We have completed our very rapid regional survey of the world; and what do we find? By no means is it case after case of one region corresponding to one type of man and to one type of culture. It might be that, given persistent physical conditions of a uniform kind, and complete isolation, human life would in the end conform to these conditions, or in other words stagnate. No one can tell, and no one wants to know, because as a matter of fact no such environmental conditions occur in this world of ours. Human history reveals itself as a bewildering series of interpenetrations. What excites these movements? Geographical causes, say the theorists of one idea. No doubt man moves forward partly because nature kicks him behind. But in the first place some types of animal life go forward under pressure from nature, whilst others lie down and die. In the second place man has an accumulative faculty, a social memory, whereby he is able to carry on to the conquest of a new environment whatever has served him in the old. But this is as it were to compound environments--a process that ends by making the environment coextensive with the world. Intelligent assimilation of the new by means of the old breaks down the provincial barriers one by one, until man, the cosmopolitan animal by reason of his hereditary constitution, develops a cosmopolitan culture; at first almost unconsciously, but later on with self-conscious intent, because he is no longer content to live, but insists on living well. As a sequel to this brief examination of the geographic control considered by itself it would be interesting, if space allowed, to append a study of the distribution of the arts and crafts of a more obviously economic and utilitarian type. If the physical environment were all in all, we ought to find the same conditions evoking the same industrial appliances everywhere, without the aid of suggestions from other quarters. Indeed, so little do we know about the conditions attending the discovery of the arts of life that gave humanity its all-important start--the making of fire, the taming of animals, the sowing of plants, and so on--that it is only too easy to misread our map. We know almost nothing of those movements of peoples, in the course of which a given art was brought from one part of the world to another. Hence, when we find the art duly installed in a particular place, and utilizing the local product, the bamboo in the south, let us say, or the birch in the north, as it naturally does, we easily slip into the error of supposing that the local products of themselves called the art into existence. Similar needs, we say, have generated similar expedients. No doubt there is some truth in this principle; but I doubt if, on the whole, history tends to repeat itself in the case of the great useful inventions. We are all of us born imitators, but inventive genius is rare.