We cannot take the time to note all of Hildegard’s minor variations from the natural science of her time, but may note one or two characteristic points in which her views concerning the universe and nature seem rather daring and unusual, not to say crude and erroneous. In the Scivias she represents a blast and lesser winds as emanating from each of four concentric heavens which she depicts as surrounding the earth, namely, a sphere of fire, a shadowy sphere like a skin, a heaven of pure ether, and a region of watery air under it.[356] In the Liber divinorum operum she speaks of winds which drive the firmament from east to west and the planets from west to east.[357] In the Subtilitates Hildegard seems to entertain the strange notion that rivers are sent forth from the sea like the blood in the veins of the human body.[358] One gets the impression that the rivers flow up-hill toward their sources, since one reads that “the Rhine is sent forth by the force of the sea”[359] and that “some rivers go forth from the sea impetuously, others slowly according to the winds.”
Since Hildegard lived on the Nahe or Rhine all her life she must indeed have been absorbed in her visions and monastic life not to have learned in which direction a river flows; and perhaps we should supply the explanation, which she certainly does not expressly give in the Subtilitates, that the sea feeds the rivers by evaporation or through subterranean passages. Perhaps a passage in the Causae et curae may be taken as a correction or explanation of the preceding assertions, in which case that work would seem to be of later date than the Subtilitates. In it too Hildegard states that “springs and rivers” which “flow from the sea” are better in the east than in the west, but her next sentence straightway adds that they are salt and leave a salt deposit on the sands where they flow which is medicinal.[360] The waters rising from the southern sea are also spoken of by her as salt.[361] Even in the Causae et curae she speaks of the water of the great sea which surrounds the world as forming a sort of flank to the waters above the firmament.[362]
Suggestions concerning drinking-water.
On the subject of whether waters are wholesome to drink or not Hildegard comes a trifle nearer the truth and somewhat reminds us of the discussions of the same subject in Pliny and Vitruvius.[363] She says that swamp water should always be boiled,[364] that well water is better to drink than spring-water and spring-water than river water, which should be boiled and allowed to cool before drinking;[365] that rain-water is inferior to spring-water[366] and that drinking snow-water is dangerous to the health.[367] The salt waters of the west she regards as too turbid, while the fresh waters of the west are not warmed sufficiently by the sun and should be boiled and allowed to cool before using.[368] The salt waters arising from the south sea are venomous from the presence in them of worms and small animals. Southern fresh waters have been purged by the heat, but make the flesh of men fatty and of black color.[369] Hildegard is not the first author to advise the boiling of drinking-water,[370] but she certainly lays great stress on this point.
The devil as the negative principle.
While the scheme of the universe put forward by ancient and medieval science is, as we have seen, on the whole adopted even in Hildegard’s most visionary writings, it is equally true that the religious interest is by no means absent from her two works of medicine and natural history. In the first place, the devil is a force in nature which she often mentions. Her opening the Causae et curae with a discussion of creation—of course a usual starting-point with the medieval scientist—soon leads her to speak of the fall of Lucifer. She has a rather good theory that Lucifer in his perverse will strove to raise himself to Nothing, and that since what he wished to do was Nothing, he fell into nothingness and could not stand because he could find no foundation under him.[371] But after the devil was unable to create anything out of nothing and fell from heaven, God created the firmament and sun, moon, and stars to show how great He was and to make the devil realize what glory he had lost.[372] Other creatures who willingly join themselves to the devil lose their own characteristics and become nothing.[373] Lucifer himself is not permitted to move from Tartarus or he would upset the elements and celestial bodies, but a throng of demons of varying individual strength plot with him against the universe.[374] But in other passages Hildegard seems to admit freely the influence, if not the complete presence, of the devil in nature. And he has the power of deceiving by assumed appearances, as Adam was seduced by the serpent.
Natural substances and evil spirits.
Indeed, the dragon to this day hates mankind and has such a nature and such diabolical arts in itself that sometimes when it emits its fiery breath, the spirits of the air disturb the air.[375] This illustrates a common feature of Hildegard’s natural history and pharmacy; namely, the association of natural substances with evil spirits either in friendly or hostile relationships. In the preface to the first book of the Subtleties she states that some herbs cannot be endured by demons, while there are others of which the devil is fond and to which he joins himself. In mandragora, for example, “the influence of the devil is more present than in other herbs; consequently man is stimulated by it according to his desires, whether they be good or bad.”[376] On the other hand, the holm-oak is hostile to the spirits of the air; one who sleeps under its shade is free from diabolical illusions, and fumigating a house with it drives out the evil spirits.[377] Certain fish, too, have the property of expelling demons, whether one eats them or burns their livers or bones.[378] Finally, stones and metals have their relations to evil spirits. It is advisable for a woman in childbirth to hold the gem jasper in her hand, “in order that malignant spirits of the air may be the less able to harm her and her child; for the tongue of the ancient serpent extends itself towards the perspiration of the child, as it emerges from the mother’s womb.”[379] Not only does the touch of red-hot steel weaken the force of poison in food or drink, but that metal also signifies the divinity of God, and the devil flees from and avoids it.[380]
Stars and fallen angels: sin and nature.
It is perhaps not very surprising that we should find in Hildegard’s works notions concerning nature which we met back in the Enoch literature, since some of her writings take the same form of recorded visions as Enoch’s, while one of them, the Liber vitae meritorum, is equally apocalyptic. At any rate, in the Scivias in the second vision, where Lucifer is cast out of glory because of his pride, the fallen angels are seen as a great multitude of stars, as in the Book of Enoch, and we are told that the four elements were in harmony before Lucifer’s fall.[381] The disturbing effect of sin, even human, upon nature is again stated in the Causae et curae, where it is said that normally the elements serve man quietly and perform his works. But when men engage in wars and give way to hate and envy, the elements are apt to rage until men repent and seek after God again.[382] In the Liber vitae meritorum, too, the elements complain that they are overturned and upset by human depravity and iniquity.[383]