or the light, has occurred. Its history is written indelibly in the rocks. And, as we shall argue, this is the supreme lesson of evolution--that progress is possible, because progress has occurred. Assuredly we should never use this word "progress" without reminding ourselves of the cardinal distinction that exists between two forms that it may manifest. There is a progress which consists in and depends upon an advance in the constitution of the living individual; and, so far as we are more mental and less physical than the men who have left us such relics as the Neanderthal skull, in so far we exemplify this kind of progress. But, on the other hand, we can claim progress as compared with even the Greeks in some respects, though there is no evidence whatever that, so far as the individual is concerned, there is any natural, inherent, organic progress. But we know more. Our school-boys know more than Aristotle. We stand upon Greek shoulders. This is traditional progress--something outside the germ-plasm; a thing dependent upon our great human faculty of speech. That, surely, is why the word infantine was rightly used in our first paragraph. For we may ask why, if man be millions of years old, any record of progress should be a matter of only a few thousand years--perhaps not more than fifteen or twenty. The answer, I believe, is that traditional progress depends upon the possibility of tradition. Now speech, apart from writing, involves the possibility of tradition from generation to generation, and I am very sure that "Man before speech" is a myth; the more we learn of the anthropoid apes the surer we may be of that. But, after all, the possibilities of progress dependent upon aural memory are sadly limited; not only because it is easy to forget, but because it is also conspicuously easy to distort, as a familiar round-game testifies. The greatest of all the epochs in human history was that which saw the genesis of written speech. I believe that hundreds of thousands, nay millions, of preceding years were substantially sterile just because the educational acquirements of individuals could be transmitted to their children neither in the germ-plasm (for we know such transmission to be impossible), nor outside the germ-plasm, by means of writing. The invention of written language accounts, then, we may suppose, for the otherwise incomprehensible disparity between the blank record of long ages, and the great achievement of recent history--an achievement none the less striking if we remember that the historical epoch includes a thousand years of darkness. Thus, as was said at the Royal Institution in 1907, when discussing the nature of progress, we may argue in a new sense that the historians have made history: it is the possibility of recording that has given us something to record.