ALEXANDRIAN SCIENCE AND MEDICINE

12 May

In the ancient world, Alexandria,  the city in Egypt named for Alexander the Great  (356–323 B.C.E.), represented  wealth and stability,  a fusion of the ancient lore of Egypt and the most dynamic elements of Greek civi- lization.  Among  the greatest  treasures  of the city were its museum and library. The scholars who worked at the museum and library, under the sponsorship   of  the  rulers  of  Alexandria,   participated in  an  unprec- edented intellectual experiment. According to some estimates, the Alexandrian  library contained  more than 700,000 scrolls. The librarians collected, confiscated,  copied, and edited many manuscripts, including the  texts  now  known  as the  Hippocratic collection.  In  discussing  the authenticity of various  works  in the  Hippocratic collection,  Galen  of Pergamum   claimed  that   the  rulers  of  Alexandria   were  so  eager  to enhance  the  library  that  they  confiscated  all  books  found  on  ships entering the harbor. Galen warned that many forgeries had been created to satisfy the Alexandrian  passion for book collecting. The magnificent facilities of the museum are said to have included zoological and botan- ical gardens,  lecture  halls,  and  rooms  for  research  and  teaching.  To encourage the exchange of ideas, the scholars took their meals together in the great hall of the museum; the meals were free and the salary of the professors  was tax exempt.  Unfortunately, no contemporary accounts of the famous  museum  have survived and the evidence concerning  the medical research conducted  at the museum is ambiguous.

Many  sciences flourished  at  Alexandria,   although   research  was primarily  oriented  towards  fields with  practical  applications, such  as medicine and  engineering.  Medical  experts were expected to supervise city and army sanitation and train  military doctors.  Most  importantly, for a brief and rare interval,  the practice  of human  dissection  was not only tolerated,  but actively encouraged.  Perhaps  the Egyptian  tradition of cutting  open  the body  and  removing  certain  organs  as part  of the embalming  ritual  helped  overcome  traditional Greek  antipathy to the mutilation of  corpses.  Alexandrian   scientists  helped  establish  two  of the major  themes of Western  medical theory:  first, that  systematic  dis- section  provides  essential  information about  structure   and  function; second, that  this knowledge is valuable  in and  of itself, even if it pro- vides little or nothing  of immediate  practical  value to clinical medicine, patient  care, or public health.

Alexander  the great

Alexander  the great  and his physicians. As he died, Alexander  allegedly said, ‘‘I am dying with the help of too many physicians.’’ For   medical  science,  the  Hellenistic  period   (roughly   the  time between the death  of Alexander  to about  30 B.C.E.,  when the Romans annexed  Egypt)  is most  notable  for  the  work  of its most  famous,  or infamous,  anatomists—Herophilus (ca. 330/320–260/250 B.C.E.) and Erasistratus (ca.  310–250 B.C.E.).  Unfortunately, so  little  direct  infor- mation about the Alexandrian era has been preserved that the exact relationship between these anatomists and the city of Alexandria remains obscure.  Historians agree that  both  Herophilus and  Erasistratus  were skillful anatomists who  eagerly exploited  the  opportunity to  conduct studies of human  bodies, but it is not clear whether  anatomists of this era performed  some of their studies on living human  beings or confined themselves  to  postmortems. Anatomists might  also  have  used  their patients and students as experimental  subjects for less invasive research. When Christian theologians such as Tertullian and St. Augustine wanted evidence of the heinous acts committed  by the pagans,  they pointed  to the  notorious Herophilus and  accused  him  of  torturing six hundred human beings to death. The Roman encyclopedist Celsus charged Herophilus and Erasistratus with performing  vivisection on condemned criminals  awarded  to  them  by  the  rulers  of  Alexandria.  While  these accusers were obviously not eyewitnesses, some historians  have accepted their allegations; others remain skeptical.

