|The Canon of Medicine|
|The Book of Healing|
|Hayy ibn Yaqdhan|
|Criticism of Avicennian philosophy|
The Canon of Medicine (Arabic: القانون في الطب Al-Qanun fi al-Tibb "The Law of Medicine"; Persian: قانون طب Qanun "Law"; Latin: Canon Medicinae "Canon of Medicine"; Chinese: 回回藥方 / 回回药方 Huíhui Yàofāng "Prescriptions of the Hui Nationality") is a 14-volume medical encyclopedia written by Persian scientist and physician Ibn Sīnā (Avicenna) and completed in 1025. The book was based on a combination of his own personal experience, medieval Islamic medicine, the writings of the Roman physician Galen, the Indian physicians Sushruta and Charaka, and Persian medicine, in addition to aspects of Chinese materia medica. Originally written in the Arabic language, the book was later translated into a number of other languages, including Persian, Latin, Chinese, Hebrew, German, French and English. The Canon is considered one of the most famous books in the history of medicine.
Also known as the Qanun, which means "law" in both Arabic and Persian, the Canon of Medicine remained a medical authority up until the 18th century and early 19th century. It set the standards for medicine in Europe and the Islamic world, and is Avicenna's most renowned written work alongside The Book of Healing. Qanun was used at many medical schools—at University of Montpellier, France, as late as 1650. Much of the book was also translated into Chinese as the Huihui Yaofang (Prescriptions of the Hui Nationality) by the Hui people in Yuan China. The Canon also formed the basis of Unani medicine, a form of traditional medicine practiced in India. The principles of medicine described by the Canon ten centuries ago are still taught at UCLA and Yale University, among others, as part of the history of medicine.
The Canon is considered the first pharmacopoeia, and among other things, the book is known for the introduction of systematic experimentation and quantification into the study of physiology, the discovery of the contagious nature of infectious diseases, the introduction of quarantine to limit the spread of contagious diseases, and the introduction of evidence-based medicine, experimental medicine, clinical trials, randomized controlled trials, efficacy tests, clinical pharmacology, neuropsychiatry, physiological psychology, risk factor analysis, and the idea of a syndrome in the diagnosis of specific diseases.
"One of the most famous exponents of Muslim universalism and an eminent figure in Islamic learning was Ibn Sina, known in the West as Avicenna (981-1037). For a thousand years he has retained his original renown as one of the greatest thinkers and medical scholars in history. His most important medical works are the Qanun (Canon) and a treatise on Cardiac drugs. The 'Qanun' is an immense encyclopedia of medicine. It contains some of the most illuminating thoughts pertaining to distinction of mediastinitis from pleurisy; contagious nature of phthisis; distribution of diseases by water and soil; careful description of skin troubles; of sexual diseases and perversions; of nervous ailments."
The book explains the causes of health and disease. Ibn Sina believed that the human body cannot be restored to health unless the causes of both health and disease are determined. He defined medicine (tibb) as follows:
"Medicine is the science by which we learn the various states of the body; in health, when not in health; the means by which health is likely to be lost; and, when lost, is likely to be restored. In other words, it is the art whereby health is concerned and the art by which it is restored after being lost."
Avicenna regarded the causes of good health and diseases to be:
The Qanun distinguishes mediastinitis from pleurisy and recognises the contagious nature of phthisis (tuberculosis of the lung) and the spread of disease by water and soil. It gives a scientific diagnosis of ankylostomiasis and attributes the condition to an intestinal worm. The Qanun points out the importance of dietetics, the influence of climate and environment on health, and the surgical use of oral anaesthetics. Ibn Sina advised surgeons to treat cancer in its earliest stages, ensuring the removal of all the diseased tissue. The Qanun 's materia medica considers some 800 tested drugs, with comments on their application and effectiveness. He recommended the testing of a new drug on animals and humans prior to general use.
