^ In 
 fact, aU. the raptores, of whatever habit, and almost all 
 birds of similar habit elsewhere, are nearly or quite desti- 
 tute of decorative colouring. 
 
 On the other hand, among the insessores we find an 
 immense number of the most brilliant of all organic 
 creatures. Especially remarkable are the humming-birds 
 and the sun-birds. Now, Prince Lucien Bonaparte has 
 abundantly shown that the former family are really the 
 allies of our dingy northern swifts, and that the sun-birds 
 are not at all connected with them genetically. But both 
 families feed upon the mixed nectar and insects which 
 they catch in bright-coloured entomophilous flowers, and 
 both are equally noticeable for their exquisite metallic 
 gloss, their varied hues, and the profusion of their decora- 
 tive devices, such as crests, ruffs, feather lappets, and long 
 tail-plumes. Is it not a significant fact that these two 
 families, one in the western hemisphere and the other in 
 the eastern, separately developed from dingy ancestors, 
 should have acquired exactly the same exquisite plumage 
 under exactly like conditions of food ? We can hardly 
 resist the inference that a taste for colour has been aroused 
 
 1 I am aware that all sucli general- its ensemble, and not to look at single 
 
 isatious will be attacked by bringing cases. 
 
 up isolated instances, such as the - While following approximately 
 
 king- vulture, who may lay some claim the real biological order in these cases, 
 
 to be moderately coloured ; but I must I do not scruple to introduce analo- 
 
 beg the reader to take each group in gous instances from any other tribe 
 
 when necessary.
 
 170 THE COLOUR-SENSE, 
 
 in their constant search after flowers, and that this taste 
 has reacted through sexual selection upon their own 
 appearance. 
 
 JSText in importance to these two families come the 
 parrot group. These are either fruit-eaters, or else, as in 
 the case of the lories, they feed upon nectar. And here I 
 venture to borrow Mr. Wallace's words. "No group of 
 birds," says he — "perhaps no other group of animals — 
 exhibits within the same limited number of genera and 
 species so wide a range and such an endless variety of 
 colour. As a rule parrots may be termed green birds, the 
 majority of the species having this colour as the basis of 
 their plumage, relieved by caps, gorgets, bands, and wing- 
 spots of other and brighter hues. Yet this general green 
 tint sometimes changes into light or deep blue, as in some 
 macaws; into pure yellow or rich orange, as in some of 
 the American macaw-parrots (Conurus) ; into purple, grey, 
 or dove-colour, as in some American, African, and Indian 
 species ; into the purest crimson, as in some of the lories ; 
 into rosy-white and pure white, as in the cockatoos ; and 
 into a deep purple, ashy or black, as in several Papuan, 
 Australian, and Mascarene species. There is in fact hardly 
 a single distinct and definable colour that cannot be fairly 
 matched among the 390 species of known parrots. Their 
 habits, too, are such as to bring them prominently before 
 the eye. They usually feed in flocks ; they are noisy, and 
 so attract attention ; they love gardens, orchards, and open 
 sunny places ; they wander about far in search of food, 
 and towards sunset return homewards in noisy flocks, or 
 in constant pairs. Their forms and motions are often 
 beautiful and attractive. The immensely long tails of the 
 macaws, and the more slender tails of the Indian parra- 
 quets ; the fine crest of the cockatoos ; the swift flight of 
 many of the smaller species, and the graceful motions of 
 the little love-birds and allied forms ; together with their 
 affectionate natures, aptitude for domestication, and powers 
 of mimicry — combine to render them at once the most
 
 DIREC T RE A CTION. j 7 1 
 
 conspicuous and the most attractive of all tlie specially 
 tropical forms of bird-life." ^ 
 
 Even the minor variations of these three great groups — 
 the humming-birds, the sun-birds, and the parrots — show 
 us a like result. For there is one sub-family of the former 
 group — the Phaethornidas — which have not taken to flower 
 haunting, but which catch minute insects on exposed 
 situations; and these are described by Mr. Wallace, not 
 in that language of sapphire, ruby, and amethyst which is 
 lavished on their congeners, but simply as " small brown 
 humming-birds." 2 "The members of all these genera," 
 says Mr. Gould in his magnificent work on the Trochilidse, 
 " are remarkable for being destitute of metallic brilliancy, 
 and, as their trivial name of ' hermits ' implies, for affect- 
 ing dark and gloomy situations. They constitute perhaps 
 the only group of the great family of humming-birds which 
 frequent the interior of the forests, and there obtain their 
 insect food — some from the underside of the leaves of the 
 great trees, while others assiduously explore their stems 
 in search of such lurking insects as may be concealed in 
 the crevices of the bark. It has been said that spiders 
 constitute the food of many species of this group." And 
 he adds significantly a few lines further down, " in the 
 colouration of their plumage both sexes are generally 
 alike." ^ Then, again, we learn of the Arachnotherae, or 
 spider-hunters, " which are sun-birds without any metallic 
 or other brilliant colouring," that they hunt for food among 
 the anemophilous and uncoloured blossoms of the palm- 
 trees.* So, too, among the sombre vegetation of New Zea- 
 land an anomalous night-parrot {Strigaps hctbroptilus) is 
 found, which lives in crevices of the ground, or in rocks 
 
 1 Tropical Nature, p. 100. argument here employed, for the 
 - Ibid., p. 136. brilliant mass of colour would natu- 
 
 2 JMonograph. of the Trochilidse, rally he to them the empirical symbol 
 Introduction, p. 36. of food, and they cannot possibly dis- 
 
 ^ Of course the other humming- tinguish between the circumstances 
 
 birds and sun-birds also live mainly which lead to the presence of honey 
 
 upon insects found in flowers, but and of insects in the blossoms they 
 
 this does not militate against the suck.
 
 172 THE COLOUR-SENSE. 
 
 and tree-roots, only coming out after dark, and its colour 
 is spoken of as " dull yellowish green." ^ Bfere one may 
 feel almost certain that the primitive bright hue has be- 
 come faded and dingy owing to the altered habits of the 
 bird, which would effectually prevent the action of sexual 
 selection. 
 
 Scarcely less interesting are the group of pigeons, 
 which fall under two principal heads, so far as our present 
 purpose is concerned, the fruit-pigeons and the ground- 
 pigeons. The former class are extremely brilliant in their 
 colouring, comprising a large number of the most beauti- 
 ful knoAvn birds ; while the latter almost always display 
 sombre dove-colours, slates, and browns.^ ]N"ow, the fruit- 
 pigeons are "especially arboreal in their habits," and 
 " their nourishment consists for the most part of fruits :" 
 while the ground-pigeons feed almost entirely on seeds. 
 
 The toucans form another group in which like adapta- 
 tions occur. They live nearly altogether upon fruits, 
 though they also devour birds' eggs, fish, reptiles, and 
 insects, to a slight extent. The exquisite colours wdiich 
 adorn their large bills, besides the varied black, white, 
 green, red, and yellow of their plumage, are well enough 
 known to call for no further detail.^ 
 
 Several other families, allied to one or other of the 
 preceding groups, are almost equally noticeable for their 
 magnificent colouration. First on the list may come the 
 Australian honey-suckers, and the plantain-eaters of 
 Africa, whose name sufficiently proclaims their habits. 
 I^ext, we may place the allied genus of Touracos, " gene- 
 rally of a green colour, with the quill feathers of the wing 
 and tail violet or red." The birds-of-paradise, too well 
 known to need description, feed on fruits, though some 
 species are flower-suckers. The barbets, known by such 
 
 1 Hochstetter's New Zealand, p. 3 gee on the colours and food of 
 
 167. toucans, Gould, "Monograph of the 
 
 - Jerdon, Bii'ds of India, vol. ii. p. Eamphastid*,"i9<mm. 
 446.
 
 DIRECT REACTION. 173 
 
 expressive names as golclen-throated, blue-tliroated, crim- 
 son-breasted, and so forth, live almost exclusively on 
 fruits and the buds of flowers. The ornithological reader 
 will have no difficulty in filling in other cases for himself. 
 
 Again, many of the tropical birds, less brilliant on the 
 whole than these pure vegetable-feeders, yet still remark- 
 able for beautiful colouration, live upon a mixed diet of 
 fruits, tropical insects, eggs, lizards, and other bright-hued 
 foods. " Owing to the prevalence of forests and the 
 abundance of flowers, fruits, and insects," says Mr. 
 "Wallace, " tropical, and especially equatorial, birds have 
 become largely adapted to these kinds of food ; while the 
 seed-eaters, which abound in temperate lands, where 
 grasses cover much of the surface, are proportionately 
 scarce." To this cause, I believe, we may trace the general 
 brilliancy of tropical as compared with temperate birds, 
 especially among the great groups of passeres and picarise. 
 
 Among other instances, which I can only note briefly, 
 may be mentioned the trogons, w^hich are in all cases 
 conspicuous for their varied beauty ; but those which in- 
 habit America are more gorgeous than the Indian species ; 
 and fruit forms part of the diet among the former, while 
 that of the latter is mainly composed of insects. ^ Mr. 
 Gould mentions that the stomach of T. collaris contained 
 on dissection " fruits and caterpillars." ^ The swallows 
 of temperate climates are plainly coloured, as might be 
 expected from the nature of their food ; but their 
 allies, the rollers, decked in gorgeous violet, blue, and 
 green, live upon "insects and fruits" in sub-tropical 
 countries : and with them may be included the exquisite 
 todies, with their green plumage and gay scarlet breasts.^ 
 The lovely motmots of tropical America and the West 
 Indies feed upon insects, fruits, and lizards.* The diet of 
 
 1 Jerdon, Birds of India, vol. i. p. voc. See also under T. mdanopterus 
 200. and T. pavoninus. 
 
 2 Monograph of the Trogonidse, suh ' Gray, Genera of Bird-', i. 62. 
 
 4 Ibid., i. 77.
 
 174 THE COLOUR-SENSE, 
 
 i\\Q Eiirylcdmus is described as consisting of "insects, at 
 times berries and fruits." ^ The omnivorous crow family 
 are dingy creatures, usually with no colouring save black 
 and white ; but their near relations, the jays, have a much 
 more vegetal diet, and are often decorated with very 
 striking colours. In summer they " visit gardens, tempted 
 by tlie cultivated fruits," and they also feed on eggs and 
 insects. The hornbills live almost entirely on fruit and 
 eggs ; and their large beaks are coloured somewhat after 
 the same fashion as the toucans. But I shall not extend 
 this list, which might be easily enlarged with numberless 
 other instances. I shall ask the reader instead to glance 
 over any ornithological work, and to notice the universal 
 coincidence of coloured food and coloured plumage for 
 himself.^ 
 
 On the other hand, most of the seed -eating and omni- 
 vorous birds are dull brown, black, or otherwise dingy in 
 their plumage. All our own small field-birds may be 
 roughly included under this generalisation. Such are the 
 starlings, finches, sparrows, larks, thrushes, ouzels, wag- 
 tails, titmice, nightingales, swallows, and martins. Many 
 of these live upon seeds and grains; others search for 
 larvae, insects, mollusca, and other small animals, often 
 amid dung or like refuse. Even amongst these, we find 
 instances which bear out our general theory. Thus the 
 thrushes as a rule are very modest in their plumage ; but 
 the fruit-feeding orioles have comparatively bright hues. 
 So, too, while most of the finches are plainly clad, the 
 forestine rose-finches have exquisite tints of pink and 
 crimson. Ac^ain, among: our owm birds, the few briditer- 
 coloured species point somewhat in the same direction : 
 for the bullfinch, the most notable of them, has very 
 arboreal habits, feeds upon various berries, and attacks 
 flower-buds in gardens to such an extent that it has be- 
 
 1 Gray, Genera of Birds, i. 6'S- for inclusion here in full, so I have 
 
 2 I find the number of cases col- only selected hap-hazard a few of the 
 lected in nij notes quite too bulky most striking.
 
 DIRECT RE A CTION. 175 
 
 come a perfect nuisance to gardeners : and I find the food 
 of the Bohemian chatterer specified as consisting of " the 
 berries of the mountain ash, hawthorn, and ivy," toojether 
 with the fruit of the juniper. 
 
 Intermediate between these two classes of brilliant and 
 dingy birds come a number of moderately-beautiful tribes, 
 some of which nearly equal the parrots and humming- 
 birds, while others scarcely rise above the level of 
 European song-birds. The birds of this division are 
 more or less forestine in their habits, live amid a very 
 varied environment, and feed upon insects (often very 
 brilliant) or vegetal matters, including seeds, fruits, bulbs, 
 flower-buds, and leaves. Besides the rollers, todies, and 
 motmots already mentioned, we may class here the 
 cuckoos, wood - peckers, pastors, grossbeaks, manakins, 
 pacJiyccphalincG, flycatchers, hoopoes, bee - eaters, jaca- 
 mars, and kingfishers. It would take up too much space 
 to specify all instances in full ; but I have satisfied my- 
 self that a general connection may be traced amongst 
 them all, on the average, between bright food and pretty 
 colourim:^. 
 
 The cases so far examined belong to the great central 
 group of birds which composes the common orders 
 Columbne, Scansores, and Passeres : we may glance briefly 
 at the more divergent orders, whose habits have produced 
 a very different structure. The swimming birds, with 
 webbed feet, are seldom conspicuous for their colouring. 
 The marine species (as penguins, auks, puffins, grebes, 
 gulls, and albatrosses) are more or less whitish, with 
 a toning-down of black or grey. But the ducks and 
 flamingoes, which live amid a much more varied environ- 
 ment, and feed off more diversified food, are often adorned 
 with conspicuous colours. Tliese, I confess, cannot always 
 be explained by our present principle. 
 
 The wading birds (snipes, storks, cranes, herons) display 
 for the most part only cinereous or other dingy plumage. 
 Psoiohia, however, a brilliant South American crane, is a
 
 176 THE COLOUR-SENSE. 
 
 tropical forestine bird, and feeds on fruits and grains.^ 
 The scarlet ibis of the Amazons has also the common bril- 
 liancy of its country, which may be equally noticed in the 
 roseate spoonbill. Here, as elsewhere, I must ask the 
 reader to take each order or family in the mass, omitting 
 such aberrant cases as do not readily admit of explanation. 
 
 The running birds (ostriches, emus, cassowaries, apteryx) 
 have little beauty of colouring. The most brilliant among 
 them, the cassowary, whose naked head and neck are 
 tinted with red and blue, is also the most frugivorous of 
 its order, feeding upon fruits, herbage, and seeds ; while 
 the dingiest of all, the apteryx, has purely nocturnal 
 habits, and feeds upon insects. 
 
 The only real difficulty is presented by the gallinaceous 
 birds, and these must be allowed at first sight to offer a 
 great obstacle to our theory. But even here a little con- 
 sideration considerably modifies the opinion we form at 
 a cursory glance. To begin with, most species, like the 
 grouse, partridges, quails, and guinea-fowls, are by no 
 means remarkable for the purity or intensity of their hues. 
 There is really only one family, that of the Phasianidae or 
 pheasants, including the turkeys and peacocks, which can 
 lay claim to much beauty on the score of colour. Even 
 among the pheasants themselves many species are far 
 from brilliant ; and when we come to compare the whole 
 family with that of the parrots or the humming-birds, we 
 shall find that the peacock alone can fairly come into com- 
 petition with the typical fruit-eaters and flower-feeders. 
 Moreover, the pheasants as a group are thoroughly fores- 
 tine birds ; they pass their life in the midst of brilliant 
 objects, and many of these serve them as food. Turkeys 
 in the wild state feed on grain, berries, fruits, grass, and 
 insects, being especially fond of locusts and grasshoppers. 
 The diet of the true pheasants comprises the same varied 
 items, and Yarrell mentions blackberries, sloes, haws, and 
 acorns as among their favourite viands in English copses. 
 
 ^ Gray, Genera of Birds, iii. 550.
 
 DIRECT RE A CTION. i / 7 
 
 The forests of the Himalayas and of the Malay Archi- 
 pelago, with their great brilliant fruits and flowers, and 
 their exquisite insects, form the haunts of the most 
 beautiful species of pheasants. The peacock in the wild 
 state is also a jungle-frequenter, and feeds upon grain, 
 fruits, and insects. On the whole, I think it may be 
 fairly said that the gallinaceous birds, though not strong 
 supports for our general theory, may be regarded as 
 friendly neutrals at least. The dingy species are skulkers 
 in underbrush, who feed off small grain, seeds, bulbs, and 
 insects; while the brilliant species are tropical or sub- 
 tropical forestine birds, whose food comprises many bright- 
 coloured objects, both animal and vegetal.^ 
 
 Passing on to the mammalia, we find facts of the same 
 sort presented on every side. The whole lower series, 
 whether among marsupials, pachyderms, cetacea, rumi- 
 nants, carnivora, or insectivora, show us almost uniformly 
 tints of black, brown, grey, or dingy yellov\\ It is true 
 that many animals, like the zebras, tigers, spotted deer, 
 and giraffes, have very noticeable alternations of light and 
 dark shades, but they do not yield us pure spots of green, 
 blue, red, or yellow. When we come to the essentially 
 arboreal mammals, however, the tree rodents and the 
 quadrumana, we get many comparatively brilliant species. 
 The squirrels are often remarkable for their beautiful 
 colours, and the so-called flying- squirrels call for special 
 notice in this respect. The contrast between these pretty 
 little creatures and their allies, the mice, rats, beavers, and 
 water-voles, strongly brings out the peculiarity of their 
 hues. So, too, the purely frugivorous monkeys give us 
 a variety of colour which we find nowhere else among the 
 mammalia : and in the scarlet faces of many among them, 
 or most remarkably of all in the bright red and blue of 
 
 1 It is worthy of note that one other swimmers, while its external 
 Sub-Antarctic species, Chionis alba, configuration long caused it to be 
 living on the sea-shore, has the cha- included among the waders, 
 racteristic colouring of the gulls or 
 
 2kl
 
 178 THE COLOUR-SENSE. 
 
 the mandrill, we have the only 'pure tints which are to be 
 found in the whole class. Compared with the nocturnal 
 bats, we see at once the action of sexual selection. 
 
 Lastly, I should like to add that while I attribute 
 special importance to the nature of the food, I do not 
 deny that the whole environment must have a consider- 
 able modifying influence upon the tastes, and therefore 
 upon the colouration of each species; and accordingly 
 I freely allow the general truth of my friend Mr. Eomanes' 
 theory upon this subject, though I cannot agree with him 
 in settino- down the growth of tastes to mere association. 
 
 I am aware that this long catalogue, by mixing up the 
 more certain with the less certain instances, has presented 
 the evidence in its weakest light. To redress the balance, 
 then, let us recapitulate the main facts from another point 
 of view. 
 
 Mowers are the most brightly-coloured of all vegetal 
 productions. Among the creatures which find their food 
 in flowers may be mentioned butterflies, the most brightly- 
 coloured of all insects, besides humming-birds and sun- 
 birds, the most brightly-coloured of all vertebrates. Other 
 flower-haunting insects are the rose-beetles, loveliest of all 
 the Coleoptera, and many more of the handsomest species. 
 Other flower-haunting birds are the lories, far the most 
 beautiful among the parrot tribe, and some of the birds-of- 
 paradise. The pretty little barbets also feed in part on 
 flowers. The butterflies, rose-beetles, humming-birds, sun- 
 birds, and lories have been highly modified in adaptation 
 to the blossoms in which they find their food. 
 
 Fruits rank second in beauty among vegetal organs. 
 First in the list of creatures which feed upon fruits may 
 be mentioned the whole tribe of parrots, macaws, and 
 cockatoos, the brightest in hue of all birds, except the 
 flower-feeders. Xext we may place the toucans, with 
 their gaudy beaks, and with them the hornbills. Then 
 come the fruit-pigeons, whose gorgeous tints contrast 
 strongly with those of their seed-eating congeners. After
 
 DIRECT REACTION, 197 
 
 these succeeds a whole host of orioles, blue-birds, birds- 
 of-paradise, plantain-eaters, and less conspicuous fruit- 
 feeders, every one of whom has some beauty of colouring 
 which recalls its habitual food. Again, the frugivorous 
 bats, and the fruit-eating quadrumana, including the 
 gorgeous mandrill, are the most highly-coloured of the 
 mammalia. Finally, the frugivorous lizards must not be 
 forgotten among the list. Of these, the parrots, toucans, 
 and fruit-pigeons have been specially modified to suit 
 their peculiar food. 
 
 Third in point of colouring we may place the insects 
 themselves, which have based their own beauty upon that 
 of the flowers. The creatures which prey upon these may 
 be divided into two classes, the partly frugivorous, and the 
 wholly insectivorous. Among the former we may specially 
 note as brilliantly-coloured the rollers, todies, motmots, 
 many trogons, hoopoes, some birds-of-paradise, and jays. 
 Among the latter we may note the dragon-flies and tiger- 
 beetles, in the insect world itself; the jacamars, bee-eaters, 
 fly-catchers, and many other bright small kinds of birds ; 
 and the Draco, with many less brilliant lizards. On the 
 whole, these various animals are inferior in beauty of 
 colour to the flower-feeders or fruit-eaters, but are still 
 very bright in their hues. It should be further noted that 
 most of them are closely allied with frugivorous or flower- 
 haunting species, from which they may in some cases be 
 descended, and that many live habitually in the midst of 
 an environment distinguished for the general brilliancy of 
 its colours. 
 
 Next, we may descend to these same creatures them- 
 selves, looked upon as tertiary causes of colouring in 
 others. Among the bright objects which feed upon these 
 birds or reptiles may be noticed many brilliant snakes and 
 some lizard-eating birds. These, too, live amid an environ- 
 ment of considerable beauty. 
 
 Last on the list we may place the marine creatures, 
 fishes or crustaceans, which pass their time among the
 
 i8o THE COLOUR-SENSE. 
 
 gorgeous productions of tropical seas, and whose own 
 colouring may possibly reflect that of their varied and 
 exquisite surroundings. 
 
 Now let us look at the reverse picture of those classes 
 which are specially deficient in pure and conspicuous 
 colouring. 
 
 First in order of ugliness must be placed the carrion- 
 feeders, who live upon decaying bodies or animal excre- 
 ments. Among insects, we may notice the flies which 
 swarm about carcasses or dung, several dingy beetles, and 
 all the other ugly creatures which we always surprise in 
 such situations. Among birds, the vultures, condors, 
 turkey-buzzards, and other like obscence voluci-es, show cor- 
 respondingly dull colours. Among mammals, the hyenas 
 and jackals may fall nearly under the same category. 
 It is worth notice that all these creatures have for 
 naturally frugivorous man a certain weird and uncanny 
 appearance, which seems not entirely dependent upon as- 
 sociation with their hideous mode of life. It may also be 
 observed that those races of mankind which have most 
 fully adopted the habit of feeding upon carrion or filthy 
 prey, such as worms, insects, &c., are often the blackest, 
 most squalid, and least aesthetic of the whole human 
 species.^ 
 
 Second in dinginess rank the nocturnal animals. Among 
 insects, we have the moths, and many such tribes as ear- 
 wigs and cockroaches. Among birds, we get the owls 
 which exactly reproduce the moths in colour ; besides the 
 goat-suckers, the apteryx, and numerous other aberrant 
 types. Among mammals, we liave the mass of bats, and 
 several quadrumanous animals. All these are remarkable 
 for a certain general murkiness of hue, which cannot 
 otherwise be described, but which can be felt as differing 
 from the hideousness of the carrion-feeders on the one 
 
 1 For the evidences on which this Spencer's "Descriptive Sociology," 
 assertion is based, too numerous for under heading " ^Esthetic Senti- 
 quotation here, see Mr. Herbert ments,"jpassiwi.
 
 DIRECT REACTION. l8i 
 
 hand, and the cinereous tone of the carnivorous birds on 
 the other. It should further be noted that the owls and 
 bats have eyes specially modified for darkness, by the 
 absence of the cones, which we have seen reason to conclude 
 are the special organs of colour-perception ; while I have 
 alreadypointed out a corresponding structural peculiarityin 
 the eyes of nocturnal insects. The subterranean mole may 
 perhaps be grouped in the same class. 
 
 Third in this connection we may place the rapacious 
 animals generally. Fishes supply us with the shark and 
 pike. Eeptiles include the crocodiles and many snakes. 
 Birds yield instances in the raptores as a whole, — eagles, 
 hawks, falcons, — and in isolated cases such as the shrike. 
 Mammals add the wolves, bears, and insectivores. The 
 larger cats, however, together with the green snakes, must 
 be specially excepted, their colouring, as we shall see 
 hereafter, being protective in its arrangement. So, of 
 course, must be the animals already enumerated among 
 the brilliant class, which feed upon unusually bright- 
 coloured prey. 
 
 Other cases must be roughly enumerated in a single 
 paragraph. The larger marine creatures are usually dull : 
 as witness whales, porpoises, walruses, seals, and turtles. 
 Fresh-water animals are less bright than the smaller 
 marine and terrestrial fauna : take for examples river-fish, 
 fresh-water molluscs, water-beetles, otters, voles, coots, 
 and most water-fowl. The mass of herbivores are quiet 
 in colouring, though often pretty according to our deve- 
 loped Aryan taste. Omnivorous animals, like crows, pigs, 
 and men, are not usually bright in their tints. Seed-eat- 
 ing birds have mostly grey or neutral plumage. Marine 
 birds are, as a rule, whitish or grey. In short, the im- 
 mense majority of animals v*^hich do not feed on bright- 
 coloured food are of plain hues, in which black or white 
 predominates, in certain muddy mixtures, with very little 
 tinge of red, yellow, green, or blue, and with no spots, 
 bands, or markings of pure analytic colours.
 
 i82 THE COLOUR-SENSE. 
 
 Lastly, intermediate between the two classes of brilliant 
 and dull-coloured animals, we get what may be called the 
 transitional stage. This stage shows a general tendency 
 to pure colours, more or less subdued by plainer inter- 
 mixtures ; but it does not often exhibit perfectly unmixed 
 shades of crimson or azure. It is represented in many 
 insects, especially among the Lepidoptera and Coleoptera ; 
 in the remaining insessores and gallinaceous birds; in 
 squirrels, monkeys, and many frugivorous mammals ; 
 and in numbers of snakes, lizards, and amphibia. Most 
 of these may be said to hover on the border between 
 bright and dingy foodstuffs, varying from flies, grubs, 
 slugs, brownish seeds, and small grey birds or mammals, 
 to gay fruits, butterflies, birds' eggs, banded snails, bright 
 little reptiles, and birds of handsome plumage. As a 
 whole, an approximate correspondence can be traced be- 
 tween the average brilliancy of their food and the average 
 brilliancy of their own colouring. 
 
