( :\Hi 



ai'tilicinlh' sliiniil.itcd. llic coiiiiiciisaloi-v pause afha- llic cxlra-svslolc 

 is nol as in llic IVoii's licarl Iriilv (•(iiii|H'iisal(>r\ l»iil iiiosllv ot' loo 

 slioi-| a «hiralioii. Soiiiclimcs il was (•(Mnpldcl v (•(»in|»('iisal(irv, il was 

 n(>\'(M- ('iilii-ch' iiiissiiiLi', il \n as uciKM-allv sliorlciicd and lluai al anv 

 i'alc nol (M|nallv slioricncd. 



Tli('\ sa\ on lliis snhjccl (I.e. pa.Lic 2'i()): ,,As Ioiili' as llic interval 

 ".1.S--J; is of considcrahle len^lli llie conipcnsalorv panx' in llic 

 ••auricle is irnh (•oni|»(aisal(»i'v. llial is llic inicrxal Wclwccn llic lasl 

 ••sponlaiK'ons conlraclion and Ihc itosl-coinpcnsatorv is (Mpial lo Iwd 

 ••anriculai' ex des. Wlicn liowcvor llic sliinidns falls cai-licr in llic 

 ■'in-ilahlc period, no Iimic conij^Misalion occnrs, llie posl-conipcnsalorv 



•'conlraclion Itcinu' prcnialiirc w licii .l^ — A^ is sliori llic (-(tni- 



"pcnsalion (ol linie \\'.1 Ixd'ore llie lii'sl nalnral c(Milraclioii isalwavs 

 ••iniperfecl." 



Tlie explanalion ol ihis (liiTerênce is accoi-dinu' lo llieiii: ••eillier 

 ••|lic> conlraclion \\a\(' pass(^s trom llie anricle lo llie ureal \"eins 

 •'and there sels np a forced contraction w Inch i-elnrninii' to the 

 "ani'icle causes the prenialnre svshde, or the ii'rilahililv of the ain'icle 

 "U'radnalU increases niilil it cidminales in a conlraclion which is 

 "independcnl of Ihc ureal \ciiis an<l iinlialed in ihe anricidar nniscle 

 ••itself. As to which of these two is the coi-recl explanalion we arc 

 "iniahle to ,ui\'e anv o[»inion and feel that it woidd he nselcss lo 

 ••Italance prol»al)ililies hefore the ino\'enients of the ureat xciiis ha\e 

 "heeii e\aniiiie<l." 



Foi-merh- I myself expressed Ihe snpposilion. thai the mammalian 

 anricdc nnulil possess a urealei' antoinalic irrilaltility . hecanse in the 

 phyloLicnelic dc\-clopmenl a pai't of sinus and xcna wonhl he taken 

 lip iji the anricdc. 



II. Vj. 11f,kiN(; (2) has also heen ahle lo cslahlisii the diircrence 

 dcscrilxMl foi' the lirsl lime hy (VsuNY and .Mvttiikws; he says: 



'•The earlier the momcnl of slimiilalion falls in the irritahle |)ci-io<l 

 •■of the anri(de, the shoiier llic arlilicial l)i,Li-cminns is linlerxal Itelween 

 "lasl sponlaiieons and post-compensatory systole): the later it falls, 

 '•the more the diiralioii of ihe arlilicial l)iL;einiiin> approacdics thai of 

 ••two normal cardiac pci-iods." He continues: '■the pause (after the 

 '•e.xlra-syslole of the anricle) lasts lonucr according lo ihe moment 

 ••of slimidation falling earlier in the irritable period." So here too 

 he assumes the law of the cons(M'\alion of the physiolouical period 

 of slimiilalion : ■•aher die lle/.ichiiim' isl keine so eiidache wie am 

 \ enlrikel". 



\\\' had all o\-erlooke(l, that ArACKKN/ii', (3) had hecome con\inced 

 alread\ in 1S1)4 after a careful aiialysi> of 1 he \ fiioiis and lixcr jndse 



