FoundationsThe main features of Greek medical thought were those of an ancient empirical lay medicine on the one hand and on the other the mathematical-astronomical knowledge of the Assyrian-Babylonians and the sanitary regulations of ancient Egypt and Judea. Under the stimulation of Greco-Italic philosophy and criticism, these disparate thoughts commingled and thus came the synthesis and foundation of what we know as Hippocratic Medicine. Greek medicine and philosophy was to endure five major migrations but remained, withal, a vital and progressive force that endured unbroken for some 800 years. In a sense, the Greeks picked up the gauntlet where it had been dropped a millennium before by the Egyptians. It began in the Ionian cities of Asia Minor in 600 BCE where it flourished until 530 BCE when they were subjugated by the Persians. When Athens eventually broke the back of the Persian occupation she became the home of the golden age of Greek culture -- the so-called Classical Period (480-330 BCE). However, as has so often happened throughout history, complacency and arrogance took its inevitable toll resulting in a gradual decline of Greek culture into decadence.
Thence came the boy general Alexander who created a vast empire during his brief lifetime, conquering Persia (and thereby acquiring Egypt) and ranging as far as the Indus Valley. He established the city of Alexandria in the Nile delta where it, a seaport and gateway city, became the center of scientific discovery and advancement -- flourishing for 300 years -- the Alexandrian Period (330-30 BCE). Upon the death of the last Greek ruler of Egypt, Cleopatra, Egypt became a Roman province and the mantel of Alexandrian tradition fell upon the shoulders of the Romans -- who were not equal to the task. Described as one of the most superstitious of cultures, the Greek medical tradition languished in its hands (the Greco-Roman Period, 30 BCE-200 AD). It was kept alive as a mere shadow of its former self in the eastern, Byzantine Empire, for a somewhat longer period and by a different culture entirely.
Thales of Miletus (639-544 BCE), regarded by Plato and Aristotle as the initiator of philosophy, was a merchant and traveler of some renown, journeying widely in both Egypt and Mesopotamia. He established the art and science of geometry, physics (physis -- a concept holding that there is a universal substance throughout the cosmos) and astronomy undoubtedly absorbing much of the knowledge available in the countries he visited.
During this time period, three different and important schools of thought arose -- Pythagorean, Eleatic, Asklepian.* Pythagoras (580-489 BCE) established his famous school in southern Italy. Devoted to the more esoteric considerations of mysticism and mathematics -- the actual physical world had little meaning or place. Theories were not supported by observation nor experimentation in this philosophy. From the Pythagorean school came the doctrine of the four humors as developed by Empedocles of Agrigentum (504-443 BCE)** and that of the three spirits as promulgated by Philolaus of Tarentum (480-400 BCE). Both of these theories were to dog, confuse, and befuddle medicine for centuries. The four humors (blood, yellow bile, black bile, and phlegm) were matched to the four elements (fire, air, water, earth) and the four sacred colors of the alchemists -- red, yellow, black, white.
The doctrine of the three spirits of man stated that the vegetative spirits, which were located at the navel, were shared with all things that grow. The animal spirits which gave rise to movement and sensation were located in the heart and were shared with all beasts. The rational spirit was situated in the brain and was possessed by man alone.
Alcmæon (500 BCE) of the Pythagorean School differed somewhat from the
rather bizarre thinking of those of his brethren. He considered the brain to
be the center of sensation as well as the seat of the soul. Interestingly,
he gave the first known description of the optic nerves connecting the eye
with the brain. Unfortunately this view was not maintained in classic times
-- not even among the disciples of Hippocrates -- wherein anatomical
structure was interpreted as subservient to function. Function itself was
dominated by the Pythagorean doctrine of the three spirits of man or of the
four humors as expounded by Hippocrates himself.
The Eleatic school exemplified by the teachings of Leucippus of Miletus (440 BCE) and by Democrites of Abdera (460-370 BCE) was more materialistic, describing everything in the universe in terms of atoms. It is to Democrites that we owe our first knowledge of the anatomy of the eye (Figure 1). He conceived of the ocular globe as a simple structure having two coats corresponding to the corneo-scleral and choroid-retinal layers containing a homogeneous humor connected, as Alcmæon had said, by a hollow tube to the brain.
Still, despite advances in other areas, one branch of medical practice continued the earlier Egyptian philosophy of the temple. That is, medicine was a function of the priesthood who in this case were those of the Greek God of Medicine -- Asclepios (Æsculapius) -- the pupil of the centaur Chiron. There was even then, however, the stirrings of a different and more rational philosophical approach amongst various groups. As is often the case, the most important difference of opinion arose amongst the most devout -- in this case the Asclepian priesthood itself.
