As a whole, the growth of Buenos Aires presents the same feature of regularity, on account of the uniformity of the soil, as the spread of colonization over the plain of the Pampas. The city is distributed in concentric zones, and it is thus a model on a small scale of the distribution of the various types of exploitation on the Pampa which surrounds it. The central nucleus, the business quarter, contains not only the offices, but the warehouses of imported goods. Round this centre, with a radius of one to three miles, are the residential quarters in which the density is greatest (250 to 350 to the hectare). Beyond this the density sinks to less than 200 per hectare and less than fifty on the outskirts. The central quarters developed the maximum density after 1900. Those of the first outer zone have gained greatly between 1904 and 1909. Since the latter date, the progress of these quarters has been arrested in turn, and the recent growth is mainly in the remote working-class suburbs in the south and on the bank of the Riachuelo. Buenos Aires has preserved in its central district, and reproduces in all its outer districts, the primitive draught-board plan of a Spanish colonial city. This plan is not suited to its needs to-day. The rapid growth of the city and its expansion--the mean density is not more than fifty-four inhabitants to the hectare, as against 360 at Paris--complicate the problem of transport. At the present time the city is considering plans for reconstructing its thoroughfares and making diagonal streets, starting from the centre and following the direction of the main streams of traffic. In this way the city would reproduce the fan-wise distribution of railways over the Pampean plain. Buenos Aires is the intermediary between the provinces and oversea countries. It has three titles to this profitable part. In the first place, it is the chief centre of the import trade. The merchants of the cities in the interior are customers of the Buenos Aires importers, and are closely bound to them by a system of long-term credit. Buenos Aires is, secondly, the centre for the distribution of the European capital which has been used in the development of the country. Lastly, it divides immigrant workers amongst the provinces, just as it divides capital. As an immigration port its position is unrivalled. The efforts that were made to divert part of the immigrants to Bahia Blanca failed, and direct immigration to the Santa Fe province ceased at the close of the first period of colonization, about 1880. It is also at Buenos Aires that immigrants who are not going to settle in Argentina embark; re-emigration, which is regarded as a national plague by Argentine economists, is another source of profit to the capital. Hence the fortune of Buenos Aires is due in the first place to the close contact between the economic life of Argentina and that of Europe and North America.