 If all these be mere coincidences, they seem to me 
 without exception the most extraordinary coincidences 
 ever observed in nature. But even a list such as this 
 cannot at all adequately represent the real state of the 
 case. I may therefore be pardoned if I mention that the 
 generalisation here so insufficiently enforced has been 
 thrust upon me by three separate sets of observations. 
 First came my own constant observation, that within the 
 sphere of my daily experience, in walks and excursions, 
 in Europe, North America, and the West Indies, I found 
 such a correspondence between bright food and bright 
 colouring, or dull food and dull colouring, to obtain in a 
 vast majority of cases. Secondly, visits paid for the pur- 
 pose to the Zoological Gardens, the British and other 
 Museums, and the various aquariums, in order to satisfy 
 myself as to such correspondence, greatly increased my 
 belief in its truth. After examining the several brilliant 
 species, I made inquiry into trustworthy books as to the 
 nature of their food, and I almost always found that the
 
 DIRECT RE A CTION. 1 83 
 
 rough generalisation I had provisionally framed was thus 
 greatly supported. I may add, too, that the mass of 
 specimens, as seen in a garden or a cabinet, produces a 
 far more vivid impression on the mind than is possible 
 from the mere mention of isolated names. Thus a single 
 instance, like that of the peacock or the flamingo, has great 
 weight under ordinary circumstances, when thought of in 
 isolation ; but when one turns from a case full of the 
 gallinaceous birds or the Avaders, to a case full of flower- 
 haunting humming-birds or fruit-eating parrots, the dif- 
 ference in the whole averasje of instances is seen to be 
 simply infinite. Accordingly, I would strongly urge those 
 who wish to judge of my theory for themselves, to make 
 such careful comparisons in person, at some one of our 
 great zoological collections. Thirdly and lastly, during 
 the whole course of my reading in the works of traveller- 
 naturalists, I have been invariably struck by the same 
 connection of food and hue. Especially has this connec- 
 tion been thrust upon me once more by Mr. Wallace's 
 admirable work on " Tropical Nature," which has ap- 
 peared since the present volume was wholly planned, and 
 in great part written. And since this theory is the part of 
 my work to which I myself attach the greatest import- 
 ance, and for which I expect the greatest amount of hos- 
 tile criticism, I venture to add a few typical passages 
 from my notes, gathered from those works which have so 
 often stood us in good stead already, and jotted down in 
 passing, while the theory was still vaguely evolving itself 
 in my mind. They may help to show the reader the style 
 of suggestion which comes upon one from every side with 
 reference to this subject. 
 
 Of the fruit-pigeons. Dr. Jerdon says, " These pigeons 
 are of very large size, with rich and metallic colours ; " ^ 
 but of the ground pigeons and doves, which "feed chiefly 
 on grains," he observes, " they are of more dull and sombre 
 colours." ^ Mr. Wallace speaks over and over again of 
 
 1 Birds of ludia, vol. ii. p. 455. - Ibid., p. 461.
 
 i84 THE COLOUR-SENSE. 
 
 similar species, such as the lovely little fruit-eating 
 Ftilinopus pulchellus, wliicli " is of a beautiful green 
 colour above, with a forehead of the richest crimson, 
 while beneath it is ashy white and rich yellow, banded 
 with violet red." ^ Then we have the exquisite Nicobar 
 pigeon, which eats "fallen fruits," ^ the "very handsome 
 fruit-pigeon " {Carjpophaga concinna), which lives on nut- 
 megs,^ and the "pretty little flower-pecker" {Prionochilus 
 aureolmibatiis), whose name sufficiently declares its golden 
 markings. Once more, Scissirostrum Pagei belongs to a 
 family generally dull, but has yellow bill and feet, and a 
 tail of " vivid crimson ; " ^ and on inquiry, we see that it 
 feeds upon fruit. Soon after, we read concerning a flock 
 of the " fine crimson lory {Eos rubra), a parroquet of a vivid 
 crimson colour," that " they settled down upon some 
 flowering tree, on the nectar of which lories feed." ^ Then 
 again we have the " large green barbets {Megalcema versi- 
 color^), something like small toucans, . . . whose head and 
 neck are variegated with patches of the most vivid blue 
 and crimson."*^ On another page we meet with a lovely 
 small fruit-pigeon (Ftilinojoiis roseicollis), "whose entire 
 head and neck are of an exquisite rosy pink colour, 
 contrasting finely with its otherwise green plumage."^ So, 
 when we turn to Sir Emerson Tennant, we find the " very 
 beautiful pigeon " Carpophaga Torringtonice;^ the exquisite 
 flowers, haunted by lovely butterflies ; and the magnificent 
 bats and flying squirrels, which feed on fruits. Mr. Bates 
 similarly tells us how along the Amazons the butterflies 
 were found in great brilliancy on the flowery parts,^ while 
 amongst them flitted " fiery red " dragon-flies ; how " from 
 the wild fruit-trees we often heard the shrill yelping of 
 the toucans ; " ^^ how the pretty cigana (Opisthoco77ms 
 cristatics), a gallinaceous bird, eats various wild fruits, and 
 how at one place on the river, where he " was surprised 
 
 1 Malay Archipelago, p. 528, « Ceylon, p. 174. 
 
 - Ibid., p. 345. 2 Ibid., p. 291. ^ Naturalist -on the Amazons, pp. 
 
 ^ Ibid., p. 274. ^ Ibid., p. 297. 20, 274, et ah 
 
 6 Ibid., p. 28. 7 Ibid., p. 123. io Ibid. 5 p. 26.
 
 DIRECT REACTION, 185 
 
 at tlie number and variety of "brilliantly-coloured butter- 
 flies," lie also noticed the " glossy-green beak and rose- 
 coloured breast " of a " beautiful bird " {Trogon melanurus), 
 and the "golden-bronze and steel colours" of a jacamar 
 {Galbula viridis), which fed on these very insects.^ On the 
 other hand, he notes how, near Santarem, " the pastures 
 are destitute of flowers, and also of animal life, with the 
 exception of a few small plain-coloured birds." ^ I could 
 multiply these instances by dozens, but I only select the 
 first which I find on my notes, to show the sort of evi- 
 dence which suggested and supported the theory,^ and by 
 observing which it may be most easily confirmed. Indeed, 
 whenever I find mention of any brilliant creature, be it 
 Indian Goliath-beetle,* South- American longicorn,^ scarlet- 
 faced monkey,^ gay-coloured squirrel,'^ handsome bats,^ or 
 fairy blue-birds,^ I almost always notice, either coupled 
 with the fact, or on further search, that the animal in 
 question feeds upon bright-coloured food. 
 
 It will perhaps seem like pushing the conclusion be- 
 yond reasonable limits if I go on to say, that in some cases 
 one may even possibly detect a correspondence in actual 
 tint between the animal and its food. Yet even this 
 appears not wholly impossible. Of course no stress can 
 be laid on some two dozen or so of such instances, some of 
 which may be really protective; but the hint is worth 
 throwing out, for future verification or disproof, as the 
 case may be.^*^ 
 
 ^ Naturalist on the Amazons, p. 71. •* Hooker's Himalayan Journals, ii. 
 
 2 Ibid., p. 183. 98. 
 
 5 It is worth while, perhaps, to ^ Bates, w6i sttp?*^, p. no. 
 
 add that the original idea of the ^ Ibid., p. 326. 
 
 causal connection between flowers or ^ Wallace, Malay Archipelago, p. 
 
 fruits and a taste for colour, which I 123. 
 
 first worked out in my " Physiological ^ ^iv Emerson Tennant, Ceylon, 
 
 Esthetics," and afterwards in this p. 135. 
 
 volume, was set up in my mind ^ Jerdon, Birds of India, vol. ii. 
 
 while watching the humming-birds, p. 105. 
 
 tropical robins, butterflies, beetles, ^^ I had collected a few cases, but 
 
 and lizards, together with the bios- omit them, as being hitherto in- 
 
 soms, berries, and capsicums, in my suflicient. 
 own garden in Jamaica.
 
 1 86 THE COLOUR-SENSE. 
 
 And now tliat we have completed this part of our 
 inquiry, let us once more return to Mr. Wallace's 
 objection against sexual selection, from the root upward. 
 When we were considering its applicability to insects, I 
 pointed out that the " theory of typical colours " really 
 suffices to cover the whole difficulty ; and the same argu- 
 ment will apply to vertebrates ; for if recognisability is 
 a requisite of the typical colouring, it may well happen 
 that those species which feed on brilliant objects, being 
 always on the look-out for patches of colour, will be 
 mutually attracted to one another ; and the taste thus set 
 up and strengthened from generation to generation may 
 become an additional cause for differentiating the nascent 
 species from others of different habits. As the taste for 
 brilliancy and the frugivorous mode of life will go hand 
 in hand with one another, it will naturally happen that 
 some variety of colour will become the recognised dif- 
 ferentia of the particular species, whereby its members 
 mutually know their own fellows from all other kinds. 
 And at the same time, inasmuch as all species of flower- 
 feeders and fruit-eaters are not coloured alike, and have 
 not the same ornamental adjuncts, I fail to see the force 
 of Mr. Wallace's argument that all individuals seem to 
 pair off in the long run ; for the cesthetically- endowed 
 individuals would pair off with one another, while the 
 sesthetically-deficient would be left for their likes ; and 
 the difference thus initiated, correlated as it must neces- 
 sarily be with other peculiarities of taste and habit, would 
 become in turn the starting-point for a fresh differen- 
 tiation. Indeed, if I may say so without presumption 
 concerning so great a naturalist, Mr. Wallace seems to me 
 here to have fixed his eyes rather upon the loroclud, the 
 made species, than upon the 'process, the species-making.^ 
 
 Moreover, it is noteworthy that among these same 
 brilliant creatures, which owe their colours ultimately to 
 
 ^ See especially "Tropical Nature/' p. 206.
 
 DIRECT RE A CTION. i Sy 
 
 tlieir briglit-hued food, we find the greatest profusion of 
 other apparently esthetic and sexual ornaments. The 
 butterflies, besides their colours, are remarkable for their 
 queer tails and other appendages, as well as for those 
 allurements of scent which F. Mtiller has pointed out. 
 The beautiful fishes are likewise the species in which 
 stranc^e excrescences occur. The lizards have an immense 
 number of ornamental devices, like pouches, knobs, a.nd 
 horns. The humming-birds and sun-birds are distinguished 
 by their ruffs, crests, lappets, and tail-feathers. The 
 parrots and birds - of - paradise affect similar tricks of 
 plumage ; which are also found in the hoopoes and many 
 of the semi-brilliant class. The handsome gallinaceous 
 birds have combs and wattles. And while we find few 
 such ornamental modifications among the lower mammalia, 
 it is a fact pregnant with import that the frugivorous and 
 arboreal rodents or quadrumana repeat the very same 
 peculiarities of crests, tufts, and beards which are so 
 common amongst the similarly-environed forest birds. 
 Any one who w^ill take the trouble to look through the 
 immense collection of instances in Mr. Darwin's "De- 
 scent of Man," will see at a glance that the most brilliant 
 tribes are also, on the whole, the most ornamented. 
 
 On the other hand, one may hazard the rough genera- 
 lisation, that the animals which appeal to their mates by 
 the sense of hearing are not those which appeal by the 
 sense of colour. The stridulating insects and the singing 
 birds are usually plain in their external appearance. It 
 might seem as though the habits of some races had led 
 them to attach more importance to sounds, while the 
 habits of others led them to attach more to colour. In 
 any case, we may be quite certain that no such taste is 
 fortuitous and isolated. It must bear some definite 
 relation to the general mode of life throughout the race. 
 
 One more question remains. Mr. Wallace observes 
 with great truth that colour may be regarded as a normal 
 product of organisation, whose presence in animals does
 
 i88 THE COLOUR-SENSE. 
 
 not need to "be explained so mncli as its absence. But 
 the difficulty at once crops up — what colour ? I have not 
 space fully to follow up this ultimate problem ; but we 
 may find room for a few brief suggestions. 
 
 Almost all the ornamental appendages of animals are 
 modifications of the skin or its equivalent. They are 
 found most frequently and strikingly in the male sex : 
 and they are most conspicuous during the breeding 
 season. Whatever we may think of their functions, we 
 must agree that they are, on the whole, products of high 
 vitality. They represent part of the excess of nutriment 
 over expenditure.^ 
 
 But these dermal adjuncts do not probably take away 
 anything from the effective energies of the organism. As 
 Mr. Lowne well puts it, in his able and suggestive work 
 on " The Philosophy of Evolution," the formation of pig- 
 ments and like matters is apparently due to the waste- 
 products of the other organs. " The dermal appendages 
 of reptiles and the feathers of. birds, rich in pigment and 
 nitrogen, are probably entirely excrementitious to the 
 other tissues, and, without doubt, depend in great part for 
 their origin on the solid nature of the excretion of the 
 kidneys. Birds especially, leading a very active life, 
 excrete material rich in nitrogen ; and the feathers, which 
 are shed periodically, enable them to throw off that ele- 
 ment without overtaxing their renal organs." And again, 
 " A given pabulum being supplied, certain essential struc- 
 tures are nourished, and the residue is economised in the 
 production or modification of other parts, often giving rise 
 to ornamental appendages or bright colours ; whilst the 
 action of the same principle correlates the modifications 
 of different organs or parts with each other." 2 
 
 Hence we can understand why the more active and 
 energetic sex should possess a greater number of highly 
 
 1 Tropical Nature, p. 194. Nutrition, in which these passages 
 
 2 The Philosophy of Evolution, occur, should be consulted with re- 
 p. 75. The whole of the chapter on ference to this interesting question.
 
 DIRECT RE A CTION. 1 89 
 
 developed dermal adjuncts, and should often display much 
 brighter colours than the females. We can also see why 
 these integumentary modifications should be largest and 
 most expanded in the most active races, such as butter- 
 flies, birds, flying-lizards, and arboreal mammals ; while 
 conversely, the possession of these very organs, in the case 
 of flying animals at least, is itself a cause of their in- 
 creased locomotive power. Here we notice a remarkable 
 instance of that close interaction between structure and 
 function which has been pointed out by Mr. Herbert 
 Spencer, — the function first developing the structure, and 
 each increment of structure permitting increased func- 
 tion, which once more becomes in turn the parent of 
 further structural modifications. 
 
 But we do not yet see why the pigments which are 
 deposited in the dead processes of the skin, should possess 
 one colour rather than another. The answer to this ques- 
 tion must ultimately depend upon the habits and needs of 
 each species. Where protective colouring proved most 
 useful to the race, it would be acquired, as Mr. Wallace 
 has well pointed out, among the infinite possible varieties 
 of these very changeful substances ; but where attractive 
 hues were of greater advantage, they would be retained 
 by sexual selection. Mr. Wallace has shown why ^pig- 
 mcnt should be developed in the feathers of birds and the 
 scales of butterflies ; but it does not seem to me that he 
 has sufficiently shown why one pigment rather than an- 
 other should be developed. The black colouring of the 
 crow, and the dusky wings of owls and moths, are just 
 as much products of that integumentary modification on 
 which he lays so mucli stress, as are the bright hues of 
 butterflies or the plumage of parrots. In fact, it seems 
 to me that Mr. AVallace does not sufiiciently distinguish 
 between pigment and bright pigment. 
 
 On the whole, therefore, while fully recognising the 
 value of Mr. Wallace's arguments with regard to the 
 origin of pigments, the relation of ornament to activity.
 
 I90 THE COLOUR-SENSE. 
 
 the protective use of subdued colour in certain cases to 
 one or other sex, and so forth, I am still inclined to think 
 that the general coincidence between bright food and 
 bright colour noticed above, does really warrant a belief 
 in such a simple form of sexual selection as that here 
 advocated. Especially am I inclined to suppose that 
 differences of taste thus originated may themselves be 
 active differentiating agents for the production of new 
 species with correlated habits. 
 
 A few further suc^erestions and observations of a (i^eneral 
 character may here be added, merely as hints for those 
 who wish to pursue the subject independently. 
 
 The brightest colouration and most developed orna- 
 mental adjuncts seem to be confined to very small and 
 active animals, such as butterflies, beetles, humming- 
 birds, siin-birds, and flying-lizards. Those of the some- 
 what larger creatures, parrots, toucans, fishes, snakes, and 
 greater reptiles or amphibia, are, on the whole, not quite 
 so brilliant or so largely developed ; and the activity of 
 these species is less than that of the preceding group. 
 On the other hand, the larojest animals of each sjreat divi- 
 sion, among vertebrates at least, show a decided tendency 
 toward very dull and inconspicuous hues; take as ex- 
 amples the sharks, sturgeons, sun-fish, tunny, and cod; 
 the oriaantic salamander ; the crocodiles, turtles, and cjreat 
 snakes ; the ostriches, emus, eagles, condors, storks, 
 swans, and penguins; the whales, walruses, elephants, 
 hippopotami, rhinoceroses, gorillas, bears, buffaloes, and 
 elks. These are mostly slow and inactive animals, and 
 they are also little distinguished for expanded epidermal 
 modifications. Indeed, it may be said, roughly speaking, 
 that all very large birds or mammals show more or less 
 tendency to lose or minimise their feathers or hair. 
 
 Those larger animals which, like the mandrill, the casso- 
 wary, and the king- vulture, display brilliant colouring, 
 have it disposed in small patches on a particular portion 
 of the body, not over its whole surface.
 
 DIRECT REACTION. 191 
 
 Flying animals seem to show special sestlietic tastes. 
 At least, they are largely provided with apparent sexual 
 allurements. Such are the colours of birds, flying-lizards, 
 and butterflies; the perfumes of some Lepidoptera; the 
 stridulating organs of insects and the song of birds ; and 
 the frills, ruffs, crests, lappets, or tails of birds and butter- 
 flies. Of course, the origin of these may be largely 
 accounted for by the causes which Mr. Wallace assigns ; 
 but their selection and persistence seems to imply an 
 unusual aesthetic sensibility. It is among birds alone, too, 
 that we find clear evidence of sesthetic feelings, as with 
 the magpies and bower birds. Now, is it not possible 
 that the comparative security which each flying race 
 obtained on its first development, permitted the various 
 species to indulge their taste to a greater degree than 
 would have been the case with terrestrial creatures.^ 
 Would not flying creatures be more likely to notice and 
 follow the attraction of such a sense-stimulation than 
 sluggish terrestrial animals ? And might not the intro- 
 duction of predatory species at a later date, capable of 
 preying on these classes, afterwards modify the coloura- 
 tion or other sexual allurement according to varying 
 circumstances ? For example, may not the growth of 
 insect-eating birds have affected butterflies in various 
 ways, so as to preserve those with protective or warning 
 colours, while yet leaving many traces of the primitive 
 sexual colouration ? or may not the presence or absence 
 of hawks and birds of prey have determined the develop- 
 ment of song or colour respectively as an allurement in 
 each species of bird ? Does not the abundance of coloured 
 animals in certain isolated lands, lying close to great con- 
 tinents, point toward the conclusion, that where special 
 immunity from enemies exists, the aesthetic fancy can be 
 more implicitly followed ? And may not Mr. Wallace's 
 
 1 "The most conspicuous pigeons, have the fewest enemies." — Wallace, 
 whether by colour or by their crests, Tropical Nature, p. loj. 
 are all found in countries where they
 
 192 THE COLOUR-SENSE. 
 
 own remarks upon the humming-birds of Juan Fernandez 
 possibly bear the same construction ? 
 
 A similar hint may be thrown out with regard to fish, 
 which bear somewhat the same relation to the other 
 inhabitants of the ocean as flying creatures bear to the 
 terrestrial animals. Indeed, the analogy between the fins 
 of a gurnard and the wings of a butterfly must have been 
 forced upon any one who has seen those exquisite fish in 
 an aquarium. Again, the whole group of higher arboreal 
 mammals have some considerable likeness to birds and 
 the other winged animals in the activity of their move- 
 ments, and the comparative security of their elevated 
 position, while their tendency to produce such forms as 
 the flying squirrels, the anomalurus, the galeopithecus, 
 and the bats, shows how close the functional and adaptive 
 resemblance may sometimes become.^ Now, we have 
 already seen that these arboreal animals are on the whole 
 much more brightly coloured than other mammals, and 
 we have also noted their tendency to develop hairy 
 appendages, such as beards, ruffs, and top-knots. More- 
 over, some of them are also distinguished for their loud 
 and piercing cries (produced in the case of the howlers by 
 a special organ), which may be compared with the song of 
 birds, and the presumably sexual noises given out by some 
 other creatures. 
 
 Here, too, we see a striking analogy between the 
 development of the sense of sight in general and of the 
 colour-sense. For eyes, as we observed in Chapter iii., are 
 most developed in the most locomotive races ; and the 
 colour-sense, the highest mode of sight, seems to be most 
 highly developed only in exceptionally locomotive races. 
 It would appear natural that only very mobile animals 
 could derive any special advantage from the indications 
 afforded by colour, and hence we may account for the 
 
 1 The flying-squirrels are \x\ all other flying mammals are nocturnal 
 cases "remarkable for the vivacity that they may be safely left out of 
 of their colouring." So many of the the account.
 
 DIRECT RE A CTION. 1 93 
 
 special share which flying insects and birds have borne in 
 the production of bright-hued flowers and fruits, as well 
 as for the frequent brilliancy of their own colouration. 
 
 Once more, it is worth noting that the hair of mammals 
 seems very little adapted for the display of brilliant and 
 pure pigments. The best that can be said of the hues 
 produced is that they are bluish, rufous, or white, never 
 that they are scarlet, purple, golden, or bright blue. The 
 only cases in which mammals present really brilliant 
 colouring are those like the mandrill and certain other 
 monkeys, where the pigment is displayed beneath patches 
 of bare skin, not in the hair or other epidermal modifica- 
 tion. 
 
 After these remarks it is hardly necessary for me to add 
 that I attach full weight to Mr. Wallace's general prin- 
 ciples with regard to the importance of activity and of 
 extended tegumentary surfaces as a groundwork for the 
 production of colour or ornamental adjuncts. But I 
 regard sexual selection, in the modified sense already 
 noted, as the agency by which the particular colours and 
 ornaments have been chosen from the whole possible 
 number, and fixed in the typical specific mould. 
 
 Finally, it may be well to point out that a certain 
 analogy seems to exist between the commonest animal 
 pigments, and those of fruits and flowers. Some of the 
 colours of animals fade after death, whence we may con- 
 clude that the substances of which they are composed 
 remain in a state of comparative chemical instability. 
 But most of the colours here treated of remain permanently 
 after death, as maybe seen in the case of stuffed birds and 
 preserved insects. Accordingly, these bodies may be con- 
 sidered with great probability as comparatively stable in 
 chemical composition, and as little affected by the danger 
 of oxidisation. So we may perhaps guess that they are 
 themselves oxidation products whose affinities are nearly 
 saturated. If so, they might fall ultimately under the 
 same category with the colouring matter of flowers, 
 
 N
 
 194 THE COLOUR-SENSE. 
 
 fruits, fading leaves, and other bright-hued vegetal pro- 
 ducts. 
 
 The reader will doubtless object that this chapter is far 
 from being conclusive. I am well aware of its deficiencies 
 in this respect, and shall feel fully satisfied if it only prove 
 suggestive.
 
 ( 195 ) 
 
 CHAPTER X. 
 
 THE INDIRECT REACTION OF THE COLOUR-SENSE 
 UPON THE ANIMAL INTEGUMENTS. 
 
 In the last chapter we dealt with those cases in which 
 the colour-sense of animals directly reacts upon the 
 species themselves which possess it, by causing the more 
 brilliantly-coloured among them to be specially favoured 
 as parents of future generations. In the present chapter 
 we must examine that other class of cases in which the 
 colour-sense of one species indirectly reacts upon the 
 appearance of other species, by causing all those in- 
 dividuals which present certain tints or spots to be 
 destroyed, and only sparing those which present certain 
 other tints or spots. In other words, the last chapter 
 dealt with sexual selection; the present chapter deals 
 with natural selection. In the first case certain special 
 hues are favoured and, therefore, perpetuated; in the 
 second case certain special hues are disadvantageous and, 
 therefore, weeded out. Hence the action of the former 
 cause is direct, the action of the latter indirect. Sexual 
 selection actively chooses the beautiful, natural selection 
 passively permits the fittest to survive. 
 
 Many of the cases which fall under the present head 
 have already been cited elsewhere as proofs of the exist- 
 ence of a colour-sense in insects or vertebrates. Never- 
 theless, we may once more recapitulate them here, partly 
 for the sake of formal completeness, but partly also to 
 exhibit their mutual relations in a new and more syste- 
 matic light. We shall thus be enabled with greater
 
 196 THE COLOUR-SENSE. 
 
 clearness to perceive how strong is the cumulative evi- 
 dence which they afford for the general diffusion of a 
 colour-sense throughout the animal world. At the same 
 time, as this part of the subject has ere now been fully 
 investigated by Mr. Darwin, Mr. Wallace, and numerous 
 other well-known naturalists, I shall only attempt to give 
 a very brief reasoned resume of their labours, without 
 references or details ; referring those readers who wish for 
 fuller information on the point to the original works from 
 which my selection is made. 
 
 The colours produced (or rather spared) by natural 
 selection fall under two groups, the Imitative and the 
 Prohibitive. 
 
 By imitative colours we imply those which resemble 
 the hues of some other body in such a manner as to 
 insure protection or some other benefit for the species 
 which possesses them. They may be useful for either of 
 two purposes, — to escape the notice of enemies, or to 
 deceive prey. In the first case, they enable the animal 
 to avoid being itself devoured ; in the second case, they 
 enable it to devour others more easily, and so to secure 
 a larger amount of food than less deceptively-coloured 
 compeers. In the former instance, we must suppose that 
 the majority of the original species which did not possess 
 the imitative colouring have been discovered and devoured 
 by enemies endowed with a colour-sense, while those 
 w^hich did possess the imitative colouring have continually 
 survived. In the second instance, we must suppose that 
 the individuals which had no imitative colouring have 
 failed to secure sufi6.cient food, through betraying their 
 presence too readily to their prey, while those which had 
 such colouring have successfully deceived their quarry, 
 and so continually survived. We might compare the 
 first case to that of a man who disguises himself in order 
 to escape the observation of his enemies ; and the second 
 case to that of a man who hides himself under boughs 
 and leaves to get a nearer shot at game. Practically,
 
 INDIRECT RE A CTION. 1 97 
 
 however, it is often hard to say for which of these two 
 purposes a particular colour has been developed; and 
 often the same colouring must enable the animal both to 
 deceive its enemies and to escape the observation of its 
 prey. We shall not, therefore, attempt in the sequel to 
 distinguish between them. 
 
 One large class of imitative colours consists of a general 
 resemblance to the whole surrounding environment. Of 
 this we have cases in the soles and other flat-fish which 
 exactly imitate the colour and speckled appearance of the 
 sand on which they lie — so much so that even a careful 
 human observer is often deceived at a distance of a few 
 feet. Other instances are those of the birds, reptiles, and 
 insects of Sahara, all of which, as Canon Tristram observes, 
 copy closely the grey hue of the desert around them. 
 Arctic animals are almost universally white. The fishes 
 and Crustacea which live among the sargasso weed have 
 a general yellow tint which renders them indistinguishable 
 from the surrounding masses of algse. Large marine 
 animals, as Mr. Darwin points out, have their backs dark 
 and their bellies whitish, which exactly corresponds to 
 the general distribution of light and shade, as a spectator 
 looks up or down in the water. Forestine birds and 
 reptiles have ordinarily a ground-tint of green ; and small 
 green snakes and lizards are commonly found among grass 
 or low herbacje. Geckos are marbled like the walls and 
 rocks on which they run. Some sea-side butterflies have 
 sand-coloured wings. Aphides and many leaf-eating cater- 
 pillars are bright green in hue. Other instances are too 
 numerous for insertion here. It is worth notice, however, 
 that we find the general tendency to imitative colouring, 
 in accordance with the whole environment, most strongly 
 displayed where the environment is most uniform in its 
 hues — as in Sahara, the Arctic snows, the sargasso sea, 
 or the sands of the sea-bottom ; because, in such circum- 
 stances, any variation of tint would be especially notice- 
 able. Where the general distribution of colour is most
 
 198 THE COLOUR-SENSE. 
 
 varied, as in tropical forests, we find the greatest variety 
 of animal colours ; while the imitative devices are usually- 
 far more specialised, so as to resemble some particular 
 object in the environment, not the prevailing hue of the 
 environment as a whole. 
 
