Quotation from: The Chessmen of Mars

Written by: Edgar Rice Burroughs

The watcher saw the creature take its prisoner by the arm and
lead it back to the enclosure, and even across the distance that
separated them from him he could note dejection and utter
hopelessness in the bearing of the prisoner, and, too, he was
half convinced that it was a woman, perhaps a red Martian of his
own race. Could he be sure that this was true he must make some
effort to rescue her even though the customs of his strange world
required it only in case she was of his own country; but he was
not sure; she might not be a red Martian at all, or, if she were,
it was as possible that she sprang from an enemy people as not.
His first duty was to return to his own people with as little
personal risk as possible, and though the thought of adventure
stirred his blood he put the temptation aside with a sigh and
turned away from the peaceful and beautiful valley that he longed
to enter, for it was his intention to skirt its eastern edge and
continue his search for Gathol beyond.