by Will Durant
The unicorn is a very fierce beast with only one horn. To capture it a virgin maid is placed in the field. The unicorn approaches her, and resting in her lap, is so taken. By the beast Christ is figured; by the horn his insuperable strength…. Resting in the womb of a virgin, he was taken by the hunters—i.e., Christ was found in the form of a man by those who loved him.42
The most scientific work of medieval biology was Frederick II’s De arte venandi cum avibus, a 589-page treatise on “the art of hunting with birds.” It was based partly on Greek and Moslem manuscripts, but largely on direct observation and experiment; Frederick himself was an expert falconer. His description of bird anatomy contains a great number of original contributions; his analysis of the flight and migration of birds, his experiments on the artificial incubation of eggs and the operations of vultures show a scientific spirit unique in his age.43 Frederick illustrated his text with hundreds of drawings of birds, perhaps from his own hand—drawings “true to life down to the tiniest details.”44 The menagerie that he collected was not, as most contemporaries thought, a whim of bizarre display, but a laboratory for the direct study of animal behavior. This Alexander was his own Aristotle.
IV. MATTER AND ENERGY
Physics and chemistry did better than geology and biology; their laws and marvels have always harmonized better than a “Nature red in tooth and claw” with a theistic view of the world. Their vitality is suggested near the outset of this period by the efforts of Oliver of Malmesbury to make an airplane; in 1065 his contraption was ready, he soared in it from a high place, and was killed.45
The science of mechanics produced in the thirteenth century a remarkable figure, a Dominican monk who anticipated several basic conceptions of Isaac Newton. Jordanus Nemorarius became the second General of the Dominican Order in 1222; that such a man could do such brilliant work in science bears witness—if Albert and Thomas were not enough—to the intellectual eagerness of the Preaching Friars. In three mathematical treatises rivaling those of Fibonacci in courage and influence, he accepted the Hindu numerals, and advanced algebra by regularly using letters instead of figures for his general formulas. His Elementa super demonstrationem ponderis studied the component of gravity along a trajectory, and laid down a principle now known as the axiom of Jordanus: that which can raise a certain weight to a certain height can raise a weight K times heavier to a height K times less. Another treatise, De ratione ponderis (perhaps by a pupil), analyzed the notion of statical moment—the product of a force into its lever arm—and anticipated modern ideas in the mechanics of the lever and the inclined plane.46 A third treatise, ascribed to “the school of Jordanus,” gave tentative expression to the theory of virtual displacements—a principle developed by Leonardo da Vinci, Descartes, and John Bernoulli, and finally formulated by J. Willard Gibbs in the nineteenth century.
The progress of mechanics slowly affected invention. In 1271 Robert of England clearly stated the theory of the pendulum clock. In 1288 we hear of a great clock in a tower at Westminster, and, about the same time, of similar giants in churches on the Continent; but there is no certain indication that these were fully mechanical. The first clear mention of a clock operated by pulleys, weights, and gears is dated 1320.47
The most successful branch of physics in this period was optics. The Arabic treatises of al-Haitham, translated into Latin, opened almost a new world to the West. In an essay on the rainbow Robert Grosseteste, about 1230, wrote of a
third branch of perspective… untouched and unknown among us until the present time… [which] shows us how to make things very far off seem very close at hand, and how to make large objects which are near seem tiny, and how to make distant objects appear as large as we choose.
These marvels, he adds, can be achieved through breaking up “the visual ray” by passing it through several transparent objects or lenses of varying structure. These ideas fascinated his pupil Roger Bacon. Another Franciscan monk, John Peckham, probably also a pupil of Grosseteste at Oxford, dealt with reflection, refraction, and the structure of the eye in a treatise Perspectiva communis; when we recall that Peckham became Archbishop of Canterbury we perceive again an unsuspected entente between science and the medieval Church.
