Galen 3
Galen
Of Pergamum / ENCYCLOPÆDIA
BRITANNICA
b. AD 129,, Pergamum, Mysia, Anatolia
[now Bergama, Tur.]
d. c. 216
Byname OF GREEK GALENOS, Latin GALENUS, Greek physician, writer, and philosopher who exercised a dominant influence on medical theory and practice in Europe from the Middle Ages until the mid-17th century. His authority in the Byzantine world and the Muslim Middle East was similarly long-lived.
Early life and training
The son of a wealthy
architect, Galen was educated as a philosopher and man of letters. His hometown,
Pergamum, was the site of a magnificent shrine of the healing god, Asclepius,
that was visited by many distinguished figures of the Roman Empire for cures.
When Galen was 16, he changed his career to that of medicine, which he studied
at Pergamum, at Smyrna (modern Izmir, Tur.), and finally at Alexandria in
Egypt, which was the greatest medical centre of the ancient world. After more
than a decade of study, he returned in AD 157 to Pergamum, where he served as
chief physician to the troop of gladiators maintained by the high priest of
Asia.
In 162 the ambitious Galen
moved to Rome. There he quickly rose in the medical profession owing to his
public demonstrations of anatomy, his successes with rich and influential
patients whom other doctors had pronounced incurable, his enormous learning, and
the rhetorical skills he displayed in public debates. Galen's wealthy
background, social contacts, and a friendship with his old philosophy teacher Eudemus
further enhanced his reputation as a philosopher and physician.
Anatomical and medical studies
Galen regarded anatomy
as the foundation of medical knowledge, and he frequently dissected and
experimented on such lower animals as the Barbary
ape (or African monkey), pigs, sheep, and goats. Galen's advocacy of
dissection, both to improve surgical skills and for research purposes, formed
part of his self-promotion, but there is no doubt that he was an accurate
observer. He distinguished seven pairs of cranial nerves, described the valves
of the heart, and observed the structural differences between arteries and
veins. One of his most important demonstrations was that the arteries carry
blood, not air, as had been taught for 400 years. Notable also were his vivisection
experiments, such as tying off the recurrent laryngeal nerve to show that the
brain controls the voice, performing a series of transections of the spinal cord
to establish the functions of the spinal nerves, and tying off the ureters to
demonstrate kidney and bladder functions. Galen was seriously hampered by the
prevailing social taboo against dissecting human corpses, however, and the
inferences he made about human anatomy based on his dissections of animals often
led him into errors. His anatomy of the uterus, for example, is largely that of
the dog's.
Galen's physiology was a
mixture of ideas taken from the philosophers Plato and Aristotle as well as from
the physician Hippocrates, whom Galen revered as the fount of all medical
learning. Galen viewed the body as consisting of three connected systems: the
brain and nerves, which are responsible for sensation and thought; the heart and
arteries, responsible for life-giving energy; and the liver and veins,
responsible for nutrition and growth. According to Galen, blood is formed in the
liver and is then carried by the veins to all parts of the body, where it is
used up as nutriment or is transformed into flesh and other substances. A small
amount of blood seeps through the lungs between the pulmonary artery and
pulmonary veins, thereby becoming mixed with air, and then seeps from the right
to the left ventricle of the heart through minute pores in the wall separating
the two chambers. A small proportion of this blood is further refined in a
network of nerves at the base of the skull (in reality found only in ungulates)
and the brain to make psychic pneuma,
a subtle material that is the vehicle of sensation. Galen's physiological theory
proved extremely seductive, and few possessed the skills needed to challenge it
in succeeding centuries.
Building on earlier
Hippocratic conceptions, Galen believed that human health requires an
equilibrium between the four main bodily fluids, or humours--blood,
yellow bile, black bile, and phlegm. Each of the humours is built up from the
four elements and displays two of the four primary qualities: hot, cold, wet,
and dry. Unlike Hippocrates, Galen argued that humoral imbalances can be located
in specific organs, as well as in the body as a whole. This modification of the
theory allowed doctors to make more precise diagnoses and to prescribe specific
remedies to restore the body's balance. As a continuation of earlier Hippocratic
conceptions, Galenic physiology became a powerful influence in medicine for the
next 1,400 years.
Galen was both a universal
genius and a prolific writer: about 300 titles of works by him are known, of
which about 150 survive wholly or in part. He was perpetually inquisitive, even
in areas remote from medicine, such as linguistics, and he was an important
logician who wrote major studies of scientific method. Galen was also a skilled
polemicist and an incorrigible publicist of his own genius, and these traits,
combined with the enormous range of his writings, help to explain his subsequent
fame and influence.
Influence
Galen's writings achieved
wide circulation during his lifetime, and copies of some of his works survive
that were written within a generation of his death. By AD 500 his works were
being taught and summarized at Alexandria, and his theories were already
crowding out those of others in the medical handbooks of the Byzantine world.
Greek manuscripts began to be collected and translated by enlightened Arabs in
the 9th century, and in about 850 Hunayn
ibn Ishaq, an Arab physician at the court of Baghdad, prepared an annotated
list of 129 works of Galen that he and his followers had translated from Greek
into Arabic or Syriac. Learned medicine in the Arabic world thus became heavily
based upon the commentary, exposition, and understanding of Galen.
Galen's influence was initially almost negligible in western Europe except for drug recipes, but from the late 11th century Hunayn's translations, commentaries on them by Arab physicians, and sometimes the original Greek writings themselves were translated into Latin. These Latin versions came to form the basis of medical education in the new medieval universities. From about 1490, Italian humanists felt the need to prepare new Latin versions of Galen directly from Greek manuscripts in order to free his texts from medieval preconceptions and misunderstandings. Galen's works were first printed in Greek in their entirety in 1525, and printings in Latin swiftly followed. These texts offered a different picture from that of the Middle Ages, one that emphasized Galen as a clinician, a diagnostician, and above all, an anatomist. His new followers stressed his methodical techniques of identifying and curing illness, his independent judgment, and his cautious empiricism. Galen's injunctions to investigate the body were eagerly followed, since physicians wished to repeat the experiments and observations that he had recorded. Paradoxically, this soon led to the overthrow of Galen's authority as an anatomist. In 1543 the Flemish physician Andreas Vesalius showed that Galen's anatomy of the body was more animal than human in some of its aspects, and it became clear that Galen and his medieval followers had made many errors. Galen's notions of physiology, by contrast, lasted for a further century, until the English physician William Harvey correctly explained the circulation of the blood. The renewal and then the overthrow of the Galenic tradition in the Renaissance had been an important element in the rise of modern science, however.