"The region termed 'the Putumayo,' consisting principally of the area drained by two tributaries of the Iça or Putumayo River, the Igaraparaná and the Caraparaná, lies far from the main stream of the Amazon, and is rarely visited by any vessels save those belonging to the Peruvian Amazon Company. The only other craft that penetrate that district are steamers of the Peruvian Government sent occasionally from Iquitos. Brazilian vessels may ascend the Japurá, known in Peru and Colombia as the Caquetá, until they draw near to the mouth of the Cahuinari, a river which flows into the Japurá, flowing in a north-easterly direction largely parallel with the Igaraparaná, which empties into the Putumayo after a south-easterly course. The region drained by these three waterways, the Caraparaná, the Igaraparaná, and the Cahuinari, represents the area in part of which the operations of the Peruvian Amazon Company are carried on. It is impossible to say what the Indian population of this region may be. Generally speaking, the upper and middle courses of these rivers are, or were, the most populous regions. This is accounted for by the greater absence of insect pests, due to the higher nature of the ground, which rises at La Chorrera to a level of about 600 feet above the sea, with neighbouring heights fully 1,000 feet above sea-level. The lower course of the Igaraparaná, as well as of the Putumayo itself, below the junction of the Igaraparaná down to the Amazon, is through a thick forest region of lower elevation, subject largely to annual overflow from the flooded rivers. Mosquitoes and sand flies and the swampy soil doubtless account for the restriction of the Indians to those higher and drier levels which begin after the Igaraparaná has been ascended for about one hundred miles of its course. In this more elevated region there are no mosquitoes and far fewer insect plagues, while permanent habitations and the cultivation of the soil are more easily secured than in the regions liable to annual inundation. "In a work officially issued by the Peruvian Government at Lima in 1907, entitled 'En el Putumayo y sus Afluentes,' by Eugenio Robuchon, a French explorer who was engaged in 1903 by Señor Julio C. Arana in the name of the Government to conduct an exploring mission in the region claimed by the firm of Arana Brothers, the Indian population of that firm's possessions is given at 50,000 souls. M. Robuchon lost his life near the mouth of the Cahuinari in 1906, and the work in question was edited from his diaries by Señor Carlos Rey de Castro, Peruvian Consul-General for Northern Brazil. The figure of 50,000 Indians is that given by this official as 'not a chance one.' "In the prospectus issued at the formation of the Peruvian Amazon Rubber Company in 1908, Señor Arana is represented as claiming that there were then 40,000 Indian 'labourers' dwelling within the area of his Putumayo enterprise.