“The _naualli_, or magician, is he who frightens men and sucks the blood of children during the night. He is well skilled in the practice of this trade, he knows all the arts of sorcery (_nauallotl_) and employs them with cunning and ability; but for the benefit of men only, not for their injury. Those who have recourse to such arts for evil intents injure the bodies of their victims, cause them to lose their reason and smother them. These are wicked men and necromancers.”[6-*] It is evident on examining the later works of the Roman clergy in Mexico that the Church did not look with any such lenient eye on the possibly harmless, or even beneficial, exercise of these magical devices. We find a further explanation of what they were, preserved in a work of instruction to confessors, published by Father Juan Bautista, at Mexico, in the year 1600. “There are magicians who call themselves _teciuhtlazque_,[6-†] and also by the term _nanahualtin_, who conjure the clouds when there is danger of hail, so that the crops may not be injured. They can also make a stick look like a serpent, a mat like a centipede, a piece of stone like a scorpion, and similar deceptions. Others of these _nanahualtin_ will transform themselves to all appearances (segun la aparencia), into a tiger, a dog or a weasel. Others again will take the form of an owl, a cock, or a weasel; and when one is preparing to seize them, they will appear now as a cock, now as an owl, and again as a weasel. These call themselves _nanahualtin_.”[6-‡] There is an evident attempt in this somewhat confused statement to distinguish between an actual transformation, and one which only appears such to the observer. In another work of similar character, published at Mexico a few years later, the “Road to Heaven,” of Father Nicolas de Leon, we find a series of questions which a confessor should put to any of his flock suspected of these necromantic practices. They reveal to us quite clearly what these occult practitioners were believed to do. The passage reads as follows, the questions being put in the mouth of the priest: “Art thou a soothsayer? Dost thou foretell events by reading signs, or by interpreting dreams, or by water, making circles and figures on its surface? Dost thou sweep and ornament with flower garlands the places where idols are preserved? Dost thou know certain words with which to conjure for success in hunting, or to bring rain? “Dost thou suck the blood of others, or dost thou wander about at night, calling upon the Demon to help thee? Hast thou drunk _peyotl_, or hast thou given it to others to drink, in order to find out secrets, or to discover where stolen or lost articles were? Dost thou know how to speak to vipers in such words that they obey thee?”[6-§]