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Medical Sciences in the Islamic Civilization: Scholars, Fields of Expertise and Institutions

Islamic medicine goes back to the time of the Prophet Muhammad, and it received its impetus from both his encouragement and example. Hareth Ibn Kelda was an Arab established at Mecca, and from him the Prophet obtained something more than the rudiments of medicine, an accomplishment which contributed greatly to his success [1]. The Prophet attended the sick, gave consultations, and imparted his learning to his wives, and crucially, he recognized the paramount importance of hygiene, and inculcated its maxims upon every occasion [2]. "God has not caused a single disease to descend upon men without providing a remedy," "Diet is the principle of cure, and intemperance the source of all physical ills," were some of the aphoristical sayings whose truth he constantly impressed upon his followers [3].

Following his example, his companions and early Caliphs gave great support to medical learning, teaching and practice, and by the high Middle Ages, Islamic medicine was ripe with accomplishments. Some such achievements are outlined by Campbell:

"The Arabians raised the dignity of the medical profession from that of menial calling to the rank of one of the learned professions; they were the first to introduce systematically arranged illustrations in their medical writings, and also gave us their system of numbering which has all but replaced the cumbersome Roman numerals. They also developed the science of chemistry as applied to medicine, and considerably improved the art of dispensing by the introduction of such elegant preparations as rose and orange water. To the Arabians we owe the introduction of the idea of the legal control of qualifying examinations for admission to the medical profession, and though the idea of establishing hospitals did not originate with them, they were responsible for the establishment of a large number of these institutions [4]."

Durant makes another excellent summary of Islamic medical achievements, which is abridged here [5]. The Muslims, he says "established the first apothecary shops and dispensaries, founded the first medieval school of pharmacy, and wrote great treatises on pharmacology. Muslim physicians were enthusiastic advocates of the bath, especially in fevers and in the form of the steam bath. Their directions for the treatment of smallpox and measles could scarcely be bettered today. Anesthesia by inhalation was practiced in some surgical operations…. No man could legally practice medicine without passing an examination and receiving a state diploma; druggists, barbers, and orthopedists were likewise subject to state regulation and inspection. The physician-vizier Ali ibn Isa organized a staff of doctors to go from place to place to tend the sick; certain physicians made daily visits to jails; there was an especially humane treatment of the insane [6]."

"The Arabs," in the words of Scott, "were the first to perform the important operation of lithotomy and to reduce old dislocations. They knew how to ligature the arteries four centuries before Ambrose Pare. They used hooks for the extraction of polypi. They made frequent and intelligent use of counter-irritants. The seton is their invention. The application of leeches in apoplexy was a common incident in their practice. They were familiar with the effects of caustics and acids as escharotics. They substituted refrigerants for tonics in certain affections of the nerve-centres. They understood the value of cold water in arresting hemorrhage. They originated the modern method of bandaging. The treatment of slow fevers, like typhoid, by baths of low temperature, was frequently employed by them; it was recommended by Razes nine hundred years before its announcement to the present generation as a new and remarkable discovery. To Ibn Zuhr medical science owes the operation of tracheotomy and the original description of pericarditis. Abulcasis, in explaining lithotomy, advises the section used by surgeons ever since he wrote, in the 10^th century. Nor had the advantages derived from anaesthesia escaped the notice of these profound and ingenious observers. They suggest the administration, in decoction, of darnel—the Lolium Temulentum— and other plants of narcotic properties, until complete loss of consciousness and sensation is obtained, to facilitate the performance of severe operations. Even the results of microbial infection appear to have been recognized by them, although its cause remained unknown. Nor in that early day was the care of animals neglected, and the name of Abu Bakr Ibn Badr has descended to posterity as that of a famous veterinary surgeon [7]."

Muslim science and medicine in particular, were so much more advanced in comparison to Western Christian counterpart. The 12th century Muslim historian, Usama Ibn Munquidh, relates an anecdote on the authority of Guillaume de Bures, with whom he travelled from acres to Tiberias: "There was with us in our country,' said Guillaume, "a very doughty knight, who fell ill and was at the point of death. As last resource we applied to a Christian priest of great authority and entrusted the patient to him saying, ‘Come with us to examine such and such a knight.' he agreed and set off with us. Our belief was that he had only to lay hands upon him to cure him. As soon as the priest saw the patient, he said, ‘bring me wax.' We brought him some, and he softened it and made (two plugs) like the joints of a finger, each of which he thrust into one of the patient's nostrils; whereupon he expired. ‘He is dead,' we exclaimed. `Yes,' replied the priest; ‘he was suffering, and I plugged his nostrils so that he might die and be at peace! [8]"

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Figure 2: Page from the Latin translation of Isagoge Johannitii in Tegni Galeni, a medical book by Hunayn ibn Ishaq (ca. 809-873). (Source).

