Under　his　successors；　particularly　the　third　Ptolemy；　the　museum　developed；　more　especially　the　library；　which　contained　more　than　half　a　million　volumes。　The　teachers　were　drawn　from　all　centres；　and　the　names　of　the　great　Alexandrians　are　among　the　most　famous　in　the　history　of　human　knowledge；　including　such　men　as　Archimedes；　Euclid；　Strabo　and　Ptolemy。
  In　mechanics　and　physics；　astronomy；　mathematics　and　optics；　the　work　of　the　Alexandrians　constitutes　the　basis　of　a　large　part　of　our　modern　knowledge。　The　school…boy　of　todayor　at　any　rate　of　my　daystudies　the　identical　problems　that　were　set　by　Euclid　300　B。C。；　and　the　student　of　physics　still　turns　to　Archimedes　and　Heron；　and　the　astronomer　to　Eratosthenes　and　Hipparchus。　　To　those　of　you　who　wish　to　get　a　brief　review　of　the　state　of
  science　in　the　Alexandrian　School　I　would　recommend　the　chapter　in　Vol。　I　of　Dannemann's　history。＇31＇
  ＇31＇　Friedrich　Dannemann：　Grundriss　einer　Geschichte　der　Naturwissenschaften；　Vol。　I；　3d　ed。；　Leipzig；　1908。
  Of　special　interest　to　us　in　Alexandria　is　the　growth　of　the　first　great　medical　school　of　antiquity。　　Could　we　have　visited　the　famous　museum　about　300　B。C。；　we　should　have　found　a　medical　school　in　full　operation；　with　extensive　laboratories；　libraries　and　clinics。　Here　for　the　first　time　the　study　of　the　structure　of　the　human　body　reached　its　full　development；　till　then　barred　everywhere　by　religious　prejudice；　but　full　permission　was　given　by　the　Ptolemies　to　perform　human　dissection　and；　if　we　may　credit　some　authors；　even　vivisection。　The　original　writings　of　the　chief　men　of　this　school　have　not　been　preserved；　but　there　is　a　possibility　that　any　day　a　papyrus　maybe　found　which　will　supplement　the　scrappy　and　imperfect　knowledge　afforded　us　by　Pliny；　Celsus　and　Galen。　　The　two　most　distinguished　names　are　Herophiluswho；　Pliny　says；　has　the　honor　of　being　the　first　physician　〃who　searched　into　the　causes　of　disease〃　and　Erasistratus。
  Herophilus；　ille　anatomicorum　coryphaeus；　as　Vesalius　calls　him；　was　a　pupil　of　Praxagoras；　and　his　name　is　still　in　everyday　use　by　medical　students；　attached　to　the　torcular　Herophili。　Anatomy　practically　dates　from　these　Alexandrines；　who　described　the　valves　of　the　heart；the　duodenum；　and　many　of　the　important　parts　of　the　brain；　they　recognized　the　true　significance　of　the　nerves　（which　before　their　day　had　been　confounded　with　the　tendons）；　distinguished　between　motor　and　sensory　nerves；　and　regarded　the　brain　as　the　seat　of　the　perceptive　faculties　and　voluntary　action。　Herophilus　counted　the　pulse；　using　the　water…clock　for　the　purpose；　and　made　many　subtle　analyses　of　its　rate　and　rhythm；　and；　influenced　by　the　musical　theories　of　the　period；　he　built　up　a　rhythmical　pulse　lore　which　continued　in　medicine　until　recent　times。　　He　was　a　skilful　practitioner　and　to　him　is　ascribed　the　statement　that　drugs　are　the　hands　of　the　gods。　There　is　a　very　modern　flavor　to　his　oft…quoted　expression　that　the　best　physician　was　the　man　who　was　able　to　distinguish　between　the　possible　and　the　impossible。