The Arabic text of the Persian Qanun was translated into Latin as Canon medicinae by Gerard of Cremona in the 12th century and into Hebrew in 1279. Henceforth the Canon served as the chief guide to medical science in the West and is said to have influenced Leonardo da Vinci. Its encyclopaedic content, its systematic arrangement and philosophical plan soon worked its way into a position of pre-eminence in the medical literature of Europe, displacing the works of Galen and becoming the text book for medical education in the schools of Europe. The text was read in the medical schools at Montpellier and Leuven as late as 1650, and Arnold C. Klebs described it as "one of the most significant intellectual phenomena of all times." In the words of Dr. William Osler, the Qanun has remained "a medical bible for a longer time than any other work". The first three books of the Latin Canon were printed in 1472, and a complete edition appeared in 1473. The 1491 Hebrew edition is the first appearance of a medical treatise in Hebrew and the only one produced during the 15th century. In the last 30 years of the 15th century it passed through 15 Latin editions. In recent years, a partial translation into English was made.
The influential Canadian physician, Sir William Osler, described the Canon as "the most famous medical textbook ever written" noting that it remained "a medical bible for a longer time than any other work." In 2006, Professor John Urquhart noted the relevance of the Canon to modern medicine, comparing it to an influential medical work of the 19th century, The Principles and Practice of Medicine (1892) by Osler himself, and concluded:
"If the year were 1900 and you were marooned and in need of a guide for practical medicine, which book would you want by your side?" My choice was Ibn Sina. A leading reason is that Ibn Sina gives an integrated view of surgery and medicine, whereas Osler largely shuns intervention. Ibn Sina, for example, tells how to judge the margin of healthy tissue to take with an amputation, a basic topic uncovered by Osler. The gap between medicine and surgery is now closing, with the advent of interventional cardiology, gastroenterology, radiology, etc. Ibn Sina correctly saw medicine and surgery as one.
Mona Nasser Aida Tibi and Emilie Savage-Smith note: "The enduring respect in the 21st century for a book written a millennium earlier is testimony to Ibn Sina's achievement."
The Canon of Medicine was the first book dealing with evidence-based medicine, experimental medicine, clinical trials, randomized controlled trials, efficacy tests, risk factor analysis, and the idea of a syndrome in the diagnosis of specific diseases.
According to Toby Huff and A. C. Crombie, the Canon contained "a set of rules that laid down the conditions for the experimental use and testing of drugs" which were "a precise guide for practical experimentation" in the process of "discovering and proving the effectiveness of medical substances."
The emphasis of the Canon on tested medicines laid the foundations for an experimental approach to pharmacology. The Canon laid out the following rules and principles for testing the effectiveness of new drugs and medications, which still form the basis of clinical pharmacology and modern clinical trials:
The Canon lists 800 tested drugs, including plant and mineral substances, with comments on their application and effectiveness. For each one, he described their pharmaceutical actions from a range of 22 possibilities (including resolution, astringency and softening), and their specific properties according to a grid of 11 types of diseases.
While Ibn Sina often relied on deductive reasoning in The Book of Healing and other writings on logic in Islamic philosophy, he used a different approach in The Canon of Medicine. This text contributed to the development of inductive logic, which it used to develop the idea of a syndrome in the diagnosis of specific diseases. The Canon of Medicine was the first to describe the methods of agreement, difference and concomitant variation which are critical to inductive logic and the scientific method.
The book's contribution to the pharmaceutical sciences include the introduction of systematic experimentation and quantification into pharmacology and the study of physiology, the introduction of experimental medicine, evidence-based medicine, clinical trials, randomized controlled trials, efficacy tests and clinical pharmacology; the first careful descriptions of skin troubles, sexually transmitted diseases, perversions and nervous ailments; and the discovery of the healing property of gaseous mercury besides its poisonous quality; as well as the use of ice to treat fevers, and the separation of medicine from pharmacology, which was important to the development of the pharmaceutical sciences.
Avicenna wrote a separate supplement treatise dedicated to the pharmacotherapy of "Hindiba", a compound drug he suggested for the treatment of cancer and other tumors (see Cancer therapy below) and which could also be used for treating other neoplastic disorders. He gives details on the drug's properties and uses, and then gives instructions on its preparation as medication.
The Canon described no less than 700 preparations of medications, their properties, mode of action and their indications. He devoted in fact a whole volume to simple and compound drugs in The Canon of Medicine. It credits many of them to a variety of Arabic, Greek and Indian authors, and also includes some drugs imported from China, along with many of Ibn Sina's own original contributions. Using his own expertise, he was often critical of the descriptions given by previous authors and revised many of their descriptions.