It is said that certain of the priests of Asclepios, claiming direct
descent from the God and calling themselves the Asclepiadæ, dissociated
themselves from the worship of the temple and began to apply objective
methods to their practice. With them began the gradual liberation of Greek
medicine from superstition, and for the first time the physician became a
naturalist. The greatest of this school was Hippocrates of Cos (460-375 BCE,
Figure 2) who flourished in that incredible period of Athens' history which
included such luminaries as Pericles, Thucydides, Plato and Socrates who
were teaching a new science of philosophy and ethics. Sir Duke-Elder
described it as: "A time when Sophocles and Euripedes were writing
plays that still live today, and Pheidias and Praxiteles were carving forms
from marble of a grace so divine that it was small wonder that men fell down
and worshipped them as gods."
However, this version of the beginning of modern medicine does not square with history. Cos, a Greek island near Rhodes off the southwestern coast of Asia Minor, was, by 500 BCE, already famous for the quality of its medicine and physicians. The cult of Asklepiad lay healers had established themselves there around 600 BCE and are mentioned in the Iliad of Homer.*** Hippocrates was a son of one of these and was therefore closely associated with its hereditary guild or family. All the literature of the period shows that these physicians (iatros) were not dependent upon a sanctuary nor did they ascribe cures to godly miracles. It is likely that many of the priesthood of Asclepios did indeed divest themselves of theological restrictions and thought and take on the practice of the lay healers. But a priest Hippocrates was not -- nor is there any allusion to the priesthood within the Hippocratic Corpus.
Few names are held in higher honor than that of Hippocrates. Indeed his name is invested with a halo not unlike that of certain other great characters, such as Pythagoras and Socrates -- he has sometimes been invoked as if he were a saint. In fact, in the Middle Ages, he was actually grouped with the Christian saints of healing -- Cosmas and Damian. There is little that is known about him, yet the world has good reason to cherish his name. The testimony of Plato and Aristotle to his greatnmess should suffice to justify the honor paid to the "Father of Medicine".
Under his influence the shackles of mysticism which had bound medicine for so long were at last cast off. With Hippocrates medicine entered the age of reason based upon observation and for the first time it acknowledged the unknown. By dint of careful, painstaking observation and inquiry the physician became a servant of nature -- a doctor instead of a sorcerer. That is not to say that all of the writings of Hippocrates were pragmatic and without error. On the contrary, his medicine was entangled in various theories including that of the "humors", yet unlike Galen who came after, he accepted areas of uncertainty as inevitable and didn't "fill in" with teleological drivel.
Hippocrates insisted upon rigorous attention to details and urged the physician to apply himself diligently to his art saying: "Life is short and the art long; the occasion fleeting; experience fallacious, and judgment difficult." His famous oath expressed the clear necessity of an ethical attitude. "Thou shalt do no harm" has been the mainstay of the medical credo since that time. His suggestions for the proper preparation for performing surgery are also enlightening:
"The surgeon may sit or stand, but he should always be in an appropriate position in regard to his own body, to the position of the patient and to the illumination.We have two kinds of illumination, a natural one and an artificial one. The natural one cannot be controlled, but the artificial one can to a certain extent be regulated."
"Both types of illumination can be used in two different ways: Either the light comes directly from in front or it comes from the side. The oblique illumination is used only rarely and its disadvantages are obvious. With direct light, so far as available and beneficial, turn the part operated upon upwards toward the brightest light -- except such parts as should be unexposed and are indecent to look at -- thus while the part operated upon faces the light, the surgeon faces the part, but not so as to overshadow it."
"As far as the position of the surgeon's body is concerned, he should, if he is sitting, have his legs below the knees pointing vertically downward. They should not be separated too far from each other and the knees should be somewhat elevated.† He should sit at a certain distance from the patient to rest his elbows comfortably on his thighs or hold them next to his body ..."
"If the surgeon is standing, then he can use both feet equally if he just puts on a bandage, but when he operates he should put one foot on the footrest. This foot should correspond to the side of the non-operating hand."
"The nails should not protrude too much nor should the finger tips be too bare ..."
"The assistants will ... keep silent and obey their superior."
