Plato--Aristotle--Alexandrian School--Its Origin--Its Influence--
Lithotomy--Herophilus--Erasistratus--Cleombrotus--Chrysippos--
Anatomy--Empiricism--Serapion of Alexandria.
Two very eminent philosophers, Plato and Aristotle, were influenced by
the teaching of Hippocrates.
Plato (B.C. 427-347) was a profound moralist, and though possessed of one of the keenest intellects of all time, did little to advance medical science. He did not practise medicine, but studied it as a branch of philosophy, and instead of observing and investigating, attempted to solve the problems of health and disease by intuition and speculation. His conceptions were inaccurate and fantastic.
He elaborated the humoral pathology of Hippocrates. The world, he thought, was composed of four elements: fire consisting of pyramidal, earth of cubical, air of octagonal, and water of twenty-sided atoms. The marrow consists of triangles, and the brain is the perfection of marrow. The soul dominates the marrow and the separation of the two causes death. The purpose of the bones and muscles is to protect the marrow against changes of temperature. Plato divided the "soul" into three parts: Reason, enthroned in the brain; courage in the heart; and desire in the liver. The uterus, he believed, excites inordinate desires. Inflammations are due to disorders of the bile, and fevers to the influence of the elements. His theories in regard to the special senses are very fantastic, for instance, smell is evanescent because it is not founded on any external image; taste results from small vessels carrying taste atoms to the heart and soul.
Aristotle, born B.C. 334, was the son of Nichomachus, physician to the King of Macedonia, and of the race of the Asclepiads. His inherited taste was for the study of Nature; he attained the great honour of being the founder of the sciences of Comparative Anatomy and Natural History, and contributed largely to the medical knowledge of his time. Aristotle went to Athens and became a follower of Plato, and the close companionship of these two great men lasted for twenty years. At the age of 42, Aristotle was appointed by Philip of Macedon tutor to Alexander the Great, who was then aged 15, and the interest of that mighty prince was soon aroused in the study of Natural History. Aristotle and Alexander the Great, teacher and pupil, founded the first great Natural History Museum, to which specimens were sent from places scattered over the then known world. Aristotle, besides his philosophical books, wrote: "Researches about Animals," "On Sleep and Waking," "On Longevity and Shortlivedness," "On Parts of Animals," "On Respiration," "On Locomotion of Animals," and "On Generation of Animals." He was greatly helped in the supply of material for dissection in his study of comparative anatomy by his pupil, Alexander the Great. Aristotle pointed out the differences in the anatomy of men and monkeys; he described the anatomy of the elephant and of birds, and also the changes in development seen during the incubation of eggs. He investigated, also, the anatomy of fishes and reptiles. The stomachs of ruminant animals excited his interest, and he described their structure. The heart, according to Aristotle, was the seat of the soul, and the birthplace of the passions, for it held the natural fire, and in it centred movement, sensation and nourishment. The diaphragm, he believed, separated the heart, the seat of the soul, from the contaminating influences of the intestines. He did not advance beyond the conception that nerves were akin to ligaments and tendons, and he believed that the nerves originated in the heart, as did also the blood-vessels. He named the aorta and ventricles. He investigated the action of the muscles, and held that superfoetation was possible.
When Aristotle retired to Chalcis, he chose Tyrtamus, to whom he gave the name of Theophrastus, as his successor at the Lyceum. Theophrastus was the originator of the science of Botany, and wrote the "History of Plants." He also wrote about stones, and on physical, moral and medical subjects.