left　there　is　seen　the　stemma　which　appears　as　tailpiece　to　this　chapter；　put　up　by　a　young　Englishman；　William　Harvey；　who　had　been　a　student　at　Padua　for　four　years。　　He　belonged　to　the　〃Natio　Anglica；〃　of　which　he　was　Conciliarius；　and　took　his　degree　in　1602。　Doubtless　he　had　repeatedly　seen　Fabricius　demonstrate　the　valves　of　the　veins；　and　he　may　indeed；　as　a　senior　student；　have　helped　in　making　the　very　dissections　from　which　the　drawings　were　taken　for　Fabricius'　work；　〃De　Venarum　Osteolis；〃　1603。　If　one　may　judge　from　the　character　of　the　teacher's　work　the　sort　of　instruction　the　student　receives；　Harvey　must　have　had　splendid　training　in　anatomy。　　While　he　was　at　Padua；　the　great　work　of　Fabricius；　〃De　Visione；　Voce　et　Auditu〃　（1600）　was　published；　then　the　〃Tractatus　de　Oculo　Visusque　Organo〃　（1601）；　and　in　the　last　year　of　his　residence　Fabricius　must　have　been　busy　with　his　studies　on　the　valves　of　the　veins　and　with　his　embryology；　which　appeared　in　1604。　　Late　in　life；　Harvey　told　Boyle　that　it　was　the　position　of　the　valves　of　the　veins　that　induced　him　to　think　of　a　circulation。
  Harvey　returned　to　England　trained　by　the　best　anatomist　of　his　day。　In　London；　he　became　attached　to　the　College　of　Physicans；　and　taking　his　degree　at　Cambridge；　he　began　the　practice　of　medicine。　He　was　elected　a　fellow　of　the　college　in　1607　and　physician　to　St。　Bartholomew's　Hospital　in　1609。　　In　1615　he　was　appointed　Lumleian　lecturer　to　the　College　of　Physicians；　and　his　duties　were　to　hold　certain　〃public　anatomies；〃　as　they　were　called；　or　lectures。　　We　know　little　or　nothing　of　what　Harvey　had　been　doing　other　than　his　routine　work　in　the　care　of　the　patients　at　St。　Bartholomew's。　It　was　not　until　April；　1616；　that　his　lectures　began。　Chance　has　preserved　to　us　the　notes　of　this　first　course；　the　MS。　is　now　in　the　British　Museum　and　was　published　in　facsimile　by　the　college　in　1886。＇26＇
  ＇26＇　William　Harvey：　　Prelectiones　Anatomiae　Universalis；　London；　J。　&　A。　Churchill；　1886。
  The　second　day　lecture；　April　17；　was　concerned　with　a　description　of　the　organs　of　the　thorax；　and　after　a　discussion　on　the　structure　and　action　of　the　heart　come　the　lines：
  W。　H。　constat　per　fabricam　cordis　sanguinem　　per　pulmones　in　Aortam　perpetuo　　transferri；　as　by　two　clacks　of　a　　water　bellows　to　rayse　water　　constat　per　ligaturam　transitum　sanguinis　　ab　arteriis　ad　venas　　unde　perpetuum　sanguinis　motum　　in　circulo　fieri　pulsu　cordis。
  The　illustration　　will　give　one　an　idea　of　the　extraordinarily　crabbed　hand　in　which　the　notes　are　written；　but　it　is　worth　while　to　see　the　original；　for　here　is　the　first　occasion　upon　which　is　laid　down　in　clear　and　unequivocal　words　that　the　blood　CIRCULATES。　　The　lecture　gave　evidence　of　a　skilled　anatomist；　well　versed　in　the　literature　from　Aristotle　to　Fabricius。　　In　the　MS。　of　the　thorax；　or；　as　he　calls　it；　the　〃parlour〃　lecture；　there　are　about　a　hundred　references　to　some　twenty　authors。　The　remarkable　thing　is　that　although　those　lectures　were　repeated　year　by　year；　we　have　no　evidence　that　they　made　any　impression　upon　Harvey's　contemporaries；　so　far；　at　least；　as　to　excite　discussions　that　led　to　publication。　