"The long winter nights were devoted by the to the ceremonies of their secret fraternities, exhorting their most benevolent gods; rain priests in retreat invoked their anthropic deities for rain to fructify the earth, and elders taught the youths, sitting attentively at their knees by the flickering firelight, the mysteries of their life and religion. Of all the secrets of their lives none is more strictly guarded or more carefully transmitted than the knowledge of healing. The "doctor" instructs in the lore of plants, and the relation of plants to man and beast."