Writings on anatomy in the Canon are scattered throughout the text in sections regarding to illnesses related to certain body parts. The Canon included numerous discussions on anatomy and diagrams on certain body parts, including the first diagrams of the cranial sutures.
Avicenna dedicated a chapter of the Canon to blood pressure. He was able to discover the causes of bleeding and haemorrhage, and discovered that haemorrhage could be induced by high blood pressure because of higher levels of cholesterol in the blood. This led him to investigate methods of controlling blood pressure.
The Canon distinguished anatomy "from other aspects of medicine by its need for a different methodology." It thus stated:
"As for the parts of the body and their functions, it is necessary that they be approached through observation (hiss) and dissection (tashrih), while those things that must be conjectured and demonstrated by reason are diseases and their particular causes and their symptoms and how disease can be abated and health maintained."
Avicenna discovered the cerebellar vermis—which he named "vermis"—and the caudate nucleus, which he named "tailed nucleus" or "nucleus caudatus". These terms are still used in modern neuroanatomy and neurophysiology.
The Canon was also the earliest text to note that intellectual dysfunctions were largely due to deficits in the brain's middle ventricle, and that the frontal lobe of the brain mediated common sense and reasoning.
The contributions of the Canon to ophthalmology in medieval Islam include its descriptions and explanations on the physiology of eye movements, which still forms a basis of information for modern ophthalmology. He also provided useful information on the optic nerves, iris, and central and peripheral facial paralyses.
In its explanation of the cardiovascular system, The Canon of Medicine "erroneously accepted the Greek notion regarding the existence of a hole in the ventricular septum by which the blood traveled between the ventricles." This would not be corrected until Ibn al-Nafis' Commentary on Anatomy in Avicenna's Canon provides the first description of the pulmonary circulation in 1242. Ibn al-Nafis also criticized the Canon for its "statement that the blood that is in the right side is to nourish the heart", which he replaced with a theory showing insight into the coronary circulation: "the nourishment to the heart is from the blood that goes through the vessels that permeate the body of the heart." Despite these criticisms, Avicenna "had a vision of blood circulation," and "correctly wrote on the cardiac cycles and valvular function."
In cardiology, The Canon of Medicine is the first book to mention the vasovagal syncope and carotid sinus hypersensitivity. According to several scholars, "Article 5 from Book III of this encyclopedia described drop attacks following compression of the carotid artery, yawning, fatigue and flushing, which together resemble neurogenic syncope. Such a description is most likely the first mention of carotid sinus hypersensitivity and vasovagal syncope." The chapter was dedicated to “brain diseases effecting intentional movements”, and refers to carotid sinus hypersensitivity as Al-Lawa, meaning "torsion".
The Canon was a pioneering text in pulsology and sphygmology. In ancient times, Galen as well as Chinese physicians erroneously believed that there was a unique type of pulse for every organ of the body and for every disease. Galen also erroneously believed that "every part of an artery pulsates simultaneously" and that the motion of the pulse was due to natural motions (the arteries expanding and contracting naturally) as opposed to foced motions (the heart causing the arteries to either expand or contract).
The first correct explanation of pulsation was given by Avicenna, after he refined Galen's theory of the pulse and discovered the following in The Canon of Medicine:
"Every beat of the pulse comprises two movements and two pauses. Thus, expansion : pause : contraction : pause. [...] The pulse is a movement in the heart and arteries ... which takes the form of alternate expansion and contraction."
The Canon also pioneered the modern approach of examining the pulse through the examination of the wrist, which is still practiced in modern times. His reasons for choosing the wrist as the ideal location is due to it being easily available and the patient not needing to be distressed at the exposure of his/her body. The Latin translation of his Canon also laid the foundations for the later invention of the sphygmograph.
Avicenna also wrote a supplemental treatise on diagnosing diseases using only the methods of feeling the pulse and observing inhalation. He was often capable of finding the symptoms of certain diseases only by feeling a patient's pulse.
In etiology and pathology, the Canon described the contagious nature of infectious diseases such as phthisis and tuberculosis, the distribution of disease by water and soil, and the existence of sexually transmitted disease. The Canon provides a full understanding of the pathology of contagious disease.
