rive on
and on into them--

A ghostly echo touched his mind; restless, poignantly yearning. He swung
to face the locked door, knowing there could be nothing behind it. The
first real fear came to him as he did so. The thing was lonely--the
thing that watched him was as lonely as he was....

What else could any of it be but the product of a mind in the first
stage of insanity?

* * * * *

The natives came ten minutes later.

The viewscreen showed their chemically-powered vehicle emerge from the
trees and roll swiftly across the glade. Four natives were in it while a
fifth one lay on the floor, apparently badly injured.

The vehicle stopped a short distance in front of the airlock and he
recognized the native on the floor. It was Throon, the one with whom he
had been exchanging language lessons.

They were waiting for him when he emerged from the ship, pistol-like
weapons in their belts and grim accusation in their manner.

Throon was muttering unintelligibly, unconscious. His skin, where not
covered by the brown fur, was abnormal in appearance. He was dying.

The leader of the four indicated Throon and said in a quick, brittle
voice: "_Ko reegar feen no-dran!_"

Only one word was familiar: _Ko_, which meant "you" and "yesterday" and
a great many other things. The question was utterly meaningless to him.

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 for