 In a second class of cases the resemblance, though still 
 general, shows some more specialised features than those 
 noted above. Thus, many caterpillars have spots which 
 mimic the distribution of light and shade among the leaves 
 on which they feed ; and Sir John Lubbock refers to a 
 like cause the colouration of those great cats which, like 
 the leopard and jaguar, live among trees.^ Similarly, the 
 same naturalist points out that the large grass-frequenting 
 caterpillars have longitudinal lines, corresponding with 
 those of the herbage around ; while " those which live on 
 large-veined leaves have oblique lines, like the oblique 
 ribs of the leaves." The jungle cats, too, such as the 
 tiger, have perpendicular stripes, "rendering them very 
 difficult to see among the brown grass which they 
 frequent ; " while " the ground cats, such as the lion and 
 puma," falling, of course, under our previous class, " are 
 brownish or sand-colour, like the open places they in- 
 habit." Here, as before, only a few typical instances can 
 be quoted, out of many hundreds collected by various 
 careful observers. 
 
 A very specialised form of this adaptation to parti- 
 coloured environments is found amongst those animals 
 which, like the chameleon, and the chameleon-shrimp, 
 possess the power of altering their colour, in accordance 
 with the surface upon which they rest. But in this case 
 it is remarkable, as Mr. Wallace observes, that only such 
 colours can be produced as occur normally in the natural 
 environment of the particular species. 
 
 A third class of cases with imitative colouring proceeds 
 
 1 See his interesting Glasgow lecture, " On certain Relations between 
 Plants and Insects."
 
 INDIRECT RE A CTION. 1 99 
 
 from general to special resemblances. Here we may 
 place all the leaf-insects, stick-insects, and other creatures 
 which present close similarities to various surrounding 
 organic bodies. A sufficient number of these have been 
 already mentioned to avoid the necessity for repetition 
 at present. 
 
 A special case of this third class is shown in the well- 
 known phenomena of mimicry, with which ]\Ir. Bates and 
 Mr. Wallace have made us familiar. These, too, have 
 before received ample attention, and need not longer 
 detain us now. With them we may close our first divi- 
 sion of Imitative Colours. 
 
 The second division, that of Prohibitive Colours, em- 
 braces those cases where a colour acts as a warning of some 
 noxious or disagreeable quality in its possessor. These 
 colours are usually very conspicuous, as it must be sup- 
 posed that they court attention, and so prove protective 
 to the species. Among them may be noticed the bright- 
 coloured but nauseous caterpillars and butterflies, numerous 
 inedible reptiles and amphibia (such as Mr. Belt's Nicara- 
 guan frog already quoted), several birds of pugnacious 
 habits, and perhaps some beetles and dragon-flies. Mr. 
 E. N. Moseley believes that the colour of many marine 
 organisms are prohibitive, and act as warnings to hungry 
 passers-by. For my own part, however, I must confess 
 that, when I consider the universality of colour as a means 
 of attraction, I am almost as much inclined to doubt the 
 reality of these explanations as Mr. Wallace is inclined 
 to doubt the reality of sexual selection. 
 
 To sum up, we may conclude that the whole colouration 
 of the organic world is, in the rough, perfectly explicable 
 upon the hypothesis that the higher animals generally 
 possess a colour-sense essentially identical with our own ; 
 while it is absolutely inexplicable if we suppose that they 
 do not possess such a colour-sense. The inference is 
 almost irresistible, that this hypothesis is true. Our 
 cumulative proof has now been completed. We have seen
 
 2CO THE COLOUR-SENSE. 
 
 that flowers, fruits, insects, birds, and mammals, all show 
 lis just the colouration which we should naturally expect 
 if we believed all the more developed animals to see 
 colours as we see them. We have also observed that 
 many of them do undoubtedly possess such powers in a 
 manner essentially similar to ourselves. Our hypothesis 
 is thus a hypothesis w^hich explains all the facts ; the 
 cause which it postulates is a xera causa, a cause other- 
 wise known to be real and sufficient for the production of 
 the facts ; and so far as many of the cases are concerned, 
 it is not a hypothesis at all, but a known and ascertained 
 certainty. The grounds for believing in a common and 
 identical colour-sense amongst all the higher animals are 
 accordingly seen to be practically irresistible. 
 
 Note. — At the conclusion of the present portion of my work which 
 deals with the colour-sense in lower animals, it may be well to p'bint 
 out what are the chief instances of organic colouration which the 
 theories here adopted leave yet unexplained. They may be briefly 
 summed up under three heads. The first includes the radiate 
 animals, and such other marine creatures as the sea-slugs and some 
 of the lower articulates. It is possible that the colours in these 
 cases may be purely adventitious, depending entirely, hke the green 
 of leaves, on the chemical constitution of the pigmentary substance, 
 and subserving no special function as colours. This is particularly 
 likely in the case of deep-sea organisms, living at a depth where 
 little or no light can ever penetrate. (See Sir "Wyville Thomson's 
 ''Depths of the Sea," passim, and especially pp. 465, 466.) Never- 
 theless, animals found under such circumstances occasionally possess 
 very large and striking eyes (see, for examj)le, the figure of Cystosoma 
 JS'epturii in Sir W. Thomson's " Voyage of the Challenffer" p. 130), 
 so that the colours may perhaps be protective. Upon this difficult 
 subject the reader may consult Mr. Moseley's interesting papers, 
 where the colours of deep-sea organisms are explained as survivals 
 of a habit originally acquired for protective purposes in shoal water. 
 The second class includes the shells of mollusca. At present, I see 
 no other explanation of their colours save that they are purely 
 adventitious ; but this last refuge must only be regarded as pro- 
 visional, since fresh facts or suggestions are continually coming to 
 light, which enable us to discover some functional reason for what 
 at first sight appeared purely accidental. The third class includes
 
 INDIRECT RE A CTION. 201 
 
 the eggs of birds. And here I am disposed to allege as a possible 
 explanation that the colouration may act as a supplementary allure- 
 ment to the instinct of incubation, just as sexual colours act as a 
 supplementary allurement to the instinct of reproduction. This 
 theory will seem less far-fetched when we recollect the fact that the 
 eggs of reptiles, usually abandoned by the mother, are generally 
 quite dingy in their coverings, while those of birds, forming objects 
 of such great parental solicitude, are almost always more or less 
 beautiful in their hues. And if we put these indications beside the 
 other marks of eesthetic feeling in birds — their song, colour, dermal 
 adjuncts, ornamental nests, bowers, and occasional habit of abstract- 
 ing brilliant objects — the theory certainly gains in verisimilitude. 
 On the other hand, it must always be remembered that the occur- 
 rence of colour never really demands an explanation in organic 
 bodies, any more than it does in the ruby, the sapphire, or the 
 emerald. 
 
 For further details upon the colouration of animals the reader 
 must be referred to Mr. Wallace's admirable work on "Tropical 
 Nature."
 
 ( 202 ) 
 
 CHAPTER XL 
 
 THE COLOUR-SENSE IN MAN. 
 
 "We have now completed our survey of the colour- sense in 
 animals generally, and we come to consider its manifesta- 
 tion in man. 
 
 If the conclusion to which we have been led in our 
 previous investigation be correct, if all the higher animals, 
 and amongst them the quadrumana, be endowed with a 
 perception of colour substantially the same as our own, 
 then it will naturally follow that man, the descendant of 
 an advanced quadrumanous type, must have possessed the 
 same faculty from the very earliest period of his separate 
 history. The colour-sense must be a common property of 
 all mankind, in every country, and in every age. 
 
 Here, however, we are confronted by the adverse theory 
 of Mr. Gladstone and Dr. Hugo Magnus, who endeavour 
 to convince us, on the contrary, that the sense of colour is 
 quite a late and post-historical acquisition of the human 
 race. From philological evidence in the Yedas, in the 
 Hebrew scriptures, and in the Homeric poems, they con- 
 clude that some three thousand years ago the foremost 
 tribes of the Semitic and Aryan races were incapable of 
 distinguishing between red, blue, green, and yellow. 
 Starting from such an imaginary primitive state, they 
 trace up the developm.ent of the colour-sense through the 
 succeeding ages, marking out four principal stages in the 
 growth of the perception. All this startling theory they 
 set forth on purely philological grounds. I shall briefly
 
 THE COLOUR-SENSE IN MAN, 203 
 
 give the main points of their hypothesis, almost in the 
 very words of Mr. Gladstone.^ 
 
 The starting-point is an absolute blindness to colour in 
 the primitive man. Thence, in the progressive education 
 of the organ, three chief colours have been successively 
 disclosed to it, and have appeared in the order of their 
 greater or less refrangibility — red, green, violet.^ The 
 first stage attained is that at which the eye becomes able 
 to distinguish between red and black. Eed comes first 
 into our perceptions, because it is the most luminous of 
 the colours ; but, says Geiger, in the Rigveda white and 
 red are hardly severed. In the next stage of the develop- 
 ment, the sense of colour becomes completely distinct 
 from the sense of light. Both red and yellow with their 
 shades (including orange) are now clearly discerned. To 
 this stage Magnus refers the Homeric poems, in which red 
 and yellow colours are set forth, while no mention is made 
 (according to these authorities) of green or blue. The 
 characteristic of the third stage is the recognition of 
 colours which in point of luminousness belong to neither 
 extreme, but are in a mean, namely, green with its varieties. 
 Finally, in the fourth stage of the development, we find 
 an acquaintance with blue begins to emerge. This is a 
 stage not even now reached universally ; for example, in 
 Burma (it is alleged by Bastian) a striking confusion 
 between blue and green is a perfectly common phenome- 
 non, and a like confusion is not unusual among ourselves 
 by candle light.^ 
 
 Of course, the first point which strikes an evolutionist 
 on being confronted with this elaborate theory is the 
 
 ^ I have to thank Mr. Gladstone for ^ Extracted almost literally from Mr. 
 
 his courtesy in forwarding me a copy Gladstone's article on "The Colour- 
 
 of his pamphlet, and also for kindly Sense" in the "Nineteenth Cen- 
 
 calling ray attention to some con- tury," for October 1877. References 
 
 troversial articles which appeared on to the works of Geiger and Magnus, 
 
 this subject in Kosmos. as also to the various controversial 
 
 2 1 copy Mr. Gladstone's words, but papers which they have called forth, 
 
 he evidently means in the inverse will be found in full on a previous 
 
 order of their refrangibility. page.
 
 204 THE COLOUR-SENSE. 
 
 utter inadequacy of the time assigned for the origin of 
 such strong and fundamentally differentiated sensations 
 as those of colour. Had Dr. Magnus said three million, 
 or even thirty million years, the evolutionist could have 
 hesitated on the score of insufficient elbow-room; but 
 when our author suggests three thousand years for the 
 growth of a radically separate set of sentient organs, our 
 incredulity becomes absolute and irrevocable. It would 
 be useless, however, to oppose the doctrine on such purely 
 a 'priori grounds, only efficient for those who accept the 
 general hypothesis of evolution: and we must therefore 
 seek to discover w^hat a 'posteriori arguments can be urged 
 on the other side, against the philological evidence of Mr. 
 Gladstone and Dr. Magnus. 
 
 There are two kinds of proof for the universality of the 
 colour-sense in man which we may offer in opposition. 
 The first method consists in showing that all human races 
 at the present day, including the lowest savages, do 
 actually possess just the same sense of colour as our- 
 selves : whence we may argue with considerable proba- 
 bility that they derive that sense from a common ancestor, 
 and that the Homeric Akhaians were not likely to be 
 destitute of perceptions possessed by the Bushmen, the 
 Australians, and the hill-tribes of India. The second 
 method consists in showing that works of art and other 
 remains of the early historical races or of pre-historic 
 man yield evidence that the colour-sense was fully 
 developed long before the epoch of the Iliad or the Book 
 of Genesis. Both these methods of proof we shall employ 
 here. 
 
 In order to discover what was the present state of 
 colour-perception amongst existing savage races, I had 
 recourse to two plans. In the first place, I consulted a 
 large number of works by travellers and others respecting 
 modern savages, and extracted all passages which bore 
 upon the question at issue. And in the second place, I 
 supplemented the information thus obtained by direct
 
 
 THE COLOUR-SENSE IN MAN. 205 
 
 inquiries upon the subject, addressed to missionaries, 
 g-;overnment officials, and other persons working amongst 
 the most uncivilised races. I printed a circular letter, 
 which I forwarded to various parts of the world, requesting 
 iiumbered answers to the following questions : — 
 I" (i.) What is the race to whom your answers refer ? 
 
 (2.) How many colours can they distinguish ? 
 
 (3.) Can they distinguish between blue and green ? 
 
 (4.) Can they distinguish between blue and violet ? 
 
 (5.) Can they distinguish any mixed or intermediate 
 shades, such as mauve, lilac, orange, and purple ? 
 
 (6.) For how many colours have they names in their 
 language ? 
 
 (7.) Have they separate names for green and blue ? 
 
 (8.) Have they separate names for blue and violet ? 
 
 (9.) How many colours do they discriminate in the 
 rainbow ? 
 \ (10.) What pigments do they employ in personal 
 ' decoration or in ornament ? 
 
 (11.) Have they a separate name for each pigment ? 
 
 (12.) Have they separate names for any colour for 
 which they have no pigment ? " 
 
 To these questions I received a large number of 
 courteous answers, from Europe, Asia, Africa, America, 
 and the Pacific Islands ; and I may as well say at once 
 that they bore out in every case the supposition that the 
 colour-sense is, as a whole, absolutely identical through- 
 out all branches of the human race. As it would be 
 tedious, however, to print all the answers in full, as 
 numbered, in a tabular form, I shall give the whole 
 evidence together, remarking in each case whether my 
 information was derived from books or fmrn a corres- 
 pondent. 
 
 I shall also premise that, lest there should be any 
 suspicion that I myself was deficient in colour-perception, 
 I rigorously tested my own powers with all the objective 
 experiments I could hear of or devise, including Dr. Stil-
 
 2o6 THE COLOUR-SENSE. 
 
 ling's Tables for the Examination of the Colour- Sense, 
 and many like careful tests. The result proved beyond^, 
 doubt that my eyes were perfectly normal, and possessed^ 
 at least quite the full average faculties of colour dis- 
 crimination. 
 
 Probably nobody will deny that the ordinary European 
 nations, and the Chinese, Japanese, and Hindus in Asia, 
 have colour-perceptions identical with our own. The 
 mere inspection of their works of art, and especially of 
 their imitative paintings, clearly shows that they perceive 
 and represent external objects of the same hue as our- 
 selves. I shall therefore pass them over without further" 
 proof, and proceed to examine the various lower races, 
 beginning with the most advanced among them, and. 
 ending with the most degraded of all. 
 
 The North American Indians, as I can testify from 
 personal experience, make use of pigments for the" three 
 so-called primary colours, and also for green, orange, and 
 purple. My father, Mr. J. A. Allen of Kingston, Ontario , 
 who kindly undertook to distribute my circulars in 
 America, thus describes some Indian art products of the 
 unsophisticated north-western tribes. ''While I write,) 
 I have before me some leggings and mocassins, made by| 
 Indians of the far west — so far off as to be hardly reached 
 by the last outskirts of our civilisation. In these, the 
 lines of colour are never confused — never fail to corres- 
 pond, or run into one another. The leggings have orna- 
 ments in white, dark blue and pale blue, dark green and 
 pale green, and yellow, on a scarlet ground with a black 
 edge. There are also on the mocassins pale blue, purple, 
 brown, green, pink, and " solf erino, on a buff ground, with 
 a strip of scarlet binding. The pattern is strictly sym- 
 metrical: each colour being introduced at exactly the 
 same angle or portion of the pattern throughout — not 
 a confused mass of colours. They were brought . . . from 
 the Chippewa Indians, 750 miles north-west of Kingston." 
 Mr. P. B. Bell answers my questions with regard to the
 
 THE COLOUR-SENSE IN MAN. 207 
 
 Ojibways in similar language. They can clearly distin- 
 guish between blue and green, and also between blue and 
 violet, though they have no distinctive name for the latter 
 colour. They have, however, no less than seven different 
 colour-names, including separate words for green and 
 blue. Other correspondents mention like facts of other 
 tribes. In all, the power of discrimination seems quite 
 equal to our own, though the nomenclature generally 
 extends only to the four or five most markedly different 
 colours — a point to which we shall return in a later 
 chapter. 
 
 The evidence with regard to the historical races of 
 North and South America is equally strong. The ancient 
 Mexicans were famed for their mosaic of feather work, 
 and their subtle taste in colour is praised by several com- 
 petent Spanish authorities.^ I have satisfied myself, by 
 personal observation of Mexican works of art, that they 
 clearly distinguished all the colours mentioned by Mr. 
 Gladstone. The Yucatanese " painted their bodies red,"^ 
 but the children whom they offered as victims to their 
 gods were anointed blue. Stephens says that their prin- 
 cipal colours were red, green, yellow, and blue;^ while 
 Catherwood praises their harmonious blending of various 
 hues. The Chibchas, we are frequently told, had a special 
 taste for emeralds and other green stones, which is scarcely 
 consistent with the idea that they could not see their 
 colour.* The Peruvians, according to Garcilasso, were 
 "very fond of vermilion red;"^ but they too had a par- 
 ticular fancy for turquoises, emeralds, and crystals.^ It 
 is specially noticed that Atahuallpa wore a collar of large 
 emeralds. Mr. Clements K. Markham informs me that 
 
 ^ Clavigero, vii. 48, 57, et alii alibi, when possible, from other sources, or 
 
 Bee also Helps, iv. 69. In this and from direct inspection of remains, 
 many other cases I have availed my- ^ Landa, Kelacion, § 20. 
 self of the large and careful collection ^ Yucatan, vol. i., p. 205. 
 of instances in Mr. Herbert Spencer's ^ P. Simon, p. 256 ; Uricoechea, p. 
 
 "DescriptiveSociology," which, how- 52 ; Piedrahita, v. 4, &c. 
 ever, I have greatly supplemented, * Garcilasso, viii. 25. 
 
 6 Ibid., viii. 23.
 
 2o8 THE COLOUR-SENSE. 
 
 the Peruvian language had separate words for green and 
 blue ; and in one of his published works he mentions that 
 the people "knew the secret of fixing the dyes of all 
 colours, — flesh-colour, yellow, grey, blue, green, black." ^ 
 Their pottery also receives high commendation as "re- 
 markable for harmony of colour." So that, on the whole, 
 we may credit all the semi-civilised American races, not 
 only with a proper colour-sense, but also with considerable 
 artistic sensibility. 
 
 Even of the wretched Fuegians I find it noticed that 
 red is their favourite colour,^ and that they paint their 
 faces with red, black, or white. 
 
 Passing over to Africa, we meet with evidence of a 
 similar sort. The Eev. A. E. M. Wilshere of Bobbins 
 Island, Cape of Good Hope, obligingly answered my 
 questions with regard to four South African tribes, 
 Korannas, Hottentots, Makatese, and Mozambiques. In 
 every case, he found by personal inquiry that all recog- 
 nised colours were discriminated in just the same manner 
 as by Europeans. Every one of these tribes can dis- 
 tinguish between blue and green, as well as between blue 
 and violet; and they possess names for six separate 
 colours, including green and blue, but not violet ; yet as 
 they can see the latter colour, the deficiency here is simply 
 one of nomenclature. In one case, a Mozambique had no 
 native word for purple, which is wanting in his own 
 language, but had learnt the name in Dutch, and applied 
 it correctly. Mr. Wilshere is of opinion that the Africans 
 he examined could discriminate just as many colours in 
 the rainbow as he could himself. 
 
 A lady, whose name I have no authority to publish, 
 gives me a very clear account of the Bushmen, derived 
 from immediate inquiry, and marked by a careful and 
 conscientious accuracy which could not sufficiently be 
 indicated without transcribing her letter in full. The 
 
 1 Markham's Cieza, p. 405.
 
 THE COLOUR-SENSE IN MAN. 209 
 
 members of tliis race can undoubtedly distinguish red, 
 yellow, green, blue, violet, purple, and orange. Their 
 colour vocabulary is unusually full; for besides names 
 for the common primaries, " there are also various com- 
 pound names, where the names of two colours are used 
 together ; as well as further names for at least five (and 
 probably more) shades of colour; — for instance, for 
 light purple, for lavender and grey, for stone-colour, for 
 brownish green, and for blue green." At a meeting of 
 the Eoyal Society of Edinburgh, in January 1878, Bishop 
 Cotterell, formerly of Grahamstown, gave a similar account 
 of this race, whose colour-perception he believed to be 
 quite as acute as our own. Some of their paintings, 
 which have been exhibited in this country, fully bear out 
 the truth of both statements. 
 
 With regard to the common negro types, my own 
 observations made upon West Coast Africans in Jamaica 
 (not born in the West Indies, but taken from Africa 
 direct), convinced me that they could perfectly discrimi- 
 nate all colours as well as myself. The ordinary negro 
 women possess the same abundant vocabulary, as regards 
 the colours used in dress, which distinguishes their sex in 
 Europe. Nevertheless, to make assurance doubly sure, 
 I append a few references to their pigments and works 
 of art in a native state. The Congo people paint them- 
 selves with red ochre,i and the Mandingoes dye cloth blue 
 with indigo. The huts on the lower Niger are stained 
 blue and white.^ The inland negroes dye their hair 
 bright blue. Indeed, throughout all Central, Western, 
 and Northern Africa, where indigo exists, it appears to 
 form a favourite pigment. The Ashantis use red, blue, 
 yellow, and green.^ The Bushmen paint themselves with 
 red ochre,* while among the favourite beads of the Bechu- 
 
 1 Tuckey, Expedition to the Zaire, ' Beecham, Ashanti and Gold 
 p. 103. Coast, p. 147. 
 
 2 Allen and Thomson, vol. i. 'p. ^ Barrow, i. 288. 
 320.
 
 210 THE COLOUR-SENSE. 
 
 anas, Burchell mentions light blue.^ Other instances 
 might be adduced by the dozen ; but it will be better 
 simply to refer the reader to Mr. Spencer's great collec- 
 tion, or to any manufacturer of trading beads. 
 
 The Eev. F. A. Gregory of Antananarivo informs me 
 that the Malagasy people distinguish accurately between 
 all colours, and have separate names for no less than 
 thirteen hues. 
 
 Among the hill tribes of India, colour-perception seems 
 to exist in exactly similar perfection. Mr. Adarji Jivanji, 
 Deputy-Collector at Maldha, ansv/ers my questions with 
 regard to the Chondras, Gamtas, Dublas, and Bhils. These 
 aborigines can certainly distinguish between blue, green, 
 and violet, though not possessing separate names for each. 
 Other observers return similar answers for the Nagas, 
 Gonds, and like lowest races. In every case, discrimina- 
 tion seems perfect, vocabulary only being at fault. My 
 friend. Dr. W. W. Hunter, Director-General of Statistics 
 for India, in his " Comparative Dictionary of the Lan- 
 guages of India and High Asia," gives the words for 
 green, red, and black in 107 Non-Aryan dialects, includ- 
 ing those of the Todas, Khonds, Uraons, Kols, Gonds, 
 Santals, Nagas, Garos, and other low-type aborigines. '^ 
 There is also abundant practical evidence that these races 
 discriminate blue, which, according to Mr. Gladstone and 
 Dr. Magnus, represents the highest stage of colour-percep- 
 tion. The Kukis dye cloth with indigo.^ The Nagas 
 wear blue kilts,* and cotton dyed w^ith indigo, as well as 
 white cloth, wdth red and blue fringes.^ The Todas 
 embroider their mantles with blue thread.^ The Santals 
 use strips of red, blue, and yellow cloth. The Karen- 
 
 1 Southern Africa, vol. ii. p. 569. ' Stewart, in Journal of the Asia- 
 
 2 My thanks are due to Dr. Hunter tic Society of Bengal, vol. xxiv. p. 
 for kindly forwarding my circular 62,6. 
 
 letters to various Indian civil ser- * Grange, Ibid., viii. p. 469. 
 
 vants, amongst the least civilised 5 ]bid., p. 613. 
 
 tribes, and also for kindly permitting 6 King, Journal of the Anthropo- 
 
 me to use for reference his valuable logical Society, July 1870, p. 23. 
 library of works relating to India.
 
 THE COL UR-SENSE IN MAN. 2 1 1 
 
 nees of Burma wear red and blue clothing.l Here, again, 
 only the necessary limit of space prevents the multiplica- 
 tion of instances, but many hundreds could be given if 
 required, to exactly the same effect. 
 
 With regard to the Pacific Islanders, my fullest in- 
 formation comes from the Eev. S. J. Whitmee, a mis- 
 sionary in Samoa, whose name is already well known to 
 philologists and students of folk-lore, as that of a careful 
 and strictly scientific observer. Mr. "Whitmee considers 
 that the Samoans can " distinguish all the prismatic 
 colours, and many of the mixed shades." They have 
 separate names for blue and green, and others for the 
 minor modifications of these hues. They have also a 
 separate name for violet. They discriminate such inter- 
 mediate or mixed colours as mauve, lilac, orange, and 
 purple ; they use distinct terms for varieties of red (crim- 
 son and brick red) ; and they have a name for chocolate- 
 brown. On the whole, their nomenclature seems some- 
 what awkward and confused, but their perception perfect : 
 and as to taste, " they like bright colours," says Mr. 
 Whitmee, " such as mauve, bright blue, purple, magenta, 
 &c. ; but they do not mix these in a grotesque manner in 
 their dress to any great extent. . . . Large showy patterns 
 in prints, &c., they will not look at. Bright red is not 
 used to any great extent, and yellow is not at all in 
 favour." The Hawaiians are equally discriminative of 
 colour distinctions, and one whom I had the opportunitv 
 of questioning showed quite as acute sensibility as any 
 European. Mrs. Bird mentions dresses of pure white, 
 crimson, yellow, orange, scarlet, blue, or light green as 
 worn by the women ; ^ and throughout her book she bears 
 constant testimony to the universal feeling for colour 
 harmony. I specially note that she mentions the use 
 of green for decorative purposes in embroidery.^ Lord G. 
 Campbell remarks that the Admiralty Islanders who came 
 
 ^ Fytche, Burma Past and Present. ^ Hawaiian Archipelago, p. 21. 
 i. 337« ^ Ibid., p. 160.
 
 212 THE COLOUR-SENSE. 
 
 on board tlie Challenger to be painted were equally 
 pleased with daubs of red or of green pigment.^ In New 
 Guinea, blue lines are employed for tattooing,^ and the 
 natives paint their bodies with red, yellow, and black.^ 
 The petticoats worn by the women on gala days are dyed 
 red and green, with intermediate bands of straw-colour. 
 The New Zealanders stain themselves with red ochre ; but 
 I find ear-drops of green jade mentioned among their 
 favourite ornaments.* Their blue tattoo marks are too 
 well known to require special mention. As regards the 
 Malay Archipelago generally, Mr. Wallace's vocabularies 
 contain words for black, white, red, and blue in thirty- 
 three Malayan languages. Mr. W. Gifibrd Palgrave 
 mentions white, yellow, red, green, and blue among the 
 dyes used by the Philippine Islanders.^ For Australia, I 
 find in a vocabulary of the Wailwun language separate 
 words for black, red, yellow, green, and brown,^ and several 
 accompanying lists of other dialects, collected by different 
 authorities, show similar results. I may add that when- 
 ever I have had the opportunity of consulting intelligent 
 travellers upon this subject, they have always at once 
 given their opinion that the savages with whom they were 
 conversant distinguished all colours perfectly. 
 
 Finally, even the wretched Andaman Islanders, pro- 
 bably the lowest known specimens of the human race, 
 daub their faces with red and white.'^ 
 
 Such are a few selected instances from the mass of 
 evidence which might be adduced in favour of the belief 
 that all existing races possess a fully-developed colour- 
 sense. I think they will probably suffice to show the 
 general truth of our proposition. And if savages so low 
 
 \ Log-Letters from the Challenger, ^ Journal of the Anthroi^ological 
 
 p. 282. Infstitute, vol, vii. No. 3, p. 246. 
 
