( 8<S4 



iiUerxal miisl hocoiiic sliorlcr, a fact which noes wilhoiit sayiiiii", in 

 liii'. Ill re8|>. = ^5 and = .')4. 



V\-o\\\ Ihis oiisiics, Ihal when Ihc sliiimlalioii is ('j/'ccfcd hih' ni tin' 

 'iri'itiihlc nci'Kxl IIk' coiiiiii'iixiitiirii jxiiisi' is <u)ni jth'tt' and farllHM'inoi'o, 

 ilic ('(irlicr lite stliiiiiliitnni is i'lfcclcd I lie slioiii'r I In' iiilcrrdl ln-lirci'ii 



jllU'Ci'dillll Sl/sio/t' iIIkI foiJiiiniltf SIIOIltillK'OIIS sjisfoli'. 



Aiiodiei- inlliiciicc is si ill al woi-k, NNJiich also üovcmmis the IciiLilli 

 of tho |»aus(\ The earlier the slimidatioii is eHecled in ihe irrilalde 

 |)eri()d (tf llie aiiri(de. the slower the stiiuidns is coiidneted throiiiiii the 

 wall of' the heart, lor the condiictix-e |»o\nci' of the cardiac muscle 

 relniiis hut uradiiallv after the pi'ecediiiii- svslole. So ihe interval J; — i V, 

 will he loiiLicr accoi-dinu' lo the sliinidns heinu- eltecled eai-lier and 

 as this interval also doniinates the moment in which the slimnlalinii' 

 material is (h'stroxcd l»v the indnced extra c(mli-aclion it will also 

 iidlnence tin- lenuth ol the aui-icnlar interval. In lii"-. ill w hei-e the 

 slower condnction w hen the slinniliis is ellecled earlier is taken into 

 account this inlliuMice is illustrated. And in this way it is to he 

 explained, that lln' 'iii(crr<ii is /oiii/i'r aj'tcr an diiricnhir I'.r/rti-si/sfo/c 

 (tccordiiii/ fc f/i<' nioiin'iit of stinnihitioii f (till in j cdrlicr in I lie irritdhli' 

 pi'riod of fill' (luriclc foi/oirini/ ii'iicfrr iijioii tlic /in'cci/iin/ si/s/o/c. 



The diflerences in lenulh of the com|>ensatory pause after slinin- 

 lalion of liie aiu-icle are iji this way easily explained and it a])pears 

 that the rides established for the aniphihian heart hold Uitod for the 

 mammaliaji heart, in the sense howevei-, as FIf.kin(; says, thai 'Mlie 

 IJeziehung keitie so einfuehe ist". 



The peculiar modilications iii the course of the exti-a couti-action 

 when the aui'icle is stimulated, derived by Mackfazik from the venous 

 pulse, by Ci shnv and .AIatthkws from the traeiufis of the auricular 

 movements, will jirobably tind their explanation in the way in which, 

 as is proved in tig'. II, the contraction waves meet here in the auricular 



