Praxagoras
Encyclopedia
Praxagoras was an influential figure of medicine
in ancient Greece
. He was born on the Greek
island of Kos
in about 340 BC
. Both his father, Nicarchus
, and his grandfather were physicians. Very little is known of Praxagoras' personal life, and none of his writings have survived.
in 375 BC
and the founding of the school in Alexandria
, Egypt, Greek medicine became entrenched with speculation, seeing little advances in medicine. During this period four men took up the study of anatomy: Diocles of Carystus
(fl. fourth cent. B.C.), Herophilus (c. 335-280 B.C.), Erasistratus
(c. 304-250 B.C.), and finally Praxagoras.
Galen
(A.D. 129-216), a famous Greek physician, wrote of Praxagoras as this influential figure in Greek medicine and a member of the logical or dogmatic school
. Galen also probably knew of the works of Praxagoras, writing on natural sciences, anatomy, causes and treatment of disease, and on acute diseases.
Praxagoras adopted a variation of the humoral theory
, but instead of the four humors (blood
, phlegm
, yellow bile
, and black bile) that most physicians held, he insisted on eleven. Like the other Greek physicians, he believed health and disease were controlled by the balance or imbalance of these humors. For example, if the proper amount of heat is present in the organism, the process of digestion is natural. Too little or too much heat will cause a rise in the other humors, which then produces certain disease conditions. He considered digestion to be a kind of putrefaction
or decomposition, an idea that was held until the nineteenth century.
Praxagoras was also influential in the Alexandrian school in particular. After the death of Alexander the Great (356-323 B.C.), Egypt fell to the hands of General Ptolemy
, who established a modern university with the first great medical school of antiquity. Human dissection was practiced, mostly by Herophilus and Erasistratus; Praxagoras was Herophilus' teacher. Although the university in Alexandria and its massive library was destroyed by bands of conquerors, later Arabic physicians made the efforts to preserve some of the writings. After the fall of the Byzantine Empire
, Greek scholars brought back Greek medicine to the medical schools of the Western Renaissance
.
's (384-322 B.C.) anatomy
and improved it by distinguishing between artery and veins. He saw arteries as air tubes, similar to the trachea
and bronchi, which carried pneuma
, the mystic force of life. Arteries took the breath of life from the lungs to the left side of the heart
through the aorta
to the arteries of the body. He believed the arteries stemmed from the heart
, but the veins came from the liver
. Veins carried blood
, which was created by digested food, to the rest of the body. The combination of blood and pneuma generated heat. As one of the humors, thick, cold phlegm gathered in the arteries would cause paralysis
. Also, he believed that arteries were the channels through which voluntary motion was given to the body, and that the cause of epilepsy
was the blocking of the aorta by this same accumulation of phlegm
.
Aristotle
, Diocles
, and Praxogoras insisted that the heart was the central organ of intelligence and the seat of thought. Praxagoras differed with the others in that he believed the purpose of respiration was to provide nourishment for the psychic pneuma, rather than to cool the inner heat.
and motor nerves.
Praxagoras was interested in pulse and was the first to direct attention to the importance of arterial pulse in diagnosis. He insisted that arteries pulsed by themselves and were independent of the heart. Herophilus refuted this doctrine in his treatise "On Pulses." In another area, Galen criticized Praxagoras for displaying too little care in anatomy. He suggested that Praxagoras did not arrive at his theories by dissection.
The beliefs of Praxagoras held sway for centuries. For example, for nearly 500 years after his death, many still believed that arteries did not contain blood but pneuma. His most famous pupil, Herophilus, was instrumental in establishing the marvelous medical establishment at Alexandria
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
in ancient Greece
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
. He was born on the Greek
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
island of Kos
Kos
Kos or Cos is a Greek island in the south Sporades group of the Dodecanese, next to the Gulf of Gökova/Cos. It measures by , and is from the coast of Bodrum, Turkey and the ancient region of Caria. Administratively the island forms a separate municipality within the Kos peripheral unit, which is...
in about 340 BC
340 BC
Year 340 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Torquatus and Mus...
. Both his father, Nicarchus
Nicarchus
Nicarchus or Nicarch was a Greek poet and writer of the 1st century AD, best known for his epigrams, of which forty-two survive under his name in the Greek Anthology, and his satirical poetry. He was a contemporary of, and influence on, the better-known Latin writer Martial. A large proportion of...
