species of plants had actually come into existence under De Vries's personal supervision; that his experiments had been successfully repeated by other investigators; and that his work marked an epoch in the history of natural science fairly comparable with that of Darwin.

All of us know, when we stop to think of it, that the doctrine of evolution did not begin with Darwin. Long before his day students of the forms of life upon earth had held that all forms had been derived by differentiation from other forms, and that all went back ultimately to a simple form having infinite possibilities of development. This view had many adherents: botanists, zoologists, geologists, and even poets, like Tennyson, adopted it. But it remained only a theory which intelligent men might believe if they would, until Darwin, on the basis of an unexampled collection of facts and with a simplicity and candor rarely approached, made it a doctrine that must be accepted by all men not already committed by age to other views of the processes of creation. Before him all had been vague. He called attention to definite variations which might result in change of species and indicated the cause that had determined the direction of the change. The variations were matters of everyday experience, and the cause, when pointed out, seemed so familiar that everybody became a Darwinian. Most people, indeed, after the fashion of most people, became more Darwinian than Darwin himself. In the first place, they gave to his views a simplicity and a certainty which his appreciation of the complexity and difficulty of the problem would have made it impossible for him to accept; in the second place, they gave to them a rigidity that would have been incomprehensible to him, and made of them, as it were, articles of faith. In the vague, swirling chaos of genera and species and varieties Darwin distinguished two types of variation: one, that which is now known as "fluctuating;" the other, that which he called "chance variation," and which DeVries indicates more definitely as "mutation.”1 Fluctuating variation is that by which indi

1 For DeVries's theory in general cf., besides the works already cited, H. De Vries, Die Mutationstheorie (Vol. I, 1901; Vol. II, 1903) and Species and Varieties; Their Origin by Mutation (1905). For fluctuating variations, see especially Species and Varieties, chaps. xxv and xxvii, and Morgan, op. cit., chap. viii.

vidual differs from individual, oak leaf from oak leaf, race-horse from cart-horse; that variation, in short, which makes one individual a little better than another and enables a careful breeder to improve his stock; that which has changed the original sixteenpetaled chrysanthemum of Japan to the huge blossom we see at the annual flower show. What Darwin called "chance variations" and DeVries "mutations" are those sudden and unaccountable differences which, occasionally occurring, lift the individual entirely out of his class. Darwin recognized that both sorts of variations occurred, but he ascribed no great importance to the latter; and, considering the state of science at that time, this was not only natural, but probably desirable. Mutations had been carelessly observed and treated as insignificant curiosities, whereas the work of gardeners, breeders of horses, breeders of dogs, breeders of pigeons, had been carefully recorded. The improvement possible by taking advantage of these fluctuating variations was then and is now astonishing. It is not strange, therefore, that Darwin laid stress almost entirely upon the possibilities of these scarcely perceptible variations, especially since his doctrine of natural selection seemed to make Nature as careful a breeder as Man.

Since Darwin, many investigators have shown that the limit of fluctuating variations is quickly reached, and that in them lies no possibility of crossing the line that divides species from species. DeVries has gone a step farther. He has not only pointed out the distinction between species and hybrids and varieties, and the limitations of fluctuating variation; he has also developed a theory of the way in which new species come into existence and has verified. his theory by actually observing the birth of the new species. The theory is briefly this:

Mutation forms a special division of the kinds of variation.' It does not occur flowingly, but in steps, without transitional stages, and it occurs less frequently than do the common variations, which are continuously and constantly at hand. The contrast between the two kinds at once appears if one conceives that characters of an organism are made up of definite elements or units (Einheiten), sharply distinguished from one another. These units combine in groups, and in related species similar groups recur. Every addition of a unit to a group constitutes a step, originates a new group, and separates the new form sharply and definitely

as an individual species from the one out of which it has been produced. The new species is at once such, and originates from the former species without apparent preparation and without gradation. Each attribute or character of course arises from one previously present, not by normal variation, but by one small yet sudden change.1

But what has this to do with the development of literature? Literature is not a plant or an animal; it develops in accordance with the laws of its own existence.

No one, I think, is more ready than I to recognize that literature is not an organism of any kind; that principles true of the development of plants and animals have no necessary validity for works of art. But the whole process of human thought has, whether we like it or not, been transformed by the theories of Darwin. "Evolution," "adaptation to environment," "struggle for existence," "survival of the fittest," are not merely words: they are conceptions-powerful, dominating conceptions. We may misunderstand them, misuse them, deny them; the one thing we cannot do is to speak, or even think, as we should if they had never existed. We know that literature and art and social life are not plants or animals, and that they have their own laws of existence; but even if we try to keep steadily before us the fallacy residing in such terms as "organism" and "evolution," it is practically impossible to speak or think of any unified body of facts showing progressive change as men habitually spoke and thought before 1860. That we should still speak and think as if the needs of human thought could be met by a mere chronological record is not to be wished; but it is equally undesirable that in our attempts to understand the processes of life we should accept for our own particular problem a formula whose only claim to attention is that it seems to solve another problem. This we have been doing, even when we were not conscious of it.