  Erasistratus　elaborated　the　view　of　the　pneuma；　one　form　of　which　he　believed　came　from　the　inspired　air；　and　passed　to　the　left　side　of　the　heart　and　to　the　arteries　of　the　body。　It　was　the　cause　of　the　heart…beat　and　the　source　of　the　innate　heat　of　the　body；　and　it　maintained　the　processes　of　digestion　and　nutrition。　This　was　the　vital　spirit；　the　animal　spirit　was　elaborated　in　the　brain；　chiefly　in　the　ventricles；　and　sent　by　the　nerves　to　all　parts　of　the　body；　endowing　the　individual　with　life　and　perception　and　motion。　In　this　way　a　great　division　was　made　between　the　two　functions　of　the　body；　and　two　sets　of　organs：　in　the　vascular　system；　the　heart　and　arteries　and　abdominal　organs；　life　was　controlled　by　the　vital　spirits；　on　the　other　hand；　in　the　nervous　system　were　elaborated　the　animal　spirits；　controlling　motion；　sensation　and　the　various　special　senses。　These　views　on　the　vital　and　animal　spirits　held　unquestioned　sway　until　well　into　the　eighteenth　century；　and　we　still；　in　a　measure；　express　the　views　of　the　great　Alexandrian　when　we　speak　of　〃high〃　or　〃low〃　spirits。
  GALEN
  PERGAMON　has　become　little　more　than　a　name　associated　in　our　memory　with　the　fulminations　of　St。　John　against　the　seven　churches　of　Asia；　and　on　hearing　the　chapter　read；　we　wondered　what　was　〃Satan's　seat〃　and　who　were　the　〃Nicolaitanes〃　whose　doctrine　he　so　hated。　　Renewed　interest　has　been　aroused　in　the　story　of　its　growth　and　of　its　intellectual　rivalry　with　Alexandria　since　the　wonderful　discoveries　by　German　archaeologists　which　have　enabled　us　actually　to　see　this　great　Ionian　capital；　and　even　the　〃seat　of　Satan。〃　　The　illustration　here　shown　　is　of　the　famous　city；　in　which　you　can　see　the　Temple　of　Athena　Polis　on　the　rock；　and　the　amphitheatre。It　s　interest　for　us　is　connected　with　the　greatest　name；　after　Hippocrates；　in　Greek　medicine；　that　of　Galen；　born　at　Pergamon　A。　D。　130；　in　whom　was　united　as　never　before　and　indeed　one　may　say；　never　sincethe　treble　combination　of　observer；　experimenter　and　philosopher。　　His　father；　Nikon；　a　prosperous　architect；　was　urged　in　a　dream　to　devote　his　son　to　the　profession　of　medicine；　upon　which　study　the　lad　entered　in　his　seventeenth　year　under　Satyrus。　In　his　writings；　Galen　gives　many　details　of　his　life；　mentioning　the　names　of　his　teachers；　and　many　incidents　in　his　Wanderjahre；　during　which　he　studied　at　the　best　medical　schools；　including　Alexandria。　Returning　to　his　native　city　he　was　put　in　charge　of　the　gladiators；　whose　wounds　he　said　he　treated　with　wine。　　In　the　year　162；　he　paid　his　first　visit　to　Rome；　the　scene　of　his　greatest　labors。　Here　he　gave　public　lectures　on　anatomy；　and　became　〃the　fashion。〃　He　mentions　many　of　his　successes；　one　of　them　is　the　well…worn　story　told　also　of　Erasistratus　and　Stratonice；　but　Galen's　story　is　worth　telling；　and　it　is　figured　as　a　miniature　in　the　manuscripts　of　his　works。　Called　to　see　a　lady　he　found　her　suffering　from　general　malaise　without　any　fever　or　increased　action　of　the　pulse。　He　saw　at　once　that　her　trouble　was　mental　and；　like　a　wise　physician；　engaged　her　in　general　conversation。　　