The Philosophy of Natural Magic, by Henry Cornelius Agrippa, L. W. de Laurence ed. , at sacred-texts.com
It is now manifest that the occult properties in things are not from the nature of the Elements, but infused from above, hid from our senses, and scarce at last known by our reason, which indeed come from the Life and the Spirit of the World, through the rays of the Stars; and can no otherwise but by experience and conjecture be inquired into by us. Wherefore, he that desires to enter upon this study must consider that every thing moves and turns itself to its like, and inclines that to itself with all its might, as well in property, viz., Occult Virtue, as in quality, viz., Elementary Virtue. Sometimes also in substance itself, as we see in salt, for whatsoever hath long stood with salt becomes salt; for every agent, when it hath begun to act, doth not attempt to make a thing inferior to itself, but, as much as may be, like and suitable to itself. Which also we manifestly see in sensible animals, in which the nutritive virtue doth not change the meat into an herb or a plant, but turns it into sensible flesh. In what things, therefore, there is an excess of any quality or property, as heat, cold, boldness, fear, sadness, anger, love, hatred, or any other passion or virtue (whether it be in them by nature or, sometimes also, by art or chance, as boldness in a wanton), these things do very much move and provoke to such a quality, passion or virtue. So fire moves to fire, and water moves to water, and he that is bold moves to boldness. And it is well known
amongst physicians that brain helps the brain, and lungs the lungs. So also it is said that the right eye of a frog helps the soreness of a man's right eye, and the left eye thereof helps the soreness of his left eye, if they be hanged about his neck in a cloth of its natural color. The like is reported of the eyes of a crab. So the feet of a tortoise helps them that have the gout in their being applied thus—as foot to foot, hand to hand, right to right, left to left.
After this manner they say that any animal that is barren causeth another to be barren, and of the animal especially the generative parts. So they report that a female shall be barren if, betimes, drink be made of a certain sterile animal, or anything steeped therewith. If, however, we would obtain any property or virtue, let us seek such animals, or such other things whatsoever, in which such a property is in a more eminent manner than in any other thing, and in these let us take that part in which such a property or virtue is most vigorous; as if at any time we would promote love, let us seek some animal which is most loving, of which kind are pigeons, turtles, sparrows, swallows, wagtails, and in these take those members or parts in which the vital virtue is most vigorous, such as the heart, breast, and also like parts. And it must be done at that time when these animals have this affection most intense, for then they do provoke and draw love. In like manner, to increase boldness, let us look for a lion, or a cock, and of these let us take the heart, eyes or forehead. And so we must understand that which Psellus the Platonist saith, viz., that dogs, crows, and cocks conduce much to watchfulness, also the nightingale and bat and horned owl, and in these the heart, head and eyes especially. Therefore, it is said, if any shall carry the heart of a crow or a bat about him, he shall not sleep till he cast it away from him. The same doth the head of a bat, dried and bound to the right arm of him that is
awake, for if it be put upon him when he is asleep, it is said that he shall not be awaked till it be taken off from him. After the same manner doth a frog and an owl make one talkative, and of these specially the tongue and heart. So the tongue also of a water-frog, laid under the head, makes a man speak in his sleep; and the heart of a screech-owl, laid upon the left breast of a woman that is asleep, is said to make her utter all her secrets. The same also the heart of the horned owl is said to do, also the suet of a hare, laid upon the breast of one that is asleep. Upon the same account do animals that are long lived conduce to long life; and whatsoever things have a power in themselves to renew themselves conduce to the renovation of our body and restoring of youth, which physicians have often professed they know to be true; as is manifest of the viper and snake. And it is known that harts renew their old age by the eating of snakes. After the same manner the phœnix is renewed by a fire which she makes for herself; and the like virtue there is in a pelican, whose right foot being put under warm dung, after three months there is of that generated a pelican. Therefore some physicians by some certain confections made of vipers, and hellebore, and the flesh of some such kind of animals, do restore youth, and indeed do sometimes restore it so, as Medea restored old Pileas. It is also believed that the blood of a bear, if it be sucked out of her wound, doth increase strength of body, because that animal is the strongest creature.