"Each maneuver should be practiced with each hand and then with both hands simultaneously (because they resemble each other) and the procedure should be pursued well and beautifully, rapidly and without effort, elegantly and without difficulties."††
All of the "writings" of Hippocrates were compiled and edited in Alexandria about 300 BCE under the supervision of Ptolemy the First, and few can actually be attributed to the master himself. Little if any anatomical descriptions are included both because the thrust of the writings is observational and also non-specific, relating mostly to an excess or lack of the four "humors". Anatomical dissection was impossible in Hippocrates' time at any rate because of the Greeks abiding reverence for the body and their insistence upon proper burial so that the dead would rest and let the living alone. This situation did not change until Plato's concept of the soul being separate from the body gained wider acceptance. It was not until the time of Aristotle that the dissection of a cadaver became morally possible. A similar situation existed in England in the 1700's and for similar reasons.
Plato compares Hippocrates with the wisest men of his time and also with
the greatest artists, like Pheidias and Praxiteles. Even today, the existing
remnants of his medical books are to be admired; however, operations on the
eye are not mentioned in the authentic books by Hippocrates. Even in the
attributed works only a few ocular procedures are noted. This is in contrast
to the many other operations described. This, of course, does not mean that
they were completely unknown. It is, however, quite certain that the
cataract operation was unknown to the School of Hippocrates as it was to the
In the second book of Hippocrates "Prognoses",
the opacification of the pupil is described only as a bad event, but not as
a curable disease. The Hippocratic books do not mention errors of refraction
either. Of course, as usual, we cannot make any definite deductions from
this obvious omission.
It is possible that these conditions were not even regarded as part of medicine during antiquity. Even Celsus who lived nearly 500 years after Hippocrates and who wrote the first complete treatise on ocular diseases does not mention refractive errors at all. On the other hand, several scholars who were practically contemporaries of Celsus, such as Seneca and Plutarch, as well as the poet Lucretius, discuss presbyopia and accommodation for near. Knowledge of ocular anatomy was somewhat more advanced than that of Democrites (Figure 3).
It does not seem likely that the school of Hippocrates avoided any surgical procedure on the lens because this was thought to be the seat of vision and therefore somehow sacred or inviolate -- they did describe the draining of hypopyon after all. Galen (that champion of teleology), who was of the opinion that the lens is the main organ for visual perception, did not hesitate to couch a cataract, but then he did not believe that a cataract was actually a disease of the lens either. At the time of Hippocrates no Greek physician was apparently aware of the fact that the well known gray opacification of the pupil which causes blindness could be cured by an operation. This operation was certainly neither invented by Greek surgeons, nor by Egyptian physicians with whom the Greeks had considerable intercourse. It is more likely that Indian physicians first practiced this operation, and the ancient Greeks, before the time of Alexander, knew even less about the Indians than we knew about the Chinese before Marco Polo.
Only four ophthalmic operations are mentioned in the Hippocratic books:
Occasionally the removal of an arrowhead from the lid is mentioned and incisions into the skin of the head as well as cranial trephinations are occasionally recommended for the treatment of eye diseases.
The Alexandrian School
The great medical school of Alexandria was founded about 300 BCE. By the time the great libraries of Alexandria and Pergamon were established, a remarkable change had taken place. Descriptive anatomy had been born as a science and student physicians began dissecting bodies as part of their training. The Alexandrian physicians revised and rewrote the entire field of science in which we are interested: physics and especially optics, even the fundamental facts of a kind of empirical chemistry (as it was necessary for the explanation of a systemic pharmacology), anatomy, physiology, pathology, therapy and surgery.
It was well, though, that this center was established in Egypt because by that time Greece had become wracked with wars and civil unrest -- not the best atmosphere to promote such pursuits. Too, in that place, the proximity to the ancient knowledge of Egypt and Mesopotamia encouraged renewed study of the old science, but the Greeks brought the ideas and the art. The true achievements came about only by close interaction with the ancient culture and civilization of the so-called barbarians; there was even intercourse with India. This kind of interaction is practically unique in the history of the world. However, we do not know exactly how this occurred and we shall perhaps never know it.
The school could not have prospered so well had it not been for the Great Library. Comprising at its peak, in 47 BCE, of some 700,000 volumes, it was maintained by (as Majno so aptly put it): "bibliomaniacs in the homeland of the papyrus, (who) bought, copied, or pirated all the literature available". Travelers were required to surrender their books on arrival. These were then copied, the original placed in the library and the cheap copy given the owner.††† Without this fever of literary eclecticism, much of the ancient knowledge would have been forever lost.
Under the reign of the Ptolemies the school flourished and for the first time an effort was made to subsidize and organize science through government grants. The Ptolemies established four great schools or museums: letters, mathematics, astronomy and medicine. Of the four schools the faculty of medicine was the largest by far yet its contributions were less than those in the other faculties taught by Euclid, Archimedes and Hero.
