In regions dotted with inhabited oases, where the human groups are separated from one another by wide desert areas, uncultivable steppes, or barren and precipitous mountains, the improvement of communications is the first condition of modern state administration and of an intensification of trade. Civilized men can overcome the natural difficulties of their environment in regard to communications, but not until they have done so does it become possible for them to live at a higher level of civilization. Friedrich Ratzel rightly says: "Modern communications are a symptom of civilization and promote civilization." The Ottoman empire and Persia, both states of wide territorial extent, suffered severely until the present century from the lack of a developed system of communications. The various parts of the country were widely separated from one another, the central power was inevitably weakened, all reform was impossible, and the exchange of goods was faced with difficulties. The regions at a distance from the Mediterranean were cut off from the world even in the nineteenth century, remote from all the great trade routes, and could not be opened up to trade and civilization, with the increase of population they bring. The mountain passes were impassable for months in winter, the deserts and steppes accessible only to the camel. The only means of rapid transport then known was the railway. In the United States, in Siberia, and in other regions, the railways had promoted territorial unification and the development of economic relations to an extent undreamed of before their coming. They had become the means of the penetration of civilization.