The  extent  or  even the  existence of the  practice  of human  vivi- section  during  the Alexandrian  era  remains  controversial because  the writings of Herophilus and Erasistratus have not survived and are known only through  the diatribes of their enemies. Accusations  made hundreds of years later cannot  be taken as definitive proof, but there is no partic- ular reason to believe that the authorities  would have prohibited human vivisection, especially if the victims were criminals or prisoners  of war. Certainly,  the  well-documented  atrocities  committed  in the  twentieth century suggest that there is no limit to the human  capacity for deprav- ity,  whether  individual  or  state-sponsored. Nor  have  the  events  that marked the beginning of the new millennium challenged such pessimistic conclusions. Even though conditions during the Hellenistic era made systematic anatomical research possible, human  dissection was still offensive  to  prevailing  sentiments,   evoked  superstitious  dread,   and created an evil reputation for Herophilus and Erasistratus.

Herophilus, Erasistratus,  and  their  colleagues  were  engaged  in constructing  an  entirely  new science of human  beings rather  than  an abstract   philosophical   system.  The  argument  that  Herophilus  would not  have made certain  errors  if he had done vivisections fails to allow for  the influence  of pre-existing  concepts  on perception  and  interpre- tation, and the intrinsic difficulty of innovative anatomical studies. Whatever  conditions  made  the  work  of  Herophilus and  Erasistratus possible did not last long. Human  dissection was probably  discontinued by  the  end  of  the  second  century  B.C.E.,  but  Alexandrian   anatomists probably  continued  to use human  skeletons  for research  and  teaching even after they were forced to confine dissection and vivisection to other animal species.

In his investigation  of the circulatory  system, Herophilus noted the difference between the arteries, with their strong pulsating walls, and the veins, with their relatively weak walls. Contrary to the prevailing assumption that  the  veins carried  blood  and  the  arteries  carried  air, Herophilus stated  that  both  kinds  of vessels carried  blood.  Intrigued by  changes   in  the  pulse  that   correlated   with  health   and   disease, Herophilus tried to measure  the beat  of the pulse using a water  clock that  had been developed in Alexandria.

Apparently known  as a chronic  skeptic,  Herophilus regarded  all physiological and pathological  theories as hypothetical  and provisional, including  Hippocratic humoralism. While he probably  did not  totally reject humoral  pathology,  he seems to have preferred  a theory  of four life-guiding  faculties  that  governed  the  body:  a nourishing  faculty  in the liver and digestive organs, a warming power in the heart, a sensitive or perceptive faculty in the nerves, and a rational  force in the brain.  In clinical practice,  Herophilus seems to have favored  more  active inter- vention than  that  recommended  by Hippocrates and he may have used the concept  of hot–cold,  moist–dry  qualities  as a guide to therapeutic decisions. Vigorous bloodletting  and a system of complex pharmaceuti- cals became  associated  with Herophilean medicine,  but  the anatomist appears  to have urged his students to familiarize themselves with dietet- ics, medicine, surgery, and obstetrics.

Little is known about  Herophilus, except that he probably  studied with the physician Praxagoras of Cos, and was said to be the author of more than fifty books, including On Anatomy, On the Eyes, and a hand- book  for  midwives, but  only a few excerpts  of his writings  have  sur- vived. There  is no  direct  evidence that  Herophilus was a member  of the  faculty  of  the  Alexandrian   museum,  or  that  he  ever carried  out any human  vivisections or dissections at that  institution. Nevertheless, his access to human  cadavers,  and  perhaps  live prisoners,  was said to be the result of governmental  support.

As a result of his extensive studies of the nervous system, including the connection  between the brain,  spinal cord  and  nerves, Herophilus rejected Aristotle’s claim that  the heart  was the most important organ of the  body  and  the  seat  of intelligence.  Herophilus argued  that  the brain was the center of the nervous system. He also described the diges- tive system, called attention to the variability  in the shape of the liver, and differentiated between tendons  and nerves.

