[15] B. Poncel, _Mes itineraires dans les Provinces du Rio de la Plata, Province de Catamarca_ (Paris, 1864). In 1854-5 the Cordillera route definitely ceased to be of commercial importance to Catamarca, and it was afterwards used merely for the export of cattle. But the attraction of Buenos Aires after 1853 was not merely due to its commercial life and its intermediate position between the provinces of the interior and Europe. It was chiefly based upon the economic development of the region of the Pampas, which began about this date, and altered the balance between the two halves of Argentina. The exploitation of the Pampa, the improvement in breeding methods, and the introduction and expansion of agriculture on the plain of the Pampa, which fill all publications on modern Argentina, are in themselves one of the great events in the economic history of the nineteenth century. They had also an indirect but profound influence upon the life of other parts of Argentina. The consuming capacity of the Pampa increased simultaneously with its wealth and population. It absorbed the products of the neighbouring provinces and in turn made customers of them, distributing amongst them, according to the services they rendered, part of the gold it obtained from beyond the Atlantic. One after the other the provinces lost the relations which had hitherto connected them with foreign lands. There was the same development all over the zone of cereals and lucerne--the direction of the stream of commerce was reversed. In some places, as at Tucuman and Mendoza the change was accomplished a generation ago. In other places, as at Salta and San Juan, it is still going on. In yet other places, the more remote valleys, like Jachal and Santa Maria, it will occur in the near future. By a singular anomaly the Far West of North America, which sprang up half a century ago, tends to withdraw more and more from the influence of the eastern States, which provided it with capital and immigrants, while the Far West of Argentina, which is just as old as the east and by no means a creation of the east, since it developed in isolation and freedom, and was already adult and rich when they came into contact, has nevertheless fallen into complete dependence upon the east in the course of a few years. The life of the whole country depended upon the great colonization movement which transformed the plain of the Pampas. This brought about an economic unity which was at once reflected in the political world. The railway from Buenos Aires reached Tucuman before 1880; Mendoza, San Juan, Salta, and Catamarca before 1890; and La Rioja before 1900. The establishment of closer economic relations between the coast and the provinces of the interior has nearly always inaugurated a period of great prosperity for the latter. In every case the influence of Buenos Aires vitalized them, put an end to their slumbers, and made them rich.