The Philosophy of Natural Magic, by Henry Cornelius Agrippa, L. W. de Laurence ed. [1913], at sacred-texts.com
The foresaid passions sometimes alter the body by reason of the virtue which the likeness of the thing hath to change it, which power the vehement imagination moves, as in setting the teeth on edge at the sight or hearing of something, or because we see, or imagine, another to eat sharp or sour things. So he, which sees another gape, gapes also; and some, when they hear any one name sour things, their tongues waxeth tart. Also, the seeing of any filthy thing causeth nauseousness. Many, at the sight of a man's blood, fall into a swoon. Some, when they see bitter meat given to any, perceive a bitter spittle in their mouth. And William of Paris saith that he saw a man, that at the sight of a medicine, was affected as much as he pleased; when, as neither the substance of the medicine, nor the odor, nor the taste of it came to him, but only a kind of resemblance was apprehended by him. Upon this account, some that are in a dream think they burn and are in a fire, and are fearfully tormented, as if they did truly burn, when, as the substance of the fire is not near them, but only a resemblance apprehended by their imagination. And sometimes men's bodies are transformed, and transfigured, and also transported; and this oft times when they are in a dream, and sometimes when they are awake. So Cyprus, after he was chosen king of Italy, did very much wonder at and meditate upon the fight and victory of bulls, and in the thought thereof did sleep a whole night, and in the morning
he was found horned, no otherwise than by the vegetative power, being stirred up by a vehement imagination, elevating cornific humors into his head and producing horns. For a vehement cogitation, whilst it vehemently moves the species, pictures out the figure of the thing thought on, which they represent in their blood, and the blood impresseth the figure on the members that are nourished by it; as upon those of the same body, so upon those of anothers. So the imagination of a woman with child impresseth the mark of the thing longed for upon her infant, and the imagination of a man, bit with a mad dog, impresseth upon his body the image of dogs. So men may grow gray on a sudden. And some, by the dream of one night, have grown up from boys into perfect men. Hereto, also, may be referred those many scars of King Dagobertus, and marks of Franciscus, which they receivedthe one, whilst he was afraid of correction, and the other, whilst he did wonderfully meditate upon the wounds of Christ. So, many are transported from place to place, passing over rivers, fires and unpassable places, viz., when the species of any vehement desire, or fear, or boldness, are impresed upon their spirits, and, being mixed with vapors, do move the organ of the touch in their original, together with phantasy, which is the original of local motion. Whence they stir up the members and organs of motion to motion, and are moved, without any mistake, unto the imagined place, not out of sight, but from the interior phantasy. So great a power is there of the soul upon the body, that whichever way the soul imagines and dreams that it goes, thither doth it lead the body. We read many other examples by which the power of the soul upon .the body is wonderfully explained, as like that which Avicen describes of a certain man, who, when he pleased, could affect his body with the palsy. They report of Gallus Vibius that he did fall into madness,
not casually, but on purpose, for, whilst he did imitate madmen, he assimilated their madness to himself and became mad indeed. And Austin makes mention of some men who could move their ears at their pleasure, and some that could move the crown of their head to their forehead and could draw it back again when they pleased, and of another that could sweat at his pleasure. And it is well known that some can weep -at their pleasure, and pour forth abundance of tears; and there are some that can bring up what they have swallowed, when they please, as out of a bag, by degrees. And we see that in these days there are many who can so imitate and express the voices of birds, cattle, dogs, and some men, that they can scarce at all be discerned. Also Pliny relates, by divers examples, that women have been turned into men. Pontanus testifieth that in his time, a certain woman called Caietava, and another one called Aemilia, who, many years after they were married, were changed into men. Now, how much imagination can affect the soul no man is ignorant, for it is nearer to the substance of the soul than the sense is, and therefore acts more upon the soul than the sense doth. So women, by certain strong imaginations, dreams, and suggestions, brought in by certain magical arts, do often bind themselves into a strong affection for any one. So they say that Medea, by a dream, was filled with love for Jason. So the soul sometimes is, by a vehement imagination or speculation, altogether abstracted from the body, as Celsus relates of a certain presbyter, who, as often as he pleased, could make himself senseless and lay like a dead man, so that when any one pricked or burnt him he felt no pain, but lay without any motion or breathing; yet he could, as he said, hear men's voices, as it were, afar off, if they cried out aloud.