For   Herophilus,  health  was  the  greatest  good.  The  aphorism, ‘‘Wisdom and art, strength  and wealth, all are useless without  health,’’ is attributed to  him.  He  is also  credited  with  the  saying:  ‘‘The best physician  is the one who is able to differentiate  the possible from  the impossible.’’ He urged physicians to be familiar with dietetics, gymnastics, drugs,  surgery,  and  obstetrics.   As  practitioners,  his  followers  were known   to  favor  bleeding  and  the  aggressive  use  of  complex  drug mixtures.

According  to  a  story  often  dismissed  as  a  myth,  an  Athenian woman   named   Agnodice   was  one  of  the  students   affiliated   with Herophilus. Distressed  by the  suffering  of women  who  would  rather die than  be examined  by a male physician,  Agnodice  disguised herself as a man  in order  to  study  medicine.  Agnodice  won the gratitude  of her female patients,  but  when her subterfuge  was discovered,  she was prosecuted   for  violating  laws  that  prohibited women  from  studying medicine. Her loyal patients  are said to have warned her male prosecu- tors  that  they  would  be  seen as  the  cruel  enemies  of  womankind if they condemned  to death their only female physician. Agnodice’s story has been used for hundreds  of years to rally support  for the education of  medical  women.  Indeed,  in writing  about  the  diseases  of  women, Hippocrates had  pointed  to  the  problem  epitomized  in  the  story  of Agnodice.  Women  were often  so  reluctant  to  discuss  their  problems with male physicians that  simple illnesses became incurable.

When scholars of the Renaissance  sought  to challenge the stifling authority of the ancients,  especially that  of Galen,  the long neglected and much vilified Herophilus was lauded as the ‘‘Vesalius of antiquity.’’ The title could also have applied to Erasistratus, another  intriguing and rather  shadowy figure, who was attacked  by Galen for the unforgivable heresy of rejecting the Hippocratic philosophy  of medicine. Galen wrote two books  against  Erasistratus and criticized his ideas whenever possi- ble. Galen  claimed that  Erasistratus and  Herophilus were contempor- aries, but Erasistratus may have been at least thirty years younger than Herophilus. According to one biographical  tradition, when Erasistratus diagnosed  his own illness as an incurable  cancer he committed  suicide rather  than  suffer inexorable  decline.

Like Hippocrates, Erasistratus was born into a medical family. Little is known about his life, other than his decision to give up medical practice to devote himself to the study of anatomy  and physiology. In a fragment preserved by Galen, Erasistratus spoke of the joys of research and how it made  the  investigator  ready  to  devote  day  and  night  to  solving every aspect  of a scientific problem.  Ancient  sources  credit  Erasistratus with over fifty books, including specialized texts on fevers, bloodletting, paral- ysis, drugs, poisons,  and dietetics. Erasistratus may have carried  out  his research at the court of Antiochus  in Seleucia, rather  than at Alexandria, but  the research  interests  of Herophilus  and  Erasistratus were strikingly similar.  There  is, however,  some indication  that  Erasistratus was more interested  in the remote  and  obscure  causes of disease than  Herophilus. Galen  accused  Erasistratus of  rejecting  the  Hippocratic philosophy  of medicine  and  following  the  teachings   of  Aristotle.   Like  Herophilus, Erasistratus  probably   tried   to   replace   humoral   theory   with  a  new doctrine.  In the case of Erasistratus, this seems to have developed  into a  pathology   of  solids  that  perhaps  did  more  to  guide  his  anatomical research than  his approach to therapeutics.

