CONTENTS. XV 



Physiology. H. Zwaardemaker ; "About odour nffiuities". 242. 



— H. J. Hambuuger: "A method to extract enzymes and pro enzymes from the mucous 

 membrane of the digestive tube and to establish the topic distribution of them". 250. 



— C. A. Pekelharing: "An investigation of Mr. J. W. A. Gewin, on the relation 

 of pepsin to chyraosin". 283. 



— G. VAN Kijnberk : "On the segmental skin-innervation by the sympathetic 

 nervous system in vertebrates, based on experimental researches, about the inner- 

 vation of the pigment-cells in flat fishes and of the pilo-motor muscles in cats." 332. 



— W. Einthoven and W. A. Jolly: "The electric response of the eye to 

 stimulation by light at various intensities". G98. 



PIGMENT-CELLS (On the segmental skin-innervation by the sympathetic nervous system 



in vertebrates, based on experimental researches about the innervation of the) in 



flat fishes and of the pilo-motor muscles in cats. 332. 

 PLACE (t.) presents a paper of Prof. J. W. Langelaan : "On the development of 



the Corpus Callosum in the human brain". 344. 

 plaitpoint line (On the course of the) and of the spinodal lines, also for the case, 



that the mutual attraction of the molecules of one of the components of a binary 



mixture of normal substances is slight. 34. 



— (The). 183. 



plane system (Some constructions deduced from the motion of a). 648. 



platinum (Some remarks on the expansion of) at low temperatures. 342. 



PODOSTEMACEAE (The development of the ovule, embryo- sac and egg in). 824. 



POLYTRICHUM (Ou a double reduction of the number of chromosomcs during the formation 

 of the sexual cells and on a subsequent double fertilisation in some species of). 359. 



POSTMA (o.). Motion of molecule-systems on which no external forces act. 390. 



POTASSIUM HYPOCHLORITE (Action of) on cinnamide. (2nd Communication). 308. 



PRESSURE COEFFICIENT (Derivation of the) of helium for the international helium ther- 

 mometer and the reduction of the readings on the helium thermometer to the 

 absolute scale. 589. 



PRODUCT (On an infinite) represented by a definite integral. 347. 



PRO-ENZYMES (A method to extract enzymes and) from the mucous membrane of the 

 digestive tube and to establish the topic distribution of them. 250. 



PULSE (Genesis of the alternating). 78. 



QUATERNARY SYSTEMS (Equilibria in). 817. 



RETD (CLE mend) and Mrs. Eleanor -M. Eeid. On Dulichium vespiforme sp. nov. 

 from the brick-earth of Tegelen. 860. 



RHOMBIC CRYSTALS (About the obliquc extinction of). 368. 



ROM BURGH (p. VAN). The decomposition of penta-erythritoltetraforraate on 

 heating. 166. 



— On lupeol. 292. 



RUTTEN (l.). On fossil Trichechids from Zealand and Belgium. 2. 



RUN BE UK (g. van). Ou the segmental skin-innervation by the sympathetic nervous 

 system in vertebrates, based on experimental researches about the innervation 

 of ihe pigment-cells in flat fishes and of the pilo-motor muscles in cats. 332. 



