While thus investigating their real and supposed power over the physical and mental world, their strictly priestly functions, as performers of the rites of religion, have not been touched upon. Among the ruder tribes these, indeed, were of the most rudimentary character. Sacrifices, chiefly in the form of feasts, where every one crammed to his utmost, dances, often winding up with the wildest scenes of licentiousness, the repetition of long and monotonous chants, the making of the new fire, these are the ceremonies that satisfy the religious wants of savages. The priest finds a further sphere for his activity in manufacturing and consecrating amulets to keep off ill luck, in interpreting dreams, and especially in lifting the veil of the future. In Peru, for example, they were divided into classes, who made the various means of divination specialties. Some caused the idols to speak, others derived their foreknowledge from words spoken by the dead, others predicted by leaves of tobacco or the grains and juice of cocoa, while to still other classes, the shapes of grains of maize taken at random, the appearance of animal excrement, the forms assumed by the smoke rising from burning victims, the entrails and viscera of animals, the course taken by a certain species of spider, the visions seen in drunkeness,[TN-16] the flights of birds, and the directions in which fruits would fall, all offered so many separate fields of prognostication, the professors of which were distinguished by different ranks and titles.[279-1] As the intellectual force of the nation was chiefly centred in this class, they became the acknowledged depositaries of its sacred legends, the instructors in the art of preserving thought; and from their duty to regulate festivals, sprang the observation of the motions of the heavenly bodies, the adjustment of the calendars, and the pseudo-science of judicial astrology. The latter was carried to as subtle a pitch of refinement in Mexico as in the old world; and large portions of the ancient writers are taken up with explaining the method adopted by the native astrologers to cast the horoscope, and reckon the nativity of the newly-born infant.