Read it through once

The Antiaris alluded to above is the famous Upas tree of Java. The tree was _said_ to grow in a desert with not another living plant within ten miles of it. Such was the virulence of its poison that there were no fish in the waters. Neither rat, nor mouse, nor any other vermin had ever been seen there; and when any birds flew so near this tree that the effluvia reached them, they fell dead--a sacrifice to the effects of its poison. Out of a population of sixteen hundred persons who were compelled, on account of civil dissensions, to reside within twelve or fourteen miles of the tree, not more than three hundred remained alive in two months. Criminals condemned to die were offered the chance of life if they would go to the Upas tree and collect some of the poison. They were provided with masks (not unlike our modern motor-veils), and yet not two in twenty returned from the expedition.