N T RO D U C T I O N purposes of identification, and she assumes, rather than spells out, the medical and physiological theories behind the uses of the plants. She does, however, follow the traditional view of created things consisting of mixtures of four elements—hot, cold, wet, dry—in which one or two qualities predominate. She combines the elements with a theological notion ultimately derived from Genesis according to which everything on earth was put there for the use of humans. Since the balance of the elements and their corresponding humors determined good or bad health in people, it was important to know the elemental qualities of plants. People could then determine their effect on the persons who ate or used them, according to whether they were in or out of humor—that is, in a balanced or unbalanced state. The most important fact Hildegard gives about the plants is whether they are hot or cold, the oppositional qualities which assume the most significance for medical purposes. After conveying this information Hildegard usually indicates what medicinal purposes the plant in question serves. Sometimes this follows fairly obviously from its qualities; at other times the connections are more tenuous. The remaining eight books of Physica, dealing with the rest of creation, probably arose from a characteristically medieval desire for completeness. For the nuns of her own convent, Hildegard wrote hymns and canticles—both words and music. Between 1151 and 1158
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