Nagualism was a powerful and mysterious cult which united Mexican and Central American tribes, belonging to different linguistic stocks, into organized opposition against the government and religion of their conquerors. The members of this intertribal organization were bound together by strange faculties and an occult learning which placed them on a par with the famed thaumaturgists and theodidacts of the Old World, and which preserved even into our days the thoughts and forms of a long-suppressed ritual. The terms "nagual, nagualism, nagualist" are not Nahuatl, but of southern origin. A nagual was a personal guardian spirit. a personal totem, chosen in accordance with fixed rules and by consultation of an elaborate calendar, which was used mainly in astrological divination. The nagualists were powerful enchanters, whom the clergy believed to be in league with the devil and who were thought to be able to transform themselves into beasts. They used in their operations an intoxicant, peyotl, and the seeds of a plant called ololiuhqui. Intoxication was an essential part in many of these severe rites Under the old regime and before the coming of the Spaniards nagualists were especially devoted to the native cult; but it is Dr. Brinton's opinion, which he sustains with great research, that on the appearance of a foreign race and a new religion a new 'motif' was given to this old cult. Those most interested in it turned their sorceries and enchantments with organized, terrific, and often with successful energy against a common enemy.