 2 Voyage of the i^a^i?esJ^a^•e, p. 262. 7 m_ John, "Transactions of the 
 
 3 Earl's Papuans, p. 26. Ethnological Society, New Series, v. 
 
 4 Anga's Australia and New Zea- 45. See also Colebrooke in "Asiatic 
 land, vol. i. p. 327. Researches, " iv. 390. 
 
 ^ ]\Ialay Life in the Philippines, 
 "Cornhill Magazine, "Aug. 1878, p. 157.
 
 THE COLOUR-SENSE IN MAN 213 
 
 as some of tliese actually enjoy sucli high powers of dis- 
 crimination, can we consistently deny the like to the early 
 Hebrews and Akhaians ? I have not so high an opinion 
 as Mr. Gladstone of the rude Homeric warriors or the 
 tierce conquerors of Lower Syria, but at least I cannot 
 believe that they were less advanced in simple sensuous 
 perceptions than the naked Todas or the wild half-human 
 Andamanese. 
 
 And now let us go on to inquire whether we cannot find 
 abundant proofs of a highly evolved colour-sense long 
 before the period to which the criticisms of Geiger and 
 Magnus refer. 
 
 First, in our backward view we will take the case of 
 Nineveh. Of the enamelled bricks dug up in this city 
 Sir A. H. Layard says, " The colors {sic) have faded, but 
 were probably once as bright as the enamels of Khorsabad. 
 The outlines are white, and the ground a pale blue and 
 olive green. The only other color used is a dull 
 yellow."^ In many of these cases blue figures occur on a 
 green ground, w^hich clearly shows that the two colours 
 were accurately discriminated. The pigments consist of 
 an antimoniate of lead for the yellow ; an oxide of tin for 
 the white; a copper for the blue; and a sub-oxide of 
 copper for the red. Of Babylonian bricks the same 
 authority observes, " The principal colours are a brilliant 
 blue, red, a deep yellow, white, and black." ^ The Eev. 
 A. H. Sayce, the distinguished Assyriologist, writes to 
 nie as follows : — " The Assyrian language seems to have 
 had no word for ' green.' Sometimes * green ' is represented 
 by arlvii, ' yellow,' but more commonly by 'saum or 'sihmu 
 ' blue' (like the Welsh glas). But the enamelled bricks 
 show that both the colours blue and green were known 
 and used." An inspection of the existing remains in the 
 
 1 Nineveh and Babylon, p. 166. Monarchies," iii. pp. 406, 407, and 
 
 2 For an account of Babylonian Layard's "Nineveh and Babylon," 
 colours, see Eawlinson's "Ancient pp. 507, 672.
 
 214 THE COLOUR-SENSE. 
 
 Louvre and the Britisli Museum will sufficiently prove to 
 the most sceptical that the colour-sense of the Assyrians 
 was essentially identical with our own. 
 
 As to the Egyptians, proof seems almost unnecessary ; 
 3^et, for the sake of formality, it must be given. " Their 
 colours," says Sir Gardner AVilkinson, "were principally 
 blue, red, green, black, yellow, and white. The red was 
 an earthy bole ; the yellow an iron ochre ; the green was 
 a mixture of a little ochre with a pulverulent glass, made 
 by vitrifying the oxides of copper and iron with sand and 
 soda ; the blue was a glass of like composition vAtlioid the 
 ochreoiLS addition ; the black was a bone or ivory black ; 
 and the white a very pure chalk." ^ Here the words 
 which I have italicised clearly prove that the difference 
 between blue and green was perfectly perceived, and that 
 pigments were specially prepared to show the two colours. 
 Again, Sir Gardner observes, " With the Egyptians the 
 favourite combination of colour was red, blue, and green ; 
 when black was introduced, yellow was added to har- 
 monise with it." Nor is this all ; for though they had 
 few mixed colours, yet " purple, pink, orange, and brown 
 are met with." A modern author, speaking of their 
 ceramic art, uses lan^juac^e of even a more decided kind. 
 
 ' do 
 
 " One finds in the rich series of the Louvre," says Jac- 
 quemart, "pieces with white glaze, heightened wdth 
 patterns incrusted or painted in black, blue, dark violet, 
 green, and even red ; the green and the copper blue blend 
 with cobalt blue, black, brown, violet of manganese, white, 
 and yellow. What proves, beside, with what certainty 
 the potters operated these combinations is, that we meet 
 with Egyptian porcelains where the diverse tints occupy 
 very confined spaces, and contrast strongly the one with 
 the other; a blue statuette has the face coloured with 
 golden yellow ; dark blue bracelets bear upon their sur- 
 face hieroglyphics in sky blue, or vice versa!' ^ ''Here, 
 
 1 Ancient Egyptians, ii. 292, 
 - History of the Keramic Art, English translation, p. 16.
 
 THE COLOUR-SENSE IN MAN. 215 
 
 then, is complete science, consummate experience, and 
 precision of execution." 
 
 But a few hours spent at the British Museum, especially 
 amongst the mummy-cases, will do more to convince the 
 reader of the Egyptian colour-sense than pages of quota- 
 tion. Among the wall-paintings, too, I would call parti- 
 cular attention to those numbered 170, 177, 180, 181, 
 and many neighbouring specimens of the eighteenth and 
 nineteenth dynasties. 
 
 As regards the date of these coloured remains, I made 
 inquiries of Dr. Birch, who kindly informed me that tlie 
 system of colouring culminated under the two dynasties 
 abovementioned, and grew gradually debased thence- 
 forward. Accordingly, the finest specimens of Egyptian 
 colouration are far anterior to the earliest conjectural 
 date ever proposed for the Homeric poems. 
 
 Can w^e go still further back, to the prehistoric age, and 
 show by the evidence of existing remains that even then 
 man possessed a developed colour-perception ? I believe 
 that we can, to some slight extent at least. 
 
 Of course, in dealing with the art-products of the most 
 primitive period, we must not expect to find such un- 
 mistakable proofs as those of pigments and paintings 
 which we meet with in Egypt and Assyria. If the savage 
 races of the present day were to die out and leave no 
 traces but those of their scanty implements, we could 
 hardly hope to discover many marks of their now un- 
 deniable use of colour. The tattooing, the body-paints, 
 the strips of coloured cloth, the flowers and feathers, all 
 would be lost by decay. Even the rude decorations of 
 the pottery would probably fade by long exposure to 
 earth, rain, and air. The only remains which could 
 convey to us some faint idea of that love for colour which 
 distinguishes the real savage w^ould be the few perma- 
 nently-coloured implements of stone or metal. I was 
 standing with a friend one day by the glass cases in the 
 Oxford Museum which contain the modern savage uten-
 
 2i6 THE COLOUR-SEXSE, 
 
 sils, when lie called my attention to a stone hatcliet (I 
 think from the Admii^alty Islands), bound to its wooden 
 handle by a coil of red and yellow cord, arranged so as to 
 form a pretty pattern. We had been talking upon this 
 very subject, and he rightly pointed out at once that if 
 the hatchet were buried in the earth for a very short 
 period, the red and yellow cord would decay, and no 
 mark of the original aesthetic intention would be left. 
 Similarly, if we did not learn from the actual words of 
 Csesar, and the constant allusions of the Eoman poets, 
 that the ancient Welsh stained their bodies blue, we 
 should know almost nothing about their sense of colour. 
 The conditions under which we find prehistoric remains — 
 buried in barrows, covered up in alluvium, sunk in lakes, 
 or hidden in the damp floor of caves — necessarily preclude 
 the possibility of obtaining any very definite information 
 on this head. Still the evidence, such as it is, distinctly 
 favours the belief in a normal colour-sense amongst these 
 most primitive men. 
 
 To begin with the highest stratum of the prehistoric 
 period, we may put in the evidence of Dr. Schliemann, 
 who gives plates of red and yellow Mycenean pottery, 
 with colours distinctly brilliant and fairly well demar- 
 cated.^ It is true, no greens or blues appear upon these 
 vessels, but the reason for this, as we shall hereafter see, 
 was much more probably due to the lack of a proper pig- 
 ment than to a deficiency of the colour-sense. Among 
 the gems of Mycenae, agate, porphyry, and greenstone 
 occur, and we can hardly doubt that their colour was their 
 chief recommendation in the eyes of the early chieftains 
 in whose graves they are discovered. Amber and lapis 
 lazuli are also found, showing a probable knowledge of 
 yellow and blu.e. Indeed, the mere fact that gold and 
 silver vessels are used, proves a certain amount of colour 
 perception, for gold only differs from silver in its colour, 
 
 1 Mycense and Tiryn?.- plates A, B, C, and D. See also "Troy and 
 its Kemains," p. 49.
 
 THE COL UR- SENSE IN MAN. 2 1 7 
 
 and could not be discriminated in any other way, except 
 by chemical tests. 
 
 But that some at least of the Bronze Acre savajres 
 possessed a taste for blue, and employed it in their arts, 
 is conclusively shown by a bracelet from the Swiss lake 
 dwellings, which has a red ground, distinctly and prettily 
 enamelled with yellow and blue bands in a regular 
 pattern.i Blue and white glass beads also form part of 
 the treasure recovered from the d6lris of these primeval 
 villages.^ 
 
 Going back to the Stone Age, we find similar evidence, 
 though of a scanty sort. " Stones remarkable either for 
 their colour or shape," says Dr. Evans, "appear at all 
 times to have attracted the attention of mankind, and 
 frequently to have served as personal ornaments."^ Among 
 the ordinary materials of stone weapons Damour mentions, 
 " quartz, agate, Hint, jasper, obsidian, fibrolite, jade, chloro- 
 melanite, amphibolite, aphanite, diorite, saussurite, and 
 staurotide ; " and we can hardly fail to notice that many 
 of these minerals are remarkable for their beauty of 
 colour. " In the Christy collection," says Dr. Evans else- 
 where, " is a hola formed of a polished spherical red stone, 
 mounted in such a manner as to show a considerable 
 portion of its surface, which has evidently been regarded 
 as too handsome to be entirely concealed by the leather."^ 
 Canon Greenwell found beads of bluish-green glass in 
 barrows in Yv^iltshire.^ Amber was also found in similar 
 situations; and beads of rose-quartz, belonging to the 
 Stone Age, are recorded at Argenteuil.*^ Pebbles, selected 
 apparently for their beauty, are constant accompaniments 
 of the dead, some of them being described as "sea- 
 green," "pink," and "red."'' How far back in time these 
 
 1 Desor and Favre, Le Bel Age du ^ Ibid., p. 378. 
 Brouze Lacustre en Suisse, p. 23, ^ British Barrows, p. 55. 
 luid plate iii. fig. 15. 6 Evans, uhi supra, p. 413. 
 
 2 Ibid., p. 15, and plate iii. fig. i. 7 ibid., p. 419. 
 ^ Ancient Stone Implements of 
 
 Great Britain, p. 422.
 
 2i8 THE COLOUR-SENSE. 
 
 deposits may reach I cannot say ; but in one case at least, 
 that of the Dardanelles remains, I find it distinctly stated 
 that they are of palaeolithic age, " and the most common 
 material is red or other coloured jasper."^ The Christy 
 collection also includes axes from Barbadoes of "green- 
 stone, mottled jade, green jasper, and a hard light green 
 slate."^ I may add that the stone implements in Dr. 
 Schliemann's Trojan collection at South Kensington from 
 all depths, though much begrimed by age, show traces of 
 deep colour in many different shades. The most conclu- 
 sive of all proofs, however, is the occurrence of ochre in 
 barrows.^ And Dr. Eollestoue informs me that he has 
 constantly found lumps of ruddle, doubtless for personal 
 ornamentation, laid by the side of the dead. He thinks 
 the general character of prehistoric remains can leave no 
 doubt on the mind of an expert that primitive man 
 possessed a considerable perception of colour. 
 
 Few and inconclusive as these facts undoubtedly are, 
 they yet afford a reasonable presumption in favour of a 
 colour-sense in the earliest members of the human race. 
 However, it w411 not be necessary to base any part of our 
 argument, as against Mr. Gladstone and Dr. Magnus, upon 
 so insecure a foundation. We may rest content with the 
 cases of the Egyptians and the modern savages, having 
 the post-historic theory here on the horns of a dilemma 
 which it cannot easily escape. If, on the one hand, we 
 put forward only the case of Egypt, it might be answered 
 tliat the development of a colour-sense is a question of 
 relative culture, not of mere chronological order ; and if, 
 on the other hand, we put forward only the case of modern 
 savages, it might be answered that the development of a 
 colour-sense is a question of chronological order, not of 
 relative culture ; but if we put forward the two cases 
 together, it will hardly be possible for any one to shirk 
 
 ^ "Wilson, Prehistoric Man, vol. i. ^ Greenwell, Eritish Barrows, p. 
 p. III. ii8. 
 
 - Ibid., vol. i. p. 123.
 
 THE COLOUR-SENSE IN MAN. 219 
 
 the first difficulty by answering ns in one way, and then 
 to shirk the second difficulty by answering us in the other. 
 When we examine the extraneous arguments by which 
 the theory is supported, we find they have very little real 
 weight. Thus it has been suggested that colour-blindness 
 may be a survival from this earliest type of vision ; but 
 when we look a little deeper into the question we recollect 
 that the commonest form of colour-blindness is that which 
 cannot discriminate red from green — whereas red ought, 
 according to the theory, to be the most universally dis- 
 criminable of all — while it is yet quite able to discriminate 
 green from blue. Furthermore, there is good reason for 
 believing that colour-blindness is far commoner in civilised 
 communities than amongst savage tribes. According to 
 M. Favre, no less than 3,000,000 persons in France are 
 afflicted with this defect, while Stilling places the propor- 
 tion in Western Europe generally at 5 per cent.^ On the 
 other hand, the abnormality appears to be infrequent or 
 unknown amongst the lower races ; so that it must be 
 regarded rather as a disease of civilisation than as a sur- 
 vival from the primitive state. Again, Dr. Magnus^ quotes 
 Geiger's remarks about the dog and the flower to prove 
 that quantitative consciousness of intensity has nothing 
 to do with qualitative consciousness of kind; or, as Mr. 
 Gladstone puts it,^ " that the dog, with his wonderful 
 faculty of scent, has no power of distinction between 
 smells which are agreeable and smells which are offensive." 
 Eeally, as we have already seen, there is no reason under 
 the sun why a dog should find the smell of flowers affect 
 him distinctively in any way ; while if we set him to track 
 a scent, crossed and recrossed from step to step by a 
 hundred varying trails, we shall see that he does possess 
 a qualitative sensibility of the very highest order. Ac- 
 cordingly the supposed analogy breaks down immediately. 
 
 1 stilling, Priifung des Farbensin- - Geschiclitliche Entwickelung des 
 nes, p. 5. Farbensinnes, p. 3. 
 
 2 The Colour-Sense, p. 3.
 
 220 THE COLOUR-SENSE. 
 
 Or, once more, to take a third instance, Mr. Gladstone 
 speaks of the difficulty experienced in distinguishing blue 
 from green by candle-light as a trace of the undifferenti- 
 ated stage ; but really violet is quite easily discriminated 
 under such circumstances, while it ought, if the theory be 
 true, to be the least discriminable of all colours ; and as to 
 the confusion itself, it is in fact objective, not subjective, 
 depending upon the peculiar constitution of certain lights 
 which do not contain all the prismatic colours in the 
 normal proportions of sunlight. One miglit almost as 
 well argue that as blue Bengal fires make everything look 
 blue, therefore blue is probably the original colour dis- 
 criminated by the eye. 
 
 Indeed, the whole hypothesis has only one weak set of 
 facts to support it, namely, the supposed testimony of 
 language. Setting aside for the present the possibility 
 that this testimony has been misinterpreted (which I hope 
 to show in the sequel), it must at least be granted that the 
 negative evidence of language by itself forms the most 
 untrustworthy ground for such a superstructure, especially 
 if contradicted by other positive proofs. I look in vain 
 through the pages of Geiger, of Magnus, and of Mr. Glad- 
 stone, for any indication that pictures, sculpture, pottery, 
 or other art products have been taken into consideration 
 at all. Every one of these students seems to have sat 
 down in his library, consulting the frail linguistic authority 
 of the Yedas, the Homeric poems, and the Hebrew pro- 
 phets ; but never to have tested the truth of the philolo- 
 gical conclusion by reference to museums and art collec- 
 tions, or even to the works of antiquaries and explorers. 
 Dr. Magnus argues a priori as to what the sensations of 
 the savage must he like ; but he has taken no pains to 
 inform himself, either by observation, inquiry, or reading, 
 what they actually are like. I cannot help believing that 
 a little more care and a little more extended search would 
 have led him to abandon his theory, based as it is upon 
 the shifting sands of half-forgotten languages. It may
 
 THE COLOUR-SENSE IN MAN. 221 
 
 seem hardly worth while to combat an opinion apparently 
 so harmless ; but every error is necessarily productive of 
 evil, because it retards the progress of discovery; and so 
 I shall not apologise for the time which I have taken in 
 endeavouring to overthrow this misleading doctrine. 
 
 Leaving aside, then, for the present the doubtful evidence 
 of language, what is the general conclusion to which we 
 are forced ? Man is the descendant of an arboreal quad- 
 rumanous animal, of frugivorous habits, who shared the 
 common vertebrate faculty of colour-perception, and the 
 common fruo-ivorous taste for brifrht hues. From the 
 earliest period of his separate development he exhibited 
 the ancestral liking by his fondness for red, green, and 
 yellow pebbles ; for ochreous earths and other pigments ; 
 and probably for flowers, feathers, and like natural objects. 
 Long before the dawn of history we find him surrounding 
 himself with these aesthetic adjuncts ; and wherever we 
 see him still in the same early stage of development, wc 
 meet with the self-same coloured ornaments. The earliest 
 historical nations discriminated and employed in decora- 
 tion every chief prismatic hue, at an age long anterior to 
 that in which we are asked to believe that the colour- 
 sense was unknown. Throughout all historical time, in 
 Egypt, Assyria, China, India, Peru, Mexico, and Western 
 Europe, colour has been distinguished and used just as it 
 is at the present day. And over the whole known world, 
 among the most civilised and the most savage races alike, 
 the perception of colour now appears to all competent 
 observers exactly identical. 
 
 Before we go on to examine the philological question, 
 we shall find it convenient to trace the aesthetic purposes 
 to which colour has been applied ; and we shall then be in 
 a position to judge why and how far the vocabulary of the 
 early Akhaians and Hebrews was deficient in terms ex- 
 pressive of distinctive hues.
 
 ( 22: 
 
 CHAPTER XII. 
 
 THE ESTHETIC VALUE OF COLOUR. 
 
 We have seen already that pleasure results from the un- 
 impeded activity of a fully-nurtured structure, in imme- 
 diate connection with a sentient centre, when not exces- 
 sive in amount, nor surpassing the limits of easy repair.^ 
 /Esthetic pleasure results from such activity when directed 
 upon objects remote from actual life-preserving function.^ 
 Accordingly, t he sesthe tjc^pleasure of cglonr i.s Xhe 
 pl easure felt in its immediate appre heusiuu by the mind, 
 apart from any idea of advantage to be gained, as, for 
 instance, from the acquisition of food. Even the lower 
 animals show some signs of a love of colour for its own 
 sake, as in the oft-quoted cases of the bower-birds and 
 many monkeys. More often, however, their appreciation 
 of colour is bound up with the essential acts of feeding 
 and reproduction, exhibiting itself only in its secondary 
 effects by the genesis of flowers, fruits, and bright-hued 
 mates. But in man the aesthetic pleasure in colour be- 
 comes strongly marked, being found amongst the very 
 lowest savages, and entering into every department of 
 industry amongst the civilised races. From the red ochre 
 and brilliant feathers of the naked Andamanese, up to the 
 paintings and decorations of European palaces, we can 
 trace its gradual development from stage to stage, becom- 
 ing more and more divorced from life-serving function 
 with every onward step, until at last the a3sthetic senti- 
 
 1 See chap, viii., ante. 
 2 See my "Physiological -iEsthetics," chap. iii. and passim.
 
 THE ESTHETIC VA ^^JE OF COLOUR. 223 
 
 menfc claims to rank with th* .oral feelings among the 
 most disinterested elements of our nature. 
 
 The simplest aesthetic feelings precede the more com- 
 plex, and the vivider precede the fainter. Hence progress 
 in aesthetics consists largely in the constantly increasing 
 appreciation of more and more delicate forms of pleasure, 
 coupled M'ith the constantly increasing sensitiveness to 
 more and more delicate shades of discord or unpleasantness. 
 The earliest aesthetic objects to obtain notice will be those 
 which most strongly excite the whole nervous organisation; 
 the more delicate and special stimulants will not be prized 
 until a later stage of evolution. Thus children and savages 
 are pleased with the mere coarse excitement of a drum or 
 a tom-tom : only after careful training can they rise to 
 comprehend the more dainty distinctions of melody and 
 harmony.. The overpowering perfumes of musk and 
 ambergris are appreciated long before the delicate sweet- 
 ness of the violet and the primrose. And in like manner, 
 the powerful stimulation of brilliancy is sooner understood 
 than the milder stimulation of the analytic colours. 
 
 Bright light affects all the nervous elements of the eye 
 at once ; the various colours only affect one set of elements 
 at a time. Whatever view we may adopt with regard to 
 the mechanism of colour-perception, whether that of Young 
 and Helmholtz, or those of their late critics, it is at least 
 certain that the direct total beam rouses a greater sum of 
 sensation in the optic nerve and its connected centres than 
 is aroused by any one of the separate components, say for 
 example the green or the blue rays. Hence we find that 
 brilliancy seems to be more prized by savages, and perhaps 
 by the lower animals, than pure colour. A few examples 
 will serve to show the truth of this generalisation. 
 
 Amongst animals, passing over the doubtful cases of the 
 glow-worm, the fire-flies, and the phosphorescent species 
 generally, we have in the attraction of most flying insects 
 towards the flame a distinct proof of the effects produced 
 by brilliancy. So, too, we know that many of the higher
 
 224 THE r LOUR-SENSE. 
 
 animals seem instinctivi drawn by tlie glow of fire ; and 
 though they will not approach it too closely, tliey show 
 decided signs of interest in its bright glare. This same 
 feeling reappears in the savage love for torchlight dances, 
 for bonfires, and for like rude pyrotechnic displays ; while 
 it reaches its culminating point in fire- works, in illumina- 
 tions, in Guy Fawkes celebrations, and in similar civilised 
 exhibitions of coarse visual stimulation. In every case we 
 feel at once that the aesthetic pleasure involved belongs to 
 the very lowest stratum of its class, the stratum which we 
 Europeans share in the greatest degree with the savage 
 members of our race. Children and uncultured adults_ 
 delight in the rude shocks of a fire-work exhibition, but_ 
 sensitive eyes and minds shrink from the excessive demand, 
 upon optic nerve and brain. 
 
 Keflected glitter or lustre ranks next in aesthetic order 
 among the visual stimulants. It still exercises the whole 
 sentient organ, but not with such violence as the pre- 
 ceding class.i Amongst animals, the taste for glitter 
 is shown by the attraction of fish towards a spoon or 
 other bright substance, by the magpie love for secreting 
 diamonds and jewellery generally, and by the common 
 practice of drawing down larks to the reflected light of 
 a mirror. The objects collected by the bower-birds are 
 often lustrous, such as shells and smooth pebbles. The 
 more beautiful animals also show a great tendency towards 
 iridescence or metallic tints, which, though they contain 
 a large element of pure colours, include likewise a great 
 deal of mere direct reflexion. Cases in point are found 
 among beetles, butterflies, humming-birds, sun-birds, and 
 lizards. Glossiness frequently occurs, apparently as a 
 sexual device, in the fur of mammals. Amongst mankind, 
 
 1 It may be noticed in passing that our admiration of the milder brilli- 
 
 our enjoyment of fire-works, bonfires, ancy of gems and crystals belongs to 
 
 glow-worms, and fire-flies, is mainly the day-time, and th'5 recuperative 
 
 confined to the night, when we can interval is gained by gjanciug rapidly 
 
 recuperate our powers of vision dur- at other objects, 
 ing the intervals of darkness ; while
 
 THE ESTHETIC V^^iVff. OF COLOUR. 225 
 
 the love for glittering ornamtg .-. certainly appears to be 
 very deep-seated, and perhaps preceded that for colour as 
 an sesthetic adjunct. At any rate, teeth, shells (especially 
 cowries, which are naturalhj polished by the overlapping 
 of the animals' bodies), bones, flints, metals, and like 
 lustrous materials, form very common adornments of 
 savage or prehistoric races. And with ourselves, the love 
 for gilding, for excessive polish, for shiny and glaring 
 materials, is a well-known symptom of had taste — that 
 is to say, it is recognised as belonging to the common and 
 universal coarse class of pleasures, not to the more delicate 
 kind which offers greater attractions to the sesthetically 
 refined. 
 
 A few more examples of the taste for lustre may here 
 be fittingly introduced, as leading up to the more restricted 
 esthetic pleasure of colour. Shells and bones form the 
 chief natural decorations of savages, especially when 
 polished by use. Fossils of shiny texture, drilled to serve 
 as beads, occur in palaeolithic deposits. Mother-of-pearl 
 and real pearls are always prized for personal adornment. 
 Among stones, carnelian, jade, jet, and crystals are in high 
 request. Long before the historic period, a regular trade 
 brought amber from the Baltic, or lapis lazuli from Persia, 
 to Mycense and Troy. Professor Eollestone informs me 
 that stone implements are found in Western Europe of a 
 material which could not be obtained nearer than the 
 mountains of Central Asia. Similarly, the common 
 hatchets of the West Indies were imported from the 
 mainland, the bright green stone of which they are made 
 not being found anywhere in the Archipelago. Our own 
 modern taste for rubies, diamonds, sapphires, and topazes 
 is directly derived from the usage of savages. Ivory, 
 tortoise-shell, Job's-tears, gru-gru nuts, and other organic 
 products capable of receiving a high polish, have always 
 been greatly prized by unsophisticated aborigines. Marble, 
 alabaster, satinstone, and granite .deserve mention in the 
 same connection. Cocoa-nut cups, clubs, war-canoes,
 
 226 THE Cny.OUR-SENSE. 
 
 skulls for drinking gobi - 'and like artistic utensils, in- 
 variably receive a glossy surface. Glass and the art of 
 glazing pottery yield proofs of the same universal taste. 
 Lastly, the inventions of lacquer, varnish, boot-blacking, 
 and other artificial means for imparting lustre to naturally 
 dull surfj^ces, derive their origin from a similar source. 
 
 But among all the lustrous objects which attract the 
 nascent aesthetic faculty of primitive man, none are more 
 important in their final effects than metals. Leaving out 
 of consideration as too remote from our present subject 
 the numberless uses of copper, bronze, tin, iron, and steel, 
 it will be enough if we glance briefly at the employment 
 of silver and gold. These had at lirst no other recom- 
 meudation than their immediate beauty, and they were 
 collected for the manufacture of goblets, masks, torques, 
 beads, earrings, and articles of personal adornment. But 
 in the course of time they became utilised as a medium 
 of exchange, owing both to the general request in which 
 they were held, and to the ease with which they could be 
 divided and reunited. Hence at the present day mankind 
 still carries on its commerce by bartering goods against 
 the very self-same bits of shiny white or yellow metal 
 which once hung round the naked necks of African, 
 American, and prehistoric chieftains. 
 
