The Canon of Medicine is Avicenna’s chief medical work, whilst his minor treatises deal with separate diseases and their treatment. Just as his Shifa was concerned with all aspects of philosophy, this voluminous undertaking, which was to become equally renowned in both the East and the West, is an encyclopedia of the medical knowledge of his day. The former was basically Aristotelian with important contributions of Avicenna’s own; this comprises in the main what Hippocrates and Galen had taught, together with the results of his medical practice and the experience that he had gained. It also includes what his immediate predecessors had written on the subject. In concept as well as in method there are points of similarity between the two books on which, we are told, he worked at the same time. The Shifa, though the whole of it has not yet been edited, has been frequently if not comprehensively studied, but the Canon though already printed in full, has been examined only in parts, and still awaits a patient and competent student. Avicenna may not be as great a physician as a philosopher, yet he is commonly referred to as “the prince and chief of physicians”; and it is supposed that with him Islamic medicine reached its zenith.

Greek medicine reached the Islamic world before philosophy. Already in Umayyad times a Persian Jew by the name of Masarjawaih had translated the Pandects of Ahron, a Christian monk who lived in Alexandria not long before the Arab conquest, into Arabic. In Baghdad, Persian and Indian medicine became incorporated with the Greek. The process had in fact already started in Gundishapur, and the teaching at that institution comprised all three elements. Thence a long line of celebrated physicians graduated and spread out over the Islamic world. They became particularly numerous at the court of the Caliphs. Some reached great eminence and even took part in public life; others helped to produce a till then non-existent Arabic literature on the subject. Among the latter, Hunain was one of the earliest and most noted. The outstanding contribution that he made to the creation of Arabic philosophical literature, through his numerous translations from Greek, has already been noted. His renderings of medical works, though smaller in number, were no less important. According to his own claim, he translated practically the whole corpus of Galenic writings which ran into some hundred and forty books. He also translated from Hippocrates, including his Aphorisms; and some of Galen’s commentaries on Hippocrates. In addition, he corrected the translation of the Materia Medica of Dioscurides; and made his own renderings of the Synopsis of Oribasius, and the Seven Books of Paul of Aegina. He did original work as well. He wrote Questions on Medicine which became well known; and another work called Ten Teatises on the Eye described as the earliest systematic textbook of ophthalmology known. His pupils continued the translation of medical books with just as much interest and care as they devoted to the philosophical works.

It has been observed that after an initial period of translation and minor works, the initiative seems to pass rapidly from the hands of the Christians and Harranians who were the pioneers, to the Muslims whether Arabs, Turks, or Persians. This is as true in medicine and the natural sciences as it was in philosophy. The time of the translators had hardly drawn to a close when Kindi and Farabi appeared on the scene, and totally eclipsed them with their original contributions. And the pupils of Hunain had not yet finished rendering Greek medical works into Arabic when Muslim physicians, mostly of Persian extraction, came along with the results of their clinical observations and personal experiences. Pandects became replaced by substantial encyclopedias, and aphorisms by hospital reports of much value. The first and, by common consent, the greatest of these was Razi, of whose philosophical ideas some mention has already been made. According to a competent critic, “Rhazes was undoubtedly the greatest physician of the Islamic world, and one of the greatest physicians of all time”. Students of medicine must be grateful that in spite of a large practice and extensive travels, he found time to write about a hundred medical books, not all of which, however, can be classified as learned works. He has a treatise On the fact that even skilful physicians cannot heal all diseases; and another On why people prefer quacks and charlatans to skilled physicians. His most celebrated work is On Smallpox and Measles, two of the most common diseases in the East. And it should be remembered that smallpox had been unknown to Greek medicine. This was translated into Latin and various other languages including English, and was printed some forty times between 1498 and 1866.

This work, supposed to give the first clear account of these two diseases that has come down to us, is eclipsed by his magnum opus described as perhaps the most extensive ever written by a medical man. His al-Hawi, meaning “The Comprehensive” and known to the Latins as Liber Continens, was an enormous manual giving the results of a life-time of medical practice. This may have been actually finished by Razi’s pupils and the material afterwards collected by his patron. Only ten out of the original twenty volumes are extant today. For each disease Rhazes first cites all the Greek, Syrian, Arabic, Persian and Indian authors, and at the end gives his own opinion and experiences, and he preserves many striking examples of his clinical insight. In Latin the work was repeatedly printed from 1486 onwards, and its influence on European medicine was considerable.

