After the time of Hippocrates, groups of teachers and practitioners split up into a variety of separate medical systems, or sects. The ideas of the philosophers Plato and Aristotle were among the important influences, for as Aristotle pointed out one might begin with philosophy but would end with medicine; or start with medicine and find oneself in philosophy.

Plato (c. 429-347 B.C.), a contemporary of Hippocrates, a student of Socrates, and the teacher of Aristotle, became one of the most influential thinkers in the history of the Western world. Some of his own heritage can be traced to Pythagorean doctrines, since mathematics, especially geometry, figured prominently in his philosophic system. Plato's interests lay mainly in the nature of the soul and matter, and his medical speculations—logical, but without direct experimentation—led to a number of faulty conclusions about the human body. However, several of these opinions were staunchly held beliefs of the time, and even some investigators of later centuries were unable to shake them. Plato's method of reasoning at a distance rather than at the dissecting table or the bedside was resurrected and perpetuated in the Middle Ages. Some of his teachings on the responsibilities of government even have a bearing on medical practice today, for Plato expected the ideal state to provide for the health of its citizens and to prevent poverty and overpopulation.

The physicians who rallied around his doctrines, particularly in the third century B.C. and after, were called Dogmatists. For them, reasoning superseded observation. Experience was indeed a means of testing, but mainly to prove the correctness of one's deduction. The Dogmatists classified all diseases according to the humors; for instance, they referred to an illness as mucous or bilious and used an appropriate remedy against the particular excess humor. They considered their practices based on Hippocrates, but except for looking to him as an authority they showed little evidence of following his spirit of objectivity or his principles of treatment. Most of the Dogmatists, and there were many, used extreme therapeutic measures, including drastic purgings and bleedings, and treated fevers with dehydrating regimens.

Praxagoras of Cos (fl. c. 340 B.C.) was among the first to separate the functions of arteries and veins, but he believed that both systems contained air. Praxagoras extended the number of humors to eleven and used bleeding extensively, but he placed emphasis on the pulse, showing that disease affected its characteristics—one of his most important contributions.

Diodes of Carystos (first half of fourth century B.C.), another famous Dogmatist, wrote many works on clinical subjects, drugs, dietetics, embryology, and anatomy. Called the Hippocrates of his time, Diodes perspicaciously distinguished between pleurisy (inflammation of the lining over the lung) and pneumonia (disease of the lung itself), between intestinal cramps and intestinal obstruction, and recognized fever as a symptom rather than a disease.

Aristotle (384-322 B.C.), son of a physician and pupil of Plato, also had profound influence on later medicine, especially among the Arabic authors. His writings illuminated an extraordinary number of fields: logic, metaphysics, psychology, politics, zoology, poetry, drama. He was also known as a great teacher and was hired by Philip of Macedonia to tutor his son Alexander.

Aristotle's methods were based on careful investigations of both animals and humans, and his studies—in which he was lavishly supported by Alexander—were milestones in science. In embryology he described the punctum saliens (the first sign of the embryo), the early development of the heart and great vessels, the beating of the embryo's heart (the first such observation), some differences between arteries and veins, the great arterial vessel the aorta (which he named), and the course of the ureter. Aristotle taught that the fetus did not breathe while in the uterus and that male and female embryos did not develop in different compartments. His writings on the anatomy of vertebrates and invertebrates were so extensive that they earned him recognition as the founder of comparative anatomy.

Yet Aristotle reflected the intellectual boundaries of his time. He believed that the doctrine of the humors had some foundation and placed the seat of intelligence in the heart. He confused nerves with ligaments and tendons (the Greeks used the same word for all three) and linked veins from the liver to the right arm and from the spleen to the left arm. Therefore, in treatment he advocated bloodletting on the side corresponding to the location of the diseased organ.

Aristotle also subscribed to dreams as portents of the future (as was typical of his time), but he was primarily an experimentalist, in contrast to Plato, whose teachings were more mystical and metaphysical. Their doctrines were to have profound influence on science and medicine in the Middle Ages and the Renaissance. Together with Hippocrates before them and Galen afterwards, they were the principal authorities of pagan, Christian, and Muslim medical thought.

Theophrastos (c. 370-285 B.C.) probably Aristotle's most famous disciple, continued the investigative and experimental approach, adding his own ideas to explain various symptoms such as fainting, dizziness, and sweating. Among his important studies on botany were descriptions of over five hundred plants, dealing with morphology, biological characteristics, and medical uses.

