merely in response to painful proddings at the tail-end. Our remaining task is to take stock of that improvement in the arts of life whereby man has come gradually to master an environment that formerly mastered him. For the Early Palaeolithic Period our evidence in respect of its variety, if not of its gross quantity, is wofully disappointing. Not to speak of man's first and rudest experiments in the utilization of stone, which are doubtless scattered about the world in goodly numbers if only we could recognize them clearly for what they are, the Chellean industry by its wide distribution leads one to suppose that mankind in those far-off days was only capable of one idea at a time--a time, too, that lasted a whole age. Yet the succeeding Acheulean style of workmanship in flint testifies to the occurrence of progress in one of its typical forms, namely, in the form of what may be termed 'intensive' progress. The other typical form I might call 'intrusive' progress, as happens when a stimulating influence is introduced from without. Now it may be that the Acheulean culture came into being as a result of contact between an immigrant stock and a previous population practising the Chellean method of stone-work. We are at present far too ill-informed to rule out such a guess. But, on the face of it, the greater refinement of the Acheulean handiwork looks as if it had been literally hammered out by steadfastly following up the Chellean pattern into its further possibilities. Explain it as we will, this evolution of the so-called _coup-de-poing_ affords almost the sole proof that the human world of that remote epoch was moving at all. If we could see their work in wood, we might discern a more diversified skill or we might not. As it is, we can but conclude in the light of our very imperfect knowledge that in mind no less than in body mankind of Early Palaeolithic times displayed a fixity of type almost amounting to that of one of the other animal species.