Perhaps the best proof of transmission is contained in the folk-lore of the tribes of the world. Nothing seems to travel as readily as fanciful tales. We know of certain complex tales, which cannot possibly have been invented twice, that are told by the Berbers in Morocco, by the Italians, the Russians, in the jungles of India, in the highlands of Tibet, on the tundras of Siberia, and on the prairies of North America; so that perhaps the only parts of the world not reached by them are South Africa, Australia, Polynesia, and South America. The examples of such transmission are quite numerous, and we begin to see that the early inter-relation of the races of man was almost world-wide. It follows from this observation that the culture of any given tribe, no matter how primitive it may be, can be fully explained only when we take into consideration its inner growth as well as its relation to the culture of its near and distant neighbors, and the effect that they may have exerted. It may be well to indicate here that there seem to have been two enormously large areas of extended diffusion. Our brief remarks on the distribution of cultivated plants and domesticated animals prove the existence of interrelations between Europe, Asia, and North Africa, from the Atlantic to the Pacific Ocean. Other cultural traits corroborate this conclusion. The gradual spread of bronze from Central Asia westward and eastward, all over Europe and over China, the area in which the wheel is used, where agriculture with plough and with the help of domesticated animals is practised, show the same type of distribution (Hahn). We may recognize the sameness of characteristic traits in this area also in other respects. Oath and ordeal are highly developed in Europe, Africa, and Asia excepting the northeastern part of Siberia, while in America they are hardly known (Laasch). Other common features of the cultural types of the Old World appear also most clearly by contrast with conditions in America. One of these features is the importance of formal judicial procedure in the Old World, and its almost entire absence among all the tribes of North and South America, who, in their general cultural development, might well be compared with the African negroes. In the domain of folk-lore I would mention the frequency of the riddle, the proverb, and the moralizing fable, which are so characteristic of an enormous part of the Old World, while they are lacking in northeastern Siberia and in America. In all these features, Europe, a large part of Africa, and Asia except in its extreme northeastern part, and its island connection east of the Malay Archipelago, form a unit.