This does not mean that northern Europe was a passive recipient. It accepted and adopted whatever and only what it would, and probably refused many a valuable suggestion. In many cases it improved on the patterns or example of its teacher and inspirer. The art of polishing stone implements and the use of bronze may not have been indigenous in Scandinavia; but here, as time went on, genuine works of art were produced superior to any in the world, far more artistic than the beautiful technique of the Egyptians. Prehistoric domestic animals were almost certainly introduced from the East. But the lake-dwellers usually improved the breed by intercrossing with forms derived from their own fauna. They increased the list of cultivated plants. The idea or conception passed from tribe to tribe, but the new stimulus did its fermenting work differently, according to the mind or medium into which it fell. There was always readaptation and more or less change. To be a wide borrower and at the same time to usually improve on one's teacher requires something very close to genius, though the originality may be less obtrusive. We have no reason to be ashamed of our Neolithic ancestors. The result of this exchange of products and ideas will be more apparent during the next period. Trade-routes and lines of communication will then become far more clear and fixed. But it is important to notice that these routes are already opening in all directions, perhaps more numerous because still experimental, tentative, and somewhat vague. The routes of transportation during prehistoric times, as usually in pioneer periods, were mainly along river valleys. Where basins almost or quite touch one another centres of contact and distribution naturally arise. Hence the prosperity of the Department of Saone-et-Loire, in France. A study of any good relief-map of Europe will show the chief routes of trade almost at a glance. The great east-and-west artery is the valley of the Danube, with its tributaries extending far northward, almost touching the headwaters of rivers flowing into the North Sea or Baltic. The westernmost north-and-south route is by sea along the Atlantic coast from Spain to England or Denmark. A second was formed by the Rhone and Rhine, eastward and parallel to the French highlands extending from the Mediterranean to Belgium, broken by the pass of Belfort. A third ran up the valley of the Elbe and down the Moldau to the Danube. This was the most important route in Europe, especially for amber. A fourth, from the Baltic to the Black Sea, followed the Vistula and the Dniester. From ancient times the Black Sea and its tributaries have been the great route of communication between the Ægean and southern Russia as well as parts of the Balkan Peninsula. During the greater part of the Neolithic period it was probably only a sluggish and irregular current of trade which trickled along most of these routes, put it was the beginning and