, and his grandfather were physicians. Very little is known of Praxagoras' personal life, and none of his writings have survived.
History
Between the death of HippocratesHippocrates
Hippocrates of Cos or Hippokrates of Kos was an ancient Greek physician of the Age of Pericles , and is considered one of the most outstanding figures in the history of medicine...
in 375 BC
375 BC
Year 375 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the First year without Tribunate or Consulship...
and the founding of the school in Alexandria
Alexandria
Alexandria is the second-largest city of Egypt, with a population of 4.1 million, extending about along the coast of the Mediterranean Sea in the north central part of the country; it is also the largest city lying directly on the Mediterranean coast. It is Egypt's largest seaport, serving...
, Egypt, Greek medicine became entrenched with speculation, seeing little advances in medicine. During this period four men took up the study of anatomy: Diocles of Carystus
Diocles of Carystus
Diocles of Carystus , a very celebrated Greek physician, was born at Carystus in Euboea, lived not long after the time of Hippocrates, to whom Pliny says he was next in age and fame. Not much is known of his life, other that he lived and worked in Athens, where he wrote what may be the first...
(fl. fourth cent. B.C.), Herophilus (c. 335-280 B.C.), Erasistratus
Erasistratus
Erasistratus was a Greek anatomist and royal physician under Seleucus I Nicator of Syria. Along with fellow physician Herophilus, he founded a school of anatomy in Alexandria, where they carried out anatomical research...
(c. 304-250 B.C.), and finally Praxagoras.
Galen
Galen
Aelius Galenus or Claudius Galenus , better known as Galen of Pergamon , was a prominent Roman physician, surgeon and philosopher...
(A.D. 129-216), a famous Greek physician, wrote of Praxagoras as this influential figure in Greek medicine and a member of the logical or dogmatic school
Dogmatic school
The Dogmatic school of medicine was an ancient school of medicine in ancient Greece and Rome. They were the oldest of the medical sects of antiquity. They derived their name from dogma, a philosophical tenet or opinion, because they professed to follow the opinions of Hippocrates, hence they were...
. Galen also probably knew of the works of Praxagoras, writing on natural sciences, anatomy, causes and treatment of disease, and on acute diseases.
Praxagoras adopted a variation of the humoral theory
Humorism
Humorism, or humoralism, is a now discredited theory of the makeup and workings of the human body, adopted by Greek and Roman physicians and philosophers, positing that an excess or deficiency of any of four distinct bodily fluids in a person directly influences their temperament and health...
, but instead of the four humors (blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
, phlegm
Phlegm
Phlegm is a liquid secreted by the mucous membranes of mammalians. Its definition is limited to the mucus produced by the respiratory system, excluding that from the nasal passages, and particularly that which is expelled by coughing . Phlegm is in essence a water-based gel consisting of...
, yellow bile
Bile
Bile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the process of digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and upon eating is discharged into the duodenum...
, and black bile) that most physicians held, he insisted on eleven. Like the other Greek physicians, he believed health and disease were controlled by the balance or imbalance of these humors. For example, if the proper amount of heat is present in the organism, the process of digestion is natural. Too little or too much heat will cause a rise in the other humors, which then produces certain disease conditions. He considered digestion to be a kind of putrefaction
Putrefaction
Putrefaction is one of seven stages in the decomposition of the body of a dead animal. It can be viewed, in broad terms, as the decomposition of proteins, in a process that results in the eventual breakdown of cohesion between tissues and the liquefaction of most organs.-Description:In terms of...
or decomposition, an idea that was held until the nineteenth century.
Praxagoras was also influential in the Alexandrian school in particular. After the death of Alexander the Great (356-323 B.C.), Egypt fell to the hands of General Ptolemy
Ptolemy I Soter
Ptolemy I Soter I , also known as Ptolemy Lagides, c. 367 BC – c. 283 BC, was a Macedonian general under Alexander the Great, who became ruler of Egypt and founder of both the Ptolemaic Kingdom and the Ptolemaic Dynasty...