One result of these studies in optics was the invention of spectacles. Magnifying glasses had been known to Greek antiquity,48 but the construction of such glasses to focus properly when near the eye seems to have awaited research in the geometry of refraction. A Chinese document of uncertain date between 1260 and 1300 speaks of glasses called ai tai, which enabled old people to read fine script. A Dominican friar, preaching at Piacenza in 1305, remarked: “It is not twenty years since there was discovered the art of making eyeglasses [occhiali], which enable one to see well…. I myself have spoken to the man who first discovered and made them.” A letter dated 1289 says: “I am so heavy with years that without the glasses called okiali, recently invented, I should not be able to read or write.” The invention is usually credited to Salvino d’Amarto, whose tombstone, dated 1317, read: “the inventor of spectacles.” In 1305 a Montpellier physician announced that he had prepared an eyewash that made spectacles superfluous.49
The attractive power of the magnet had also been known to the Greeks. Its power to indicate direction was apparently discovered by the Chinese in the first century of our era. Chinese tradition ascribes to Moslems, about 1093, the earliest use of the magnetic needle in guiding navigation. Such use was probably widespread among Moslem and Christian mariners by the end of the twelfth century. The oldest Christian reference to it is in 1205, the oldest Moslem reference is in 1282;50 but perhaps those who had long known the precious secret had been in no haste to publish it. Moreover, mariners who used it were suspected of magic, and some sailors refused to sail with a captain who kept such a demonic instrument.51 The first known description of a pivoted floating compass occurs in an Epistola de magnete by Petrus Peregrinus in 1269. This Peter the Pilgrim recorded many experiments, advocated the experimental method, and expounded the operation of the magnet in attracting iron, magnetizing other objects; and finding the north. He tried also to construct a perpetual motion machine operated by self-regenerating magnets.52
Chemistry advanced largely through alchemical research. From the tenth century onward Arabic texts in this field were translated into Latin, and soon the West steamed with alchemy, even in monasteries. Brother Elias, successor to St. Francis, edited a work on alchemy for Frederick II; another Franciscan, Grosseteste, wrote in favor of the possibility of transmuting metals; and one of the most famous of medieval books, the Liber de causis, presented alchemy and astrology in a work foisted upon Aristotle. Several European kings employed alchemists in the hope of rescuing their treasuries by changing cheap metals into gold.53 Other zealots continued the search for the elixir of life and the philosopher’s stone. In 1307 the Church condemned alchemy as a diabolical art, but its practice continued. Perhaps to escape ecclesiastical censure several authors of the twelfth or thirteenth century attributed their works on alchemy to the Moslem “Gebir.”
Medical experience with drugs added to chemical knowledge, and industrial operations almost compelled experiment or discovery. The brewing of beer, the manufacture of dyes, pottery, enamels, glass, glue, lacquer, ink, and cosmetics contributed to the science of chemistry. Peter of St. Omer, about 1270, composed a Liber de coloribus faciendis, containing recipes for the various pigments used in painting; one recipe described the making of oil colors by mixing the pigment with linseed oil.54 About 1150a treatise known as the Magister Salernus—presumably a product of the Salerno school of medicine—mentioned the distillation of alcohol; this is the first clear reference to that now universal operation. The grape-producing countries distilled wine, and called the result aqua vitae, eau de vie water of life; the North, with less grapes and bitterer cold, found it cheaper to distill grain. The Celtic term uisqebeatha, which was shortened into whisky, also meant “water of life.”55 Distillation had been known long befor
e to Moslem alchemists; but the discovery of alcohol—and, in the thirteenth century, of mineral acids—vastly enlarged chemical knowledge and industry.
Almost as important in its effects as the distillation of alcohol was the discovery of gunpowder. The old Chinese claim to priority here is now challenged; and there is no clear mention of the substance in Arabic manuscripts before 1300.56 The earliest known notice of the explosive is in a Liber ignium ad comburendos hostes, or Book of Fires for Burning Enemies, written by Marcus Graecus, about 1270. After describing Greek fire and phosphorescence Mark the Greek gave a recipe for making gunpowder: reduce to a fine powder, separately, one pound of live sulphur, two pounds of charcoal from the lime or willow tree, and six pounds of saltpeter (potassium nitrate); then mix them.57 There is no record of any military use of gunpowder before the fourteenth century.