Quite　possibly　he　knew　her　story；　for　the　name　of　a　certain　actor；　Pylades；　was　mentioned；　and　he　noticed　that　her　pulse　at　once　increased　in　rapidity　and　became　irregular。　On　the　next　day　he　arranged　that　the　name　of　another　actor；　Morphus；　should　be　mentioned；　and　on　the　third　day　the　experiment　was　repeated　but　without　effect。　　Then　on　the　fourth　evening　it　was　again　mentioned　that　Pylades　was　dancing；　and　the　pulse　quickened　and　became　irregular；　so　he　concluded　that　she　was　in　love　with　Pylades。　　He　tells　how　he　was　first　called　to　treat　the　Emperor　Marcus　Aurelius；　who　had　a　stomach…ache　after　eating　too　much　cheese。　　He　treated　the　case　so　successfully　that　the　Emperor　remarked；　〃I　have　but　one　physician；　and　he　is　a　gentleman。〃　He　seems　to　have　had　good　fees；　as　he　received　400　aurei　（about　2000）　for　a　fortnight's　attendance　upon　the　wife　of　Boethus。
  He　left　Rome　for　a　time　in　168　A。　D。　and　returned　to　Pergamon；　but　was　recalled　to　Rome　by　the　Emperor；　whom　he　accompanied　on　an　expedition　to　Germany。　　There　are　records　in　his　writings　of　many　journeys；　and　busy　with　his　practice　in　dissections　and　experiments　he　passed　a　long　and　energetic　life；　dying；　according　to　most　authorities；　in　the　year　200　A。D。
  A　sketch　of　the　state　of　medicine　in　Rome　is　given　by　Celsus　in　the　first　of　his　eight　books；　and　he　mentions　the　names　of　many　of　the　leading　practitioners；　particularly　Asclepiades；　the　Bithynian；　a　man　of　great　ability；　and　a　follower　of　the　Alexandrians；　who　regarded　all　disease　as　due　to　a　disturbed　movement　of　the　atoms。　Diet；　exercise；　massage　and　bathing　were　his　great　remedies；　and　his　mottotuto；　cito　et　jucundehas　been　the　emulation　of　all　physicians。　　How　important　a　role　he　and　his　successors　played　until　the　time　of　Galen　may　be　gathered　from　the　learned　lectures　of　Sir　Clifford　Allbutt＇32＇　on　〃Greek　Medicine　in　Rome〃　and　from　Meyer…Steineg's　〃Theodorus　Priscianus　und　die　romische　Medizin。〃＇33＇　From　certain　lay　writers　we　learn　that　it　was　the　custom　for　popular　physicians　to　be　followed　on　their　rounds　by　crowds　of　students。　Martial's　epigram　（V；　ix）　is　often　referred　to：
  Languebam：　sed　tu　comitatus　protinus　ad　me　　　　　Venisti　centum；　Symmache；　discipulis。　Centum　me　tegigere　manus　Aquilone　gelatae　　　　　Non　habui　febrem；　Symmache；　nunc　habeo。
  ＇32＇　Allbutt：　　British　Medical　Journal；　London；　1909；　ii；　1449；　1515；　1598。
  ＇33＇　Fischer；　Jena；　1909。
  And　in　the　〃Apollonius　of　Tyana〃　by　Philostratus；　when　Apollonius　wishes　to　prove　an　alibi；　he　calls　to　witness　the　physicians　of　his　sick　friend；　Seleucus　and　Straloctes；　who　were　accompanied　by　their　clinical　class　to　the　number　of　about　thirty　students。＇34＇　But　for　a　first…hand　sketch　of　the　condition　of　the　profession　we　must　go　to　Pliny；　whose　account　in　the　twenty…ninth　book　of　the　〃Natural　History〃　is　one　of　the　most　interesting　and　amusing　chapters　in　that　delightful　work。　He　quotes　Cato's　tirade　against　Greek　physicians；corrupters　of　the　race；　whom　he　would　have　banished　from　the　city；then　he　sketches　the　career　of