 Passing on from the general stimulation of the total 
 light-beam, direct or reflected, to the partial stimulation 
 of its various components — the analytic colours — we have 
 V next to inquire, Has any one colour a decided aesthetic 
 superiority over any other ? The answer must distinctly^ 
 be. Yes. The red and orange end of the spectrum js 
 decidedly the most pleasurable : while the central colours, 
 green and blue, are decidedly the least so.i 
 
 Many separate reasons conduce to this effect. In the 
 first place, we have already seen that greens and blues are_ 
 
 1 I have discovered experimentally that of colour ; and that amongst 
 that infants respond to the stimula- colours, red is the first to attract 
 tion of light before they respond to their attention.
 
 THE ESTHETIC VALUE OF COLOUR. 227 
 
 by far the commonest colours in nature, being those of 
 the whole grass-clad fields, forest stretches, and wide 
 ocean below, and also of the great open sky overhead. 
 On the other hand, red and orange are by far the most 
 unusual hues, being, practically speaking, unknown in the 
 ordinary inorganic environment, and only found in a few 
 minor parts of animal or vegetal organisms. Hence the 
 structures in our eyes which are percipient of red, are far 
 less frequently exercised than those which are percipient 
 of green and bhie.i So it will follow that they are gene- 
 rally in that highly unstable and fully-nurtured state in 
 which they are capable of pleasurable stimulation. The 
 structures for the perception of green and blue, on the 
 contrary, being habitually stimulated to the proper extent, 
 do not yield any specially agreeable feelings under ordi- 
 nary circumstances. 
 
 Again, the luminous intensity of red, orange, and 
 yellow is considerably greater than that of green, blue, 
 and violet. Hence their stimulating powers may be 
 plausibly considered as greater than those of the less 
 luminous colours. I am glad to be able to state that I 
 owe this suCTo-estion to Dr. Mamus and Mr. Gladstone. 
 It is, doubtless, to their higher luminous qualities that 
 the red and orange rays owe that pungency and strength 
 which is one of their distinguishing characteristics. They 
 may be considered to approach nearest in this respect to 
 the brilliancy of direct total light. 
 
 1 Some of the critics wlio kindly Sciences," vol. xiii. p. 402, of wliich 
 
 noticed my work on "Physiological I have given an abstract in "Mind," 
 
 Esthetics," seem to have supposed for January 1879), it must at least be 
 
 that the truth of this result would allowed that the centres percipient 
 
 depend upon our acceptance of of red cannot be the same as the 
 
 Young's theory of colour-perception, centres percipient of green and blue, 
 
 with which it was there affiliated. Accordingly, they must be usually in 
 
 Such, however, is not necessarily the a comparatively high state of nutri- 
 
 case. Whatever may be the ultimate tion, fitted for the production of 
 
 mechanism of the nerve terminals pleasurable sensations. In fact, the 
 
 for the receijtion of colour-stimula- conclusion rests upon the general 
 
 tion (see an able paper by Mr. G. conditions of sensibility, and is quite 
 
 Stanley Hall, in the " Proceedings of independent of any particular theory 
 
 the American Academy of Arts and of vision.
 
 N^ 
 
 228 THE COLOUR-SENSE. 
 
 But above either of these causes we may place, I think, 
 the hereditary tendency of the human eye, derived from 
 our early frugivorous ancestors. Eed, orange, and yellow 
 arc the common hues by which fruits may be distin- 
 guished from the surrounding masses of green foliage. 
 Accordingly, the eyes of frugivorous animals must be con- 
 tinually on the alert for such colours ; and the organs for 
 their perception, besides being immediately strengthened, 
 must also gain numerous connections with other nervous 
 centres, which will permit the escape of comparatively 
 voluminous emotional waves. I do not mean that these 
 colours will come to be intellectually associated with the 
 pursuit of food, for although such is doubtless the case, 
 that fact would not in itself suffice to account for the 
 pleasure aroused ; but I mean that the increased calibre 
 of the nervous organs thus exercised, and the number of 
 additional channels thus provided for the overflowing 
 nervous energy, would conspire to produce a direct and 
 immediate sensuous pleasure. This pleasure would result 
 from the mere act of perceiving red, not from the mediate 
 recognition of red as a symbol of food. 
 
 From the combination of these three causes, it happens 
 that the sensation of red or orange is the most agreeable 
 of all the pure colour-perceptions. And as the earliest 
 and least cesthetically developed races pay attention only 
 to the strongest stimulants, leaving out of consideration 
 the more delicate, we may say roughly that amongst all 
 savage tribes red is 'par excellence, and above all others the 
 decorative colour. Dr. Magnus has noted this fact, and 
 uses it as an argument in favour of his theory that rec 
 formed the first part of the visible spectrum to be sepa- 
 rately cognised by the human eye. Mr. Gladstone speaks 
 of " the prominence which that colour acquired both in 
 the initial stages of the painter's art, and in the costumes 
 of high personages. It had, as it were, got a start, and ha 
 the first possession of the ground, which, in costume pai 
 ticularly, it has retained. But," continues the author, an
 
 THE ^ESTHETIC VALUE OF COLOUR. 229 
 
 h ere I am pleased that I can thoroughly agree with him, 
 " vwe must remember that, in public exhibition and cere- 
 rcConial, it is, from its luminous character, highly satisfac- 
 topry to the eye." Of course, we must further remember 
 tl>iat red forms the favourite colour, not only of primitive 
 n^.ian and of modern savages, but also of the young and 
 tile coarse-natured among our European nations. The 
 Oentral African is bribed with yards of red calico ; the 
 West Indian negress adorns herself in a red turban ; the 
 bfJiby in its cradle jumps at a bunch of red rags ; the 
 LMdon servant-maid trims her cap with scarlet ribbons, 
 ai^d admires the soldier's coat as the most beautiful of 
 hiaman costumes. 
 
 : But there exists yet another and more mechanical reason 
 w hy red came early into favour for decorative purposes. 
 Olf all primitive pigments, by far the commonest and easiest 
 t(<^ obtain are ochreous earths. Blue dye can only be ex- 
 triacted in an early culture from certain vegetal substances, 
 wihich require comparatively advanced skill for their pro- 
 di^ction ; w^hile greens are chiefly obtained from minerals 
 of rare occurrence. But red earths may be found almost 
 everywhere, and the method of their application is as 
 si:iiple as the ruddling of sheep. Hence we find traces of 
 thje use of ochre where scarcely any other pigments are 
 kitiown. Lumps of red clay lie beside the prehistoric 
 dead in their rude barrows ; and red stains for the body 
 compose the chief decoration of modern savages. Almost 
 everywhere that we find mention of red pigment amongst 
 uncivilised races, inquiry shows that ochre is the material 
 from which it is obtained. Thus the New Zealanders 
 paint their skins red — with ochre ; the Bushmen in like 
 manner redden their bodies — with ochre; the people of 
 the Congo do the same — with ochre. Of the Australians, 
 the Tasmanians, the Fuegians, the Tannese, the Andaman 
 Islanders, I see it similarly mentioned that they employ 
 ochre for their personal decoration. So, too, in higher arts, 
 the red and yellow of the Trojan and Mycenean pottery
 
 230 THE COLOUR-SENSE. 
 
 are clay colours. The Egyptian red, as we have already 
 seen, was " an earthy bole," and the yellow " an iron ochre-" 
 Even among ourselves ruddle still performs many usefi^l 
 functions, and ranks as the simplest and easiest means of 
 making distinguishing marks on animals, sacks, and other 
 rural objects. 
 
 Occasionally the origin of the red pigment is slightly 
 different. The Samoans, I learn from Mr. Whitmee, u^e 
 a volcanic earth for this purpose; the Assyrian reiji, 
 according to Sir A. Layard, w^as a sub-oxide of coppe\'; 
 and Mr. E. S. Morse records the discovery, in prehistoric 
 shell-heaps at Omori in Japan, of pottery coloured crimsan 
 with cinnabar.^ But whatever the material employed, W'e 
 always see that the red end of the spectrum possessed and 
 still possesses peculiar attractions for undeveloped eesthetic 
 tastes. I 
 
 Besides the employment of red for sesthetic purposes in 
 the shape of pigment, we may also note its use in other 
 shapes. For example, there is the case of the red pebblfes 
 and the pretty polished lola mentioned above.^ The Mexi- 
 cans used orange feathers for many decorative appliances ; 
 and the well-known cloaks of the Hawaiian kings were 
 composed of the beautiful plumage of Mdithreptes pacifica 
 (note the name — as might be expected, a honey-feeder). 
 The crimson hibiscus is a favourite flower amongst the 
 West Indian negroes, whose huts may generally be descried 
 at some distance by means of its massive blossoms. And 
 I find the same brilliant flower twice mentioned by Lord 
 George Campbell as a decoration of the person, once in the 
 case of a girl at Kandavu, Fiji, and again in the wigs of 
 the savage Papuans at Humboldt Bay.^ 
 
 1 Nature, Nov, 29, 1877. will forgive me. But whenever a tp- 
 
 - In this chapter, where I am pre- ference has already been appendec; 1 
 
 senting the facts in a slightly different do not think it necessary to repeat i : 
 
 point of view, I am compelled un- here. 
 
 avoidably to repeat some of the in- ^ Log-Letters from the Challenr,r, 
 
 stances given in the preceding one, pp. 150-249. 
 
 for which repetition I trust the reader
 
 THE /ESTHETIC VALUE OF COLOUR. 231 
 
 Next to red (with which must be included orange and 
 yellow) in the order of aesthetic appreciation comes blue. 
 This colour is comparatively common in nature, being the 
 hue of the clear sky (in a few rare conditions only, for the 
 sky of cloudy countries is whity-grey, and that of the 
 tropics an indefinite haze), as well as of the enclosed sea 
 in bays.^ Moreover, it is wanting in luminous intensity, 
 and is therefore very far from being a pungent colour. 
 However, in the third factor of asthetic effectiveness, the 
 hereditary tendency of humanity, blue is doubtless com- 
 paratively strong; for a large number of fruits have a 
 more or less bluish or purplish tinge. Accordingly, it 
 ranks second in development amongst the favourite colours 
 of mankind. Wherever only two hues are employed in 
 decoration, those hues are generally red and blue. Indeed, "^ 
 if we use at random two words as summing up the totality 
 oj our colour-tastes, those two words wdll be red and blue. 
 ^'" ellow is aBsthetically a mere species of red, while green 
 Idas very little pleasurable effect, except to highly- cultivated 
 eyes. 
 
 ^ Accordingly, wherever a blue pigment exists in an ac- 
 cessible form, the use of blue is common. We have seen 
 already that blue enamel, blue glass beads, and blue lapis 
 lazuli occur in prehistoric remains ; but the want of a 
 proper dye seems generally to have prevented its popular 
 use." Thus, while the Egyptians and Assyrians employed 
 it abundantly, no trace of it occurs upon the Trojan or 
 Mycenean pottery. But the ancient Welsh stained their 
 bodies with woad, and all the Polynesian races' tattoo 
 themselves in blue lines. Many of the lowest Indian hill 
 tribes — Kukis, Nagas, Todas, and Santals — use indigo for 
 dyeing cloth. The same dye is also widely employed 
 throughout Central Africa. The bluish purple Bougain- 
 
 1 I know no commoner instance of sea are blue. It is only true, when 
 
 the inaccuracy of ordinary language carefully tested, in about one experi- 
 
 with regard to colour than the fumi- ence out of fourteen, 
 liar statement that the sky and the
 
 232 THE COLOUR-SENSE. 
 
 villea almost vies with the crimson hibiscus in the favour 
 of savages ; and Bonwick mentions by name white, red, 
 and blue species of flowers used by the Tasmanians in 
 personal decoration.^ 
 
 _Green appears -to-jaia-the least effective resthetically of 
 all colours :|J mean, of course, to the ordinary mass of 
 mankind, for it must be remembered that the cultivated 
 taste generally gives a verdict exactly opposed to that of 
 the multitude. It is the commonest of all colours in the 
 natural environment of man ; it has but little luminous 
 intensity; audit is not connected hereditarily with any 
 special function. Accordingly, I find it seldom mentioned 
 among the decorative colours employed by savage tribes, 
 and even then it is usually introduced as a contrast to 
 red. While the Santals wear strips of red, blue, and 
 yellow cloth ; while the Nagas dress in white cotton with 
 red and blue fringes ; I do not meet with any mention fli' 
 green dyes among the Indian hill tribes. And this is vet^e 
 natural if we recollect that, amid their green leafy sur-| 
 roundings, it would yield A^ery little contrast and posses^ 
 very little decorative value. However, as we mount in thi3 
 scale, we find that the women of New Guinea dye their 
 petticoats red and green, with intermediate strips of 
 yellow; while the Ashantis employ all four decorative 
 colours, red, blue, yellow, and green. Of course, with the 
 Mexicans, Peruvians, Egyptians, and Assyrians, all these 
 colours were in common use, and green was raised to a 
 place of equal importance with red and blue. 
 
 Yet, as a rule, where green rises to the position of a 
 decorative colour, I am inclined to think that we can 
 usually trace a special reason in the circumstances of the 
 particular race. Green forms the opposite pole from red, 
 in that red is the pungent and stimulative colour, while 
 green is the restful and reparative colour. Owing to the 
 larcre amount of green in the natural environment, our 
 
 1 Daily Life of the Tasmanians, p. 27.
 
 THE ESTHETIC VALUE OF COLOUR. 233 
 
 eyes appear to be adapted for continuous languid stimula- 
 tion by that gentle excitant, which forms the mean of the 
 
 I total spectrum. On the other hand, owing to the ancestral 
 
 [ habits of our race, our eyes appear to be adapted for sudden 
 and pleasurable excitation by red, which rapidly glides into 
 
 I fatigue. Accordingly, we desiderate green as a relief. In 
 
 I tHe normal circumstances of humanity, surrounded by 
 trees and fields, this relief is abundantly present. But 
 in the civilised cities, with their greys and stone-blues, 
 green does not occur with sufficient frequency, and hence 
 it is hailed as a fresh and pleasant change. Added to 
 
 ^"^Vhich, it is joined in the civilised mind with various 
 associated emotions, either actually felt or dimly sug- 
 gested. And as its pleasure is the least directly stimulat- 
 ing, the most gentle and modest of all, it naturally ranks 
 highest of any colour in the hierarchy of the sesthetically 
 cultivated. 
 
 ^ ISTow, it would seem as though the use of green in 
 
 flecoration were almost exclusively confined to those 
 
 Jpeople who live an indoor life. It is among the civilised 
 
 '"''^or semi- civilised nations that we see it most employed; 
 and where it is found in the case of savages (as the 
 Samoans and Hawaiians) it has generally been introduced 
 from Europe or America. Moreover, it seems to be in 
 special favour among the Persians ; ^ and it may perhaps 
 be suggested that Persia is a peculiarly arid country, where 
 green is decidedly wanting in the landscape. It also ranks 
 high among the Arabs, and among many inhabitants of 
 cold climates. Those who have seen a Canadian Christmas, 
 w^ith its monotonous field of snow outside, and its gay 
 decorations of evergreens and red berries indoors, will 
 thoroughly understand the rationale of this preference. 
 
 To the last, the use of green remains chiefly supple- 
 mentary. It is employed in bouquets as a relief, and 
 in decorations as an element with red and blue; but 
 
 1 Von Bezold, Theory of Colour, American translation, pp. 212, 215.
 
 234 THE COLOUR-SENSE. 
 
 Ly itself it must be regarded as the least efficient of all 
 colours. 
 
 It shou^a be added, however, that from the beginning 
 green seems to have been prized in such permanent forms 
 
 as jewels or stones. Sea-green pebbles are mentioned | 
 
 among those buried in the barrows : and jade ranks as one '\ 
 
 of the commonest materials for polished hatchets. Green- ■ 
 
 stone, green jasper, and light green slate are also frequently I 
 
 employed for like purposes ; and emeralds, malachite, or ! 
 
 other similar minerals, have been universally prized for ■ 
 
 their beauty. The Central American and South American j 
 
 Indians seem to have had an extraordinary taste for green | 
 
 jewels, for which I confess I can see no sufficient reason. , ! 
 
 Perhaps it may have depended simply upon an accidental^ ^ 
 
 frequency of such stones in that tract of country. How4 L \ 
 
 ever, an explanation is here certainly desirable. U 
 
 On the other hand, children and savages take little 
 
 notice of vegetal greens, and usually arrange red and blue , ^ 
 
 flowers entirely by themselves, without that admixture ofi i ' 
 
 relieving foliage which a more refined taste imperatively! I 
 
 demands. ^^ 
 
 As regards the various mixed or intermediate colours — j 
 
 purple, orange, lilac, mauve, and so forth — their effective- j 
 
 ness depends mainly upon their similarity to red on the i 
 
 one hand or blue on the other. In proportion as they , 
 
 approach green they are less and less pleasurable : while, • 
 
 of course, those of the red end are, on the whole, greater | 
 
 favourites than those of the violet. Purple forms an \ 
 
 intermediate term, being brilliant in the exact ratio of the i 
 
 red rays which it contains. Of course, among civilised A 
 
 people, such colours possess the additional charm of U 
 
 novelty and variety. I 
 
 A few more words must be added as to the mode in [' 
 which the various colours are used. In the earliest stage 
 they are merely daubed on in isolation, as by the Anda- 
 manese who plasters his head with ochre, or the ancient 
 Welsh who stained their bodies with woad. A little
 
 THE ESTHETIC VALUE OF COLOUR. 235 
 
 higher up in the scale, the colours are used in hars or 
 strips, of violent contrast. Black, white, and red are the 
 favourite pigments, each being well pronounced and 
 standing out boldly against its neighbour. Then conies 
 the addition of blue, and finally that of green. Above 
 this level we find the employment of intermediate hues, 
 such as yellow, orange, and pink. Last of all, the colours 
 are mixed in shades of varying intensity, and we get 
 the whole wealth of the entire spectrum, as in modern 
 European art. 
 
 Again, the variety of form gives another element of 
 evolution, into which, however, it would be improper to 
 enter in the present volume, restricted as it is to the exa- 
 mination of the simple colour-sense. Here it must suf- 
 fice briefly to point out the upward movement from the 
 simple bars or strips of the savage, through the graceful 
 curve lines of the Polynesians, to the arabesques and 
 decorative harmonies of the Moors ; or from the red and 
 yellow imitative figures of the Hawaiians, through the 
 bright primary wall-paintings of the Egyptians, to the 
 landscapes and the figure-pieces which adorn the walls of 
 Our Salons and our Academies. 
 
 Both these lines of evolution, however, suggest a further 
 consideration of great importance. While primitive man 
 cares only for the pungent and brilliant stimulation of the 
 primary colours, in all their fullest intensity of light, and 
 pays little attention to their darker shades or duller mix- 
 tures, the aesthetically cultivated have learnt to notice and 
 iippreciate the fainter pleasures which arise from these 
 .t,lif]jhter and more delicate stimulations. They are thus 
 enabled to vary and enlarge their means of visual grati- 
 fication, and to dispose their various-coloured objects in 
 Jar more numerous and more subtle combinations. "While 
 tlie Australian knows only two or three invariable 
 .Arrangements of red, black, and white, the civilised 
 decorator is able to ring the changes perpetually 
 tipon ever- varying harmonies and contrasts of faint
 
 236 THE COLOUR-SENSE. 
 
 yellows, pale Hues, rich purple-greys, and dark olive- 
 greens. By artfully devising here a stimulation, there a 
 relief, here a mass of comparatively brilliant pungency, 
 there a field of mild retiring neutral tints, he succeeds in 
 sustaining and recruiting the sensuous pleasure of colour 
 from moment to moment, without ever causing: us fatigue 
 or overtaxing a single sentient structure. 
 
 And now we must pass on to a second point of view, 
 that of the objects which are employed for the aesthetic 
 gratification of the colour-sense. These, on the whole, 
 afford a strong confirmation of the theory with regard to 
 the orig^in of our aesthetic feeling^ which is here advocated, 
 as the greater part of them consist of the very objects 
 which owe their development to the colour-sense of 
 animals. 
 
 Fruits themselves, though their utilitarian associations 
 prevent them from standing in the front rank of aesthetic 
 objects, are yet undoubtedly beautiful in colour and 
 shape. And when we survey them amid their native 
 boughs, few lovelier sights can be found than the brighter 
 and prettier among them. An orange tree laden with its 
 golden spheres, an apple orchard weighed down with its 
 ruddy pippins, a holly-bush covered with its crimson berries, 
 are some of the most exquisite pictorial sights which can 
 be seen on earth. Especially aesthetic do fruits become, 
 when, as in the case of the rowan, the spindle-tree, and 
 the solanum, they are incapable of being used as food, and 
 so can only minister to the pure pleasure of sight. In 
 most instances, however, the beauty of fruits falls a little 
 short of the aesthetic limit in the actuality, at least when 
 they have been picked and are ready for table. Yet even 
 so, when decorated with green leaves, and interspersed 
 with flowers, their falling short is very slight indeed, \i 
 not purely hypercritical. But as objects of pictorial 
 imitation they have always been in high favour ; while 
 they enter largely into the composition of poetry, as ideal 
 stimulants of aesthetic feeling.
 
 THE ESTHETIC VALUE OF COLOUR. lyj 
 
 Nevertheless, it should be noted that fruits in the 
 actuality are closely allied with the frugivorous instincts 
 of our race, and that the origin of our whole taste for 
 colour may still be clearly descried in the imprint which 
 they have left upon our minds. Every child naturally 
 puts a bright-coloured berry into its mouth; and it is 
 difficult to keep the hands of urchins off the scarlet 
 clusters of the arum or the brilliant crimson fruits of 
 the yam. Even babies automatically strive to place 
 every bright object which they see between their lips ; 
 and the sweetmeats which are manufactured for their 
 pleasure bear attractive strips of red, blue, and yellow 
 colouring. These and fifty other minor indications show 
 us from moment to moment that the developed love for 
 colour is a transference of feeling from its original alliance 
 with the common food-stuffs of the species. 
 
 The aesthetic pre-eminence of flow^ers has never been 
 doubted. In the actuality they form the commonest 
 decoration of the savage home and the civilised garden, of 
 the labourer's cottage and the royal palace. In imitation, 
 they have been barbarously travestied with paper, wax, or 
 feathers, and parodied in cotton upon bonnets, hats, or 
 dresses. In the direct pictorial representation they have 
 been favourite subjects of artistic handling from the days 
 of the Egyptians downward. And as elements of poetry, 
 they have been celebrated from the rose of Sharon and 
 the hyacinth of Homer to Wordsworth's daisy and Tenny- 
 son's lily. But we must not forget that herein we are 
 practically confessing the identity of our own colour- 
 tastes with those of the bees and butterflies, for whose 
 attraction these floral gems were first developed. 
 
 Fruits being, so to speak, the primitive and positive 
 element in our love for colour, flowers may be regarded 
 as one among the earliest classes to which the feeling is 
 transferred. Even monkeys are not wholly insensible to 
 their charms, though they display their affection, like our 
 own little children, chiefly by pulling to pieces the objects
 
 238 THE COLOUR-SENSE. 
 
 of their regard. We have no evidence, of course, whether 
 primitive man cared for flowers; but the presumption 
 from the case of existing savages would certainly lead us 
 to suppose that he did. I have already noted that the 
 Tasmanians and Australians employ bright blossoms in 
 their personal decorations ; and the South Sea Islanders 
 positively revel in garlands and nosegays. Even the 
 stern American Indians show considerable love for these 
 bright natural objects, and I find it noted of the Chibcha 
 women that they wore flowers in their hair. A little plot 
 of half -uncultivated garden commonly surrounds the very 
 rudest huts. As to ourselves, so far as my observation 
 goes, I am inclined to think that our children notice 
 flowers as soon as they take note of anything which is 
 not good to eat, while I had hard work in Jamaica to 
 keep the hands of little negroes off the purple and crimson 
 plants in my garden-plot. Finally, our own conserva- 
 tories, flower-shows, and floral decorations show us the 
 same taste pushed to its furthest extreme.^ 
 
 It is worth while to observe, en passant, that though 
 our children pick bunches of flowers they never pick 
 bunches of leaves, a fact full of import as to the aesthetic 
 value of green. Similarly, although adults intersperse 
 their bouquets with foliage as a relief, they seldom 
 arrange leaves by themselves. If they do, the leaves 
 must present some special feature, like those of ferns, 
 which attract us sometimes by their exquisite gloss, some- 
 times by their varied and minutely-symmetrical forms. 
 So, too, when we place a flowerless plant in our gardens, 
 it must either be recommended by such beauty of shape 
 or s^loss, as in the case of ferns, Palma Christi, and india- 
 rubber trees, or by coloured foliage, as in the case of 
 drac^na, coleus, caladium, sedum, and the other pretty 
 plants at present so much in fashion. It is true a culti- 
 
 1 Since this chapter was written, A. Lambert, has appeared in the 
 a most learned paper on "The Cere- "Nineteenth Century" Eeview for 
 monial Use of Flowers," by Miss Sej^tember 187S.
 
 THE /ESTHETIC VALUE OF COLOUR. 239 
 
 vated mind may derive as much pleasure from a green 
 leaf as from a scarlet geranium or a purple hyacinth ; but 
 then the pleasure in the former case is much more in- 
 direct, complex, and emotional, and in the latter cases 
 much more immediate, pungent, and sensuous. More- 
 over, the first pleasure is personal and restricted; the 
 second is generic and universal.^ 
 
 This is, perhaps, the fittest place to advert to another 
 curious fact, the fact that all our sesthetic feelings seem 
 most deeply bound up with the relics of our original out- 
 door, arboreal existence. Fruits and flowers, birds and 
 butterflies, sweet perfumes and songs of nightingales, the 
 green fields and the luscious forests, these are deep and , 
 resonant elements in our perennial love for beauty. Mr. ^ 
 Herbert Spencer has pointed out that the pleasures of a 
 day in the country, of wild scenery, and of free wandering 
 over heath and moor, are largely due to unconscious recol- 
 lections of the ante-civilised state. He even suggests that 
 the enjoyment of a picnic, with all its unconventional 
 delights, is mainly explicable as a sort of temporary 
 reversion to a primitive state. Still more obvious does 
 this become to those who have ever tried a fortnight of 
 camping-out among the Thousand Islands of the St. 
 Lawrence or the beautiful lakes of western New York. 
 But it seems to me that we may go further, and ascribe 
 our whole love of colour, perfume, and the more delicate 
 
 1 1 should like here to notice, paren- individualities in order to find out 
 
 thetically, an objection which has been what was primitive and original in 
 
 urged by favourable critics against our sesthetic nature, after discovering 
 
 parallel passages in my "Physiolo- which we may proceed to explain 
 
 gical Esthetics," and which will, what is derivative and advanced, 
 
 doubtless, be urged in like manner But I confess that the feelings which 
 
 against the above sentence. I have a painter shares with a child and a 
 
 been accused of appealing from the barbarian appear to me more im- 
 
 cultivated feeling of the artist to the portant subjects for philosophical 
 
 uncultivated feeling of the child and investigation than the feelings which 
 
 the savage, as though the latter were he only shares with a knot of some 
 
 in some way truer and better. Such half-dozen associates belonging to 
 
 has never been my intention. I have the same highly-specialised artistic 
 
 only meant to appeal to the simplest school.
 
 240 THE COLOUR-SENSE. 
 
 taste of fruits, to half-remembered habits of our early 
 ancestry. The acquired carnivorous mode of life sits 
 loosely on the outer layer of our nature ; but the hereditary 
 frugivorous instincts seem to shape all our inmost feel- 
 ings and sentiments. Bright hues, fragrant scents, sweet 
 juices, these form the earliest pleasures of childhood, and 
 remain throughout as the main sensuous factors of our 
 aesthetic nature. The very fact of their comparative 
 remoteness from our acquired and civilised habits seems 
 to make them all the more distinctively beautiful and 
 delicate. Thus, our modern dinner a la Eusse, by re- 
 moving from the table the coarse elements of meat and 
 fish, while loading the white damask with flowers, with 
 beautiful fruits, with coloured glass and porcelain dessert 
 service, seems to recall whatever is loveliest and most 
 a^thereal in our ancestral traits. On a humbler scale, the 
 mere decoration of dishes with parsley or watercress, the 
 bouquet placed in the centre of the dinner table, and the 
 very addition of cochineal to the jellies, or of Qgg and 
 beetroot to the salad, points dimly back to the same 
 half-obliterated habits, asserting themselves strongly 
 throughout our whole history. 
 