Erasistratus is said to have been a gifted practitioner who rejected the idea that  a general  knowledge  of the body  and  its functioning  in health  was necessary  to  the  practicing  physician.  Many  problems,  he argued, could be prevented or treated with simple remedies and hygienic living. Nevertheless,  he believed in studying pathological  anatomy  as a key to localized causes of disease. He was particularly interested  in the possibility that  disease and  inflammation were caused by the accumu- lation  of a localized plethora  of blood  that  forced blood  to pass from the veins into the arteries. Skeptical of many standard therapeutic meth- ods and  Hippocratic humorology, Erasistratus invoked  a mechanical, localized concept  of physiological  and  pathological  phenomena based on the atomic theory of Democritus. Like the founder of atomic theory, Erasistratus was apparently willing to speculate about  the existence of unseen entities. Having traced the veins, arteries, and nerves to the finest subdivisions  visible to  the  naked  eye, Erasistratus postulated further ramifications beyond  the  limits  of  vision.  The  invisible fabric  of  the body,  according  to Erasistratus, was made  up of a threefold  network composed  of  veins,  arteries,  and  nerves.  To  complete  his  picture  of the  fine structure  of the  body,  Erasistratus proposed  the  existence of parenchyma (material  poured  in between the network  of vessels).

Perhaps  because of his theory  that  disease was caused by a local excess of  blood,  Erasistratus paid  particular attention  to  the  heart, veins, and  arteries.  In his lost treatises,  he apparently gave a detailed description  of the heart, including the semilunar, tricuspid, and bicuspid valves. Mechanical analogies, dissections, and perhaps vivisection experiments  suggested  to  Erasistratus that  the heart  could  be seen as a pump in which certain ‘‘membranes’’ served as the flap valves. Using a combination of logic, intuition,  and imagination, Erasistratus traced the veins, arteries,  and  nerves to  the finest subdivisions  visible to  the naked  eye and speculated  about  further  subdivisions  beyond  the limits of vision. He also gave a detailed description  of the liver and gallblad- der, and  initiated  a study  of the lacteals that  was not  improved  upon until the work of Gasparo Aselli (1581–1626).

Erasistratus accepted  the traditional idea that  the function  of the arteries  was to carry pneuma (air) rather  than  blood.  The veins, which supposedly  arose  from  the liver, and  the arteries,  which were thought to arise from the heart,  were generally thought of as independent  sys- tems of dead-end canals through  which blood and pneuma seeped slowly to the periphery  of the body so that  each part  of the body could draw out  its  proper   nourishment.  He  realized,  however,  that   anatomists had to account for the fact that blood, which was supposed to be carried by the  veins, spurted  out  of torn  arteries.  In  order  to  rationalize  the inconsistencies  in  this  system,  Erasistratus argued  that  although   the veins and arteries  were functionally  separate  in healthy,  intact  individ- uals,  there  were  tiny  collapsed  or  closed  connections   between  the two  kinds  of vessels. When  an  artery  was damaged,  air  escaped  and venous  blood  was forced  through  the  connections  between  the  veins and arteries, because—as Aristotle  taught—nature abhorred a vacuum. In other words, the presence of blood in the arteries was the result of an injury or some other  pathological  condition.  Observations of engorged veins and  collapsed  arteries  in the  cadaver  would  appear  to  support these ideas.

Erasistratus concluded that disease was due to plethora, that is, an excess of blood  from  undigested  foods  that  tended  to become putrid. When  local  excesses of blood  accumulated in the  veins, the  overbur- dened vessels were damaged  and blood spilled over from the veins into the  arteries.  When  this  occurred,  the  flow of pneuma,  or  vital  spirit, which  was  supposed   to   be  distributed   by  the  arteries,   would   be obstructed. Given  this  theoretical  framework,  the  logical objective  of therapy  was to diminish the plethora  of blood.  One way to accomplish this was to interrupt the production of blood  at its point  of origin by eliminating  the supply  of food.  In addition  to emetics, diuretics,  mas- sage, hot baths, and general starvation, Erasistratus ingeniously induced a form of ‘‘local starvation’’ by tying tight bandages around the limbs to trap blood in the extremities until the diseased part of the body had used up its plethora.  The use of the ligature  to stop the flow of blood  from torn  vessels was also ascribed to Erasistratus.