It　was　not　until　twelve　years　later；　1628；　that　Harvey　published　in　Frankfurt　a　small　quarto　volume　of　seventy…four　pages；＇27＇　〃De　Motu　Cordis。〃　　In　comparison　with　the　sumptuous　〃Fabrica〃　of　Vesalius　this　is　a　trifling　booklet；　but　if　not　its　equal　in　bulk　or　typographical　beauty　（it　is　in　fact　very　poorly　printed）；　it　is　its　counterpart　in　physiology；　and　did　for　that　science　what　Vesalius　had　done　for　anatomy；　though　not　in　the　same　way。　　The　experimental　spirit　was　abroad　in　the　land；　and　as　a　student　at　Padua；　Harvey　must　have　had　many　opportunities　of　learning　the　technique　of　vivisection；　but　no　one　before　his　day　had　attempted　an　elaborate　piece　of　experimental　work　deliberately　planned　to　solve　a　problem　relating　to　the　most　important　single　function　of　the　body。　Herein　lies　the　special　merit　of　his　work；　from　every　page　of　which　there　breathes　the　modern　spirit。　　To　him；　as　to　Vesalius　before　him；　the　current　views　of　the　movements　of　the　blood　were　unsatisfactory；　more　particularly　the　movements　of　the　heart　and　arteries；　which　were　regarded　as　an　active　expansion　by　which　they　were　filled　with　blood；　like　bellows　with　air。　The　question　of　the　transmission　of　blood　through　the　thick　septum　and　the　transference　of　air　and　blood　from　the　lungs　to　the　heart　were　secrets　which　he　was　desirous　of　searching　out　by　means　of　experiment。
  ＇27＇　Harvey：　　Exercitatio　Anatomica　de　Motu　Cordis　et　Sanguinis　in　Animalibus；　Francofurti；　1628。
  One　or　two　special　points　in　the　work　may　be　referred　to　as　illustrating　his　method。　　He　undertook　first　the　movements　of　the　heart；　a　task　so　truly　arduous　and　so　full　of　difficulties　that　he　was　almost　tempted　to　think　with　Fracastorius　that　〃the　movement　of　the　heart　was　only　to　be　comprehended　by　God。〃　　But　after　many　difficulties　he　made　the　following　statements：　　first；　that　the　heart　is　erected　and　raises　itself　up　into　an　apex；　and　at　this　time　strikes　against　the　breast　and　the　pulse　is　felt　externally；　secondly；　that　it　is　contracted　every…way；　but　more　so　at　the　sides；　and　thirdly；　that　grasped　in　the　hand　it　was　felt　to　become　harder　at　the　time　of　its　motion；　from　all　of　which　actions　Harvey　drew　the　very　natural　conclusion　that　the　activity　of　the　heart　consisted　in　a　contraction　of　its　fibres　by　which　it　expelled　the　blood　from　the　ventricles。　These　were　the　first　four　fundamental　facts　which　really　opened　the　way　for　the　discovery　of　the　circulation；　as　it　did　away　with　the　belief　that　the　heart　in　its　motion　attracts　blood　into　the　ventricles；　stating　on　the　contrary　that　by　its　contraction　it　expelled　the　blood　and　only　received　it　during　its　period　of　repose　or　relaxation。　Then　he　proceeded　to　study　the　action　of　the　arteries　and　showed　that　their　period　of　diastole；　or　expansion；　corresponded　with　the　systole；　or　contraction；　of　the　heart；　and　that　the　arterial　pulse　follows　the　force；　frequency　and　rhythm　of　the　ventricle　and　is；　in　fact；　dependent　upon　it。　　