V. THE REVIVAL OF MEDICINE
Poverty always mingles myth with medicine, for myth is free and science is dear. The basic picture of medieval medicine is the mother with her little store of household remedies; old women wise in herbs and plasters and magic charms; herbalists peddling curative plants, infallible drugs, and miraculous pills; midwives ready to sever new life from old in the ridiculous ignominy of birth; quacks ready to cure or kill for a pittance; monks with a heritage of monastic medicine; nuns quietly comforting the sick with ministration or prayer; and, here and there, for those who could afford them, trained physicians practicing more or less scientific medicine. Monstrous drugs and fabulous formulas flourished; and just as certain stones held in the hand were by some believed to ward off conception, so—even in medical Salerno—some women and men ate asses’ dung to promote fertility.58
Until 1139 some members of the clergy practiced medicine, and what hospitalization could be had was usually to be found in monastic or conventual infirmaries. The monks played an honorable role in preserving the medical heritage, and led the way in the cultivation of medicinal plants; and perhaps they knew what they were doing in mingling miracle with medicine. Even nuns might be skilled in healing. Hildegarde, the mystic Abbess of Bingen, wrote a book of clinical medicine—Causae et curae (c. 1150)—and a book of Subtilitates, marred here and there with magic formulas, but rich in medical lore. The retirement of old men or women into monasteries or convents may have been motivated in part by a desire for continuous medical attendance. As lay medicine developed, and the love of gain infected monastic healing, the Church (1130, 1339, 1663) progressively forbade the public practice of medicine by the clergy; and by 1200 the ancient art was almost completely secular.
Scientific medicine survived the Dark Ages in the West chiefly through Jewish physicians, who circulated Greco-Arabic medical knowledge in Christendom; through the Byzantine culture of southern Italy; and through translations of Greek and Arabic medical treatises into Latin. Probably the School of Salerno was best situated and prepared to take advantage of these influences; Greek, Latin, Moslem, and Jewish physicians taught or studied there; and till the twelfth century it remained the leading medical institution in Latin Europe. Women studied nursing and obstetrics at Salerno;59 mulleres Salernitanae were probably midwives trained in the school. One of the most famous Salernitan products was an obstetrical treatise of the early twelfth century, entitled Trotulae curandarum aegritudinum muliebrum—Trotula on the Cure of Diseases of Women; in the generally accepted theory Trotula was a midwife of Salerno.60 Several important treatises, covering nearly all branches of medicine, have reached us from the School of Salerno. One, by Archimatheus, prescribes the proper bedside manner: the physician must always regard the patient’s condition as grave, so that a fatal end may not disgrace him, and a cure may add another marvel to his fame; he should not flirt with the patient’s wife, daughter, or maidservant; and even if no medicine is necessary he should prescribe some harmless concoction, lest the patient think the treatment not worth the fee, and lest nature should seem to have healed the patient without the physician’s aid.61
The School of Salerno gave way to the University of Naples after 1268, and little is heard of it thereafter. By that time its graduates had spread Salernitan medicine through Europe. Good schools of medicine existed in the thirteenth century at Bologna, Padua, Ferrara, Perugia, Siena, Rome, Montpellier, Paris, and Oxford. In these schools the three main medical traditions of the Middle Ages—Greek, Arabic, and Judaic—were merged and absorbed, and the entire medical heritage was reformulated to become the basis of modern medicine. Ancient methods of diagnosis by auscultation and urinalysis retained (and retain) their popularity, so that in some places the urinal became the emblem or signboard of the medical profession.62 Ancient methods of treatment by purgation and bloodletting continued, and in England the physician was a “leech.” Hot baths were a favorite prescription; patients traveled to “take the waters” of mineral springs. Diet was minutely prescribed in nearly every illness.63 But drugs abounded. Almost every element was used as a cure, from seaweed (rich in iodine), which Roger of Salerno recommended for goiter in 1180, to gold, which was imbibed to “comfort sore limbs”64—apparently our fashionable treatment for arthritis. Practically every animal organ found some therapeutic use in the medieval pharmacopeia—the horns of deer, the blood of dragons, the bile of vipers, the semen of frogs; and animal excrement was occasionally prescribed.65 The most popular of all drugs was theriacum, a weird mixture composed of some fifty-seven substances, of which the chief was the flesh of poisonous snakes. Many drugs were imported from Islam, and kept their Arabic names.