Although  Erasistratus was sometimes called a materialist,  atomist, or rationalist, he did not reject the concept of animating  spirits. Appar- ently  he  believed  that   life  processes  were  dependent   on  blood  and pneuma,  which was constantly  replenished by respiration. Two kinds of pneuma  were found  in the body:  the vital pneuma  was carried  in the arteries  and  regulated  vegetative  processes.  Some of the vital pneuma got  to  the  brain  and  was changed  into  animal  spirits.  Animal  spirits were responsible  for movement  and sensation  and were carried  by the nerves, a system of hollow tubes. When animal spirits rushed into mus- cles, they caused distension that resulted in shortening of the muscle and thus  movement.   Perhaps   inspired  by  the  experimental   approach  of Strato  (one of Aristotle’s favorite students),  Erasistratus is said to have attempted to provide quantitative solutions  for physiological problems. In one experiment, Erasistratus put a bird into a pot and kept a record of the  weight of the  bird  and  its excrement.  He  found  a progressive weight  loss  between  feedings,  which  led  him  to  conclude  that  some invisible emanation was lost by vital processes.

A story concerning  Erasistratus as a medical practitioner demon-strates  his  powers  of  observation  and  insight  into  the  relationship between afflictions of mind and body. When Seleucus, one of Alexander’s generals, married  a woman named Stratonice, his son Antiochus  fell in love with  his stepmother. Desperately  trying  to  hide  his feelings, the young  man  fell ill and  seemed  close to  death.  Many  physicians  had failed to help him when Erasistratus determined that an affliction of the mind had weakened the body through  sympathetic  relationships. While carefully  assessing  his  patient’s  physiological  reactions  to  the  people who visited him, Erasistratus discovered the stammering,  blushing, pal- pitations,  and pallor that followed each visit by Stratonice. Erasistratus reasoned  that  although  we can consciously conceal our thoughts,  their influence on the body cannot  be controlled.  This story was retold many times for its literary merit, but the medical insights were largely ignored. Similar incidents  appear  in the biographies  of other  great  physicians, including  Galen  and  Avicenna,  and  were often  cited  in the  extensive medieval and Renaissance  literature  concerning love-sickness.

For  two  hundred  years,  the  museum  of Alexandria  supported a high level of creativity in science, technology, and medicine, and trained numerous  physicians, engineers, geographers,  astronomers, and mathe- maticians. Although  it is difficult to assess the vitality of such a complex institution, there is some evidence that medical science was already slip- ping into a state of decline during the time of Herophilus and Erasistratus. The tension  that  always exists in medicine between disinterested  scien- tific research  and  the immediate  needs of the sick grew and  disrupted the ancient  search for harmony  and  balance  between the scientist and the  healer.  Critics  of anatomical research  charged  that  such  pursuits distracted physicians from caring for patients. Much of the deterioration of scientific research  at Alexandria  can be blamed  on the tumultuous political  climate,  but  scientists and  scholars  seem to have been under- mining the structural supports  of their own houses of learning by attack- ing rival  schools  of thought,  or  by leaving Alexandria  to  established new schools  elsewhere. Later  writers  satirized  the museum  as a place where large numbers of scholars were kept like birds in a henhouse, end- lessly squawking  and bickering. Finally, the worst of fates fell upon the Alexandrian  scientists; they were persecuted,  their grants  were cut off, and they had to turn to teaching to eke out a living in new places.

The decline of the Alexandrian  tradition was not limited to medi- cal science. Little  of the work  of the museum  or library  has survived. The  first  major  episode  in the  destruction of the  library  occurred  in 48 B.C.E.   during  the  riots  sparked  by the  arrival  of Julius  Caesar  and some three thousand legionnaires. After Caesar conquered  Egypt, Alexandria  was reduced to the status  of a provincial  town in the great Roman   Empire.  Later,  Christian  leaders  encouraged   the  destruction of the Temple of Muses and other pagan institutions. According to tra- dition, in 395, the last scholar at the museum, a female philosopher  and mathematician named  Hypatia, was  dragged  out  of  the  museum  by Christian  mobs and beaten to death. The Muslim conquest of the city in the  seventh  century  (642–646) resulted  in the  final  destruction of the library  and the loss of its precious  manuscripts.

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