Here　was　another　new　fact：　that　the　pulsation　in　the　arteries　was　nothing　else　than　the　impulse　of　the　blood　within　them。　　Chapter　IV；　in　which　he　describes　the　movements　of　the　auricles　and　ventricles；　is　a　model　of　accurate　description；　to　which　little　has　since　been　added。　　It　is　interesting　to　note　that　he　mentions　what　is　probably　auricular　fibrillation。　　He　says：　〃After　the　heart　had　ceased　pulsating　an　undulation　or　palpitation　remained　in　the　blood　itself　which　was　contained　in　the　right　auricle；　this　being　observed　so　long　as　it　was　imbued　with　heat　and　spirit。〃　He　recognized　too　the　importance　of　the　auricles　as　the　first　to　move　and　the　last　to　die。　　The　accuracy　and　vividness　of　Harvey's　description　of　the　motion　of　the　heart　have　been　appreciated　by　generations　of　physiologists。　　Having　grasped　this　first　essential　fact；　that　the　heart　was　an　organ　for　the　propulsion　of　blood；　he　takes　up　in　Chapters　VI　and　VII　the　question　of　the　conveyance　of　the　blood　from　the　right　side　of　the　heart　to　the　left。　　Galen　had　already　insisted　that　some　blood　passed　from　the　right　ventricle　to　the　lungsenough　for　their　nutrition；　but　Harvey　points　out；　with　Colombo；　that　from　the　arrangement　of　the　valves　there　could　be　no　other　view　than　that　with　each　impulse　of　the　heart　blood　passes　from　the　right　ventricle　to　the　lungs　and　so　to　the　left　side　of　the　heart。　How　it　passed　through　the　lungs　was　a　problem：　　probably　by　a　continuous　transudation。　　In　Chapters　VIII　and　IX　he　deals　with　the　amount　of　blood　passing　through　the　heart　from　the　veins　to　the　arteries。　Let　me　quote　here　what　he　says；　as　it　is　of　cardinal　import：
  〃But　what　remains　to　be　said　upon　the　quantity　and　source　of　the　blood　which　thus　passes；　is　of　a　character　so　novel　and　unheard　of　that　I　not　only　fear　injury　to　myself　from　the　envy　of　a　few；　but　I　tremble　lest　I　have　mankind　at　large　for　my　enemies；　so　much　doth　wont　and　custom　become　a　second　nature。　　Doctrine　once　sown　strikes　deeply　its　root；　and　respect　for　antiquity　influences　all　men。　Still　the　die　is　cast；　and　my　trust　is　in　my　love　of　truth；　and　the　candour　of　cultivated　minds。〃＇28＇　Then　he　goes　on　to　say：
  ＇28＇　William　Harvey：　　Exercitatio　Anatomica　de　Motu　Cordis　et　Sanguinis　in　Animalibus；　Francofurti；　1628；　G。　Moreton's　facsimile　reprint　and　translation；　Canterbury；　1894；　p。　48。
  I　began　to　think　whether　there　might　not　be　A　MOVEMENT；　AS　IT　WERE；　IN　A　CIRCLE。　　Now　this　I　afterwards　found　to　be　true；　and　I　finally　saw　that　the　blood；　forced　by　the　action　of　the　left　ventricle　into　the　arteries；　was　distributed　to　the　body　at　large；　and　its　several　parts；　in　the　same　manner　as　it　is　sent　through　the　lungs；　impelled　by　the　right　ventricle　into　the　pulmonary　artery；　and　that　it　then　passed　through　the　veins　and　along　the　vena　cava；　and　so　round　to　the　left　ventricle　in　the　manner　already　indicated。〃＇29＇
  ＇29＇　Ibid。　p。　49。
  The　experiments　dealing　with　the　transmission　of　blood　in　the　veins　are　very　accurate；　and　he　uses　the　old　experiment　that　Fabricius　had　employed　to　show　the　valves；　to　demonstrate　that　the　blood　in　the　veins　flows　to