The Canon of Medicine
The Canon of Medicine (original title in Arabic:    "Al-Qanun fi al-Tibb" which translates to The Law of Medicine) is a 14-volume Arabic medical encyclopedia written by the Persian Muslim scientist and physician Ibn Sina (Avicenna) and completed in 1025. Written in Arabic, the book was based on a combination of his own personal experience, medieval Islamic medicine, the writings of the Greek physician Galen, the Indian physicians Sushruta and Charaka, and ancient Arabian and Persian medicine. The Canon is considered one of the most famous books in the history of medicine.
Also known as the Qanun, which means "law" in 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 well-renowned written work. Qanun was used at many medical schoolsat University of Montpellier, France, as late as 1650. The principles of medicine described by him ten centuries ago in this book, are still taught at UCLA and Yale University, among others, as part of the history of medicine.
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.
George Sarton, the father of the history of science, wrote in the Introduction to the History of Science:
"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 fi-l-Tibb' 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."

# Overview
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. Ibn Sina stated that medicine (tibb) is the science by which we learn the various states of the human body when in health and when not in health, and the means by which health is likely to be lost, and when lost, is likely to be restored. In other words, medicine is the science whereby health is conserved and the art whereby it is restored after being lost.
Avicenna regarded the causes of good health and diseases to be:
- The Material Causes
- The Elements
- The Humors
- The Variability of the Humors
- The Temperaments
- The Psychic Faculties
- The Vital Force
- The Organs
- The Efficient Causes
- The Formal Causes
- The Vital Faculties
- The Final Causes
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 760 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 earliest known copy of the Canon of Medicine dated 1052 is held in the collection of the Aga Khan and is to be housed in the Aga Khan Museum planned for Toronto, Ontario, Canada.

## Influence in Europe
The Arabic text of the 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.

# Experimental medicine
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."

## Clinical 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 drug must be free from any extraneous accidental quality."
- "It must be used on a simple, not a composite, disease."
- "The drug must be tested with two contrary types of diseases, because sometimes a drug cures one disease by Its essential qualities and another by its accidental ones."
- "The quality of the drug must correspond to the strength of the disease. For example, there are some drugs whose heat is less than the coldness of certain diseases, so that they would have no effect on them."
- "The time of action must be observed, so that essence and accident are not confused."
- "The effect of the drug must be seen to occur constantly or in many cases, for if this did not happen, it was an accidental effect."
- "The experimentation must be done with the human body, for testing a drug on a lion or a horse might not prove anything about its effect on man."

## Inductive logic
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. Ibn Sina contributed inventively to the development of inductive logic, which he used to pioneer the idea of a syndrome in the diagnosis of specific diseases. In The Canon of Medicine, Avicenna was the first to describe the methods of agreement, difference and concomitant variation which are critical to inductive logic and the scientific method.

## Pharmaceutical sciences
Avicenna'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.

## Pharmacotherapy
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.

## Pharmacy
Ibn Sina 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 drugs in The Canon of Medicine.

# Anatomy and Physiology
The contributions of Avicenna's Canon to physiology include the introduction of systematic experimentation and quantification into the study of physiology.
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.

## Blood pressure
Avicenna dedicated a chapter of the Canon to blood pressure. He was able to discover the causes of bleeding and heamorrhage, and discovered that heamorrhage 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.

## Neuroanatomy and neurophysiology
Avicenna discovered the cerebellar vermiswhich 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.
He was also the earliest 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.

## Ophthalmology
Avicenna's contributions to ophthalmology in medieval Islam include his 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.
Another contribution Avicenna made to ophthalmology was his suggestion that "the optic nerves did cross."

## Pulsology and sphygmology
Avicenna was a pioneer 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."
Avicenna 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 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.

# Etiology and Pathology
In etiology and pathology, Avicenna discovered 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. He fully understood the pathology of contagious disease.
Avicenna 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. He also described the first known treatments for cancer.
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.