Usama also narrates the following incidents, which are contained in his Kitab al-i'tibar [9]. Usama's account tells of the crudities of Western treatment [10]. The writer's uncle, a Muslim Prince, had sent a doctor to a Frankish neighbour at the latter's request. When the doctor returned after a surprisingly short period, he had a remarkable tale to tell. They brought before me, he said, a knight in whose leg an abscess had grown; and a woman afflicted with imbecility. To the knight I applied a small poultice until the abscess opened and became well; and the woman I put on a diet and made her humour wet. Then a Frankish physician came to them and said, "This man knows nothing about treating them." He then said to the knight "Which wouldst thou prefer, living with one leg or dying with two?" The latter replied "Living with one leg". The physician said "Bring me a strong knight and a sharp axe." A knight came with the axe. And I was standing by. Then the physician laid the leg of the patient on a block of wood and bade the knight strike his leg with the axe and chop it off at one blow. Accordingly he struck it - while I was looking on - one blow, but the leg was not severed. He dealt another blow, upon which the marrow of the leg flowed out and the patient died on the spot. He then examined the woman and said, "This is a woman in whose head there is a devil which has possessed her. Shave off her hair." Accordingly they shaved it off and the woman began once more to eat their ordinary diet-garlic and mustard. Her imbecility took a turn for the worse. The physician then said 'The devil has penetrated through her head.' He therefore took a razor, made a deep cruciform incision on it, peeled off the skin at the middle of the incision until the bone of the skull was exposed and rubbed it with salt. The woman also expired instantly. Thereupon I asked them whether my services were needed any longer, and when they replied in the negative I returned home, having learned of their medicine what I knew not before [11].

Scott, further observes in relation to such contrast, that "Five centuries after the Moorish physicians of Spain had treated disease by the rational principles of medicine, surgery, and hygiene, Europe still adhered to the archaic conceptions of barbaric ignorance; to the belief that all illness was a manifestation of divine displeasure; to the possession by evil spirits; to the delusive expedients of priestly artifice,—the exhibition of relics, the muttering of texts, the performance of exorcisms [12]."

These treatments contrast sharply with the Muslim, professional, and above all humane, approach. ‘Heroic' treatment was adopted only where milder means had proved unsuccessful, and whenever possible, the curative powers of nature were allowed full exercise; and a change of climate, especially in pulmonary affections, was one of the principal resources of the Moorish physicians [13]. Al-Zahrawi, for instance, demonstrates his humanity and psychological insight when talking about phlebotomy, venesection, or, in plain English, bleeding, a practice of which doctors used to be inordinately fond:

"Let him endeavour on that day to have his mind free from all such spiritual afflictions as anxiety, anger, or fear. There should also be in the place where he is sitting such things as are customary for men to enjoy, such as perfumes, aromatics, and music, and the like [14]."

There is a very human touch in al-Zahrawi's gruesome description of the treatment of nasal polyps. He explains how you deal with them, with hook and scalpel, then tells what must be done if the polyp is in the upper part of the ethmoid bone where your instruments cannot reach. In this case you must take a linen thread, rather thick, which may knotted; the idea is to get the thread into the nose, with the other end coming out of the mouth then, using the thread as a saw, you saw the polyp off. Now how do you get the thread into that position? Al-Zahrawi's directions are firm; he obviously was not going to put up with any nonsense from patients:

"Let the patient contrive to get one end of the thread into his nose with a probe or anything he can. Let him make a full inspiration until it reaches the cartilage and comes out through the throat. Boys at school often do this sort of thing; it is quite easy for anyone who wishes [15]."

Al-Zahrawi is one of the many Muslim physician scholars that marked the medieval Islamic period. Some such names and their accomplishments ought to be cited before other accomplishments of Muslim medicine are looked at.

