XXVr CONTENTS. 



w I N K L E u fc.) presents a paper of ür. A. Gorter : "Tlie cause of sleep." 86. 



— presents n paper of Dr. G. van Uijnbekk : "Üii the fact of sensible skin areas 

 dying away in a centripetal direction." 346. 



— presents a paper of Prof. J. K. A. Wertiieim Salomonson : "On tactual after- 

 images." 481. 



— and G. van Eijnberk. Structure and function of the trunk-dermatoma. IV. 347. 



— Something concerning the growth of the lateral areas of the trunk-dermatomata 

 on the caudal portion of the upper extremity. 392. 



WOLFF (l. k.) and C. A. Lobrï ue Bruyn. Can the presence of the molecules in 

 solutions be proved by application of the optical method of Tyndall. 73.5. 



WOLFF (l. K.) and A. Smits. The velocity of transformation of carbon monoxide. II. 66. 



XANTHINE DERIVATIVES (Investigations of some) in connection with the internal muta- 

 tion of plants. 203. 



ZEEMAN (p. ). Extract from the Report made by the committee for awarding the 

 Buys— Ballot medal. 78. 



— and J. Geest. On the double refraction in a magnetic field near the components 

 of a quadruplet. 19. 



Zoology. Hans Strahl : "The process of involution of the mucous membrane of the 

 uterus of Tarsius spectrum after parturition." 302. 



— A. A. W. Hubrecht: "On the relationship of various invertebrate phyla." 839 



— Max Weber : ''On some of the results of the Siboga-Expedition." 846. 