## Bacteriology and microbiology
The Canon stated that bodily secretions are contaminated by "foul foreign earthly bodies" before a person becomes infected, but he did not view these bodies as primary causes of disease.

## Cancer therapy
In cancer therapy, Avicenna 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.
Another method for treating cancer first described by Avicenna was a surgical treatment. He 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.

## Hepatology
Avicenna's advances in hepatology include his introduction of new methods of hepatitis treatment.

## Quarantine
The Canon introduced quarantine as a means of limiting the spread of contagious diseases.

# Neurosciences and Psychology
In Islamic psychology and neurosciences, Ibn Sina noted the close relationship between emotions and the physical condition and felt that music had a definite physical and psychological effect on patients.

## Clinical psychology and psychotherapy
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 that he 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. Ibn Sina 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.

## Neurology and neuropathology
Avicenna's contributions in neurology and neuropathology include his diagnosis of facial nerve paralysis, his distinction between brain paralysis and hyperaemia, and most importantly his discovery of meningitis. He diagnosed meningitis as a disease induced by the brain itself and differentiated it from infectious brain disease, and was also able to diagnose and describe the type of meningitis induced by an infection in other parts of the body.

## Neuropsychiatry and neuropsychology
Ibn Sina was a pioneer of neuropsychiatry and neuropsychology. He first described numerous neuropsychiatric conditions, including hallucination, insomnia, mania, nightmare, melancholia, dementia, epilepsy, paralysis, stroke, vertigo and tremor. Avicenna dedicated three chapters of The Canon of Medicine to neuropsychiatry.
He 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. He also discovered a condition resembling schizophrenia which he described as Junun Mufrit (severe madness), which he clearly distinguished from other forms of madness such as mania, rabies, and manic depressive psychosis. He 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. He wrote that such patients need to be restrained, in order to avoid any harm they may cause to themselves or to others.
Avicenna also dedicated a chapter of the Canon to mania and rabies, where he described mania as bestial madness characterized by rapid onset and remission, with agitation and irritability, and described rabies as a type of mania.

## Psychoanalysis
In The Canon of Medicine, Avicenna extended the theory of temperaments to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." Avicenna's work is thus considered a "forerunner of twentieth century psychoanalysis."

## Psychophysiology and psychosomatic medicine
Ibn Sina was a pioneer 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) when he was treating a very ill patient by "feeling the patient's pulse and reciting aloud to him the names of provinces, districts, towns, streets, and people." He noticed how the patient's pulse increased when certain names were mentioned, from which Avicenna deduced that the patient was in love with a girl whose home Avicenna was "able to locate by the digital examination." Avicenna advised the patient to marry the girl he is in love with, and the patient soon recovered from his illness after his marriage.
Avicenna also gave psychological explanations for certain somatic illnesses, and he always linked the physical and psychological illnesses together. He described melancholia (depression) as a type of mood disorder in which the person may become suspicious and develop certain types of phobias. He stated that anger heralded the transition of melancholia to mania, and explained that humidity inside the head can contribute to mood disorders. He 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. He also wrote about symptoms and treatments for nightmare, epilepsy, and weak memory.

# Surgery
In surgery, Avicenna was the first to describe the surgical procedure of intubation in order to to facilitate breathing.

## Anesthesia
The Canon described the "soporific sponge", an anasthetic imbued with aromatics and narcotics, which was to be placed under a patient's nose during surgical operations.

## Hirudotherapy
Hirudotherapy, the use of medicinal leech for medical purposes, was introduced by Avicenna in The Canon of Medicine. He 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.

# Other contributions

## Chromotherapy
Avicenna, who viewed colour to be of vital importance in diagnosis and treatment, made significant contributions to chromotherapy. He wrote 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. He 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."

## Phytotherapy
In phytotherapy, Avicenna 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.

## Temperaments
The Canon of Medicine adopted the ancient theory of Four Humours and Four Temperaments and extended it to encompass "emotional aspects, mental capacity, moral attitudes, self-awareness, movements and dreams." Avicenna summarized his own theory of four temperaments in a table presented as follows: