"The economic development of Amazonia was prodigiously rapid. In 1890 it exported 16,000 tons of rubber; in 1900, 28,000 tons; in 1905, 33,000 tons. It became, next to San Paulo, the most important centre of exportation in Brazil.[21] The cities increased in size; the population of Para surpassed 100,000; that of Manaos attained to 50,000; and this growth of the cities, which was more rapid than the growth of the total population, is an index to the rapidity of the commercial development of the country. The Amazon became one of the great river highways of the world, serving not only the Brazilian Amazon, but also the regions of Peru which are crossed by the upper tributaries, and a portion of Venezuela, where products descend to Manaos by the Rio Negro. "The exportation of rubber created wealth on all sides. All other occupations were abandoned for the collection of rubber. The herds of cattle on Marajo and the cocoa plantations along the banks were neglected. Similarly, in the neighbouring districts of Guiana the fields and plantations were abandoned on the discovery of 'placer' gold. No one thought of anything but rubber. Up to that time the country had produced its own food; now it had to resort to importation. It became a market in which the other States of Brazil were able to sell their products at a highly profitable rate. All these changes were due to the importation of labour from Ceará."[22] * * * * * We have seen elsewhere that the ocean steamer which carries us up the Amazon will reach the Peruvian port of Iquitos, a place of much importance, due to its position in the very heart of the continent, the centre of a vast tributary region, whose value the future will better be able to estimate. A region of the utmost interest lies before the traveller who will adventure himself upon these tributary streams and the diversified territories which they drain. There might be fleets of motor-boats upon these waterways, whether bent upon pleasurable exploration, whether upon business and trade. The civilized folk of the eastern slopes of the great Cordillera are, metaphorically, stretching out their arms towards the east, casting eager glances thereover, for from thence must come economic prosperity and civilized peoples. And now, once more, a glance at the past in the great valley, though brief, at those influences which have tried to make for good as against evil: the forces of the Church and the missionary.