It is worthless going through all Islamic physicians, some sources such as the web-site Muslimheritage.com having already devoted large space to many such physicians. Here, there won't be much on the scholars who have already been widely written about in the web-site already cited, and also in literature as a whole, scholars such as Ibn Sina, Al-Razi, Ibn Al-Nafis, etc, but on other scholars such as Al-Majussi, Ibn al-Quff, Al-Tabari (the medical scholar), who have not benefited of much focus, but whose contributions to the subject have been crucial.

Haly Abbas, as he is best known in medical histories, whose real name is Ali ibn-al-Abbas al-Majusi, was born in Ahwaz (died in Shiraz in 994/5). He studied medicine under Abu Mahir Musa ibn Yusuf ibn Sayyar in Shiraz and referred to him in grateful terms more than once [16]. Later Ali Abbas was court physician to the great patron of medicine, Azud al-Dawlah, in Shiraz, before he went to Baghdad, and later built the famous Azudi Hospital in that city [17]. But before going to Baghdad he had built a fine hospital in Shiraz, where Ali ibn Abbas was the physician [18].

Ali ibn Abbas was not a prolific writer, in fact his only book, named in Arabic, Kitab al-Maliki, the Royal Book, or in Latin, Liber Regius, made up for the paucity of his writings; Browne calls, the Liber Regius as "the most accessible and most readable of the great Arabic Systems of Medicine [19]." Ali ibn Abbas, who according to Haskins was "one of the outstanding Arabic writers", had planned his al-Malaki (or Regalis Dispositio) as a comprehensive treatise on medicine, intermediate between Al-Razi's two works: the enormous al-Hawi (The Comprehensive Book) and the concise Liber medicinalis [20]. This book (of which a copy is preserved in the National Library of Medicine at Bethesda) is very well systematised and organised [21]. The Arabic text consists of 400,000 words and is divided into 20 discourses, each divided into numerous chapters, of which the first ten deal with the theory, and the second ten with the practice of medicine; the nineteenth discourse, containing 110 chapters, is devoted entirely to surgery [22]. The work is divided into two basic volumes of ten chapters each, one volume covering theory, the other practice. The first volume deals with historical sources, anatomy, faculties, the six primaeval functions, classifications and causations of disease, symptoms and diagnosis, urine, sputum, saliva and pulse as an aid to diagnosis, external or visible manifestations of disease, and internal diseases like fever, headache, epilepsy, and warning signs of death or recovery [23]. The second volume deals with hygiene, dietetics, cosmetics, therapy with simple drugs, therapy for fevers and diseases of organs; that is respiration, digestion, reproduction etc. There is a chapter on surgery, orthopaedics, and finally treatment by compound medicaments [24].

The introductory part of the book, the first three chapters of the first discourse, was devoted to a review of the earlier authorities in medicine. Ali Abbas found Hippocrates too concise and Galen too diffuse, al-Razi's al-Hawi too discursive and badly organised, and his al-Mansruri too concise [25]. Ali Abbas then discusses his own writing of the Liber Regius, in which he adopts a middle ground between prolixity and undue conciseness. This he shows by his description of pleurisy. He begins with the definition of the condition and its cause; then he gives the four essential symptoms of the lesion - fever, cough, chest pain and dyspnoea; then he discusses the prognosis and finally the treatment [26]. At the end of the chapter he puts under emphasis the importance of the training a physician should follow:

"And of those things which are incumbent on the student of this art are that he should constantly attend the hospitals and sick-houses; pay unremitting attention to the conditions and circumstances of their inmates, in company with the most acute professors of Medicine; and enquire frequently as to the state of the patients and the symptoms apparent in them, bearing in mind what he has read about these variations, and what they indicate of good or evil. If he does this, he will reach a high degree in this art. Therefore it behoves him who desires to be an accomplished physician to follow closely these injunctions, to form his character in accordance with what we have mentioned therein, and not to neglect them. If he does this, his treatment of the sick will be successful; people will have confidence in him and be favorably disposed towards him, and he will win their affection and respect and a good reputation; nor withal will he lack profit and advantage from them. And God Most High knoweth best [27]."

Browne calls attention to an important discussion in the Liber Regius that gives the first intimation of a capillary circulation. This passage, which occurs in the chapter treating of the Animal Virtues or Vital Functions, deals chiefly with the two opposite movements of expansion and contraction, which in the heart and arteries constitute diastole and systole, and the respiratory movements of inspiration and expiration. These movements are compared to those of bellows, except that they are produced by internal, not by external, forces; and it is supposed by the writer that the heart draws air from the lungs to mix with the blood for the elaboration of the vital spirit, just as the lungs inhale it from without, and that the vaporised vitiated air is expelled by the reverse process [28]. Then he goes on to say:

"And you must know that during the diastole such of the pulsating vessels (i.e. the arteries) as are near the heart draw in air and sublimated blood from the heart by compulsion of vacuum, because during the systole they are emptied of blood and air, but during diastole the blood and air return and fill them. Such of them as are near the skin draw air from the outer atmosphere; while such as are intermediate in position between the heart and the skin have the property of drawing from the non pulsating vessels (i.e. the veins) the finest and most subtle of the blood. This is because in the non-pulsating vessels (i.e. the veins) are pores communicating with the pulsating vessels (i.e. the arteries). The proof of this is that when an artery is cut, all the blood which is in the veins also is evacuated [29]."

In Salerno, Italy, and under Constantine the African's versions (Constantine was the Tunisian born scholar) was made the translation of Ali Abbas al-Majusti's Kitab al-Malaki. Thus from Al-Qayrawan north to Europe arose "a generation of prominent medical teachers [30]." Stephen of Antioch, for instance, a Pisan, trained apparently in the school of Salerno in Sicily, followed his countrymen to Antioch (Syria). There, he translated in 1127 the medical writings of Ali Ibn Abbas and planned further versions from the Arabic [31]. Stephen's translation of the Liber Regalis is found in numerous manuscripts and two early editions printed at Venice in 1492 and at Lyons in 1523 [32]. The book (like most Muslim works of the sort) includes the usual two parts: Theoretica and Practica (theory and practice), each in ten books. The Theoretica had previously been translated into Latin under the title Pantegni by Constantine the African, whilst the second half, Practica, was translated partly by both him, and his pupil John ‘the Saracen' and a Pisan physician named Rusticus during the great expedition against Majorca in 1114 [33]. Stephen notes in the preface that when he came upon Ali's book in Arabic, he found there was no complete Latin version, while what Constantine had translated suffered from omissions and transpositions, which prompted him to prepare an entirely new version [34].

Ibn al-Quff, born in Karak (Jordan, 1233; d. Damascus, 1286), was involved in medicine, physiology, natural sciences, and philosophy. Ibn al-Quff's father, Muwaffaq al-Din Yaqub, was a Christian Arab (an adherent of the Imperial Orthodox Church), who held an important governmental position under the Ayyubids in Karak. These facts are reflected in his cognomens al-Masihi (the Christian) and al-Karaki. When Muwaffaq al-Din was promoted to the position of a secretary-scribe of the high court, the family moved to Sarkhad in Syria. There Muwaffaq al-Din met and formed a close friendship with the physician-historian Ibn Abi Usaybiah (1203-1270) [35], who spoke of him as "a learned scholar, unequaled scribe in the elegance and perfection of his handwriting, a man of letters, a competent historian, and a pleasant companion, witty and respectable [36]."

Upon the father's request, Ibn Abi Usaybiah agreed to teach young Ibn al-Quff the healing art. The tutor was soon impressed by the brilliance and aptitude for learning of his new student. He also found him fond of reading biographies of illustrious sages, and inclined to quiet, thoughtful meditations. Ibn Abi Usaybi'ah began to teach young Ibn al-Quff with the assistance of preliminary and fundamental texts on the healing art, such as the Masa'il (an introduction to medicine) of Hunayn ibn Ishaq, and the Aphorisms and the Prognosis of the Hippocratic corpus in the Arabic version as rendered also by Hunayn ibn Ishaq. Through the study of leading manuals, such as those by al-Razi, Ibn al-Quff was instructed by Ibn Abi Usaybiah in the classification and treatment of diseases, and their causes and symptoms [37].

Later, Ibn al-Quff's father was transferred to the high court in Damascus, and the family moved to the Syrian capital. Here, Ibn al-Quff studied metaphysics, philosophy, medicine, natural sciences, and mathematics. He was then appointed an army physician-surgeon at the citadel of Ajiun in Jordan, where he stayed for several years. After his fame had spread, he was transferred to Damascus, where until his death at the age of fifty-two, he taught medicine and performed his professional duties among the soldiers stationed at the citadel [38].