The School of Alexandria and its successors developed the anatomy of the eye under the leadership of the great anatomist Herophilus of Chalcedon (344-280 BCE) who was an avid exponent of the importance of the brain and was the first to understand the nature and significance of nerves. More importantly, from the standpoint of ophthalmology, he wrote a treatise on the anatomy of the eye, describing the uvea with the ciliary processes and coining the term -- retina. He also conducted dissections of the human body -- in public, out of doors.§ Erasistratos of Chios (309-260 BCE)§§ ascribed to the brain more of its true nature and traced the larger nerves in the body to that organ. He also explained the superior intelligence of man as being due to the complexity of the cerebral convolutions. He also turned away from the teachings of Hippocrates and proposed the theory that the body was made up of atoms requiring pneuma to be activated. His medical methods were also more moderate and Methodistic. Followers of Herophilus and Erasistratos became embroiled in an acrimonious debate for centuries. Galen considered himself a part of the tradition of Hippocrates as manifested through Herophilos with his emphasis on humoral doctrine and anatomy -- he reviled Erasistratos because of his disagreement with the humoral concept. Thus the teachers propounded, the followers disputed, the practioners wrangled and the patients hoped.§§§
This knowledge of anatomy provided the Alexandrian physicians a basis for the understanding and treatment of ocular diseases. It is therefore not surprising that later Greek authors, like Oribasius, Ætius and Theophilus copied or excerpted these anatomical findings. Nothing better was produced by the Arabs, their followers or the physicians of the Renaissance.
The Alexandrian school gave a very detailed description of couching of the opaque lens. The degree of sophistication in the method shows it to have been highly evolved at the time of its description. None of this usage or practice came into being overnight -- much of what was known could not have evolved very rapidly but seems to have been handed down (and perhaps added to) over a considerable period of time. It is therefore unlikely that it was developed by the Alexandrians but was imported. How this came about is unknown and may never be known, because not a single one of the original Alexandrian books has been preserved into our times. We do not even have reports from contemporaries, but only some casual remarks by later authors such as Galen and Celsus. The loss of this written treasure is one of the great tragedies of the human experience and set the stage for the strange and bizarre notions which settled around medicine in later years and which prevailed in one form or another into the 19th century.
As to vision itself, the emanation hypothesis of vision -- propounded by Pythagoras -- held sway. Accepted in one form or another with its many obscurities by such philosophers as Epicuros (341-270 BCE), Euclid (3rd century BCE), Hipparchos (2nd century BCE), and eventually by Ptolemy (2nd century AD) in Alexandria, and propagated to Arabic and thence to western medicine by the writings of Galen (AD 130-200) -- it claimed that vision was accomplished by the emission of a subtle "visual spirit" or "pneuma". This originated in the brain, the center of sensation and the seat of the ruling soul (probably located in the ventricles), circulated constantly through the hollow optic nerves (which were considered to be extensions of the brain itself) into the eye, and filled the crystalline lens from which it emanated in linear rays resembling sunlight (in the form of a cone) into space. In this view the lens was the essential organ of vision, and the retina, a thinned expansion of the optic nerve, acted as a guide to enable the visual spirit to reach this vital organ and with its blood vessels also served as a means of nourishment to the vitreous and thus to the lens.
The alternative and rival view of Democrites (5th century BCE), accepted and elaborated by Aristotle, that light was an activity of an external ethereal substance originating from luminous or illuminated bodies was largely ignored, although an attempt was made by Plato (429-327 BCE) to combine the two opposing views in his somewhat vague concept that the rays of "inner light" emanating from the eye united with the rays of "outer light" emitted by the luminous object to accomplish the visual act. In this theory, if the corpuscles of inner light were sufficiently large to split up the outer light, the eye saw black; if they were small enough to be split up themselves, the eye saw white; colors emerged by different reactions of the two streams, and dazzling when the process of splitting occurred close to the eye. In either case vision centered upon the lens which acted as the essential organ of photoreception, a function conferred upon it by the circulating visual spirits.
Regardless that they may have differed in their opinions as to the nature of vision, the Alexandrian scholars seem to have agreed that light traveled in a straight line and at high speed. The major part of their knowledge of optics, however, concerned itself with catoptrics -- the optics of mirrors or reflection.‡ It will suffice at present to say that the ancient scholars were hampered in their understanding of optics by their almost complete misunderstanding of vision and refraction.
** Likely refined from the Egyptian concept of whdw.
*** The men of Tricca and Ithome's hills