 Both fruits and flowers are comparatively evanescent 
 sesthetic objects. They soon fade and lose their beauty. 
 But feathers, which perhaps rank next in order of historical 
 occurrence, retain their brilliant hues for a considerable 
 period. And just as our sense for the beauty of fruits 
 and flowers is a proof of the community of taste which 
 exists between frugivorous man and the fruit-eating and 
 flower-feeding animals, — the parrots, toucans, humming- 
 birds, bees, and butterflies, — so our sense for the beauty of 
 feathers is an echo of the taste which originally produced 
 them by sexual selection in the species to which they 
 belons. Feathers form almost universal ornaments of 
 savage or civilised humanity. The American Indians 
 thrust them into their head-dress in the shape of a crest 
 or crown. The Hawaiians wove from them their famous
 
 THE ESTHETIC VALUE OF COLOUR. 241 
 
 cloaks and idols. The Mexicans employed them for their 
 beautiful mosaics. Eastern nations early prized the pea- 
 cock for his splendid tail-plumes. And now, in our 
 barbarous civilisation, millions of humming-birds from 
 Trinidad and South America come yearly to Europe for 
 the bonnets of our English ladies; ostrich-farms at the 
 Cape supply our savage court-dress ; and marabou plumes 
 decorate the heads of our Belgravian beauties. The bird- 
 of-paradise forms a regular article of commerce ; grebe 
 and swans' down line our mantles and jackets ; even our 
 very funerals are surmounted with the black-dyed nodding 
 plumage of tropical birds. Our military officials wear 
 feathers as the mark of highest distinction ; and the heir- 
 apparent to the British crown uses them as his armorial 
 cognisance. Is it not worth noting, too, as a symptom 
 of the permanent character which marks governmental 
 ceremonial, that the use of feathers is especially bound 
 up with our military system and court etiquette ? Have 
 w^e not here a direct survival from the simple ornaments 
 of the savage chief ? 
 
 ISText, perhaps, in our conjectural order of transference 
 might come the taste for shells, pearls, coral, and like 
 organic substances. This taste we find almost universal 
 among modern savages, and it extends far back into the 
 prehistoric age. Mother-of-pearl is a favourite ornamental 
 material, which has retained its popularity into modern 
 times. ]N'ecklets of cowries or the turbo are common 
 savage adornments, which have not yet died out in civi- 
 lised lands. Coral still holds its ground in Europe, and 
 large quantities are exported to China and Japan. On 
 the whole, however, despite the few collections of shells 
 on a cottager's mantelpiece, the love of these marine pro- 
 ductions has died out far more than the previous tastes. 
 
 Coeval, doubtless, with the habit of gathering these 
 treasures of the sea-shore is that of picking up bright- 
 coloured pebbles or crystals. Of this we have already 
 seen numerous examples, and further repetition w^ould 
 
 Q
 
 242 THE COLOUR-SENSE. 
 
 only fatigue the reader. A mere brief list of some prin- 
 cipal varieties must suffice — sucli as the diamond, ruby, 
 sapphire, topaz, garnet, carbuncle, amethyst, jasper, 
 emerald, beryl, jacinth, onyx, opal, and turquoise ; marble, 
 porphyry, granite, serpentine, malachite, jade, fluor spar, 
 amber, satin-stone, agate, alabaster, lapis lazuli, quartz, 
 and bloodstone. 
 
 The use of decorative metals is closely bound up with 
 that of the preceding class. The brilliancy and the colour 
 of gold and silver early attracted the attention of primitive 
 man. Used in conjunction with the precious stones, they 
 compose what we know as jewellery, which forms one of 
 the chief decorative appliances of all savage and civilised 
 races. The taste which begins with the gold neck orna- 
 ments of the barbaric king, culminates in our own jewel- 
 lers' shops, our regalia, our gold and silver plate, our city 
 maces, our military uniforms, our ecclesiastical ornaments, 
 and our Albert Memorials. Here, again, it is interesting 
 to note the connection of state ceremonial and religious 
 ritual with the earliest decorative devices of primitive 
 chieftains. 
 
 All the objects which we have hitherto examined agree 
 in one particular — they are self-coloured. Man finds them 
 as he uses them, and transfers at once to the brilliant 
 gewgaws the taste which was developed upon the bright- 
 hued fruits. It is the property of natural colouration 
 which gives to some of them their special value. Flowers 
 and fruits, besides being transitory, are common and univer- 
 sal, and so they are only prized for their immediate beauty. 
 Feathers and shells, though more permanent, are still too 
 easily procured to rank high in exchange value. But 
 jewels and precious metals, besides being indestructible, 
 are naturally rare, and cannot be artificially multiplied ; 
 so that their value is proportionately and permanently 
 great. Yet it may be noted that their aesthetic rank is 
 not so elevated as that of flowers or even of beautiful 
 feathers (though here many will disagree), partly, perhaps,
 
 THE ESTHETIC VALUE OF COLOUR. 243 
 
 because of the strong element of glitter and powerful total 
 stimulation, but still more, I fancy, because the economical 
 value has vulgarised them hopelessly, reducing them from 
 the level of beautiful natural objects to the position of 
 mere high-priced baubles. 
 
 The class which we have next to examine, however, is 
 that of materials not naturally coloured, but artificially 
 stained or dyed. Man at length progresses beyond the 
 mere passive stage of aesthetics, and enters upon the active 
 career" of the artist. No longer content simply to gaze 
 with pleasure upon the fruits, flowers, birds, butterflies, 
 shells, corals, and precious stones which nature has beauti- 
 fied beforehand for his admiration, he begins on his own 
 account to increase the stock of coloured objects by the 
 application of pigment. 
 
 ^ Pigment stands in the same relation to the natural taste 
 for colour as sugar to the natural taste for sweetness, or 
 artificial essences to the natural taste for perfume. 
 
 We get the first stage of this active process in tlie use 
 of ochre, chalk, and charcoal, for the decoration of the hair 
 and body. These pigments represent a very elementary 
 form of painting, because in their case a friable substance 
 is merely applied to another body, so that small fragments 
 adhere by their own nature or by simple wetting. The 
 expression of vegetable juices gives us a step in advance, 
 as in the case of woad, indigo, logwood, and the like. The 
 dyeing of cloth carries us still further on the upward 
 march ; and the discovery of mixed pigments, applied 
 with a stamp or brush, puts a culminating touch to the 
 process. Dyeing and painting revolutionise the whole 
 environment of semi-civilised man, until at last, if the 
 reader will cast his eye around the room in which he sits, 
 he will see that scarcely an object can be found in it which 
 has not received some purely decorative addition of pig- 
 ment, stain, or polish. 
 
 Side by side with this great change goes the discovery 
 of glass, porcelain, and other materials which imitate the
 
 244 THE COLOUR-SENSE. 
 
 natural colouring of precious stones. The numerous 
 changes which can be rung upon these various materials, 
 together with pigments, dyes, and textile fabrics, would 
 demand a separate history, and cannot, therefore, be ade- 
 quately treated in a single chapter. 
 
 But it must be remembered that wdiile mankind have 
 been transferring their native love for colour to these new 
 objects, aud exercising their sense upon these artificial 
 stimulants, the taste must have been widening and deep- 
 ening from day to day. It might have seemed to the 
 reader at first that these sesthetic feelings, derived from 
 a remote ancestry, must be growing perpetually weaker 
 with the lapse of time, so that some fear might arise for 
 their iinal obsolescence. But, really, man has gone on 
 from age to age, surrounding himself more and more with 
 beautiful flowers, bright clothing, decorative furniture, 
 works of art, and all other exquisitely-coloured objects, so 
 that what was at first a mere passing fancy for pebbles 
 and shells, has developed at length into a perfect neces- 
 sity of his fully-evolved nature. As an able writer in 
 the '• Eevue Philosophique " has pointed out, even the 
 veriest boor would now feel half his existence cut from 
 under him if the whole aesthetic element were removed 
 out of his life. 
 
 A third point of view must engage our attention for a 
 while before we quit the subject of the sesthetic value of 
 colour. I mean the gradual progress in disinterestedness^ 
 which marks the evolution of the sesthetic feelings. 
 
 The starting-point of visual aesthetics, as w^e have 
 already seen, is the appreciation of bright colour in the 
 fruits which form the common food of the original species. 
 A close connection with vital function is here obvious 
 and unmistakable. The simplest transference from this 
 primordial pleasure consists, doubtless, in the mere tran- 
 sient interest in brilliant objects of the nearer environ- 
 ment, such as flowers, parrots, or butterflies. Not only 
 the quadrumana, but savage or uncultured man himself,
 
 THE ESTHETIC VALUE OF COLOUR. 2;5 
 
 displays little interest in such, intangible and distant 
 manifestations of colour as the rainbow or the sunset. 
 But monkeys are reported to pull to pieces handsome 
 blossoms, to snatch the longer feathers from unsuspecting 
 birds, and to dart after beautiful butterflies which flit past 
 them on the wing in the brio-ht sunlioht. No doubt their 
 interest is quite as momentary as that of the child who 
 tears out the ray-fiorets of a daisy, or chases a Camber- 
 well beauty across the meadow ; yet if the facts as com- 
 monly related be really true, they show at least some 
 slight disinterested love for colour, inasmuch as coloured 
 bodies are instinctively selected as objects of passing 
 pursuit, while green leaves or brown insects attract little 
 or no attention. 
 
 The monkey, however, goes no further in his aesthetic 
 career than this first simple step — for, of course, we must 
 count the phenomena of sexual selection as manifesta- 
 tions of purely interested feeling. But man proceeds to 
 employ the objects wdiich he collects as means for his 
 own personal decoration. The adornment of the body 
 thus constitues the second stage of disinterested aesthetic 
 progress. Flowers stuck into the rude head-dress, or 
 woven into festoons for wreaths and girdles, form one of 
 the earliest and most natural ornaments. But beautiful 
 as these simple articles of dress must always be, they fade 
 too soon for permanent use. Accordingly, shells, corals, 
 pebbles, precious stones, feathers, and furs supersede them, 
 where obtainable, as decorative appliances. The first 
 function of pigment is for daubing the hair and body; 
 while tattooing, originally a form of subordinative mutila- 
 tion, grows at last into a mere aesthetic practice. As 
 knowledge and arts increase, rude textile fabrics come into 
 use, and being dyed or stained with red, yellow, and blue, 
 form personal adornments for the savage chief. Of course, 
 the whole original object of dress was that of decoration, 
 the ideas of warmth and decency only coming in as after- 
 thoughts at a later period. Amongst the lower races, men,
 
 246 THE COLOUR-SENSE. 
 
 not women, monopolise the handsomest costumes, which 
 are worn as marks of distinction rather than as purely 
 aesthetic adjuncts. Here, once again, we note that the 
 employment of colour in male dress survives amongst our- 
 selves mainly in connection with military, ecclesiastical, 
 and governmental etiquette. 
 
 Yet even the humming-birds have passed beyond this 
 second stage of disinterested aesthetic feeling, and reached 
 the third step, which we have next to consider ; for, as Mr. 
 Gould tells us, they decorate their nests with pretty bits 
 of lichen or brilliant feathers, interwoven with the mate- 
 rials of the outer wall. Much more have our old friends 
 the bower-birds overstepped this higher limit, by posi- 
 tively instituting what may be described as Assembly 
 Rooms, adorned with all kinds of coloured or shining 
 objects. Obviously, the ornamentation of your home is 
 one degree more disinterested than the ornamentation of 
 your own person, and that of your temples or public build- 
 ings, one degree more so than that of your home. Both 
 these steps are soon taken in the course of human evolu- 
 tion. The ncOToes of the Niojer stain the exterior of their 
 huts with blue and white ; while the people of High Asia 
 commonly paint theirs with grotesque figures. Amongst 
 our own houses, external painting is, of course, very 
 common, especially in countries where wood is largely 
 employed as a building material. But internal decoration 
 carries us a step higher, because it does not bear the same 
 impress of mere ostentatious display; it shows more 
 ingrained personal aesthetic sensibility, and less love of 
 admiration at the hands of others. The West Indian 
 negroes dress in very bright colours, and, on the whole, 
 with admirable taste — the brilliant hues setting off with 
 effect the natural darkness of their skin — but they seldom 
 or never do anything toward the decoration of their huts, 
 which are mere square blocks of mud wall, lightly roofed 
 with palm-thatch. A step higher up, the West African 
 negroes paint their huts externally, while inside they
 
 THE AESTHETIC VALUE OF COLOUR. 247 
 
 remain mere brown and dirty hovels. But the cultivated 
 civilised man thinks more of surrounding himself, under 
 his own roof, with beautiful and ennobling works of art, 
 than of making a boastful external show before the eyes 
 of his neighbours. 
 
 Under the same heading, we may notice the cultivation 
 of flowers in gardens and windows. This practice exhibits 
 a considerable advance upon the mere casual taste for 
 picking pretty blossoms, and also upon the collection of 
 naturally-grown flow^ers for personal decoration. It testi- 
 fies to aesthetic forethought, and gives room for immense 
 disinterested developments of aesthetic feeling. Gardens 
 of more or less rude construction are found very far down 
 in the scale of humanity, and they continue to be objects 
 of solicitude up to the very highest level of civilisation. 
 
 The habit of keeping birds (especially those of bright 
 plumage, like parrots, cockatoos, and peacocks) as domestic 
 pets, deserves a passing notice in the same connection. 
 How low down in the scale of civilisation this practice 
 may extend I cannot say; but I observe that Captain 
 Moresby^ mentions it as prevailing among the savage 
 Papuans. 
 
 If the mere common savacie decorates his own little 
 
 o 
 
 hut with pigment, skulls, shells, and flowers, much more 
 will the great chief gather around his dwelling these 
 aesthetic adjuncts, and others of higher kind. Only kings 
 in Hawaii were permitted to use the feathers of the 
 Melithreptes, from which the royal robes were woven. 
 Purple has always been a pcculium of kingship, and the 
 palace is naturally thought of as a finer and more brilliant 
 building than the hut or house of a subject. Even the 
 veriest savages have distinctions of dress and decoration 
 for their chiefs ; and when we come to the royal abodes 
 of Egypt, Assyria, Mexico, and Peru, we see at once how 
 large a share monarchy has borne in the development of 
 artistic handicraft, which, of course, entails a corresponding 
 
 1 Discoveries in New Guinea, p. 219.
 
 248 THE COLOUR-SENSE, 
 
 development of the aesthetic feelings. Solomon's house 
 and ivory throne/ as well as his " apes and peacocks," ^ 
 will immediately occur to the Biblical student. If we 
 trace this influence down through history, we shall find 
 that princes have always been the great patrons of fine 
 art, and that painting in particular has been almost 
 entirely fostered under the protection of monarchs and 
 aristocracies.^ But these royal decorations react upon 
 the popular taste, and finally afford new outlets for the 
 disinterested aesthetic sentiment of the people. Hitherto, 
 the sense of beauty has been more or less linked with the 
 feeling of proprietorship : beyond this line it gains more 
 and more, with every step, in abstractness and remoteness 
 from the personality of the individual. 
 
 Eeligion, however, does still more for the aesthetic 
 sentiment than even governmental adjuncts. If the 
 house of the chief receives exceptional decoration, much 
 more does the house of that deified ghost-chief, the god. 
 Wherever we look, w^e see that all the resources of art, 
 infantile or full-grown, are most fully employed in the 
 service of religion. Painting, sculpture, music, the thou- 
 sand minor arts of decoration and dress, all combine to 
 do honour to the gods of the country. From the West 
 African fetish, through the Polynesian shrines, the Indian 
 topes, the Chinese pagodas, the Mexican and Peruvian 
 temples, the mysterious colonnades of Egypt, the massive 
 architecture of Babylon or Nineveh, the Hellenic Parthe- 
 nons, the Italian Capitols, to the modern mosques of 
 Islam and the towering cathedrals of Christendom, we 
 find the highest artistic handicraft of every age and race 
 lavished upon the dwelling-place of the national deities. 
 The few traces of aesthetic feeling in the Hebrew Scriptures 
 
 1 I Kings vii. ^ ibid. x. 22. as a curious fact tliat had it not been 
 
 ^ Thus it turns out that (paradoxical for the royal parks and gardens, Lon- 
 
 as it must at first sight appear) even don and Paris woidd have been left 
 
 kings and queens are not without their almost entirely destitute of open 
 
 ultimate uses. It has often struck me breathing-spaces.
 
 THE ESTHETIC VALUE OF COLOdiRY. 251 
 
 are connected with the workmanship of the Tabern-at a 
 the Temple, and the hieratic dress. I have pointed 011 ^ 
 elsewhere ^ how large a part the religious sentiment has 
 borne in the genesis of the sublime : it must here suffice 
 thus briefly to hint at the impetus which it has given to 
 the kindred feeling^ of the beautiful. Whether we look at 
 the endless painted images of Karnak or at the stained 
 windows of Salisbury, we must equally recognise the 
 enormous influence of relidon in the OTOwth of disinterested 
 
 o o 
 
 gesthetic feelincr. 
 
 The remaining steps of the process would carry us too 
 far into the general realm of aesthetics, if treated in full 
 detail. Enough has been done already to show the main 
 course of evolution, whereby the love for colour becomes 
 extended and divorced from the personality of the sentient 
 mind. The final step, it seems to me, is taken, when we 
 arrive at the pure love of colour in nature for its own 
 sake, the love which draws the cultivated man to gaze 
 with delight upon the autumn hues, the rainbow, the sun- 
 set clouds, or the myriad tints of sea, and sky, and plain, 
 and forest. In works of art, so many additional factors of 
 plot-interest,~of admiration for imitative skill, or of critical 
 appraisement, enter into the total of our consciousness, 
 that we can hardly analyse our feeling into its simple 
 constituents; but when we look upon the crimson and 
 golden hues of evening, the thrill of pleasure which echoes 
 through our brain represents, I believe, almost the purest 
 form of disinterested love for mere colour. 
 
 1 See "The Origin of the Sublime," in "Mind" for July 1878.
 
 248 ( 250 ) 
 
 CHAPTER XIII. 
 
 THE GROWTH OF THE COLOUR-VOCABULARY. 
 
 The names of colours are abstract words : they repre- 
 sent an attribute, not an object. Accordingly, they do 
 not belong to the class of words which, form the voca- 
 bulary of young children or of primitive men. They 
 arise gradually, during the course of human evolution, 
 personal and collective, in proportion as they are required" 
 by the needs of the individual or the race. A child of 
 two years old (or a little more) knows very well the 
 names of grapes, strawberries, and oranges ; but for purple, 
 crimson, and orange as a colour, it has as yet no appro- 
 priate verbal symbol.^ If you ask it what it calls these 
 things, it will answer at once, "glape," '' tlawbellie," or 
 " olage," as the case may be ; but if you ask it, " what 
 colour is this ? " it has no answer ready, because it does 
 not even comprehend the question. 
 
 Intelligent adults who have received a philosophical 
 education — or rather, an education in philosophy — have 
 grown so accustomed to the conception of substance as 
 composed of attributes, so habituated to the analytical 
 mode of regarding concrete objects, that they find a dif- 
 ficulty in realising the mental state of the unsophisticated 
 human being. An educated man, if asked to describe a 
 grape, would answer, " It's a small, round, sweet, purple 
 
 ^ I am not speaking here by guess-work, but stating the result of numerous 
 actual experiments.
 
 GROWTH OF THE COLOUR-VOCABULARY. 251 
 
 fruit, which grows in clusters on a twining vine ; " l but a 
 labourer would have recourse to better known concrete ob- 
 jects, and reply, " It's something like a plum, only about the 
 size of a cherry, and grows in bunches the same as currants." 
 Or again, if a naturalist discovers for the first time a new 
 animal — say an argus pheasant — he will minutely charac- 
 terise its shape, size, colour, external appearance, and 
 internal structure, detailing all these points in extremely 
 abstract language ; whereas, a countryman who goes to 
 the Zoological Gardens will simply describe it as " be- 
 tween a peacock and a guinea-hen." In every case, the 
 average intelligence of mankind endeavours to grasp an 
 idea by means of concrete realities. Only by an effort is 
 it able to resolve the complex whole into its ultimate 
 analytic constituents. 
 
 We shall fall into many errors, therefore, if w^e insist 
 upon reading the simple language of primitive man by 
 the light of our developed experience. Evolution for ever 
 impresses upon us the lesson, that if we would be good 
 philosophers we must forget our philosophy. Thus, the 
 formal logician was prepared to interpose his learned 
 objection just above, when I said that the names of 
 colours are abstract. For the purposes of his artificial 
 system, with its propositions and denotations and in- 
 tensions, blue and green are concrete terms. I have no 
 fault to find with the expression ; when writing logically, 
 we must all allow the truth of the distinction. But from 
 the point of view of psychology, every word which does 
 not denote a concrete thing in its totality, or a picturable 
 action, must be regarded as abstract. While general 
 
 1 I have purposely given the natu- diameter, round, instead of spherical, 
 
 ral answer of an ordinary, well-edu- and siocet as a symbol of the compound 
 
 cated, non-botanical speaker. But and delicate grape-flavour. Then, 
 
 see how absurdly inadequate the de- again, we have no information whe- 
 
 scription really is ! Setting aside its ther it is a" stone-fruit " or a " berry, " 
 
 total want of structural detail, and and whether it is edible or poisonous- 
 
 merely regarding it from a practical Yet the description is really a very 
 
 point of view, what a vague expres- good one as descriptions go. 
 sion is small, in lieu of a measured
 
 252 THE COLOUR-SENSE. 
 
 names are not real abstractions, "because they describe in- 
 discriminable individuals/ adjectives are real abstractions, 
 because they describe a single property viewed in isolation 
 from the other properties of the objects in which it is an 
 element. 
 
 The names of colours, then, are abstract words ; but, like 
 all other abstracts, they necessarily take their rise from a 
 concrete. A-^uinient^s^Bflexien-willr--shew-"as^ -th^^ the 
 evolutiQn.ofdanguaga_(3q^iild_iiot-proGeedr-otherwase. The 
 earliest names must be names of thingjs or of visible and 
 audible actions. These must afterwards be applied to. 
 other like things or to similar attributes, by slight changes 
 in their meaning. Unless primitive man in the search for 
 a means of intercommunication had hit upon the plan of 
 framing a conventional word to express an abstract idea — 
 a plan obviously itself too abstract in its nature for adop- 
 tion by any but a high order of intelligence — he must 
 clearly proceed by forming new words out of the old, by 
 likening the unnamed to the nameable. And as a matter 
 of fact, philological analysis shows us that such has been 
 the actual course of development — that every abstract 
 word can be ultimately traced back to a root of extreme 
 concreteness, and every expression of attribute can be 
 shown to belong in its origin to a definite subject. 
 
 It would be easy to give a philological analysis of the 
 common colour names, such as red, green, blue, and yellow, 
 in several ancient and modern languages, which would 
 bear out the truth of this assertion ; but I prefer to take 
 
 ^ I have no room here for the dis- "Papa;" it only slowly grows to 
 
 cussion of this side-issue, but I may demarcate the actual Papa from other 
 
 just point out in passing that the men. We recognise meat before we 
 
 word man is not in practice arrived at recognise heef and mutton ; or tree, 
 
 (as logicians tell us) by abstracting before oak and elm. Nobody knows 
 
 from the various individual men what one pin or one <s.%% from another ; 
 
 is common to each, but by the childish they are thought of as the same : and 
 
 mind recognising originally a number if we are shown two in succession or 
 
 of exactly similar units, some of which the one twice over, our impressions 
 
 it afterwards learns to discriminate, are absolutely identical. 
 A child at first regards all men as
 
 GROWTH OF THE COLOUR-VOCABULARY. 253 
 
 examples from a later date, and to show the origin of one 
 or two very new expressions, whose meaning is too plain 
 to admit of any doubt. Though this method has far less 
 appearance of learning than the other, it carries a great 
 deal more conviction to the general reader i-fe we can^ 
 e^^y see that rose-coloured is directly derived from the 
 known w^ord and the known concrete object, a rose ; 
 whereas most people must take on trust the origin of hrown 
 from an Indo-European verb meaning to burn, or that of 
 the heraldic gules from a Persian word glml, which desig- 
 nates the same favourite flower. 
 
 Among such new terms of undoubted derivation, we 
 may take as specimens lilac, lavender, and violet, which 
 are borrowed from the concrete names of flowers; and 
 orange, cherry, ajyple-green, which are borrowed from those 
 of fruits. So, too, to go a little further back, we have 
 'pink from the well-known blossom ; and the almost obso- 
 lete saffron, a favourite colour-epithet with Elizabethan 
 poets. Again, we find the Erench words cerise, mauve, 
 and 4cru in common use among drapers and their lady- 
 customers ; and when we inquire into their meaning, we 
 see at once that the first is the same as our cherry^ the 
 second is the name of the marsh-mallow, and the third 
 (literally unUeached) is a derivative of the Latin crudus ; 
 so that in every case, when we go back a little Avay, we 
 see that the abstract colour-term is always a special 
 application of a very concrete primitive object-name. y 
 
 i^act, when we wish to express a hitherto unnamea^ 
 colour, the simplest way of doing it is to take an object 
 which possesses that colour, and apply its title a3 ana^^^ 
 jective to the thing which we wish to describe./hAr^ar—- 
 ticular shade of very light yellow has no distinctive name 
 at a particular time ; but we must call it something for 
 some special purpose, and so we think of its nearest 
 common representative, a primrose. Thenceforward, the 
 'new name becomes an adjective, and we ask naturally 
 for a yard of primrose ribbon. Kow, what we see civil-
 
 254 THE COLOUR-SENSE. 
 
 ised men doing to-day under our own eyes, primitive men 
 did centuries ago, when they framed the earliest colour 
 names. ^It would seem at present as though the various 
 terms for colours might be divided into two classes, the 
 truly abstract, such as Uite, green, yellow, and the concrete 
 used abstractly, such as lilac, orange, pink. The former 
 class appear to have no other meaning than that of pure 
 colour ; while the latter class are clearly derived from the 
 names of concrete objects. I But in reality, the difference 
 between them is merely one of time. Abstract colour 
 terms are the names of concretes, whose original significa- 
 tion has been forgotten. 
 
 Yet another general principle of vocabularies must be 
 considered, if we wish rightly to comprehend the growth 
 of colour names. Words arise just in proportion to the 
 necessity which exists for conveying their meaning. For 
 example, to take the specific case of colours, we have seen 
 a large number of colour terms introduced within our own 
 memory, because the hues to which they referred had 
 become fashionable as dyes for dress materials. Such 
 are the instances of mauve, 4cru, solferino, magenta, and 
 cardinal, every one of which has obtained a definite name 
 only because it had been employed in the drapery trade. 
 In short, we invent words as we need them. 
 
 Armed with these general truths, let us endeavour to 
 trace out the origin and development of the colour- 
 vocabulary. 
 
 Primitive man in his very earliest stage will have no 
 colour terms whatsoever. He will speak of concrete 
 objects only, and when he uses their names he will use 
 them as implying all their attributes. He does not need 
 to say red hlood, for all blood is red ; nor green leaves, for 
 all leaves are green. Blood and leaf by themselves are 
 quite sufficient for every one of his simple purposes. 
 