Despite his absorbing responsibilities as physician-surgeon for the Mamluk army, Ibn al-Quff was also a prolific author. Ibn al-Quff's main works are a medical compendium, Kitab jami' al-gharad fi hifd al-Sihha wadaf al-marad (Compendium of What One Should Know to Preserve One's Health and Avoid Disease), and a treatise on surgery, Kitab al-umda fi sinaat al-jiraha (The Pillar of Surgery) [39]. The second of these works is divided into two parts, theory and practice, each of which contains ten chapters [40]. The first part begins with an elaborate anatomical introduction, then deals with pathology, and a classification of diseases [41]. In chapter 19 the author explains four methods of circumcision, and a new method of lithotomy applicable to women [42]. In Kitab al-Umda, Ibn al-Quff also describes the vital connection between the arteries and veins and the passage of life-giving blood and pneuma from the former to the latter; a reference to the capillaries made nearly four centuries before the work of Malpighi, who benefited from the use of the microscope [43]. Ibn al-Quff also explains the function of the cardiac valves, their number, and the direction in which they open and close. He also appealed for all the Arab lands to standardise the weights and measures used in pharmacy and medicine [44].

Ibn al-Quff also wrote an elaborate commentary on Hippocrates' Aphorisms, Kitab al-usul fi sharb al-fusul, which is extant; and commentaries on the Qanun and the Kitab al-isharat of Ibn Sina, which are lost. Various other medical works are ascribed to him [45]. His Jami al-Gharad on embryology, child growth, diet and drug therapy, the preservation of health, and physiognomy contains original approaches and ideas. For example, he theorised on the genesis of the embryo and the stages it passes through in its growth, especially the appearance of a foam like cluster after the sixth day of fertilisation, and on the early formation of the embryo after the twelfth day. He spoke of how "the head distinctly emerges as separate from the shoulders . . . and that the brain is the first major organ to develop [46]." Also found are his instructions on what should be done to the infant at birth and thereafter, which are of great historical interest [47].

Finally, from the eastern side of Islam is al-Tabari, not the historian, but the medical scholar. At this juncture, too, there appeared an encyclopaedic work, Ali Tabari's Paradise of Wisdom, which gave an overall picture of the position of Arab men of learning. The son of a doctor of Tabaristan, Ali Tabari came to Baghdad, and eventually, at the age of seventy, was there converted to Islam [48]. At that advanced age he produced an apologetic which was well above the ordinary. His major work is a series of observations on the most diverse subjects, the documentary sources of which are Greek and Indian. From preliminary philosophic discussions the book moves on to embryology and a consideration of the health value of different kinds of food and drink. A quick survey of the number of muscles, nerves, and veins is then followed by a review of tastes, smells, and colours, and methods of treatment based on pharmacology and toxicology [49]. Next came a chapter on a subject new in Muslim medical literature: a study of climates, waters, and seasons in relation to health. Then, an outline of cosmography and astronomy, followed by an essay on the utility of medicine, with a summary of Indian medicine. A final section deals with general pathology, diseases of the head, heart, and intestines, nervous diseases, and fevers. The work was in many respects ahead of its time. It is interesting to note the order of diagnostic procedure laid down: the appearance and nature of the affected part, signs of palpitation, any disturbance of function, difficulty of evacuation, possible secondary effects, and lastly, the interrogation of the patient [50].

The accomplishments of the Muslim scholars on medicine in the Iberian Peninsula have been largely seen on MuslimHeritage.com to warrant any more space. All that is necessary here is this briefest outline by Scott who sums up their accomplishments. No names in the long catalogue of Muslim genius, Scott holds, stand higher than those of Abulcasis (Al-Zahrawi), the originator of modern surgery, ; than Ibn Zuhr (Avenzoar), whose family was prominent for three hundred years in the medical annals of Muslim Spain; than Averroes, whose great professional attainments have been obscured by his pre-eminent reputation as a natural philosopher. Arib Ibn Said al-Khatib, whose works exceeded a thousand in number, composed treatises on gynecology and obstetrics, and was the author of the Calendar of Cordova, a wonderful compilation of medical truths, surgical maxims, astronomical and agricultural knowledge. Ibn Wafid, of Toledo, who lived in the 10^th century, and whose extraordinary abilities made him conspicuous among hundreds of eminent contemporaries, consumed twenty years in the preparation of his work on the general practice of medicine. Ibn-Zuhr was the first to discover that scabies was produced by a diminutive parasite, and to prescribe sulphur as a remedy. The treatise of Mohammed Ibn Qassum on diseases of the eye occupied six hundred pages; that of Mohammed al-Temini on hernia and tumors nearly four hundred. Daoud-al-Agrebi wrote on fumigations, collyriums, hemostatics; he recommends the administration of narcotics in lithotomy, in the incision of abscesses, and in emasculation for the production of eunuchs. Saladin-Ibn-Yusuf published a book on the anatomy of the eye and the theories of vision [51].

