The 100 Most Influential Scientists of All Time (3 page)

I
n the
Iliad
, the writer Homer mentions Asclepius only as a skillful physician and the father of two Greek doctors at Troy, Machaon and Podalirius. In later times, however, he was honoured as a hero, and eventually worshiped as a god. Asclepius (Greek: Asklepios, Latin: Aesculapius), the son of Apollo (god of healing, truth, and prophecy) and the mortal princess Coronis, became the Greco-Roman god of medicine. Legend has it that the Centaur Chiron, who was famous for his wisdom and knowledge of medicine, taught Asclepius the art of healing. At length Zeus, the king of the gods, afraid that Asclepius might render all men immortal, slew him with a thunderbolt. Apollo slew the Cyclopes who had made the thunderbolt and was then forced by Zeus to serve Admetus.

Asclepius's cult began in Thessaly but spread to many parts of Greece. Because it was supposed that Asclepius effected cures of the sick in dreams, the practice of sleeping in his temples in Epidaurus in South Greece became common. This practice is often described as Asclepian incubation. In 293 BCE his cult spread to Rome, where he was worshiped as Aesculapius.

Asclepius was frequently represented standing, dressed in a long cloak, with bare breast; his usual attribute was a staff with a serpent coiled around it. This staff is the only true symbol of medicine. A similar but unrelated emblem, the caduceus, with its winged staff and intertwined serpents, is frequently used as a medical emblem but is without medical relevance since it represents the magic wand of Hermes, or Mercury, the messenger of the gods and the patron of trade. However, its similarity to the staff of Asclepius resulted in modern times in the adoption of the caduceus as a symbol of the physician and as the emblem of the U.S. Army Medical Corp.

The plant genus
Asclepias
, which contains various species of milkweed, was named for Asclepius. Many of these plants possess some degree of medicinal value.

(b.
c
. 460 BCE, island of Cos, Greece—d.
c
. 375 BCE, Larissa, Thessaly)

H
ippocrates was an ancient Greek physician who lived during Greece's Classical period and is traditionally regarded as the father of medicine. It is difficult to isolate the facts of Hippocrates' life from the later tales told about him or to assess his medicine accurately in the face of centuries of reverence for him as the ideal physician. About 60 medical writings have survived that bear his name, most of which were not written by him. He has been revered for his ethical standards in medical practice, mainly for the Hippocratic Oath, which, it is suspected, he did not write.

What is known is that while Hippocrates was alive, he was admired as a physician and teacher. In the
Protagoras
Plato called Hippocrates “the Asclepiad of Cos,” who taught students for fees. Further, he implied that Hippocrates was as well known as a physician as Polyclitus and Phidias were as sculptors. Plato also referenced Hippocrates in the
Phaedrus
, in which Hippocrates is referred to as a famous Asclepiad who had a philosophical approach to medicine.

Meno, a pupil of Aristotle, specifically stated in his history of medicine the views of Hippocrates on the causation of diseases, namely, that undigested residues were produced by unsuitable diet and that these residues excreted vapours, which passed into the body generally and produced
diseases. Aristotle said that Hippocrates was called “the Great Physician” but that he was small in stature.

Hippocrates appears to have traveled widely in Greece and Asia Minor practicing his art and teaching his pupils. He presumably taught at the medical school at Cos quite frequently. His reputation, and myths about his life and his family, began to grow in the Hellenistic period, about a century after his death. During this period, the Museum of Alexandria in Egypt collected for its library literary material from preceding periods in celebration of the past greatness of Greece. So far as it can be inferred, the medical works that remained from the Classical period (among the earliest prose writings in Greek) were assembled as a group and called the works of Hippocrates (
Corpus Hippocraticum
).

The virtues of the Hippocratic writings are many, and, although they are of varying lengths and literary quality, they are all simple and direct, earnest in their desire to help, and lacking in technical jargon and elaborate argument. The works show such different views and styles that they cannot be by one person, and some were clearly written in later periods. Yet all the works of the
Corpus
share basic assumptions about how the body works and what disease is, providing a sense of the substance and appeal of ancient Greek medicine as practiced by Hippocrates and other physicians of his era. Prominent among these attractive works are the
Epidemics
, which give annual records of weather and associated diseases, along with individual case histories and records of treatment, collected from cities in northern Greece. Diagnosis and prognosis are frequent subjects.

Other treatises explain how to set fractures and treat wounds, feed and comfort patients, and take care of the body to avoid illness. Treatises called
Diseases
deal with serious illnesses, proceeding from the head to the feet,
giving symptoms, prognoses, and treatments. There are works on diseases of women, childbirth, and pediatrics. Prescribed medications, other than foods and local salves, are generally purgatives to rid the body of the noxious substances thought to cause disease. Some works argue that medicine is indeed a science, with firm principles and methods, although explicit medical theory is very rare. The medicine depends on a mythology of how the body works and how its inner organs are connected. The myth is laboriously constructed from experience, but it must be remembered that there was neither systematic research nor dissection of human beings in Hippocrates' time. Hence, while much of the writing seems wise and correct, there are large areas where much is unknown.

