However, in Bartholomew’s first book, whose subject is God, the first two chapters are taken entirely and perhaps discreetly, since the difficult problem of the Trinity is under discussion, from an Extra of Innocent III, while the third chapter is drawn from more varied authorities, such as Augustine, the treatise on the Trinity ascribed to Boethius,[1330] and the more recent Hugh and Richard, both of St. Victor. Presently the theme of divine names is discussed[1331] and Bartholomew lists and explains the ten Hebrew names of God, which are found also in Isidore, namely: El, Eloe, Sabbaoth, Zelioz or Ramathel, Eyel, Adonay, Ya, Tetragrammaton, Saday, and Eloym.
The nature of demons.
In the second book on the properties of angels is also discussed the nature of demons.[1332] They are naturally perspicacious in matters of science and powerful by their “sense of nature”—a phrase which we have already met in William of Auvergne, whom, however, I think Bartholomew does not cite; perhaps it was a technical expression that spread rapidly from mouth to mouth of medieval psychologists as such expressions do today,—experience of time, and knowledge of Scripture. They can predict many future events, partly because their knowledge of nature gained through their subtler senses is superior to man’s, partly because of their longer lives which permit them to learn more, partly by angelic revelation. Their bodies were celestial before they transgressed but now are aerial. Apuleius’s characterization of them is repeated via Augustine, whose explanation is also given, that they know occult virtues in nature which are hidden from us and by which they are able to accelerate natural processes and work feats of magic such as those performed by Pharaoh’s magicians.
Psychology and physiology.
Bartholomew’s third book may be described as psychological and discusses the human mind or soul (anima), of which definitions by various Greek philosophers are repeated, and the senses. The fourth and fifth books are physiological. These three books seem to be based mainly upon the writings of Constantinus Africanus; less frequently Aristotle and other authorities are cited. One treatise is ascribed to Avicenna and Constantinus which is not in Peter the Deacon’s list of the latter’s works, namely, a treatise on poisonous animals and poisons and presumably a translation of Avicenna by Constantinus.[1333] In this connection we are told that while some animals have poisonous tongues like snakes, others have medicinal and healing tongues like the dog, as Cassiodorus says, and either from the goodness of nature or from some occult property.[1334] We have already noted elsewhere Bartholomew’s acceptance of the usual medieval theory of three brain cells devoted to three mental faculties, in which connection he cites Johannitius or Hunain ibn Ishak.[1335] In discussing the disease of melancholia Bartholomew tells of a noble whom he knew who imagined that he was a cat and insisted upon sleeping under the bed in order to watch the mouse holes.[1336] In a later passage in his seventh book Bartholomew repeats Constantinus’ distinction between mania as an infection of the anterior cell of the brain with injury to the imagination and melancholia as an infection of the central cell with loss of one’s reason.[1337]
Vision and perspective.
In discussing vision Bartholomew gives the views of “an author of the science of perspective” precedence over those of Constantinus.[1338] This author believes that in vision three coterminous pyramids or cones are formed with the apex of each in the pupil of the eye and the base formed by the object seen. One pyramid is made up of species from the object coming along straight lines to the center of the eye. The second pyramid is made by the vision going out from the eye to the object seen. The third pyramid consists of light, which, as Bartholomew explains elsewhere[1339] on the authority of Basel and Dionysius and Augustine, is a distinct substance by which other bodies are illuminated. Light was created three days before sun and moon which are simply vehicles for it. But while this light is always shining, whether visibly or invisibly, it produces illumination only when other bodies are in a condition to receive it. The human eye can see itself only by the reflection of rays, “and possibly the vision delights in the sight of a mirror because through reflection of rays it is, by returning to itself, fortified as it were and in a way strengthened.”[1340]
Medieval domestic science.
Bartholomew’s sixth book is entitled, “Of ages,” but really deals more with matters of daily family and domestic life, discussing in addition to age, death, infancy, childhood, manhood, such family relationships as father, mother, and daughter, and such domestic concerns as servants, food and drink, dinners and banquets, sleep and waking, dreams and exercise. This last topic of exercise is discussed largely in the words of a sermon by Fulgentius, but in other chapters Bartholomew writes so vividly from his own observation that he deserves quotation, although the themes are somewhat of a digression from our main subject.[1341]
The medieval domestic servant.