unavoidably arose a tiresome uniformity of measure, which, as Dr Burney says, "no resources of melody could disguise." Lacking the complex rhythm obtained by our equal bars and unequal notes, the only rhythm was that produced by the quantity of the syllables, and was of necessity comparatively monotonous. And further, it may be observed that the chant thus resulting, being like recitative, was much less clearly differentiated from ordinary speech than is our modern song. Nevertheless, considering the extended range of notes in use, the variety of modes, the occasional variations of time consequent on changes of metre, and the multiplication of instruments, we see that music had, towards the close of Greek civilization, attained to considerable heterogeneity: not indeed as compared with our music, but as compared with that which preceded it. As yet, however, there existed nothing but melody: harmony was unknown. It was not until Christian church-music had reached some development, that music in parts was evolved; and then it came into existence through a very unobtrusive differentiation. Difficult as it may be to conceive, à priori, how the advance from melody to harmony could take place without a sudden leap, it is none the less true that it did so. The circumstance which prepared the way for it, was the employment of two choirs singing alternately the same air. Afterwards it became the practice (very possibly first suggested by a mistake) for the second choir to commence before the first had ceased; thus producing a fugue. With the simple airs then in use, a partially harmonious fugue might not improbably thus result; and a very partially harmonious fugue satisfied the ears of that age, as we know from still preserved examples. The idea having once been given, the composing of airs productive of fugal harmony would naturally grow up; as in some way it did grow up out of this alternate choir-singing. And from the fugue to concerted music of two, three, four, and more parts, the transition was easy. Without pointing out in detail the increasing complexity that resulted from introducing

notes of various lengths, from the multiplication of keys, from the use of accidentals, from varieties of time, from modulations and so forth, it needs but to contrast music as it is, with music as it was, to see how immense is the increase of heterogeneity. We see this if, looking at music in its ensemble, we enumerate its many different genera and species--if we consider the divisions into vocal, instrumental, and mixed; and their subdivisions into music for different voices and different instruments-if we observe the many forms of sacred music, from the simple hymn, the chant, the canon, motet, anthem, &c., up to the oratorio; and the still more numerous forms of secular music, from the ballad up to the serenata, from the instrumental solo up to the symphony. Again, the same truth is seen on comparing any one sample of aboriginal music with a sample of modern music-even an ordinary song for the piano; which we find to be relatively highly heterogeneous, not only in respect of the varieties in the pitch and in the length of the notes, the number of different notes sounding at the same instant in company with the voice, and the variations of strength with which they are sounded and sung, but in respect of the changes of key, the changes of time, the changes of timbre of the voice, and the many other modifications of expression. While between the old monotonous dance-chant and a grand opera of our own day, with its endless orchestral complexities and vocal combinations, the contrast in heterogeneity is so extreme that it seems scarcely credible that the one should have been the ancestor of the other.

§126. Were they needed, many further illustrations might be cited. Going back to the early time when the deeds of the god-king, chanted and mimetically represented in dance; round his altar, were further narrated in picture-writings on the walls of temples and palaces, and so constituted a rude literature, we might trace the development of Literature through phases in which, as in the Hebrew Scriptures, it pre

sents in one work, theology, cosmogony, history, biography, civil law, ethics, poetry; through other phases in which, as in the Iliad, the religious, martial, historical, the epic, dramatic, and lyric elements are similarly commingled; down to its present heterogeneous development, in which its divisions and subdivisions are so numerous and varied as to defy complete classification. Or we might track the evolution of Science: beginning with the era in which it was not yet differentiated from Art, and was, in union with Art, the handmaid of Religion; passing through the era in which the sciences were so few and rudimentary, as to be simultaneously cultivated by the same philosophers; and ending with the era in which the genera and species are so numerous that few can enumerate them, and no one can adequately grasp even one genus. Or we might do the like with Architecture, with the Drama, with Dress. But doubtless the reader is already weary of illustrations; and my promise has been amply fulfilled. I believe it has been shown beyond question, that that which the German physiologists have found to be a law of organic development, is a law of all development. The advance from the simple to the complex, through a process of successive differentiations, is seen alike in the carliest changes of the Universe to which we can reason our way back, and in the carliest changes which we can inductively establish; it is seen in the geologic and climatic evolution of the Earth, and of every single organism on its surface; it is seen in the evolution of Humanity, whether contemplated in the civilized individual, or in the aggregations of races; it is seen in the evolution of Society, in respect alike of its political, its religious, and its economical organization; and it is seen in the evolution of all those endless concrete and abstract products of human activity, which constitute the environment of our daily life. From the remotest past which Science can fathom, up to the novelties of yesterday, an essential trait of Evolution has been the transformation of the homogeneous into the heterogeneous.

§ 127. Hence the general formula arrived at in the last chapter needs supplementing. It is true that Evolution, under its primary aspect, is a change from a less coherent form to a more coherent form, consequent on the dissipation of motion and integration of matter; but this is by no means the whole truth. Along with a passage from the coherent to the incoherent, there goes on a passage from the uniform to the multiform. Such, at least, is the fact wherever Evolution is compound; which it is in the immense majority of cases. While there is a progressing concentration of the aggregate, either by the closer approach of the matter within its limits, or by the drawing in of further matter, or by both; and while the more or less distinct parts into which the aggregate divides and sub-divides are severally concentrating; these parts are also becoming unlike—unlike in size, or in form, or in texture, or in composition, or in several or all of these. The same process is exhibited by the whole and by its members. The entire mass is integrating, and simultaneously differentiating from other masses; and each member of it is also integrating and simultaneously differentiating from other members.

Our conception, then, must unite these characters. As we now understand it, Evolution is definable as a change from an incoherent homogeneity to a coherent heterogeneity, accompanying the dissipation of motion and integration of matter.

CHAPTER XVI.

THE LAW OF EVOLUTION CONTINUED

Does

128. But now, docs this generalization express the whole truth? Does it include everything essentially characterizing Evolution and exclude everything else? it comprehend all the phenomena of secondary re-distribution which Compound Evolution presents, without comprehending any other phenomena? A critical examination of the facts will show that it does neither.

Changes from the less heterogeneous to the more heterogeneous, which do not come within what we call Evolution, occur in every local disease. A portion of the body in which there arises a morbid growth, displays a new differentiation. Whether this morbid growth be, or be not, more heterogeneous than the tissues in which it is seated, is not the question. The question is, whether the organism as a whole is, or is not, rendered more heterogeneous by the addition. of a part unlike every pre-existing part, in form, or composition, or both. And to this question there can be none Again, it may be contended that the earlier stages of decor position in a dead body involve increase of heterogeneity. Supposing the chemical changes to commence in some parts sooner than in other parts, as they commonly do; and to affect different tissues in different ways, as they must; it seems to be a necessary admission that the entire body, made up of undecomposed parts and parts decomposed in various modes and

but an affirmative answer.