The Aztec Treasure-House by Thomas A. Janvier

Even with El Sabio reduced to this condition of complete quiescence, the Aztlanecas, soldiers as well as priests, still were terribly afraid of him; being firmly convinced, as was not at all unnatural, that for the time being there was embodied in him a devil of a most dangerous sort. Therefore they were but too glad to yield to Pablo's burning eagerness to get to the poor ass; and when he called for aid to carry the exhausted creature out from the amphitheatre, and so away from among the dead and wounded and from the dreadful smell of blood, Young and I promptly were pushed forward and ordered to perform this piece of work that even the bravest of them shrunk from undertaking.

However, there was no real peril in it, for El Sabio was so weak that he could not even stand, and still less was he strong enough to kick anybody. Lifting him in this dull, limp state, and carrying him up the steep steps, was heavy work for us, wounded and weary as we were; but with Pablo's help we managed it, and so got him up from the depths of the amphitheatre to its windward side -- where a fresh sweet breeze that was blowing, and some water that a soldier brought when Pablo called for it, in a little while put new life into him. Why the ass was not made to pay the penalty of his sins, by being there and then killed, at first was a good deal of a puzzle to me; but presently, from the talk that went on about us while Pablo ministered to him, and while the wounded lying around the altar were being cared for, and the dead borne away, I gathered that no one dared to kill him for fear of being himself possessed by the devil that needs must enter another body upon being thus set free. And as this seemed to be a view of the case that was worth encouraging, I very gravely told one of the priests that I myself had seen a man all in an instant go raving mad upon slaying one of these creatures and so letting the devil loose from him. As this story was circulated among the crowd I was glad to perceive that the dread of El Sabio obviously greatly increased.