In addition to the Dogmatists, other systems of medicine arose. In the third century B.C., under the philosophical influence of the Skeptics, there emerged a group of physicians called Empiricists, for whom the effects of treatment were what mattered, not possible reasons for illness. One's previous experience with symptoms displayed by a patient should indicate the probable outcome and most effective treatment for a malady. In these views the Empiricists followed the Hippocratic principles of observation, experience, and prognosis, yet some Empiricists who wrote on Hippocrates were highly critical of his teachings, probably because of the humoral explanations in the Collection. Not seeking causes or reasons for results, they ended up rejecting inquiry into anatomy or physiological mechanisms. Even Philinos of Cos (third century B.C.) who studied under Herophilos, one of the great Alexandrian anatomists, did not consider human dissection of practical use. The outstanding Empiricist Heraclides (second century B.C.) wrote extensively on symptomatology and surgery. He also made many contributions to pharmacy.

In the first century B.C., the influence of Greek medicine received great impetus in Rome through the personality and teachings of Asclepiades. About 50 B.C., one of his followers, Themison, founded another medical system, Methodism, which abandoned the doctrines of the four humors that had dominated Greek pathologic thinking for centuries. In his system disease was caused by constriction or relaxation of the "pores," as judged by evacuations, secretions, and feverishness in the sick. All other information was useless. If the "pores" were contracted, the physician ordered a scant diet, warm baths, poultices, humid air, bleeding, and medications to produce evacuations. Against the opposite, a relaxed condition, he prescribed an increased food intake, cold baths and air, and styptic medications to induce constriction.

Another system, Pneumatism, was opposed to Dogmatism, Empiricism, and Methodism. Also Greek in origin, it had its principal influences in Rome in the first and second century A.D. Athenaeus of Cilicia, the founder of Pneumatism, applied the all-pervading cosmic principle of the ancient Stoics to a general physiologic view that people breathed in this spirit, the pneuma, which went first to the heart and then through the arteries to all parts of the body. Conceptions of disease involved complicated theoretical relationships among the pneuma, warmth, and moisture inside the body. Yet despite the abstruse wanderings of their theories and their employment of medicines combined from an extraordinary number of drugs (one remedy is said to have contained over six hundred substances), the practices of the Pneumatists were often pragmatic. For instance, bleedings were infrequent and limited. Furthermore, Athenaeus had concern for public health, including maintenance of unpolluted water and adequate housing.

A final sect, Eclecticism, arose from the Pneumatists. Adhering to no single, consistent system, the followers chose ideas according to their own needs to explain and treat illness. Even Galen considered himself an Eclectic.

One of the early Eclectics was Archigenes (c. A.D. 100), who was active principally in Rome. As we learn from Galen, his observations on symptomatology, physical diagnosis, and drug therapy were brilliant, but his contributions to surgery are remembered best. For instance, he described amputation with considerable perceptiveness: ligating the main vessel first; using temporary tight constriction above the level of incision to control bleeding; operating not just for established gangrene but also for extensive injuries that would result in gangrene. Furthermore, he counseled against surgery for people who might be too weak to withstand the trauma.

Among other Greek writers during the Roman hegemony over Greece was Aretaeus of Cappadocia (c. A.D. 120-180), whose writing, as translated by Francis Adams, was precise although sometimes pedantic. He gave vivid descriptions of many diseases, including a type of diabetes, and what might have been diphtheria, pneumonia, and migraine. In suggesting that jaundice was due to obstruction of the biliary ducts he indicated an advanced understanding over earlier times. Following Hippocrates he paid attention to the environment as well as the patient's makeup. He subscribed to the doctrine of the pneuma, but in treatment used all the methods of his period: regimens, diet, and drugs (some of which were drastic). However, he continued to minister to the sick even after it was hopeless, a practice not widely advocated. "When he can render no further aid, the physician alone can still mourn as a man with his incurable patient. This is the physician's sad lot."

The tenets of the various sects of medicine (Dogmatism, Empiricism, Methodism, Pneumatism, and Eclecticism) extended from the fourth century B.C. well into the Christian era. While these systems were developing, the most important locus of medical thought and practice was the great center of Greek learning at Alexandria, founded in 331 B.C. by Alexander the Great and governed by a dynasty stemming from his general Ptolemy. Indeed, most of the originators of the medical sects were students at one time at Alexandria. Scholars flocked there from all over the world, and the prestige of having studied at Alexandria, one of the greatest cities of the Hellenic world, was prized and recognized. The Ptolemaic rulers gave lavish financial support to the researchers in all fields, including philosophy, mathematics, astronomy, music, poetry, history, and especially the natural sciences. Ptolemy I Soter (r. 305-284 B.C.) and Ptolemy II Philadelphos (r. 285-246 B.C.) founded botanical and zoological gardens and also two building complexes, the Museum and the Serapeum, each with a vast library where the most renowned investigators and writers of many different racial and cultural backgrounds could assemble to study and to teach.

