He dropped his hand a little nearer his blaster as the leader spoke again; a quick succession of unknown words that ended with a harshly demanding "kreson!"
Kreson meant "now," or "very quickly." All the other words were unfamiliar to him. They waited, the grim menace about them increasing when he did not answer. He tried in vain to find some way of explaining to them he was not responsible for Throon's sickness and could not cure it.
Then he saw the spray of leaves that had caught on the corner of the vehicle when it came through the farther trees.
They were of a deep purple color. All the trees around the ship were almost gray by contrast.
Which meant that he was responsible for Throon's condition.
The cold white light of the ship's floodlights, under which he and Throon had sat for day after day, contained radiations that went through the violet and far into the ultraviolet. To the animal and vegetable life of the dark world such radiations were invisibly short and deadly.
Throon was dying of hard-radiation sickness.
It was something he should have foreseen and avoided—and that would not have happened had he accepted old Throon's pantomimed invitation, in the beginning, to go with him into the village to work at the language study. There he would have used a harmless battery lamp for illumination ... but there was no certainty that the natives were not planning to lay a trap for him in the village and he had refused to go.
It did not matter—there was a complex radiation-neutralizer and cell-reconstructor in the ship which would return Throon to full, normal health a few hours after he was placed in its chamber.
He turned to the leader of the four natives and motioned from Throon to the airlock. "Go—there," he said in the native language.