708 



figure decreases from the first systole to tlie third included, and the 

 height of the T-oscillation increases. A line of connection between 

 the R and the T is not to be observed in this figure, because the 

 T is immediately connected with the R. 



Fig. 9 may still find a place here. This figure shows bigeminus- 

 groups, after poisoning with veratrine, resulting from the falling 

 away of every third auricle- and ventricle-systole. During the second 

 ventricle-systole of each group the impulse-transmission through 

 the ventricle is retarded more considerably than during the first. 

 This appears from the wider R-oscillation of the second ventricle- 

 systole. But the T-oscillation is much more negative, and the line 

 of connection between the R and the T has descended much lower. 



The bigeminusgroups, which I published in J915,^) show likewise 

 analogous pro|)ortions. The R-oscillation of the 2'"^ systole is here 

 wider, and the positive T-oscillation smaller than that of the 'P^ 

 systole of each group. 



111. The electnnjrnins of the anticijmted ventricle-systoles. 



With regard to this series of experime)its a short communication 

 will be sufficient. In a former communication ") these were already 

 mentioned and explained with figures. The anticipated ventricle- 

 systoles were excited by extra-stimulation of the auricle, which 

 brought about extra-systoles of these parts of the heart. After such 

 an extra-systole the impulse proceeded along the atrio-ventricular systems 

 of connection towards the ventricle, wliich consequently was brought 

 to contraction at an earlier moment of the ventricle-period. 



The place where the impulse enters into the ventricle at these anti- 

 cipated ventricle-systoles, was consequently the same as for the normal 

 periodical ventricle-systoles. For this reason there was no objection to 

 compare the electrograms of these anticipated ventricle-systoles with 

 those of the periodical ventricle-systoles. It is obvious, that the velo- 

 city of impulse-transmission through the ventricle during the 

 anticipated ventricle-systoles was inferior to that of the periodical 

 ventricle-systoles and the retardation was the more considerable 

 according to a ventricle-systole being more anticipated. In accordance 

 herewith the R-oscillation of the ventricle-electrograms of the anti- 

 cipated ventricle-systoles was wider than that of the periodical 



*) S. DE Boer: Die Folgen der Extrareizung fur das Elektrogramm des Frosch- 

 herzens. Zeitschrift fur Biologie, Bd 6a, 1915, Seite 440, Fig. 8. 



3) Koninklijke Akademie van Wetenschappen, Verslag van de gewone Vergade- 

 ring der Wis- en Natuurk. afdeeling van 30 Juni 1917, Deel XXVI bldz. 422, and 

 Proceedings Vol. XX page 404 