[1] S.P. Scott, History of the Moorish Empire, Philadelphia: The Lippiuncot Company, 3 vols.; vol. 3, p. 505.

[4] D. Campbell, Arabian Medicine and its Influence on the Middle Ages, Amsterdam: Philo Press, 1926 (reprinted 1974), p. xiii.

[5] W. Durant, The Age of Faith, New York: Simon and Shuster, 1950, pp. 245-246.

[8] E. G. Browne, Arabian Medicine (1921), reprint Cambridge University Press, 1962 (Gryphon Books, 2001), p. 70.

[9] G. Sarton, Introduction to the History of Science, Williams and Wilkins Company, 1950, vol. 2, p. 447.

[10] W. Montgomery Watt, The Influence of Islam on Medieval Europe, Edinburgh, 1972, p. 65; C. Hillenbrand, The Crusades, Islamic Perspectives, Edinburgh University Press, 1999. p. 352.

[14] G. Lewis, "The Surgery of Albucasis", Islamic Culture, vol. 73, 1999, pp. 21-36; p. 28.

[16] A. Whipple, The Role of the Nestorians and Muslims in the History of Medicine, Ann Arbor, Michigan: University Microfilms International (1980), Microfilm xerography, 1977, 1980, p. 41.

[18] Cyril. A. Elgood, A Medical History of Persia and the Eastern Caliphate. From the Earliest Times until the Year A.D. 1932, Cambridge, 1951, p. 155 ff.

[20] C. H. Haskins, Studies in Medieval Culture, Oxford, 1929 (reprint New York: Frederick Ungar, 1965), p. 131.

[21] H.F. Nagamia, "An Introduction to the History of Islamic Medicine", Islamic Culture, vol. 73, 1999, pp. 1-19; p. 11.

[22] A. Whipple, The Role of the Nestorians and Muslims in the History of Medicine, op. cit., p. 41.

[23] H. F. Nagamia, "An Introduction to the History of Islamic Medicine", op. cit., p. 11.

[25] A. Whipple, The Role of the Nestorians and Muslims in the History of Medicine, op. cit., p. 41.

[30] Max Meyerhof, "Science and Medicine", in The Legacy of Islam, eds. Sir Thomas Arnold and Alfred Guillaume (Oxford: The Clarendon Press, 1931), p. 351.

[35] Ibn abi Usaybi'a, 'Uyun al-anba' fi tabaqat al-atibba, ed. by August Müller, Konigsberg, 1884.

[36] S.K. Hamarneh, "Ibn Al-Quff", Dictionary of the Middle Ages, edited by Joseph Strayer. New York: Charles Scribner's Sons, 1989-, 12 vols.; vol. 11, p. 238.

[39] Antoine Barthélémy Clot (Clot bey), Note sur la fréquence des calculs visicaux en Egypte et sur la méthode employée par les chirurgiens arabes pour en faire l'extraction (28 pp., Marseilles 1830); E. Wiedemann, "Beschreibung von Schiangen bei Ibn Qaff", Beiträge 50, Sitzungsberichte der phys. med. Sozietat (Erlangen), vol. 48, 1918, pp. 61-64.

[40] G. Sarton, Introduction to the History of Science, op. cit., vol. 2, p. 1099.

[45] G. Sarton, Introduction to the History of Science, op. cit., vol. 2, p. 1099.

[48] G. Wiet, V. Elisseeff, P. Wolff, and J. Naudu, History of Mankind, vol 3: The Great Medieval Civilisations (translated from the French). George Allen & Unwin /UNESCO, 1975, p. 645.