The Canon also distinguished between mediastinitis and pleurisy, provided careful descriptions of skin troubles, perversions, and nervous ailments." Meningitis was also first described in The Canon of Medicine, which also described the first known treatments for cancer. The book also recognized the parasitic diseases of Ascaris, Enterobius, tapeworms, and Guinea worms.
Since the Canon, Bimaristan hospitals were created with separate wards for specific illnesses, so that people with contagious diseases could be kept away from other patients who do not have any contagious diseases.
In cancer therapy, the Canon recognized cancer as a tumor. He noted that a "cancerous tumour progressively increases in size, is destructive and spreads roots which insinuate themselves amongst the tissue elements." He also attempted the earliest known treatments for cancer. One method he discovered was the "Hindiba", a herbal compound drug which Ibn al-Baitar later identified as having "anticancer" properties and which could also treat other tumors and neoplastic disorders. After recognizing its usefulness in treating neoplastic disorders, Hindiba was patented in 1997 by Nil Sari, Hanzade Dogan, and John K. Snyder. The preferred medication the Canon recommended for skin cancer and skin conditions in general was zinc oxide.
Another method for treating cancer first described in the Canon was a surgical treatment. It stated that the excision should be radical and that all diseased tissue should be removed, which included the use of amputation or the removal of veins running in the direction of the tumor. He also recommended the use of cauterization for the area being treated if necessary. However, the Canon notes that surgery should only be used as a last resort and that caution should be taken, pointing out that "most of the time, excision increases the cancer."
The Canon of Medicine supports the ancient theory of Four Humours, but refines in various ways. In disease pathogenesis, for example, Avicenna "added his own view of different types of spirits (or vital life essences) and souls, whose disturbances might lead to bodily diseases because of a close association between them and such master organs as the brain and heart. An element of such belief is apparent in the chapter of al-Lawa" (see Cardiology section), which relates "the manifestations to an interruption of vital life essence to the brain." He combined his own view with that of the Four Humours to establish a new doctrine to explain the mechanisms of various diseases in another work he wrote, Treatise on Pulse:
“From mixture of the four [humors] in different weights, [God the most high] created different organs; one with more blood like muscle, one with more black bile like bone, one with more phlegm like brain, and one with more yellow bile like lung.
[God the most high] created the souls from the softness of humors; each soul has it own weight and amalgamation. The generation and nourishment of proper soul takes place in the heart; it resides in the heart and arteries, and is transmitted from the heart to the organs through the arteries. At first, it [proper soul] enters the master organs such as the brain, liver or reproductive organs; from there it goes to other organs while the nature of the soul is being modified in each [of them]. As long as [the soul] is in the heart, it is quite warm, with the nature of fire, and the softness of bile is dominant. Then, that part which goes to the brain to keep it vital and functioning, becomes colder and wetter, and in its composition the serous softness and phlegm vapor dominate. That part, which enters the liver to keep its vitality and functions, becomes softer, warmer and sensibly wet, and in its composition the softness of air and vapor of blood dominate.
In general, there are four types of proper spirit: One is brutal spirit residing in the heart and it is the origin of all spirits. Another – as physicians refer to it – is sensual spirit residing in the brain. The third – as physicians refer to it – is natural spirit residing in the liver. The fourth is generative – i.e. procreative – spirits residing in the gonads. These four spirits go-between the soul of absolute purity and the body of absolute impurity.”
The Canon also adopted the ancient theory of Four Temperaments and extended it to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." It summarized Avicenna's own theory of four temperaments in a table presented as follows:
|Morbid states||inflammations become febrile||fevers related to serious humour, rheumatism||lassitude||loss of vigour|
|Functional power||deficient energy||deficient digestive power||difficult digestion|
|Subjective sensations||bitter taste, excessive thirst, burning at cardia||Lack of desire for fluids||mucoid salivation, sleepiness||insomnia, wakefulness|
|Physical signs||high pulse rate, lassitude||flaccid joints||diarrhea, swollen eyelids, rough skin, acquired habit||rough skin, acquired habit|
|Foods & medicines||calefacients harmful, infrigidants beneficial||infrigidants harmful, calefacients beneficial||moist articles harmful||dry regimen harmful, humectants beneficial|
|Relation to weather||worse in summer||worse in winter||bad in autumn|
In Islamic psychology and neurosciences, the Canon noted the close relationship between emotions and the physical condition, and the author felt that music had a definite physical and psychological effect on patients.
