KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROCEEDINGS OF THE MEETING 
of Saturday March 27, 1915. 
Vor. XVII. 
President: Prof. H. A. Lorentz. 
Secretary: Prof. P. ZreMaN. 
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 
Afdeeling van Zaterdag 27 Maart 1915, Dl. XXIII. 
OEE ER Ne ES 
S. pr Borr: “On the heart-rhythm”. II, (Communicated by, Prof. J. K. A. Weerritrim 
SALOMONSON), p. 1135. 
P, H. GarrÉ: “On the relation between departures from the normal in the strength of the 
trade-winds of the Atlantic Ocean and those in the waterlevel and temperature in the 
northern European seas”, (Communicated by Dr. J. P. vaN DER STOK), p. 1447. 
H. R. Krurr and Jac. van per Seek: “The connexion between the limit value and the 
concentration of Arsenic 'Trisulphide sols”. (Communicated by Prof. E. Conen, p. 1158. 
R. A. WeEERMAN: “Action of sodium hypochlorite on amides of #-oxyacids. A new method 
for the degradation of sugars.” (Communicated by Prof. A. P. N. FRANCHIMONT), p. 1164. 
H, Trrropr: “Theoretical determination of the entropy constant of gases and liquids”. (Com- 
municated by Prof. H‚ A. Lorentz), p. 1167. 
P, Enrenrest: “On interference phenomena to be expected when Röntgen rays pass through 
a di-atomic gas”. (Communicated by Prof. H. A, Lorenrz), p. 1184. 
H. A. Brouwer: “On the granitic area of Rokan (Middle Sumatra) and on contact-pheno: 
mena in the surrounding schists.” (Communicated by Prof. G. A. F, Motenaraarr), p. 1190. 
Errata, p. 1202. 
Physiology. — “On the heart-rhythm.” ‘) U. By Dr. S. pr Boer. 
(Communicated by Prof. J. K. A. WeRrHEIM SALOMONSON). 
(Communicated in the meeting of February 27, 1915). 
Pulsus bi-, tri- and polygeminus. 
In my former communication I incidentally called the attention 
to the fact that pulsus bigeminus occurs as a transition-period from 
the normal heart-rhythm to the halved one. In the following pages 
I intend to communicate, in what way the normal heart-rhythm can 
through different intermediate periods pass into the halved one. As 
an example of this manner of halving the following experiment 
may serve: 
1) According to investigations made in the physiological laboratory of the 
University of Amsterdam. 
75 
Proceedings Royal Acad. Amsterdam. Vol. XVII. 
