“became mere slaves to the company, for rubber-making occupied all their time, the victim having to search far and wide for the giant vines from which the sap is extracted. They were not even fed by their taskmasters, their only remuneration being merchandise or mitakos [pieces of brass wire] in ridiculously small quantities. . . . The natives bitterly bemoaned the scarcity of the rubber-producing lianas, and piteously begged to be allowed to perform other service than rubber-gathering.”