In clinical psychology and psychotherapy, Avicenna often used psychological methods to treat his patients. One such case study is when a prince of Persia had melancholia and suffered from the delusion that he is a cow, and who would low like a cow crying "Kill me so that a good stew may be made of my flesh" and would never eat anything. Avicenna was persuaded to the case and sent a message to the patient, asking him to be happy as the butcher was coming to slaughter him, and the sick man rejoiced. When Avicenna approached the prince with a knife in his hand, he asked "where is the cow so I may kill it." The patient then lowed like a cow to indicate where he was. "By order of the butcher, the patient was also laid on the ground for slaughter." When Avicenna approached the patient pretending to slaughter him, he said, "the cow is too lean and not ready to be killed. He must be fed properly and I will kill it when it becomes healthy and fat." The patient was then offered food which he ate eagerly and gradually "gained strength, got rid of his delusion, and was completely cured."
Among the many other psychological disorders described in the Qanun, one is of unusual interest: love sickness. Ibn Sina is reputed to have diagnosed this condition in a Prince in Jurjan who lay sick and whose malady had baffled local doctors. He noted a fluttering in the Prince's pulse when the address and name of his beloved were mentioned. The great doctor had a simple remedy: unite the sufferer with the beloved.
The book's contributions in neurology and neuropathology include its diagnosis of facial nerve paralysis, its distinction between brain paralysis and hyperaemia, and most importantly the discovery of meningitis. It diagnosed meningitis as a disease induced by the brain itself and differentiated it from infectious brain disease, and its author was also able to diagnose and describe the type of meningitis induced by an infection in other parts of the body.
The Canon was a pioneering text in neuropsychiatry and neuropsychology. It first described the neuropsychiatric conditions of hallucination, insomnia, mania, nightmare, melancholia, dementia, epilepsy, paralysis, stroke, vertigo and tremor. Three chapters of The Canon of Medicine were dedicated to neuropsychiatry.
The book defined madness (Junun) as a mental condition in which reality is replaced by fantasy, and discovered that it is a disorder of reason with its origin in the middle part of the brain. It also described a condition resembling schizophrenia which it referred to as Junun Mufrit (severe madness), which was clearly distinguished from other forms of madness such as mania, rabies, and manic depressive psychosis. The author observed that patients suffering from schizophrenia-like severe madness show agitation, behavioural and sleep disturbance, give inappropriate answers to questions, and in some cases are incapable of speaking at times. The book states that such patients need to be restrained, in order to avoid any harm they may cause to themselves or to others.
A chapter of the Canon was also dedicated to mania and rabies. It described mania as bestial madness characterized by rapid onset and remission, with agitation and irritability, and described rabies as a type of mania.
The Canon of Medicine extended the theory of temperaments to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." This work may thus be considered a "forerunner of twentieth century psychoanalysis."
The Canon was an early text in psychophysiology and psychosomatic medicine, and the first to recognize 'physiological psychology' in the treatment of illnesses involving emotions, and developed a system for associating changes in the pulse rate with inner feelings, which is seen as an anticipation of the word association test attributed to Carl Jung. Avicenna identified love sickness (Ishq) ... illnesses together. It described melancholia (depression) as a type of mood disorder in which the person may become suspicious and develop certain types of phobias. It stated that anger heralded the transition of melancholia to mania, and explained that humidity inside the head can contribute to mood disorders. It recognized that this occurs when the amount of breath changes: happiness increases the breath, which leads to increased moisture inside the brain, but if this moisture goes beyond its limits, the brain would lose control over its rationality and lead to mental disorders. It also described symptoms and treatments for nightmare, epilepsy, and weak memory.
"Urinating in bed is frequently predisposed by deep sleep: when urine begins to flow, its inner nature and hidden will (resembling the will to breathe) drives urine out before the child awakes. When children become stronger and more robust, their sleep is lighter and they stop urinating."
Hirudotherapy, the use of medicinal leech for medical purposes, was introduced by The Canon of Medicine. It considered the application of leech to be more useful than cupping in "letting off the blood from deeper parts of the body." He also introduced the use of leech as treatment for skin disease. Leech therapy became a popular method in medieval Europe due to the influence of his Canon.
