vidual men: Marathon and Waterloo, Alexander, Cæsar, Alfred, Napoleon. Of pervasive social movements, tendencies of human feeling and thought, developments of industries, institutions, laws, and customs by a gradual process in which great numbers of personally insignificant men played their part, little account was taken. Facts were facts, and had no hidden significance, no mutual interaction, no cumulative force, momentum, or direction.

Far otherwise do we interpret the story of the world. Inspired by the great doctrine of the nineteenth century, the doctrine of evolution, first formulated by biology, but immediately applied to all realms of knowledge, we read in events a continuous movement, a coherent growth, a gradual, vast, and single process. For us, individual events and men sink into insignificance in comparison with the great drama of which they are only acts and actors. For us, great popular movements, instinctive strivings, of which the men and women under their sway were unconscious, vast blossomings of vital energy the roots of which were far below the surface of the human mind, rise into relief as the true interests of the historian, and we interpret all particular happen

ings and special persons in the light of these universal tendencies. In geology we trace the continuous formation of the earth through innumerable years; in zoölogy we study those slow but constant transformations of animals which are effected by natural selection and the survival of the fittest; in sociology we examine the painful yet inevitable crystallization out of the human spirit of such ideas as responsibility, liberty, justice; in philosophy we learn of the subtle implications of our nature, and so learning, substitute a human God for the idols of savages and the remote tyrannical deities of half-developed religions. There is not a branch of our thought in which this way of interpreting life as a process, this conceiving of it as dynamic and vital rather than static and inert, has not enlarged our outlook, deepened our sense of the sacredness and wonder of the universe, and filled our spirits with a new freedom, enthusiasm, and hope.

Peculiarly interesting is the application of this mode of study to the art of music. The expression of feeling through sounds combined in beautiful forms, gives us an opportunity, as cannot be too often pointed out,* for a much freer and * See the author's "From Grieg to Brahms," pp. 219–223.

more self-determined activity than we can enjoy in our other artistic pursuits. Because the art of music, both in its material and in its content, is less shackled, less thwarted in its characteristic processes, than the representative arts, its evolution is remarkably obvious and easy to trace. Its material, in the first place, is a product of man's free selection; that complex system of musical tones which he has constructed by many centuries of work, is his own, to use as he will, in a sense in which language, natural objects, and physical substances can never be. Whereas the growth of poetry, of painting, of sculpture, of architecture, is complicated and distorted by a thousand external conditions, that of music is determined by its own inner laws alone,-by the laws, that is to say, of sound-production, of sound-perception, and of psychology. In the second place, the content of music, that which it expresses by means of these freely selected and composed tones, is purely internal. It is easy to see that the objects of musical expression, namely, human emotions in their essence, reduced, so to speak, to their lowest terms, are more fluid to manipulation than the comparatively fixed, indocile, and external objects of the

representative arts. By virtue, then, both of its material medium and of its ideal content, music enjoys, among human modes of expression, a unique freedom and autonomy. It grows, not under pressure from outside, but by its own inner vitality; its forms are determined, not by correspondence with anything in the heavens or on the earth, but, like those of the snow-crystals, by the inexorable laws that govern it; and the particular changes it undergoes in its evolution, marking merely successive incarnations of tendencies and potencies always implicit in it, can be traced with comparative ease, clearness, and certainty.

But however unmistakably musical history may reveal an evolutionary process, it does not reveal that process as perfectly regular and uniform. That general tendency from a low toward a high state of organization, with increase in definiteness, coherence, and heterogeneity, which readers of Herbert Spencer expect in any evolutionary series, does characterize the growth of music as a whole; but within the large general process we also observe, as we do in many other cases of evolution of any degree of complexity, many momentary phases sharply marked

off from one another, many separate and distinct periods, like the chapters in a book or the acts in a play. Each period, beginning tentatively, maturing slowly, and culminating in music which carries its characteristic effects to the highest possible pitch, is succeeded by another, presenting the same phases of growth, but seeking effects quite different. All the periods hang together in a large view; yet they are, after all, diverse in character, and therefore capable of being distinguished, and even dated.

An analogy offered by certain well-known chemical processes may help to make comprehensible this periodic nature of musical evolution. Chemists have a term, "critical point," by which they name a stage in the behavior of a substance, under some systematic treatment, at which it suddenly undergoes some striking change, some catastrophic transformation. Put, for example, a lump of ice in a crucible and apply an even heat by which its temperature is raised, say, one degree each minute. Here is a systematic treatment of the ice, a steady influence exerted upon it. Yet, curiously enough, this ice which is being so equably acted upon will not change its form in the equable, regular