As the supply of trained physicians increased, governments began to regulate medical practice. Roger II of Sicily, probably influenced by old Moslem precedents, restricted the practice of medicine to persons licensed by the state. Frederick II (1224) required for such practice a license from the School of Salerno. To obtain it the student had to survive a three-year course in scientia logicalis—presumably meaning natural science and philosophy; he had then to study medicine at the school for five years, pass two examinations, and practice for a year under the supervision of an experienced physician.66
Every city of any importance paid physicians to treat the poor without charge.67 Some cities had a measure of socialized medicine. In Christian Spain of the thirteenth century a physician was hired by the municipality to care for a specified part of the population; he made periodically a medical examination of each person in his territory, and gave each one advice according to his findings; he treated the poor in a public hospital, and was obliged to visit every sick person three times a month; all without charge, except that for any visit above three in any month he was allowed to ask a fee. For these services the physician was exempted from taxes, and received an annual salary of twenty pounds,68 equivalent to some $4000 today.*
As licensed physicians were not numerous in thirteenth-century Christian Europe, they earned good fees, and had a high social status. Some amassed considerable fortunes; some became art collectors; several won an international reputation. Petrus Hispanus—Peter of Lisbon and Compostela—migrated to Paris and then to Siena, wrote the most popular medieval handbook of medicine (Thesaurus pauperum—Treasure of the Poor) and the best medieval discussion of psychology (De anima), became Pope John XXI in 1276, and was crushed to death by a falling ceiling in 1277. The most famous Christian physician of this period was Arnold of Villanova (c. 1235–1311). Born near Valencia, he learned Arabic, Hebrew, and Greek, studied medicine at Naples, taught it or natural philosophy at Paris, Montpellier, Barcelona, Rome, and wrote a great number of works on medicine, chemistry, astrology, magic, theology, wine making, and the interpretation of dreams. Made physician to James II of Aragon, he repeatedly warned the King that unless he protected the poor against the rich he would go to hell.70 James loved him nevertheless, and sent him on many diplomatic missions. Shocked by the misery and exploitation that he saw in many countries, he became a follower of the mystic Joachim of Flora, and declared, in letters to princes and prelates, that the wickedness of the mighty and the luxury
of the clergy heralded the destruction of the world. He was accused of magic and heresy, and was charged with having alchemically produced ingots of gold for King Robert of Naples. He was condemned by an ecclesiastical court, but was released from prison by Boniface VIII. He successfully treated the old Pope for kidney stones, and received from him a castle at Anagni. He warned Boniface that unless the Church should be thoroughly reformed the divine wrath would soon descend upon her; soon thereafter Boniface suffered famous indignities at Anagni, and died in despair. The Inquisition continued to pursue Arnold, but kings and popes protected him for their ailments’ sake, and he died by drowning on a mission from James II to Clement V.71
Surgery in this period fought a two-front war against the barbers on one side and general practitioners on the other. For a long time the barbers had given enemas, pulled teeth, treated wounds, and let blood. Surgeons who had received formal medical training protested against the tonsorial performance of such ministrations, but the law defended the barbers throughout the Middle Ages. In Prussia till the time of Frederick the Great it remained one of the duties of the army surgeon to shave the officers.72 Partly through this overlapping of functions, the surgeons were considered inferior to the physicians in science and society; they were looked upon as simple technicians obeying the directions of the doctor, who usually, before the thirteenth century, disdained to practice surgery himself.73 Surgeons were further discouraged by fear of imprisonment or death if their procedures failed; only the bravest undertook dangerous operations; and most surgeons, before such an enterprise, required a written guarantee that no harm would come to them in case of failure.74