The Canon, which described colour to be of vital importance in diagnosis and treatment, made significant contributions to chromotherapy. It stated that "Color is an observable symptom of disease" and also developed a chart that related colour to the temperature and physical condition of the body. His view was that red moved the blood, blue or white cooled it, and yellow reduced muscular pain and inflammation. The author further discussed the properties of colours for healing and was "the first to establish that the wrong colour suggested for therapy would elicit no response in specific diseases." As an example, "he observed that a person with a nosebleed should not gaze at things of a brilliant red color and should not be exposed to red light because this would stimulate the sanguineous humor, whereas blue would soothe it and reduce blood flow."
In dermatology, the preferred medication the Canon recommended for skin conditions, including skin cancer, was zinc oxide. Though today it is no longer used for treating skin cancer, it is still widely used today to treat a variety of other skin conditions, in products such as baby powder and creams to treat diaper rashes, calamine cream, anti-dandruff shampoos, and antiseptic ointments.
In endocrinology, the Canon provided a detailed account on diabetes mellitus in The Canon of Medicine, "describing the abnormal appetite and the collapse of sexual functions and he documented the sweet taste of diabetic urine." Like Aretaeus of Cappadocia before him, the Canon recognized a primary and secondary diabetes. It also described diabetic gangrene, and treated diabetes using a mixture of lupine, trigonella (fenugreek), and zedoary seed, which produces a considerable reduction in the excretion of sugar, a treatment which is still prescribed in modern times. It also "described diabetes insipidus very precisely for the first time", though it was later Johann Peter Frank (1745-1821) who first differentiated between diabetes mellitus and diabetes insipidus.
The Canon of Medicine was the first book to offer instruction for the care of the aged, foreshadowing modern gerontology and geriatrics. A chapter entitled "Regimen of Old Age" stated that "old folk need plenty of sleep. Time spent on the couch should be liberal—more than is legitimate for adults." It further stated that after waking up, the body should be anointed with oil "to stimulate the sensitive faculties". Regarding exercise, it recommended walking or horse-riding. It stated:
"The factors to consider in regard to exercise in old people are the various bodily states of different persons; the sequels likely to arise from their ailments; and their previous habits as regards exercise."
The book said that if the body is healthy, it can perform attempered exercises, but if one part of the body is infirm, "then that part should not be exercised until after the rest", and that exercises are not to be strictly graduated "as if the body were to be strengthened". The Canon recognized four periods of life: the period of growth, prime of life, period of elderly decline (from forty to sixty), and decrepit age. He states that during the last period, "there is hardness of their bones, roughness of the skin, and the long time since they produced semen, blood and vaporal breath". However, he agreed with Galen that the earth element is more prominent in the aged and decrepit than in other periods. Avicenna did not agree with the concept of infirmity, however, stating:
"There is no need to assert that there are three states of the human body—sickness, health and a state
which is neither health nor disease. The first two cover everything."
Thesis III of the Canon discussed the diet suitable for old people. Avicenna wrote that they should be given food in small amounts at a time and that they can have two to three meals a day, divided up according to the digestive powers and general condition of the old person in question. He also recommended fruits, such as figs and prunes. He also stated:
"Some laudable nutrition may be allowed at bedtime, [but] robust old folk may have a more liberal supper, as long as they avoid any gross aliment... all hot, sharp or dessicative foods, such as dishes made with vinegar, salt, hot aromatics, seasonings and pickles. [Milk is good for the aged, being] nutritious and humectant in nature. [Yet] articles of food with a laxative action are most appropriate for the elderly."
"Strong clysters (enemata) must be avoided because they dry up the gut. An unctuous enema is
beneficial in cases where the bowels have been constipated for several days. ... Evacuations must be procured with as little stress as possible in the aged and decrepit, for it is to their advantage to get bowels opened gently."
In phytotherapy, the Canon introduced the medicinal use of Taxus baccata L. He named this herbal drug as "Zarnab" and used it as a cardiac remedy. This was the first known use of a calcium channel blocker drug, which were not used in the Western world until the 1960s.
"Students of the history of medicine know him for his attempts to introduce systematic experimentation and quantification into the study of physiology."