Thus, when, some fifteen years ago, I began to study the origins of the modern drama, I was not conscious of the influence of Darwin; but I believed, as we all believed, that all things came into existence gradually, by almost imperceptible modifications of something that had existed before. The problem before me therefore seemed to be

1 Die Mutationstheorie, Vol. I, Preface, translated by White, with modifications.

the problem of collecting the evidence of these gradual and scarcely perceptible changes. When all the evidence was in hand, it appeared that, in this case at any rate, the conditions of change had been very different from what the theory presupposed. There was no gradual accumulation of scarcely perceptible variations, changing the non-dramatic into the dramatic so insensibly that the moment of the change could not be indicated. On the contrary, there was a large amount of variation of non-dramatic form which, however wide the variation, never resulted in drama; and then with absolute suddenness came the drama, created at one moment, created without any reference to the futile variations that had preceded. These variations I call futile, not because they lack interest or possible significance, but because they did not and could not develop out of their own class. There was the ritual of the mass, capable, as many scholars-Alt and Schaff and Klein and Davidson'—have shown, of developing into drama. But it did not develop. There was epic poetry, which even in the days of the English Cynewulf, as Cook' has clearly shown, was dialogic and vivid, and dealt with material that later was made the subject of plays. There were sermons, which, as Rand' has pointed out, discussed the subjects discussed in the liturgical drama, and which used dialogue to heighten effect-sermons which would have been drama if they had not remained something else. But all these promising variations remained just what they were: the mass never became anything but the mass; epic poetry gained vividness, yet it remained epic poetry; sermons grew interesting, but they did not originate the drama; estrif and debat and epic comedy and tragedy almost crossed the line, but they did not actually cross it. There were many things which to us seem capable of becoming drama; the only valid test of development is what actually happened. Antiphones might become more antiphonal; sermon, epic comedy, estrif, debat, might develop a more lively dialogue; none

1H. Alt, Theater und Kirche, pp. 328-53; P. Schaff, History of the Christian Church, Vol. III, p. 534; J. L. Klein, Geschichte des Dramas, Vol. IV, pp. 10 ff.; C. Davidson, Studies in the English Mystery Plays, pp. 6 ff.

2A. S. Cook, Journal of Germanic Philology, Vol. IV, pp. 421 ff.

3 E. K. Rand, Modern Philology, Vol. II, pp. 261 ff. For dramatic elements in the popular ballad, cf. G. M. Miller, University of Cincinnati Bulletin, No. 19 (Ser. II, Vol. II).

of them, as a matter of fact, became drama; none of them varied beyond its class.

But these things look very much like the drama, and good men and true have been deceived by them. Perhaps the only way in which we can avoid deception is to begin with the mediaeval drama when it was unmistakably drama, and carefully go back to the time when it came into existence. We shall thus be able to see exactly what were the effective changes. If we begin with the fifteenth century, we find three generally recognized types of the drama: mystery, miracle-play, and morality. They begin at quite different times; they are sometimes confused in modern histories, but they are not confused in the records, and their separate histories can easily be distinguished. The morality did not exist much before the fifteenth century; the miracle-play is not to be discovered before 1100; the mystery, or liturgical scripture-play, is at least two centuries older. Its beginning can be clearly traced. By one simple and definite movement, which will be discussed in a few moments, it came into existence. Before that movement there was no liturgical drama; as soon as the movement occurred, the drama existed, simple and slight, to be sure, but as clearly drama as it ever became in the whole course of its development.

Let us retrace rapidly the development of the great dramatic cycles, commonly called mysteries. In England in the fifteenth century they consisted of three main groups of scenes: (1) certain scenes from the Old Testament, such as the Creation, the Fall of Man, the Death of Abel, the Deluge, the Sacrifice of Isaac, etc.; (2) a group of New Testament scenes concerning the Birth of Christ-e. g., the Annunciation, the Journey to Bethlehem, the Birth, the Visit of the Shepherds, the Three Kings (or Wise Men of the East), the Flight into Egypt, the Slaughter of the Innocents, the Presentation in the Temple; (3) a second New Testament group, concerning the Death and Resurrection, such as the Entry into Jerusalem, the Last Supper, the Capture, the Trial, the Crucifixion, the Resurrection, the Walk to Emmaus, Doubting Thomas, etc. Special variations need not concern us now, for this is the general type. Tracing backward the history and form of these groups, we find that they are real groups, each developed