, who established a modern university with the first great medical school of antiquity. Human dissection was practiced, mostly by Herophilus and Erasistratus; Praxagoras was Herophilus' teacher. Although the university in Alexandria and its massive library was destroyed by bands of conquerors, later Arabic physicians made the efforts to preserve some of the writings. After the fall of the Byzantine Empire
Byzantine Empire
The Byzantine Empire was the Eastern Roman Empire during the periods of Late Antiquity and the Middle Ages, centred on the capital of Constantinople. Known simply as the Roman Empire or Romania to its inhabitants and neighbours, the Empire was the direct continuation of the Ancient Roman State...
, Greek scholars brought back Greek medicine to the medical schools of the Western Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
.
Praxagoras' theory of circulation
Praxagoras studied AristotleAristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
's (384-322 B.C.) anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
and improved it by distinguishing between artery and veins. He saw arteries as air tubes, similar to the trachea
Vertebrate trachea
In tetrapod anatomy the trachea, or windpipe, is a tube that connects the pharynx or larynx to the lungs, allowing the passage of air. It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus...
and bronchi, which carried pneuma
Pneuma
Pneuma is an ancient Greek word for "breath," and in a religious context for "spirit" or "soul." It has various technical meanings for medical writers and philosophers of classical antiquity, particularly in regard to physiology, and is also used in Greek translations of the Hebrew Bible and in...
, the mystic force of life. Arteries took the breath of life from the lungs to the left side of the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
through the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
to the arteries of the body. He believed the arteries stemmed from the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
, but the veins came from the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
. Veins carried blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
, which was created by digested food, to the rest of the body. The combination of blood and pneuma generated heat. As one of the humors, thick, cold phlegm gathered in the arteries would cause paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
. Also, he believed that arteries were the channels through which voluntary motion was given to the body, and that the cause of epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
was the blocking of the aorta by this same accumulation of phlegm
Phlegm
Phlegm is a liquid secreted by the mucous membranes of mammalians. Its definition is limited to the mucus produced by the respiratory system, excluding that from the nasal passages, and particularly that which is expelled by coughing . Phlegm is in essence a water-based gel consisting of...
.
Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
, Diocles
Diocles of Carystus
Diocles of Carystus , a very celebrated Greek physician, was born at Carystus in Euboea, lived not long after the time of Hippocrates, to whom Pliny says he was next in age and fame. Not much is known of his life, other that he lived and worked in Athens, where he wrote what may be the first...
, and Praxogoras insisted that the heart was the central organ of intelligence and the seat of thought. Praxagoras differed with the others in that he believed the purpose of respiration was to provide nourishment for the psychic pneuma, rather than to cool the inner heat.
Arteries and Pulses
Praxagoras' views on arteries were very influential in the development of physiology. Since the concept of nerves did not exist, Praxagoras explained the movement of arteries to the fact that arteries get smaller and smaller, and then disappear. This disappearance caused movement, a fact now attributed to nerves. However, he speculated about the role of movement and was satisfied that he had found the answer of the center of vitality and energy. His pupil, Herophilus, actually discovered both sensorySensory neuron
Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli. They are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord...
and motor nerves.
Praxagoras was interested in pulse and was the first to direct attention to the importance of arterial pulse in diagnosis. He insisted that arteries pulsed by themselves and were independent of the heart. Herophilus refuted this doctrine in his treatise "On Pulses." In another area, Galen criticized Praxagoras for displaying too little care in anatomy. He suggested that Praxagoras did not arrive at his theories by dissection.
The beliefs of Praxagoras held sway for centuries. For example, for nearly 500 years after his death, many still believed that arteries did not contain blood but pneuma. His most famous pupil, Herophilus, was instrumental in establishing the marvelous medical establishment at Alexandria
See also
- GalenGalenAelius Galenus or Claudius Galenus , better known as Galen of Pergamon , was a prominent Roman physician, surgeon and philosopher...
- HippocratesHippocratesHippocrates of Cos or Hippokrates of Kos was an ancient Greek physician of the Age of Pericles , and is considered one of the most outstanding figures in the history of medicine...
- Herophilus
- William HarveyWilliam HarveyWilliam Harvey was an English physician who was the first person to describe completely and in detail the systemic circulation and properties of blood being pumped to the body by the heart...
- Marcello MalpighiMarcello MalpighiMarcello Malpighi was an Italian doctor, who gave his name to several physiological features, like the Malpighian tubule system.-Early years:...