Besides translations and extracts, Arabic medical literature had included manuals that often took the form of pandects. These were recapitulations of the whole of medicine beginning at the head and working down to the feet; and there were also the cram books in the form of questions and answers. Now the tendency was to collect all the available knowledge and add the author’s own contributions and the results of his practice. (These works differed in size. If the compilation of Razi ran into twenty volumes, that of another physician of Persian extraction, known to the Latins as Haly Abbas (d. 994) and called by them Liber Regius, was far more modest; and so was the Firdows al-Hikma of Tabari.) There was thus a whole tradition of medical writing in existence when the Canon of Avicenna appeared. It cannot therefore claim to be entirely original in form or in subject matter; but in more ways than one, it was the culmination of all that had been done before in this field. It occupies the same position in medical literature that the Shifa has in philosophical writings, and may actually have been meant to be a counterpart of the other. The Canon is a highly compact work, giving mainly facts; it rarely indulges in general discussions. It fills a big fat volume, and yet is not unwieldy for the general practitioner to whom it is undoubtedly addressed. Of all his sixteen medical works, this is the one to which the physician can most rapidly refer. One of its distinctive features is the system of classification used; this may be thought nowadays to have been carried too far, and to be rather confusing as a result. It is divided into five books, each of which is then subdivided into different fanns, then fasl and then maqala. Book One comprises a general description of the human body, its constitution, members, temperaments and faculties. Then follows a section about common ailments, their causes and their complications. Then one about general hygiene and the “necessity of death”; and finally one about the treatment of diseases. Book Two deals with Materia Medica. Book Three is devoted to separate diseases, and is composed of twenty-two fanns. Book Four deals with those diseases that affect the whole system of the sufferer, and not only the diseased part. This book is composed of seven fanns. Book Five, which is the last, is on pharmacology, in the form known to the Islamic world as Aqrabadhin, a word mutilated and arabicized, corresponding to the Greek graphidion, meaning a small treatise; and commonly found in Latin manuscripts as Grabadin. This was a subject of some importance when it is remembered that Islamic pharmacology comprised a good deal of original work, and survived in Europe down to the beginning of the nineteenth century.

On the intrinsic value of the Canon as a permanent contribution to medical science, we are not competent to judge. Suffice it to say that when translated into Latin by Gerard of Cremona in the twelfth century, it became so highly prized that in the last thirty years of the fifteenth it was issued sixteen times; and more than twenty times in the sixteenth century. This apart from editions of separate parts of the work. In the second half of the seventeenth century it was still being printed and read, and constantly used by the practitioners. And it is supposed to have been studied as a textbook in the medical school of Louvain University as late as the eighteenth century. The medical curriculum in Vienna and Frankfurt on the Oder, in the sixteenth century, was largely based on the Canon of Avicenna and the Ad Almansorem of Rhazes. The translation of the Canon by Andrea Alpago (d. 1520) of Italy was followed by even later versions which were taught in various European universities especially in Italy and France. It superseded to a great extent the Liber Regius; and it was not until human dissection came to be allowed that European anatomists detected certain anatomical and physiological errors of Galen which had been transmitted to Europe through the works of Avicenna.

On the occasion of the celebrations in honor of Avicenna’s millenary in Tehran, competent judgments were passed on certain parts of the Canon. It appears that in pharmacology some of his contributions were original and important; e.g. he introduced many herbs into medical practice that had not been tried before; he seems to have been aware of the antiseptic effects of alcohol, for he recommends that wounds should be first washed with wine. This was probably a common practice long before him, since Zoroastrian rituals had used wine from early times, and had even provided for washing parts of the body with it.

Yet Avicenna may have been the first to realize its antiseptic properties. He also recommended the drinking of mineral waters, quite fashionable nowadays. And he suggests that experiments should be made on animals. In the field of chemistry, perhaps his greatest service was the total discrediting of alchemy. This practice had developed a regular tradition in the Islamic world. Kindi and Farabi had both argued for it as a legitimate pursuit. But it was associated mainly with the name of Jabir, known to the western world as Geber. The identity of this man has puzzled modern scholars. There was a mystic by that name, yet he could hardly have been the author of some one hundred books on the subject. In any case many had taken up alchemy and wasted their years over it. And when Avicenna came, he repudiated its whole basis clearly and emphatically. “Its possibility”, he says, “has not been made evident to me. I rather find it remote, because there is no way of splitting up one combination into another ... differentiae being unknown. And if a thing is unknown, how is it possible to attempt to produce or destroy it?”