Besides, it is to be considered that such an illusion of the sight and touch can be caused not only by the interposition of some smooth unmembered body, but also by the summoning to the fancy or imagination of certain forms and ideas latent in the mind, in such a way that a thing is imagined as being perceived then for the first time. For, as was shown in the preceding question, devils can by their own power change bodies locally; and just as the disposition or humour can be affected in this way, so can the natural functions. I speak of things which appear natural to the imagination or senses. For Aristotle in the De Somno et Uigila says, assigning the cause of apparitions in dreams, that when an animal sleeps much blood flows to the inner consciousness, and thence come ideas or impressions derived from actual previous experiences stored in the mind. It has already been defined how thus certain appearances convey the impression of new experiences. And since this can happen naturally, much more can the devil call to the imagination the appearance of a smooth body unprovided with the virile member, in such a way that the senses believe it to be an actual fact.
Secondly, some other methods are to be noted which are easier to understand and to explain. For, according to S. Isidore (Etymologiae VIII, 9), a glamour is nothing but a certain delusion of the senses, and especially of the eyes. And for this reason it is also called a prestige, from prestringo, since the sight of the eyes is so fettered that things seem to be other than they are. And Alexander of Hales,153 Part 2, says that a prestige, properly understood, is an illusion of the devil, which is not caused by any change in matter, but only exists in the mind of him who is deluded, either as to his inner or outer perceptions.
Wherefore, in a manner of speaking, we may say even of human prestidigitatory art, that it can be effected in three ways. For the first, it can be done without devils, since it is artificially done by the agility of men who show things and conceal them, as in the case of the tricks of conjurers and ventriloquists. The second method is also without the help of devils; as when men can use some natural virtue in natural bodies or minerals so as to impart to such objects some other appearance quite different from their true appearance. Wherefore, according to S. Thomas (I, 114, 4), and several others, men, by the smoke of certain smouldering or lighted herbs, can make rods appear to be serpents.
The third method of delusion is effected with the help of devils, the permission of God being granted. For it is clear that devils have, of their nature, some power over certain earthly matters, which they exercise upon them, when God permits, so that things appear to be other than they are.
And as to this third method, it is to be noted that the devil has five ways in which he can delude anyone so that he thinks a thing to be other than it is. First, by an artificial trick, as has been said; for that which a man can do by art, the devil can do even better. Second, by a natural method, by the application, as has been said, and interposition of some substance so as to hide the true body, or by confusing it in man’s fancy. The third way is when in an assumed body he presents himself as being something which he is not; as witness the story which S. Gregory tells in his First Dialogue of a Nun, who ate a lettuce, which, however, as the devil confessed, was not a lettuce, but the devil in the form of a lettuce, or in the lettuce itself. Or as when he appeared to S. Antony in a lump of gold which he found in the desert. Or as when he touches a real man, and makes him appear like a brute animal, as will shortly be explained. The fourth method is when he confuses the organ of sight, so that a clear thing seems hazy, or the converse, or when an old woman appears to be a young girl. For even after weeping the light appears different from what it was before. His fifth method is by working in the imaginative power, and, by a disturbance of the humours, effecting a transmutation in the forms perceived by the senses, as has been treated of before, so that the senses then perceive as it were fresh and new images. And accordingly, by the last three of these methods, and even by the second, the devil can cast a glamour over the senses of a man. Wherefore there is no difficulty in his concealing the virile member by some prestige or glamour. And a manifest proof or example of this, which was revealed to us in our Inquisitorial capacity, will be set forth later, where more is recounted of these and other matters in the Second Part of this Treatise.
How a Bewitchment can be Distinguished from a Natural Defect.
An incidental question, with certain other difficulties, follows. Peter’s member has been taken off, and he does not know whether it is by witchcraft or in some other way by the devil’s power, with the permission of God. Are there any ways of determining or distinguishing between these? It can be answered as follows. First, that those to whom such things most commonly happen are adulterers or fornicators. For when they fail to respond to the
