We are still very far from civilisation, but the few tens of thousands of years that separate Magdalenian man from it will be traversed with relative speed--though, we should always remember, with a speed far less than the pace at which man is advancing to-day. A new principle now enters into play: a specifically human law of evolution is formulated. It has no element of mysticism, and is merely an expression of the fact that the previous general agencies of development have created in man an intelligence of a higher grade than that of any other animal. In his larger and more plastic brain the impressions received from the outer world are blended in ideas, and in his articulate speech he has a unique means of entering the idea-world of his fellows. The new principle of evolution, which arises from this superiority, is that man's chief stimulus to advance will now come from his cultural rather than his physical environment. Physical surroundings will continue to affect him. One race will outstrip another because of its advantage in soil, climate, or geographical position. But the chief key to the remaining and more important progress of mankind, which we are about to review, is the stimulating contact of the differing cultures of different races. This will be seen best in the history of civilisation, but the principle may be recognised in the New Stone Age which leads from primeval savagery to civilisation, or, to be more accurate and just, to the beginning of the historical period. It used to be thought that there was a mysterious blank or gulf between the Old and the New Stone Age. The Palaeolithic culture seemed to come to an abrupt close, and the Neolithic culture was sharply distinguished from it. It was suspected that some great catastrophe had destroyed the Palaeolithic race in Europe, and a new race entered as the adverse conditions were removed. This was especially held to be the case in England. The old Palaeolithic race had never reached Ireland, which seems to have been cut oft from the Continent during the Ice-Age, and most of the authorities still believe--in spite of some recent claims--that it never reached Scotland. England itself was well populated, and the remains found in the caves of Derbyshire show that even the artist--or his art--had reached that district. This Palaeolithic race seemed to come to a mysterious end, and Europe was then invaded by the higher Neolithic race. England was probably detached from the Continent about the end of the Magdalenian period. It was thought that some great devastation--the last ice-sheet, a submersion of the land, or a plague--then set in, and men were unable to retreat south.