A contemporary rival center of learning existed in Pergamon, though only after c. 250 B.C., in the reign of Eumenes I. However, the Ptolemaic pharaoh jealously guarded the supremacy of Alexandria by forbidding the export of the papyrus plant or its products. It is said that because of this forced shortage of papyrus Pergamon developed a material derived from animal skin, subsequently called Pergamos (parchment).

The Alexandrian center eventually included among its savants Euclid (fl. c. 300 B.C.), who systematized previous works in geometry; probably Archimedes of Syracuse (c. 287-212 B.C.), the great physicist and expert on hydrostatics; Heron (fl. c. A.D. 62), who invented a primitive steam engine and other mechanical devices; Callimachos (c. 305-240 B.C.), the famous poet and librarian who catalogued the huge collection of scrolls; and Dionysos Thrax (c. 170-c. 90 B.C.), who laid the foundations of grammar as a discipline. Medical research in the Alexandrian Museum became famous; indeed, its reputation lasted long after the Ptolemaic dynasty ended with the death of Cleopatra VII in 30 B.C.

The two outstanding medical investigators there were Herophilos (fl. c. 280 B.C.) and Erasistratos (fl. c. 250 B.C.). Most of our knowledge of these two is derived from later commentators, especially Celsus and Galen in the Roman period.

Herophilos had been a pupil of Praxagoras of Cos, a Dogmatist, and is especially remembered for his contributions to human anatomy. In keeping with the Alexandrian attitude of using every means to accumulate information, dissection of corpses was a regular practice, probably for the first time in history. Celsus reported the rumor that the anatomists used living people, such as criminals, in vivisection, but Galen made no mention of it.

Herophilos was responsible for a multitude of discoveries about human anatomy. He described various parts of the brain, the intestinal tract, the lymphatics, the liver, the genital organs, the eye, and the vascular system. He pointed out that the heart transmitted pulsation to the arteries and described extensive variations in the pulse. Furthermore, he stated that arteries were six times thicker than veins and had different structure. Along with brilliant, accurate, objective observations, Herophilos employed the ancient doctrine of the four humors in his treatment. He used bleedings and drastic drugs to evacuate the plethora of humors. However, in the fields of surgery and obstetrics he understood much of the mechanics and generally followed pragmatic methods.

Erasistratos has been particularly commended by historians for his emphasis on physiological experimentation, but he was also an original anatomical investigator as well. He differentiated between sensory and motor nerves although he also confused ligaments with nerves as others had before him. His accurate observations extended to the structure of the brain, the trachea (windpipe), the heart, and the vascular system, including the association of ascites (fluid in the abdomen) with a hard liver (probably cirrhosis). He also described the epiglottis and explained its function of blocking off the air passages during swallowing.

Turning away from the humoral pathology embraced by Herophilos, Erasistratos was a proponent of the idea that atoms were the basis of the body's structure. Thus the later solidistic theories of the Methodists (Asclepiades and Themison) had their origin in Alexandria. Erasistratos believed that atoms required pneuma from the inspired air to be activated and that they circulated in arteries which contained no blood. But whatever his theories, his practice was to use moderate measures: diet, mild drugs, and baths, without recourse to bleedings.

Followers of Herophilus and Erasistratos became embroiled in acrimonious debate for centuries. Galen in the second century A.D., for instance, considered himself part of the tradition of Herophilos because of his emphasis on anatomy and humoral pathology, and probably also because Herophilos looked to Hippocrates. On the other hand he reviled Erasistratos for his solidistic theories and his disagreement with Hippocrates on humoral doctrines.

In retrospect we can see that many of these acid controversies were based principally on theoretical concepts. Time has wiped out their foundations. The teachers propounded, the followers disputed, the practitioners wrangled, and the sick hoped. To the extent that the physician's treatment was based on unprejudiced observations of the patient's condition, honest evaluation of past results, and sincere concern for the welfare of the ill person, the patient received benefit no matter which theory, sect, or doctrine was espoused.

Albert S. Lyons

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