Ui 



We see here alternation gradually elianp:e into halving of the rhythm, 

 most probably of the ventriole only. I often observed this halving 

 of the rhythm after alternation. The alternation is here consequently 

 a form of transition between the nornml rhythm and the halved 

 one. as I found in my frog's hearts |)oisoiied with verairine repeatedly 

 bi- and liigeniinus as traiisilion bclween these two rhythms. The 

 transition is here giadual; llie more we appniaeli llie hal\ cd i li\ llim, 

 the lower the lilde alienialiou-syslolc beei uies. During the lillle 

 systole a con^lanlly urealcr part of the licartpoirt lenuiins in rest. 



Ju Kig. 10 1 ha\e iudi>-ated i)y 

 lilies (Irawii Iransv ersally oxer the 

 venlricde the frontier l)ctween the 

 pai'l of ihc \entiicie that pulsates 

 (luring- the lillle sy.slule, and the 

 pari thai remains in rest. The |iarl 

 under llie line pulsates eonsccpienlly 

 duiing one alternalionpair onee, ami 

 ihis part becomes constantly larger, 

 the line rises gradually. So we come 

 to the conclusion that as soon as 

 the alternation occurs, halvinti' of 

 rhythm of ])art of the xenti'icle- 

 mnsculatnre takes place. The part of which the rhylhm halves 

 becomes constantly larger and laigei-, till at last the rhythm of the 

 whole ventricle halves. 'J'lie liiu's in Ihe fig. indicate thus, how 

 far the contraction continnes allernalingly in the ventiicle. 



By this investigation into the |)0lential diiferences which exist in 

 the ventricle during Ihe alternation-curves it is at the same time 

 clearly indicated that we must conceive the ventricle-electrogram as a 

 product of interference of Ihe negativities al the basis ami the point. 



Fie. 10 



LITERATURE. 



1. F. B. HoFMANN: Ueber die Aenderung dcs Contractions ablaufes ain Vuiitrikel 

 und Vorhofe des Frosehlierzens bei Frequenzandeiung und ini bypodynamen 

 Zustande. Pflügers Arcbiv. 84, 1901 Seile 131). 



2. (J. L. RiiMKE. De werking van antiarine op hel bart. Nedeil. Tijdscbr. v. 

 Geneesk. 1902, I. no. 15 biz. 869. 



3. L. J. J. MusKENS. Bijdrage tot de kennis van zenuwinvloed op de liartwerking. 

 Koninklijke Akademie van VVelenscbappen te Amsterdam. Verslag van de gewone 

 vergadering der Wis- en Naluurk afdeeling van 26 April 1907. (Tbese Proceedings 

 Vol. 10, p. 78). 



4. W. H. Gaskell. On the ibyliuii of the hc-al ol' the trog and on the nature 