 But when man comes to employ a pigment, the name of 
 the pigment will easily glide into an adjectival sense. 
 The earliest colour terms will thus be produced. I learn
 
 GROWTH OF THE COLOUR-VOCABULARY. 255 
 
 from Mr. Whitmee that the Samoans use three kinds of 
 pigment — a red volcanic earth, a molluscan purple, and a 
 turmeric ; and the names of these three pigments are 
 applied as colour terms.^ So, too, many other informants 
 have given me like instances with other races./ A large 
 proportion of our own colour terms are derived from dyes 
 or pigments. Such are crimson (or cramoisi) from the 
 Arabic karmesi, the kermes ; ^ Termilion or vermeil, from 
 vermicidics, because it was supposed to be the product of a 
 worm ; ^ gamhogef hovn Can i]xidm,ilie-^lace_£>lita-export ; * 
 indigo, from Spanish indico, the Indian dye ; ^ and saffron, 
 from the common English plant. 
 
 Moreover, we saw that red is the earliest colour used in 
 decoration, and accordingly it is the earliest colour which 
 receives a special name^ This fact has been fully brought 
 out by the researches of Geiger, Magnus, and Mr. Glad- 
 stone ; and it will not therefore be necessary tp^ accumu- 
 late further proofs in the present volume.i^l'he early 
 prominence of red, however, has left some cilrious traces 
 in language, as well as in art, to the present day, which 
 deserve a passing notice here. Ssis-rthe Indo-European 
 dialects contain a number of words for this colour from a 
 common root — e-riitli-ros, mdjeus, russus, ruadh, roth, red, 
 rouge, rolhio, roux, ruddy, &c.^ while there is no such wide- 
 spread and common root for blue — cceruleus, hlau, azul — 
 
 1 In this case and in many others, the case of the Samoans were eJe, 
 correspondents have kindly supplied 2muli, and lenga respectively. Ac- 
 me with the words used by existing cordingly I have only inserted original 
 savages, or by early historical races, words in the text when they belong 
 such as the Assyrians, Hebrews, and to languages with which I am person- 
 Peruvians ; and I might have given ally acquainted, and with which I 
 a certain false show of erudition to may reasonably expect a fair famili- 
 the present chapter by inserting the arity on the part of the reader, 
 original terms as given. But really ^ Brachet, Dictionnaire Etymolo- 
 the important point for our purpose gique de la Langue Fran^aise, sub voc. 
 is the existence of the words, not ^ Ibid., sub voc. 
 their particular form, which is only ■* Isaac Taylor, Words and Places, 
 valuable for philological students, p. 409. 
 The reader would be none the wiser ^ Ibid., p. 409. 
 if I had stated that these forms in
 
 256 • THE COLOUR-SENSE. \ 
 
 nor for green — chloros, viridis, griln} AgaifiJ we English i 
 have a great number of subordinate colour terms in popular i 
 use to express the various shades of red, such as crimson, \ 
 scarlet, vermilion, rosy, and j?m^, besides less definite words i 
 like cherry, ruddy, russet, carnation, Hushing, sanguine or 
 ensanguined, ruby, and roseate; but we have, few or no ^^^ 
 words to express the shades of green,1wniie physicists 
 have had to introduce the conventional terms indigo and 
 violet to designate the widely different but unnamed hues ; 
 which result from the quickest light- waves. Once more, \ 
 while the nouns of brightness and its opposite give us \ 
 the verbs to lighten and to darken, to whiten and to hlachen, \ 
 and while the primitive art- colour, red, gives us the verb ! 
 to redden, we have no such words in our lancruaoje as to 
 Muen and to greenen. And it is a significant fact, as \ 
 regards the aesthetic position of green, that whereas the 
 use of " blue " in laundries has given rise to a technical 
 verb of washerwomen, to blue, we have absolutely no verb 
 meaning " to green " or " to viridise." Finally, the mixed 
 colours, orange and purple, into which red enters as an 
 element, have separate popular names, but no other mixed 
 colours have any but technical designations; and while 
 these red-like words, with yellow, the adjunct of red, yield 
 us the verbs to purple, to crimson, to encarnadine, to en- 
 saffron, and so f orth,^ I cannot call to mind a single similar 
 expression with reference to the less refrangible rays. 
 /During the period or stage in which red forms the main 
 or only decorative colour, red alone has a conventional or 
 abstract name. All other hues are spoken of by com- 
 parison with well-known objects, y It is not the habit of 
 the early mind to refer to the sky as blue, or the leaves as 
 
 1 Curtius, however (" Griecliisclie the HelleniG and Italian race from 
 
 Etymologie," sub voc), identifies the their Aryan ancestors, 
 
 roots of chloros and viridis. I must ^ j^ should be added, however, that 
 
 almost confess to a little scepticism ; these words are largely due to the 
 
 but the identification, if true, would special poetical effectiveness of red, 
 
 show that green was discriminated concerning which more hereafter, 
 and named before the separation of
 
 GROWTH OF THE COLOUR-VOCABULARY. 257 
 
 green; on the contrary, it speaks of blue things as "sky- 
 faced " (ccendeus), and of green things as " sprout-like " 
 {viridis, connected with virere ; griln, green, connected 
 with groiv). The primitive man would no more think 
 of saying that the sky was sky-faced, or the leaves leaf- 
 like, than we should think of talkinsj about an oranQ;e 
 oranc^e, or a lilac lilac. 
 
 But so soon as blue becomes a recognised art-colour, 
 either through the use of pigments or of decorative jewels, 
 a name for blue springs up. One of the commonest in 
 Europe is that of azure, azur, or azul, derived from the 
 Persian Idzur, lapis lazuli.^ "We have already seen that 
 this stone was very early imported from the east, and it 
 was natural that it should give a name to the hue in ques- 
 tion, because it was largely employed for artistic purposes. 
 Emerald and turquoise are similarly used at the present day 
 to designate various shades of green. 
 
 At this second or red-blue stage, the word for blue seems 
 often to be applied also to green. This is not surprising 
 when we recollect how very little difference really exists 
 between these two colours. Indeed, I am convinced that 
 we only have separate names for them at all because the 
 commonest green in nature, that of foliage, and the com- 
 monest blue in nature, that of the seldom-seen open sky, 
 are so very wide- spread and so much more strikingly 
 different from one another than most blues and screens. 
 But if we look at a turquoise, it is very hard to say 
 whether we should assign it to the former or the latter 
 colour ; while the sea is just as often the one as the other. 
 The original assumption of some natural object on the 
 borderland between the two as the concrete name-standard 
 would quite sufficiently account for the common confusion 
 
 1 The dropping of the initial I is iiarar?^^; Arabic, ndrar?/), "or the con- 
 probably due to its being mistaken for verse instances of a neivt for an eft, le 
 the definite article — Vazur. The ana- lierre for Vicrre [hcdera) will occur to 
 logous cases of an adder for a nadder, all philological readers, 
 and un orange for un narange (Spanish,
 
 2 58 THE COLOUR-SENSE. 
 
 between tliem in language. As a matter of fact, Mr. 
 Whitmee informs me that (the word for bine in Samoan is 
 literally sea-colour. The Welsh use glas indiscriminately 
 for both ; and the Assyrians, a ccording to Mr^-Sayce, 
 described green as either blue or yellow ; bttt-we^naw in 
 eaclHGas©- tlmt the tjolours theffiffelTes-wer^^^-are-aGurately 
 distiaguished. The Quiche Indians had also one word, rax, 
 for green and bluepk y^4h€re-£an j3eJittlfi_dQubtLof their 
 prpj)©£LpfLree^tions. / I believe the same explanation must 
 be offered of the alleged fact that the Burmese confuse 
 these two central colours ; but I have not been able my- 
 self to examine Bastian's account, and the gentlemen in 
 Burma to whom I addressed inquiries on the subject did 
 not reply to my circulars. At any rate, in Burmese 
 works of art, blue and green are acurately discriminated, 
 and blended with great taste. Certainly, Professor 
 Blackie showed/ at a meeting of the Eoyal Society of 
 Edinburgh, that the Highland Scots, who call sky and 
 grass both gorm, could perfectly discriminate bd^ween the 
 two colours when tried by practical tests^ It may 
 be added that certain hues which we ordinarily class 
 roughly together as reds, for instance that of bricks and 
 that of some light pink geraniums, are quite as far apart 
 from one another in consciousness as the green of the 
 eraerald and the blue of the sapphire. j 
 
 (^Yellow generally takes its first name from gold. Aureus 
 is the common Latin epithet, and golden hair still passes 
 muster in everyday colloquial English. Yon Bezold has 
 shown that yellow seldom enters into decorative art except 
 in a metallic form, and that it never rises to the same 
 distinct aesthetic prominence as red, green, and blue.^ \ 
 
 Green, above all other colours, has few names derived 
 from pigments, because it is so seldom employed for 
 decorative purposes. Most of its designations are directly 
 
 1 Sclierzer's Ximenez, p. 15, note. 
 2 Theory of Colours, American translation, pp. 138, 181, 194.
 
 GROWTH OF THE COLOUR-VOCABULARY. 259 
 
 derived from grass or leaves ; the remainder belong origi- 
 nally to fruits, to the sea, or to precious stones. 
 
 And now we have reached the point in the development 
 of the colour-vocabulary at which most semi-civilised 
 nations, all children, and the mass of uneducated adults, 
 always remain. Six colours are commonly recognised by 
 the popular mind — black and white, red and blue, green 
 and yellow. The first pair, of course, are merely words 
 for the total beam and its negation ; the second pair form 
 the earliest aesthetic analytic colours ; and the third com- 
 plete the ordinary differentiation. Add grey and brown 
 for the intermediate or muddily-mixed shades, and we 
 have the full colour- vocabulary of everyday life. Even 
 the educated only speak of scarlet, crimson, lilac, and 
 purple under exceptional circumstances, as in literary 
 composition or for technical purposes ; but to the mass of 
 mankind these lesser distinctions of language are wholly 
 unknown. 
 
 Heraldry has stereotyped this conception of colour in 
 its set language of or and argent ; gules, azure, and ixrt ; 
 and sahle. Here we have two metallic colours, those of 
 gold and silver; and four non-metallic, black, red, blue, 
 and green. Of the latter, one name, gules, is of oriental 
 origin, and, doubtless, points to some imported Arabic 
 pigment (perhaps vermilion) ; one, azure, is also oriental, 
 and has been already explained; the third, vert, is Latin 
 and imitative ; while the fourth, salle, is derived from 
 zibellino, sihelino, or siberino, the Siberian fur.^ The only 
 compound colour known in heraldry is puiyitre, while 
 rair and ermine are, of course, mere names of light and 
 shade in material. 
 
 Tfee ^further differentiation of the colour-vocabulary 
 depends, as before, upon the practical needs of intercom- 
 munication. I-fe4sr-s^^ rc[o j, roloped amung'tbrocr c la e^oo of 
 ps£»ec:s. ^The fa^class i^S3a*-of dyers, drapers, milliners, 
 
 1 Isaac Taylor, Words and Places, p. 415.
 
 26o THE COLOUR-SENSE. 
 
 and others who have to deal with coloured articles of 
 clothing ; their vocabulary includes numerous words, such 
 as cherry, cerise, lavender, lilac, mauve, solferino, magenta, 
 ecru, p7'i7nrose, and cardinal, besides purely technical 
 names like Paris-in-flames. As might be expected from 
 the usual course of fashion, a large proportion of these are 
 French. N The second class includes painters and other 
 artists, whose colour-vocabulary consists largely of pig- 
 ment names, such as lake, madder, ultramarine, carmine, 
 Prussian blue, gamboge, and ochre. The third class is that 
 of scientific physicists, whose language comprises terms 
 like cyanogen-blue, carnation, indigo, apple-green, and 
 sulphur-yellow. It may be added that the introduction of 
 fresh pigments from time to time produces a direct result 
 in enlarging one or other of these various lists. Thus, the 
 common use of aniline dyes at the present day has given 
 rise to a considerable number of new colour-terms. 
 
 Furthermore, special technical colour- words are used in 
 restricted senses as applied to animals or other objects by 
 different trades. Thus the names chestnut, bay, sorrel, and 
 roa7i are only used of horses ; while black, ivhite, Q'^^y, ^^d 
 cream-coloured are employed with specialised significa- 
 tions of the same animals. Cats claim a monopoly of 
 tortoise-shell ; and tan (in the phrase black and tan) forms 
 the peculiar property of terriers. Hair alone is auburn, 
 ajid only eyes are hazel. 
 >o ^ I It may be interesting, before we pass away from this 
 ' part of our subject, to give a brief formal classification of 
 the various concrete origins from which abstract colour- 
 adjectives have been derived. I shall take my examples 
 only from the commonly-known English words. 
 
 Two main classes may be distinguished — the Pig- 
 mentary and the Metaphorical. 
 
 Pigmentary colour-names fall under three heads. First, 
 the material — as vermiliooi, crimson, saffron, indigo; second, 
 the local — as gamhoge, Prussian blue. Par is green ; third, the 
 conventional or artificial — as magenta, solferino, cardinal.
 
 GROWTH OF THE COLOUR-VOCABULARY. 261 
 
 The last-named head is quite modern, and of slight philo- 
 logical value. It belongs to the conscious stage of word- 
 making. 
 
 Metaphorical colour-names fall under four heads. First, 
 elemental — as shy-Uue, sea-green, muddy. Second, vegetal — 
 as green, from foliage ; as pink, molet, rose, lavender, prim- 
 rose, lilac, from flowers ; as orange, cherry, chestnut, hazel, 
 from fruits. Third, mineral — as golden, silvery, azure, sap- 
 phire, rioby, emerald, turquoise, amethyst, amber, and jetty ; 
 with which we may fairly class certain animal epithets, 
 such as coral, ivory, and pearly. Fourth, miscellaneous — 
 as sable, sanguine, snowy, chocolate. } 
 
 And now we must pass on £0 a second question, the 
 reason for the great vagueness of all colour terms. 
 
 I believe the solution of this difficulty is to be found in 
 the nature of the colour sensations themselves. They are 
 nowhere clearly marked off from one another by definite 
 lines. The solar spectrum contains an infinite gradation 
 of hues, each of which fades into its neighbour by im- 
 perceptible degrees. It is impossible to name them all, 
 because their number is really incalculable. Hence we 
 are reduced practically to inventing names for the most 
 prominent. 
 
 A glance at the other senses wiU throw much light 
 upon the present problem. In taste, we distinguish a 
 fairly large number of sensations by separate names — 
 sweet, bitter, pungent, sour, acrid, and so forth; but we 
 have no separate word for the flavour of a peach, a straw- 
 berry, and a grape. We refer to them by the concrete 
 name of the object as a whole, just as primitive man does 
 with the coloui^s. In smell, we have even a smaller 
 number of distinctive terms, for we only speak of them 
 as sweet or stinking ; and these words refer, not to the 
 intelligible qualities of the scent, but simply to its emo- 
 tional aspect. In hearing, we generally employ the two 
 expressions high and low, or their equivalents, treble and 
 bass. But here we have elaborated for special technical
 
 262 THE COLOUR-SENSE. 
 
 purposes a far more accurate and quantitative nomen- 
 clature ; a nomenclature infinitely superior to that of any 
 other sense, not excepting the sense of colour. The divi- 
 sion of the audible gamut into octaves and notes, further 
 divisible into semitones, and for very discriminative ears 
 into minor fractions, down to one-sixty-fourth of a tone, 
 enables us exactly to express in language the very minu- 
 test possible varieties of sensation. This admirable system 
 of nomenclature is rendered practicable by the peculiar 
 constitution of the ear, and by its special adaptation to 
 the regular harmonic intervals. 
 
 In sight, however, no such minute discrimination is 
 possible. We can indeed divide straight lines into inches, 
 half-inches, and eighths-of-an-inch ; while the microscope 
 further enables us to discriminate decimals, hundredths, 
 and so forth, down to extremely minute fractions. But 
 in colour our eye is not fitted for noting at once the 
 relative distance of rays in the spectrum, as our ear is 
 fitted for notinfy the relative distance of tones in the 
 gamut. Accordingly, we must have recourse to some 
 artificial system. 
 
 Such a system was proposed by Chevreul in his "Expose 
 d'un moyen de definir et de nommer les couleurs d'apres 
 une methode rationale et experimentale ; " ^ but, unfortu- 
 nately, that great chemist took for his basis the mixture of 
 pigments, not that of rays; ^ and his method is consequently 
 incorrect and insufficient. 
 
 Another plan, in common use amongst physicists, is to 
 designate the colours by their proximity to one of the 
 lettered lines in the solar spectrum. Thus cyanogen-blue 
 may be approximately defined by saying that it lies a 
 little to the violet side of the line F. But this plan is, of 
 
 1 Memoires de I'Academie des Helmlioltz's classical work on " Phy- 
 
 Sciences, vol. xxxiii., 1861. siological Optics." The English reader 
 
 - For an explanation of this cardinal will find a lucid resume of the ques- 
 
 distinction, too fundamental for ex- tion in Professor Tyndall's little book 
 
 position in the present volume, see "On Light."
 
 GROWTH OF THE COLOUR-VOCABULARY. 263 
 
 course, too indefinite and too little numerically accurate 
 for scientific use. 
 
 The only perfect method would consist in an artificial 
 division of the solar spectrum into a number of equal 
 parts, say one hundred, and the invention of a separate 
 name for each such hundredth part. This system has 
 been partially carried out, though in a very complicated 
 manner, in Lambert's colour-cone, adopted as a basis by 
 Helmholtz and Clark Maxwell. The only further modifi- 
 cation required, is that of an extended numerical nomen- 
 clature. 
 
 Before we go on to examine the application of the 
 general principles here laid down to the special cases of 
 the Hebrews and the Homeric Akhaians, adduced by Dr. 
 Magnus and Mr. Gladstone, it may be worth while to 
 glance briefly at the special poetical effectiveness of the 
 colour-vocabulary. As the authors of the Akhaian epics, 
 and of many among the Hebrew books, were themselves 
 poets, the use of colour terms by other poets may help 
 us to estimate more correctly the true value of the 
 evidence in their cases. 
 
 Eed is pre-eminently, and beyond all comparison, the 
 poetical colour. It is applied to every object which by 
 any straining of courtesy can possibly be conceived as 
 possessing it ; and it is often attributed to other objects 
 which have no claim whatsoever to the title. Thus we 
 have red gold, red lions, red right hands, red kings, the 
 red Douglas, and even red wrath. The great red sun 
 sinks nightly, amid red clouds, into the red waters of the 
 sea. Eosy- fingered dawn spreads crimson glories over the 
 empyrean ; the scarlet flush of eventide encarnadines the 
 fiery sky. A great many reasons conspire to produce this 
 effect. In the first place, red, as we have abundantly 
 seen, is the most universally pleasing of all colours. Then 
 again, it was the first colour employed in art-workman- 
 ship, and so, as Mr. Gladstone graphically puts it, " got 
 the start" of all the others. This further secured it a
 
 264 THE COLOUR-SENSE. 
 
 certain poetical prescriptiveness, especially as a stock 
 epithet in some well-known conjunctions, like those 
 noted above. Finally, its special use as an adjunct of 
 royalty or state ceremonial gives it a peculiar claim to 
 poetical use. 
 
 N'ow, I am not a great believer in that system of word- 
 counting which is so favourite a device with Mr. Glad- 
 stone. It appears to me a fallacious and illegitimate 
 application of seemingly rigorous statistical methods, for 
 the value of the word can never be properly appreciated 
 apart from its context. Nevertheless, in order to meet 
 the enemy with his own weapons, I have counted up 
 all the colour-epithets in Mr. Swinburne's " Poems and 
 Ballads," a volume which I have purposely selected, 
 because it represents the spirt of traditional poetry in its 
 purest form. I find the results to be as follows : — The 
 word red occurs in all 151 times, together with rosy, crim- 
 son, once each, and sanguine, ruddy, scarlet, twice each : 
 total of the pure red epithets, 159. Ze/Zo?^ is mentioned 
 13 times, ^(X2^/'7i?/ once ; but the more poetical word gold 
 numbers 113 repetitions, and golden 16: total of the 
 yellow epithets, 143. Purple comes in for 23 notices. 
 Grand total of red-end epithets, 325. On the other hand 
 hlue occurs 25 times, and violet once; total, 26. Green 
 obtains mention in 86 places. Total of the violet-end 
 epithets, no. The only other colour term is Irown, em- 
 ployed 10 times. Now, I acknowledge that this is an ex 
 parte statement, for three reasons : I have reckoned the 
 word gold, which is sometimes a noun and sometimes an 
 adjective, as though it were always the latter; I have 
 counted pi6?'^Ze as a red-end word, though it miglit equally 
 claim to belong to the violet ; and I have clubbed together 
 red and yellow. But Mr. Gladstone also makes ex parte 
 statements, and mine seem to me much more justifiable 
 than his. For gold is undoubtedly a favourite word in 
 poetry, largely on account of its colour and glitter ; purple 
 undoubtedly owes its effectiveness to its red, not to its
 
 GROWTH OF THE COLOUR-VOCABULARY. 265 
 
 blue element ; and the yellow of golden is a colour wliich 
 may very fairly rank with red and orange. On the other 
 hand, I have allowed all the greens, though many of them 
 are not colour-words at all, and though the number of 
 objects which may properly be called green is out of all 
 proportion to the number of objects which may properly 
 be called red. The true significance of the list is best 
 seen by comparing the 2 5 Uues with the 151 reds. To 
 adopt the statistical form, we might say (if we chose to 
 reckon the unreckonable) that red is 500 per cent, more 
 poetical than blue ! 
 
 For comparison with these results, I have also extracted 
 the colour- words from Mr. Tennyson's " Princess," and I 
 find they stand in the following proportions : — Bed occurs 
 10 times, crimson 3, rosy 3, rosed (as an adjective) once, 
 imhy once, and ruhric once ; while the verb to redden has 
 also one mention. Golden is employed 1 3 times, gold 7, 
 gilded 3, gilt twice, yellow once, orange once, and the verb 
 to gild once. Purple occurs 6 times, purpled once, and em- 
 purpled once. Total of the red-end epithets, 56. On the 
 other hand, green is used 5 times (not always as a colour 
 term). Hue once, azure three times, lilac once, and violet 
 once. Total of the violet-end epithets, ii. So that Mr. 
 Tennyson also finds red and yellow just five times as 
 poetical as green and blue. 
 
 There are, however, some other more useful deductions 
 to be made from the above lists. Observe, in Mr. Swin- 
 burne's case, the want of variety, the paucity of colour 
 terms as a whole — the total absence of orange^ lilac, pink, 
 azure, saffron, vermilion, or lavender. This absence is due 
 to the fact that Mr. Swinburne faithfully echoes the old 
 ballad poetry, with its relatively poor but strong voca- 
 bulary — its preference of bold outline to finished detail. 
 There are none of the conventional prettinesses of the 
 eighteenth century ; none of the refined distinctions of our 
 modern miniature word-painters. Mr. Tennyson puts in 
 colour phrases with the fidelity of a Dutch landscape ;
 
 266 THE COLOUR-SENSE. 
 
 but Mr. Swiuburne throws on his broad contrasts with the 
 rich sensuousness of an Egyptian or Mediaeval colourist. 
 
 Observe, too, the preponderance in both poets of gold 
 and golden. The secret of this peculiarity is to be found 
 in the emotional associations of costliness which the words 
 suggest. So we find the poets (especially the common- 
 place) are fond of silvery locks, coral lips, sapphire seas, 
 ruby wine, emerald eyes, amber tresses, ebon locks, pearly 
 teeth, and ivory brows. All these points serve to elucidate 
 the real nature of the poetic colour-vocabulary. It is 
 archaic, it seeks immediate effect, and it lays stress upon 
 associated emotions. 
 
 In order further to impress these facts, I have analysed 
 a few examples of well-known English poetry, and ex- 
 tracted the colour terms, or words bearing on colour, and 
 with the following results : — 
 
 The first two books of Mr. E. T. Palgrave's "Golden 
 Treasury of Songs and Lyrics," embracing the Elizabethan 
 and Miltonic periods, contain : pure colour-epithets — red 8 
 times, green 6, hlne i6, yelloiu 4 ; impure colour-epithets — 
 hhishing 2, crimson 2, ruby 2, rermeil 2, hricky i, sanguine 
 I, rosy 3, cramasie i, russet i, purple 4, orange i, saffron i, 
 golden 13, gilded I, greenish i, and azure I. White occurs 
 in 18 places, Hack in 6, snowy 2, whiter i, sable 4, ebon i, 
 swart I, grey 3, broion 2, and nut-brown i. Among con- 
 crete coloured objects, flower is mentioned 28 times, jpos?/ 
 twice, and blossom once; rose 21, lily 7, daffodil 2, daisy 3, 
 violet /\., primrose 2, cowslip i, may i, pansy i, woodbine i, 
 jessamine i, croiv-toe i, pink i, garland 4, and flowery 2. 
 Cherry occurs 6 times. Gold counts for 6, iwarl 6, diamond 
 I, coral 5, amber 2, sapphire 3, silver 8, ivory i,and crystal 
 8. Sunset and rainbow are mentioned once each. The 
 only other words suggesting colour are ensaffron and 
 variable in the sense of variegated. 
 
 This list, I think, serves to show two or three of our 
 main points. In the first place, it is quite clear that if 
 we take the various red and yellow adjectives, and their
 
 GROWTH OF THE COLOUR-VOCABULARY. 267 
 
 corresponding concretes, they enormously outnumber the 
 greens and blues. Next, it is instructive as showing how- 
 unfair is an enumeration by simple epithets alone. Again, 
 the number of metaphorical colour words which it contains 
 must strike us at once. And, lastly, the number of allu- 
 sions to gems, or their organic equivalents, is very great. 
 
 Gray's " Bard " yields as follows : — crimson, ruddy, hlusJi- 
 ing, and golden, once each, sable twice. Shelley's " Skylark," 
 golden twice, purple, green, blue, white, and silver, once 
 each. Shelley's " Euganean Hills," green three times, red, 
 purple, and golden twice each, crimson, blue, azure, sapphire- 
 tinted, black and grey once each. Total, red and yellow 
 14 times, blue and green 8 times. I obtain pretty similar 
 proportions in many other cases. 
 
 And now let us turn to our final question — the examina- 
 tion of the Homeric and Hebrew colour- vocabulary. 
 
 As regards the Akhaians, Mr. Gladstone tells us that 
 they could not have understood real colours by their 
 apparent colour terms, because the words are used so 
 loosely. An adjective here applied to a red object is there 
 applied to a black one. Here, green means green ; there, 
 it means fresh or young. So be it. Has Mr. Gladstone 
 never heard of red blood, red skies, red bricks, and red 
 Indians ? Do Englishmen never talk of a green old age, 
 or Americans of green corn, which is really pale yellow ? 
 Is not red blood confronted with sangre azul, and red wine 
 with the petit vin bleu ? When an untrained speaker talks 
 of purple does he not mean violet, and when he talks of 
 violet does he not mean ultramarine ? Did any man ever 
 really possess red hair or blue eyes ? In short, are not 
 colour terms always vague, and are they not vaguer 
 in the idealised language of poetry than anywhere else ? 
 The later Greeks were themselves aware of the deficiency 
 in their colour-vocabulary, as is shown by a passage in 
 Athenseus (" Deipnosophists," xviii. 31).^ Mr. Gladstone's 
 
 1 My attention was called to this son Smith in "Nature," December 
 passage by a note of Professor Robert- 6th, 1877.
 
 268 THE COLOUR-SENSE. 
 
 microscope lias brought out one result, let us see what 
 result the comparative method will bring out on the other 
 hand. I shall take the liberty of dogmatising in opposi- 
 tion to his dogmatism, and I shall leave the decision be- 
 tween us in the hands of the critical reader. ^ 
 
 The Homeric Akhaians were a sub-barbaric race, who 
 had reached the stage of culture at which the use of pig- 
 ments is practised, but who only employed red and a 
 reddish purple in staining or dyeing. Their colour- vocabu- 
 lary is exactly accommodated to such a stage. One true 
 abstract adjective exists for the colour red ; two pigmentary 
 adjectives express the red dye and the reddish purple dye : 
 a second abstract adjective denotes yellow ; and all other 
 hues are designated by metaphorical colour-terms. Fur- 
 thermore, light and shade adjectives and glitter adjectives 
 naturally preponderate over true colour epithets ; because 
 metals and precious stones, together with such other 
 similar objects as ivory and horn, were more prized than 
 dyes or pigments. 
 
