KONINKLIJKE AKADEMIE VAN WETENSCHAPPEN 
TE AMSTERDAM. 
PROCEEDINGS OF THE MEETING 
of Friday April 28, 1911. 
Doce 
(Translated from: Verslag van de gewone vergadering der Wis- en Natuurkundige 
Afdeeling van Vrijdag 28 April 1911, Dl. XIX). 
GORE EN Ts. 
L. Rurrex: “On orbitoides in the neighbourhood of the Balik-Papan Bay, East-coast of 
Borneo”. (Communicated by Prof. C. E. A. Wicumann), p. 1122. (With one map). 
G. C. J. Vosmarr: “Observations on the genus Spirastrella”®, p. 1139. 
J.G. Dusser DE BARENNE: “The action of strychnine on the central nervous system. ‘The 
segmental, strictly localized strychnine-intoxication of the dorsal spinal mechanisms: a 
contribution to the dermatomery of the hind leg in dogs”. (Communicated by Prof. 
C. WINKLER), p. 1146. 
F. A. Il. ScHREINEFMAKERS: “Equilibria in the system: Water—Sodium sulphate—Sodium 
chloride—Copper sulphate—Cupric chloride”, p. 1163. 
P. var Romeureu: “Hypaphorine and the relation of this substance with tryptophane’, p. 1177. 
D. pr Vries Remincu: “A new method of determining the arterial bleodpressure in man; at 
the same time an attempt at estimating the influence of the arterial wall on it”. (Communi- 
cated by Prof. K. F. WeENCKEBACH), p. 118i. (With one plate). 
N. L. Séuncen: “lipase produced by microbes”. (Communicated by Prof. M. W. BEIJERINCK), 
p. 1200. (With one plate). 
J. D. van DER Waars: “On the value of the critical quantities”, p. 1211. 
C. Braak: “Oa tidal forces as determined by means of WikcueEr1’s estatie scismograph”. 
(Communicated by Dr. J. P. vAN DER Stow), p. 1231. 
M. W. Brijerinck: “An experiment with Sarcina ventriculi”, p. 1237. 
W. Kapreyn: “On the eentra of the integral curves which satisfy differential equations of the 
first order and the first degree”, p. 1241. 
J. D. van per Waars: “Some remarks on the value of the volumes of the coexisting phases 
of a simp!e substance.” I, p. 1253. 
W. H. Juuvs: “The lines H and K in the spectrum of the various parts of the solar disk”, 
p. 1263. 
Il. KamerriNGu Onnes: “Further experiments with liquid helium. C. On the change of 
electric resistance of pure metals at very low temperatures ete. IV. The resistance of 
pure mercury at helium temperatures”, p. 1274.. 
Errata, p. 1276. 
74 
Proceedings Royal Acad. Amsterdam. Vol. XIII. 