Over the next four centuries, imaginative writings, some obviously fiction, were added to the original collection of Hippocratic works and enhanced Hippocrates' reputation, providing the basis for the traditional picture of Hippocrates as the father of medicine. Still other works were added to the Hippocratic
Corpus
between its first collection and its first scholarly edition around the beginning of the 2nd century CE. Among them were the Hippocratic Oath and other ethical writings that prescribe principles of behaviour for the physician.

The Hippocratic Oath dictates the obligations of the physician to students of medicine and the duties of pupil to teacher. In the oath, the physician pledges to prescribe only beneficial treatments, according to his abilities and judgment; to refrain from causing harm or hurt; and to live an exemplary personal and professional life. The text of the Hippocratic Oath (
c
. 400 BCE) provided below is a translation from Greek by Francis Adams (1849). It is
considered a classical version and differs from contemporary versions, which are reviewed and revised frequently to fit with changes in modern medical practice.

I swear by Apollo the physician, and Aesculapius, and Health, and All-heal, and all the gods and goddesses, that, according to my ability and judgment, I will keep this Oath and this stipulation—to reckon him who taught me this Art equally dear to me as my parents, to share my substance with him, and relieve his necessities if required; to look upon his offspring in the same footing as my own brothers, and to teach them this Art, if they shall wish to learn it, without fee or stipulation; and that by precept, lecture, and every other mode of instruction, I will impart a knowledge of the Art to my own sons, and those of my teachers, and to disciples bound by a stipulation and oath according to the law of medicine, but to none others. I will follow that system of regimen which, according to my ability and judgment, I consider for the benefit of my patients, and abstain from whatever is deleterious and mischievous. I will give no deadly medicine to any one if asked, nor suggest any such counsel; and in like manner I will not give to a woman a pessary to produce abortion. With purity and with holiness I will pass my life and practice my Art. I will not cut persons laboring under the stone, but will leave this to be done by men who are practitioners of this work. Into whatever houses I enter, I will go into them for the benefit of the sick, and will abstain from every voluntary act of mischief and corruption; and, further from the seduction of females or males, of freemen and slaves. Whatever, in connection with my professional practice or not, in connection with it, I see or hear, in the life of men, which ought not to be spoken of abroad, I will not divulge, as reckoning that all such should be kept secret. While I continue to keep this Oath unviolated, may it be granted to me to enjoy life and the practice of the art, respected by all men,
in all times! But should I trespass and violate this Oath, may the reverse be my lot!

Technical medical science developed in the Hellenistic period and after. Surgery, pharmacy, and anatomy advanced; physiology became the subject of serious speculation; and philosophic criticism improved the logic of medical theories. Competing schools in medicine (first Empiricism and later Rationalism) claimed Hippocrates as the origin and inspiration of their doctrines. For later physicians, Hippocrates stood as the inspirational source, and today Hippocrates still continues to represent the humane, ethical aspects of the medical profession.

(b. 384 BCE, Stagira, Chalcidice, Greece—d. 322 BCE, Chalcis, Euboea)

A
ristotle (Greek: Aristoteles) was an ancient Greek philosopher and scientist, and one of the greatest intellectual figures of Western history. He was the author of a philosophical and scientific system that became the framework and vehicle for both Christian Scholasticism and medieval Islamic philosophy. Aristotle's intellectual range was vast, covering most of the sciences and many of the arts, including biology, botany, chemistry, ethics, history, logic, metaphysics, rhetoric, philosophy of mind, philosophy of science, physics, poetics, political theory, psychology, and zoology. He was the founder of formal logic, devising for it a finished system that for centuries was regarded as the sum of the discipline. Aristotle also pioneered the study of zoology, both observational and theoretical, in which some of his work remained unsurpassed until the 19th century. His writings in metaphysics and the philosophy of science continue to be studied, and his work remains a powerful current in contemporary philosophical debate.

Aristotle divided the theoretical sciences into three groups: physics, mathematics, and theology. Physics as he understood it was equivalent to what would now be called “natural philosophy,” or the study of nature; in this sense it encompasses not only the modern field of physics but also biology, chemistry, geology, psychology, and even meteorology. Metaphysics, however, is notably absent from Aristotle's classification; indeed, he never uses the word, which first appears in the posthumous catalog of his writings as a name for the works listed after the
Physics
. He does, however, recognize the branch of philosophy now called metaphysics. He calls it “first philosophy” and defines it as the discipline that studies “being as being.”

Aristotle's contributions to the physical sciences are less impressive than his researches in the life sciences. In works such as
On Generation and Corruption
and
On the Heavens
, he presented a world-picture that included many features inherited from his pre-Socratic predecessors. From Empedocles (
c
. 490–430 BCE) he adopted the view that the universe is ultimately composed of different combinations of the four fundamental elements of earth, water, air, and fire. Each element is characterized by the possession of a unique pair of the four elementary qualities of heat, cold, wetness, and dryness: earth is cold and dry, water is cold and wet, air is hot and wet, and fire is hot and dry. Each element also has a natural place in an ordered cosmos, and each has an innate tendency to move toward this natural place. Thus, earthy solids naturally fall, while
fire, unless prevented, rises ever higher. Other motions of the elements are possible but are considered “violent.” (A relic of Aristotle's distinction is preserved in the modern-day contrast between natural and violent death.)