 The abstract red colour epithet is crutliros. This is an 
 ancient Aryan word, whose deriva(tives express the idea 
 of redness in all the languages in which they occur. It 
 would be hopeless now to decide whether it was originally 
 a pigmentary or a metaphorical adjective. Long before 
 the age at which the Homeric ballad-writers lived, it had 
 become a true abstract word. That it meant red and 
 nothing else is clear, not only from the cognate languages, 
 but also from its being applied to only four objects, 
 namely, copper (Iliad, ix. 365), nectar (Iliad, xix. 38 ; 
 Odyssey, v. 93), wine (Odyssey, v. 165 ; ix. 163, 208 ; xii. 
 19, 327 ; xiii. 69; and xvi. 444), and blood (Iliad, x. 484; 
 xxi. 21), every one of which is red. When we say red 
 
 ^ Were this a mere specialist ques- them by comparison with the language 
 
 tion of Greek scholarship I would not and the arts of people in a correspond- 
 
 f or a moment claim to be heard upon ing stage of culture elsewhere. The 
 
 it. I make no pretensions to minute matter is one for the ethnologist and 
 
 classical knowledge ; but I can read the psychologist, not for the professed 
 
 my Homeric authors, and I judge Grecian.
 
 GROWTH OF THE COLOUR-VOCABULARY. 269 
 
 we mean red, and not crimson, scarlet, russet, or any sub- 
 species. 
 
 Tlie red pigmentary epithet is some compound of 
 phoinix. What the material so named may have been 
 we cannot know with certainty ; but the uses of the word 
 show clearly that it was a bright scarlet. In Iliad, iv. 141, 
 it is mentioned as a stain employed in decorating ivory 
 to form an adjunct of chieftainship, and its colour is there 
 described as like that of fresh blood, flowing from an open 
 wound. Nothing could be clearer or more explicit than 
 this, and nobody but a theory-maker could mistake its 
 meaning. That one passage is quite enough to show 
 that the Akhaians saw red. To suppose that a race 
 devoid of colour-sense would take the trouble to use dyes 
 is about as rational as to suppose that a race of deaf-mutes 
 would spend their time in the manufacture of pianos. 
 Elsewhere the word (or its derivative) is applied to a red 
 horse and a red lion. As a blood epithet it occurs in one 
 form or another six times (Iliad, xii. 202, 220; xvi. 159; 
 xviii. 538; xxiii. 716; Odyssey, xviii. 96). It is also 
 used for cloaks and mantles, which are never called 
 erutliTos, and for a very good reason ; the pure abstract 
 colour epithet is applied to wine, copper, and blood, which 
 are self-coloured ; but the pigmentary adjective is natu- 
 rally given to the artificial objects stained with it. Thus 
 the girdle in Iliad, vi. 219; vii. 305 and Odyssey, xxiii. 
 201, is said to be dyed with phoinix. So, too, are the 
 prows of ships, like the war-canoes of so many savage 
 tribes, in the phrase phoinikopareos. Of course, the word is 
 sometimes extended to naturally-coloured objects — blood, 
 horses, and jackals — but the primitive pigmentary sense 
 is pronounced throughout, and the transference is too 
 easy and simple to call for special explanation. 
 
 A minor red pigmentary adjective is miltqmreos, also 
 applied to the war- canoes. The milt may very likely 
 have been an ochreous earth. It occurs in too specialised 
 a connection to hazard a guess upon its exact hue.
 
 270 THE COLOUR-SENSE. 
 
 The r eddish purple pigmentary adjective is porplmreos. 
 There is very little reason to doubt that this applies to 
 the Tyrian murex dye. At any rate, it was a stain em- 
 ployed for artificial colouring, and its derivation is from a 
 verb meaning to mix together, or, more literally, to middle- 
 muddle. Its commonest use is in connection with clothing, 
 especially the clothing of the chieftains. The word is 
 employed as an epithet of carpets (Iliad, ix. 200, Odyssey, 
 XX. 278), coverlets (Iliad, xxiv. 643), mantles (Odyssey, xix. 
 225), cloaks (Iliad, viii. 221, Odyssey, viii. 85), clothing 
 (Odyssey, xiii. 108), gowns (Iliad, xxiv. 796), the web in 
 spinning (Iliad, iii. 125 ; xxii. 441), and the wool on the 
 distaff (Odyssey, vi. 53, 306). It is also applied to a sort 
 of cricket ball (Odyssey, viii. 373). In all these cases, it 
 refers to objects actually dyed with the pigment. As a 
 secondary colour epithet it occurs with reference to the 
 purple rainbow (Iliad, xvii. 547), the purple stream of 
 blood (Iliad, xvii. 361), the purple sea (Iliad, i. 482, and 
 three times elsewhere), and the purpling of the soul in 
 terror (Iliad, xxi. 551). 
 
 The other red epithets are metaphorical. They include 
 " rose-like " rhodoeis, " wine-faced " oinops, and " pretty- 
 cheeked " kallipareos. 
 
 The abstract yellow colour epithet is xantJios. It is 
 applied to human hair, to horses, and to the brook of that 
 name. But in the Homeric poems, as in all other poetical 
 writing, yeUow is generally described by gold or golden. 
 
 Blue has only two words, both metaphorical. The first, 
 hualdnthinos, is derived from some flower, possibly a 
 hyacinth. It occurs but sparingly. The second word, ioeis 
 or ioeides, is undoubtedly the colour of the violet — that is, 
 ultramarine. The sea is three times spoken of as " violet- 
 faced" (Iliad, ix. 29S ; Odyssey, v. 55 ; xi. 106), and it can- 
 not be denied that the sea is sometimes (though rarely) blue. 
 ' Violetish ' is also used of blue steel. We must remember, 
 in this connection, that the pottery of Troy and Mycense 
 is coloured red and yellow, never blue. But once, in 
 Odyssey, iv. 135, we get the startling word, iodnephcs,
 
 GROWTH OF THE COLOUR-VOCABULARY. 271 
 
 " violet-darkened," or dyed blue, applied to wool. This 
 would seem as though towards the close of the epic period, 
 w^hen the Odyssean ballads w^ere composed, a blue dye 
 began to make its appearance. On this point we shall find 
 hereafter a Hebrew analogy. 
 
 Green is always designated by "grass-like" {kliloros). 
 The derivation is from kliloS, herbage. The word is seldom 
 applied to literally green objects, because such are generally 
 leaves or other vegetal products, of which the name alone 
 is sufficient to describe the colour. The ballad-maker 
 loves to dwell on red wine, scarlet robes, purple carpets, 
 golden helmets, glistening bronze ; but why should he 
 need to tell us about the common green leaves or the 
 blue sky overhead ? These things belong to the poetry of 
 civilised man, the town dweller ; but they find no natural 
 place in the rude songs which tell the tale of savage royalty 
 and bloody fights. 
 
 Herein we get the real secret of the Akhaian colour 
 nomenclature. The many brilliant objects of external 
 nature for which we require such varied names — the 
 flowers, the birds, the butterflies — these were of little 
 importance in the eyes of those bloodthirsty warriors, 
 whose greatest joy was the hharmi, the battle-ecstasy, the 
 delight in slaying. Only a very few flowers have separate 
 names in the poet's vocabulary: as a rule mere vague 
 references sufiice for all his needs. The objects which he 
 most wishes to describe are men, horses, cattle, whose 
 hues are indefinite, impure, and very variable in different 
 individuals. Bronze, gold, silver, garments, war-canoes, 
 royal furniture, sceptres, and rude palaces, these supply 
 him with a few epithets of dyes or natural colours. But 
 when he turns to nature, it is the great wholes alone 
 which attract his attention ; the sea, white, or blue, or 
 green, or grey, or purple, in its changeful moods ; the sky, 
 coppery, or azure, or leaden, or black with storm-clouds, 
 or crimson with the sunset, or gilded with the rays of 
 daAvn. Earth, mountains, rivers, sands, and rocks, all
 
 272 THE COLOUR-SENSE. 
 
 these afford him no fixed and regular sensations. Hence 
 his language is necessarily indefinite and vague. The 
 epithet that suited the sea in this line suits the sky in 
 that. What is the colour of a horse, of a cow, of the 
 human race, of water, of clouds, of the ship under weigh ? 
 Eed, or black, or white, or grey, or what you will. 
 
 In truth, the primitive man shows his acute colour 
 perceptions by the accurate manner in which he detects 
 faint undertones of hues hardly suspected at a first rough 
 glance. How sharp is the eye which notes the almost 
 imperceptible tinge of greenness in the face of fear, and 
 likens it at once to the full green of grass ? How keen is 
 the sense which catches the sliq-ht difference of shade 
 between the black Douoias and the red Doudas, between 
 the O'Connor Don and the O'Connor Eoe ! The most 
 insignificant trace of ruddiness in the soil entitles a place 
 to be called Edom, Eriithrai, or Rutland; the merest 
 suspicion of yellow gives us such names as Xantlws and 
 Hoang Ho. In short, if one object be a little darker than 
 anotlier, the quick-minded savage calls it black ; if it have 
 a tiny infusion of blueness, he says it is sky-faced. 
 
 As for the indirect traces of colour-perception in the 
 Homeric poems, I need only point to such casual references 
 in the Iliad as " saffron-robed Dawn " (Iliad, viii. i ) ; the 
 many-coloured metals of Agamemnon's armour (xi. 15); 
 the jewelled girdle of Aphrodite (xiv. 181); the silver, 
 gold, bronze, and tin of AkhiUes' shield (xviii. 474) ; or 
 the cup, " wrought by cunning Sidonian workmen, and 
 brought by Phoenician men across the sky-blue sea" 
 (xxiii..743). Then there are the occasional references to 
 flowers, roses, violets, hyacinths, and crocuses. But 
 perhaps the best proof of all is that afforded by the 
 wardrobe of Hekabe, "wherein were her many-coloured 
 {pam'poikiloi) robes, Sidonian women's work, which god- 
 like Alexander brought himself from Sidon-land, sailing 
 across the mighty sea." Amongst all these, Hekabe chose 
 for Athene " that which was loveliest in , figured dyes
 
 GROWTH OF THE COLOUR-VOCABULARY. 273 
 
 {poikilmasin), and largest eke, and as some star it shone ; " 
 and rosy-cheeked Theano laid it on the knees of the 
 golden-haired, hazel-eyed goddess. How singularly appro- 
 priate all these phrases would sound in the mouth of a 
 poet who did not know one colour from another ! 
 
 And now let us pass on to Geiger's instance of the 
 ancient Hebrews. Here I can only trust to the Authorised 
 Version of the early books, for I am no Hebraist ; but I 
 have secured the kind assistance of a distinguished 
 specialist, the Eev. T. K. Cheyne, and I venture to submit 
 my results as follows : — 
 
 The Hebrews of the kingly age were one step in advance 
 of the Homeric Akhaians, as regards their employment of 
 pigments, and the wealth of their colour- vocabulary. This 
 might naturally be expected from their closer connection 
 with the civilised communities of Egypt and Assyria. 
 They appear to have employed three pigments, a red, a 
 purple, and a blue ; and they had a word in common use 
 for OTcen. 
 
 o 
 
 The history (or legend) of the Tabernacle gives an account 
 of the objects to be offered for sacred purposes, which in- 
 clude " gold, and silver, and brass ; and blue, and purple, 
 and scarlet; and fine linen, and goats' hair; and rams 
 skins dyed red, and badgers' skins ; and shittim wood ; oil 
 for the light, spices for anointing oil, and for sweet incense; 
 onyx stones, and stones to be set in the ephod and in the 
 breastplate." ^ The curtains of the Tabernacle were to be 
 made of " fine twined linen, and blue and purple and 
 scarlet," ^ and fringed with " loops of blue." The same 
 stereotyped conjunction of "blue and purple and scarlet" 
 reappears, with true Hebrew monotony, in the veil (Exod. 
 xxvi. 31), the hanging for the door (xxvi. 36), the gate 
 of the court (xxvii. 16), and elsewhere during the subse- 
 
 ^ Exod. XXV. 4-7. I have quoted course, the date of its composition is 
 this passage entire, because it illus- purely conjectural. r 
 
 trates well the aesthetic stage of the 2 W^i^, xxvi. i. 
 time when it was written, though, of 
 
 S
 
 274 THE COLOUR-SENSE. 
 
 quent chapters no less than nine times. Various minor 
 portions of the sacerdotal costume are specially restricted 
 to one hue. Gold and other precious objects occur in 
 profusion. 
 
 The account of Solomon's Temple shows the same three 
 prevalent colours, and no others, used as pigments.^ As 
 before, the veil was made " of blue and purple and crim- 
 son and fine linen," ^ under the direction of a half-caste 
 Phoenician, whose father was a man of Tyre, " skilful to 
 work in gold and in silver, in brass, in iron, in stone, and 
 in timber ; in purple, in blue, and in fine linen, and in 
 crimson ; also to grave any manner of graving, and to find 
 out every device."^ To multiply examples would only 
 prove tedious to the reader, without adding materially to 
 the arsjument. 
 
 I learn from Mr. Cheyne that these words might be 
 more correctly translated Uue-purple, red-purple, and crim- 
 son. The first two colours were obtained from mollusca, 
 and the third from the cochineal-insect. The derivations 
 of the words meaning hlue-purple and red-purple are un- 
 known, but they occur in the same combination in Assy- 
 rian ; that of the third is from the Hebrew word for " a 
 w^orm." The term translated crimson in the Chronicles is 
 a later name for the same colour which is called scarlet in 
 Exodus, and its origin is perhaps Persian. 
 
 Furthermore, the allusions to precious stones (whether 
 the words referring to them be correctly translated in 
 every case or otherwise) clearly exhibit the aesthetic 
 standing of the people. The breastplate of judgment con- 
 tained twelve jewels — sardius, topaz, carbuncle, emerald, 
 sapphire, diamond, ligure, agate, amethyst, beryl, onyx, 
 
 1 I give no opinion upon the chro- colour perception among the Hebrews 
 
 nological and historical question, as the existence of Agamemnon or the 
 
 because I am not competent to form personality of the supposed Homer 
 
 one. The date of the writer and the with the same fact among the early 
 
 credibility of the narrative, however, Akhaians. 
 have as little to do with the fact of ^ aChron. iii. 15, etal. 3 ibid, ii. 14.
 
 
 GROWTH OF THE COLOUR-VOCABULARY. 275 
 
 and jasper.i The jewel called sapphire was certainly 
 blue ; for the " God of Israel " is described as standing on 
 " a paved work of sapphire stone " — in other words, on the 
 solid firmament.^ Solomon's Temple was " garnished with 
 precious stones for beauty,"^ and other notices of the 
 same sort occur elsewhere. 
 
 Besides these directly aesthetic accounts, we find scat- 
 tered colour terms throughout all the books. In the very 
 early myth of Joseph we read of a " coat of many colours."* 
 " Eibbands of blue " were enjoined on the people in the 
 desert.^ Eahab agrees with the spies to hang out " scarlet 
 thread " as a signal.^ Tamar wears a " garment of divers 
 colours, for with such robes were the king's virgin daugh- 
 ters apparelled."'^ Aholah, in Ezekiel's fable, doted on her 
 lovers, the Assyrians, who were ''clothed in blue;"^ and 
 Aholibah on "the images of the Chaldeans pourtrayed 
 with vermilion," "exceeding in dyed attire upon their 
 heads." Much doubt hangs over the first and fourth of 
 these renderings; but I give them in the words of the 
 Authorised Version (preserving the traditional belief) for 
 what they may be worth. 
 
 Green, however, is never mentioned during the native 
 kingly period as a decorative colour. " Green pastures " 
 in Psalm xxiii. 2, "might be better translated 'tender 
 grass ; ' " but we must remember that almost all words for 
 green originally refer to growth or freshness. On the 
 other hand, the "green herb" in Gen. i. 30 (literally 
 " every greenness of herbage") has the notion of colour 
 original, according to Mr. Cheyne, " or at least early 
 reached by usage." The corresponding word in Arabic, a 
 leading scholar in that language informs us, means rather 
 grey than green : and this vagueness is exactly paralleled 
 by that of the Greek kliloros. Both cases show, not that 
 green was unperceived, but that it ranked low in assthetic 
 value. 
 
 1 Exod. xxix, 17. 2 Ibid., xxiv. 10. ^ yvir.b. xv. 3?. ^ Josh. ii. 18. 
 ^ 2 Chron. iii. 6. ^ Qgu_ xxxvii. 3. ^2 Sam. xiii. 18. ^ ^-^^ik.. xxiii. 6.
 
 2/6 THE COLOUR-SENSE. 
 
 Yet though green found no place in the decorations of 
 the Tabernacle or the Temple, it is once mentioned in 
 the Authorised Version, among the ornaments of a foreign 
 court, when Ahasuerus the king feasted in Shushan the 
 palace, " where were white, green, and blue hangings, 
 fastened with cords of fine linen and purple to silver 
 rings and pillars of marble : the beds were of gold and 
 silver, upon a pavement of red, and blue, and white, and 
 black marble." ^ Now, though Mr. Cheyne tells me that 
 modern philology has decided in favour of the translation 
 " cotton " instead of " green," yet when we examine the 
 peculiar position of this word in the sentence, and then 
 recollect the ancient Persian fondness for green, with the 
 constant appearance of that hue on the Babylonian and 
 Ninevite enamelled bricks, I can scarcely help believing 
 that in this case the traditional rendering closely represents 
 the truth. Mr. Cheyne himself, indeed, inclines to think 
 that though the word means etymologically " cotton," yet 
 some idea of colour (he suggests " variegated ") is mixed 
 up, with it in practice. Perhaps, then, we may have here 
 an analogous advance to that of the Akhaians from red, 
 purple, and yellow decorations to the artistic employment 
 of blue. In any case, we can scarcely doubt that the 
 Hebrews after the Captivity must in great part have 
 adopted the aesthetic standard of their Semitic and 
 Aryan conquerors. 
 
 One final example of Mr. Gladstone's method must be 
 given apropos of the Hebrew colour-sense. Ezekiel de- 
 scribes in glowing language the truly oriental vision in 
 which his poetic eye beheld in imagination the glories of 
 the God of Israel, "Above the firmament," says the 
 prophet, " was the likeness of a throne, as the appearance 
 of a sapphire stone : and upon the likeness of the throne 
 was the likeness as the appearance of a man upon it. 
 And I saw as the colour of amber, as the appearance of 
 fire round about within it . . . and it had brightness 
 
 1 Esther i. 7.
 
 GROWTH OF THE COLOUR-VOCABULARY. 277 
 
 round about. As tlie appearance of the bow that is in the 
 cloud in the day of rain, so was the appearance of the 
 brightness round about it." ^ Mr. Gladstone quotes in part 
 this perfectly pellucid passage, and thus comments upon 
 it : " Which cannot be explained but by supposing that, 
 for the eye of the prophet, red was the fundamental, and 
 exclusively prevailing, colour of the rainbow." Any un- 
 prejudiced person would have imagined that the w^ords 
 " could not be explained but by supposing " the prophet 
 to mean exactly what he says — that a halo of every hue 
 in the rainbow surrounded the sapphire throne, where the 
 God of Israel was seated, begirt with amber flames, looking 
 down upon the work which was like unto the colour of a 
 beryl, and planting His foot on the firmament, whose 
 appearance was of terrible crystal. But literal interpreta- 
 tion will sometimes lead men into a strange confusion of 
 the obvious. 
 
 As for the Yedas, I shall not attempt to deal with them. 
 That " book with seven seals," as Professor Max Milller 
 calls it, can be easily made to prove that black is white, 
 or vice versa : and therefore to juggle with its colours is 
 a mere piece of simple conjuring. If the reader believes 
 that the case for Dr. Magnus has broken down so far, he 
 will hardly attach much importance to the doubtful 
 utterances of the Sanskrit Scriptures. 
 
 And now that our review is completed, it may, perhaps, 
 appear to some readers that, in combating this " historical 
 development " theory, I have been really doing battle, like 
 Don Quixote, with a perfectly harmless foe. Whereto I 
 would respectfully answer that I seem rather to be per- 
 forming the less romantic part of Sancho Panza. Sundry 
 learned writers having discovered an imaginary giant, it 
 becomes my humble duty, as a common-sense critic, to 
 point out that the monstrous being is, in fact, nothing 
 more nor less than a windmill. Such a task may be un- 
 grateful and inglorious enough, but it remains none the 
 
 ^ Ezekiel i. 26.
 
 278 THE COLOUR-SENSE. 
 
 less necessary for the prevention of further hallucinations 
 on the same subject in future. When an honest and 
 truthful knight solemnly assures us that he has met with 
 a genuine giant, the world at large naturally accepts his 
 statement in good faith, and goes on believing it until 
 some lowly squire comes forward to sift the evidence upon 
 which his assertion is based. 
 
 Finally, I hope that besides the negative task of demo- 
 lition, we have been able, in the course of our argument, 
 to build up some new and positive constructive work, 
 which will throw fresh light both on aesthetic development 
 and on the growth of special vocabularies. This must be 
 my excuse for a digression which might at first sight have 
 appeared to be leading us too far from the central subject, 
 on whose consideration we are here engaged.
 
 ( 279 ) 
 
 CHAPTER XIV. 
 
 SUMMARY AND RECAPITULATION. 
 
 Now that we have completed our survey of the Origin 
 and Development of the Colour-Sense, we may briefly 
 sum up, in a dogmatic form, the main results to which we 
 have been led in the course of our investigation. 
 
 Colour, viewed objectively, consists in the different 
 rapidity and wave-length of various sethereal undulations. 
 These undulations, taken in their totality, are called 
 light ; taken in their several component parts, they are 
 called colour. 
 
 The earliest animal eyes are cognisant of light and its 
 negation only. Next, probably, came the discrimination 
 of form. Last of all was developed the qualitative per- 
 ception of colour. 
 
 This perception was apparently first aroused in the case 
 of insects by the hues of flowers. The flowers were them- 
 selves developed by the action of the insect eyes, and 
 they reacted simultaneously upon the senses of the insects 
 to whose selection they were due. 
 
 In simple marine animals, the perception of colour was 
 probably first aroused by the animal organisms in their 
 environment. From them it was handed down to the 
 fishes and reptiles, and more remotely to the birds and 
 mammals. In the latter case, however, the sense may 
 have been quickened and kept alive by its exercise upon 
 coloured fruits, which were produced by the selective 
 action of these great classes themselves. 
 
 The general existence of a colour-sense in insects and
 
 28o THE COLOUR-SENSE. 
 
 vertebrates is shown, in some cases, by direct experi- 
 ment, in other cases by a large number of inferen- 
 tial proofs. It is a hypothesis which explains all the 
 facts in the colouration of organic bodies, and without 
 which the facts become a mere chaos of inexplicable 
 caprices.' 
 
 The constant employment of the colour-percipient struc- 
 tures in the search for food, amongst the flower-haunting 
 and fruit-eating animals, would ultimately lead to the 
 strengthening of those structures, and, consequently, to the 
 development of a concomitant pleasure. This pleasure 
 shows itself in the form of a taste for colour. Such a 
 taste is found in a large majority of the species so circum- 
 stanced. It becomes manifest partly in the selection of 
 bright foods, partly in a general love for brilliant objects, 
 but most of all in the choice of gaily-coloured partners. 
 To this cause we owe the beauty of butterflies, birds, and 
 many other animals. 
 
 Besides this direct reaction of the colour-sense upon 
 the external appearance of the creatures which possess it, 
 an indirect reaction is exerted by the constant killing off 
 of those individuals whose colouration specially exposes 
 them to attack, and the survival of those individuals 
 whose colouration affords them any means of protection, 
 either through inconspicuousness, mimicry, or any other 
 mode. In this manner a large number of animals have 
 acquired the hues which they now display. 
 
 The quadrumana, being frugivorous animals, possess 
 the colour-sense in a high degree. They show a consider- 
 able taste for bright colours, and their own appearance 
 often betrays the action of sexual selection. 
 
 Man, the descendant of the frugivorous quadrumana, 
 also possesses a very perfect colour-sense, which is equally 
 evolved in all varieties of the species, from the highest to 
 the lowest. A supposed linguistic proof to the contrary 
 is not countenanced by the other facts of the case. Direct 
 investigations show that all existino: men have like
 
 SUMMARY AND RECAPITULATION. 281 
 
 colour-perceptions ; and historical inquiry shows that the 
 same is true of all earlier races. 
 
 Man derives from his frugivorous ancestors, not onlv 
 the perception, but also the love of colour. This love is 
 shown first in personal decoration, and is afterwards 
 extended to the arts in general. The taste for colour at 
 length affects almost every object of human industry ; but 
 it must all be originally referred to the habits of our fru- 
 givorous ancestors. 
 
 The vocabulary of colour, like all other vocabularies, 
 springs up in proportion to the needs of the various 
 languac^es. 
 
 The arts employ chiefly the colours which are least 
 common in external nature, and which are also those 
 employed by fruits and flowers for the attraction of 
 animals generally. Poetry likewise uses them in the same 
 proportions, but in an ideal form. The most advanced 
 arts, however, use colour in more balanced quantities. 
 But all art, decorative or imitative, retains to the last 
 somewhat of its original character, as a direct stimulant of 
 simple chromatic pleasure. 
 
 Thus the colour-sense, in its origin and its results, is 
 seen to be one and continuous throughout. The highest 
 aesthetic products of humanity form only the last link 
 in a chain whose first link began with the insect's selec- 
 tion of bright-hued blossoms. The whole long series 
 may be briefly summed up in some such formula as the 
 following : — 
 
 Insects produce flowers. Flowers produce the colour- 
 sense in insects. The colour-sense produces a taste for 
 colour. The taste for colour produces butterflies and 
 brilliant beetles. Birds and mammals produce fruits. 
 Fruits produce a taste for colour in birds and mammals. 
 The taste for colour produces the external hues of hum- 
 ming-birds, parrots, and monkeys. Man's frugivorous 
 ancestry produces in him a similar taste ; and that taste 
 produces the various final results of human chromatic arts.
 
 282 THE COLOUR-SENSE. 
 
 What a splendid and a noble prospect for humanity in 
 its future evolutions may we not find in this thought, that 
 from the coarse animal pleasure of beholding food man- 
 kind has already developed, through delicate gradations, 
 our modern disinterested love for the glories of sun- 
 set and the melting shades of ocean, for the gorgeous 
 pageantry of summer flowers, and the dying beaut}^ of 
 autumn leaves, for the exquisite harmony which reposes 
 on the canvas of Titian, and the golden haze which glim- 
 mers over the dreamy visions of Turner ! If man, base 
 as he yet is, can nevertheless rise to-day in his highest 
 moments so far above his sensuous self, what may he not 
 hope to achieve hereafter, under the hallowing influence 
 of those chaster and purer aspirations which are welling 
 up within him even now toward the perfect day ! 
 
 THE END. 
 
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