CONTENTS 
Page 
Physiology. — The Mechanism of Diffusion of Electrolytes Through Animal 
Membranes , . , By Jacques Loeb 511 
Astronomy. — The Rotation and Radial Velocity of the Spiral Nebula N. G. 
C. 4594 . . / By Francis G. Pease 517 
Astronomy. — ^A Simple Method for Determining the Colors of the Stars . . 
By Frederick H. Scares 521 
Astronomy. — Studies of Magnitudes in Star Clusters. III. The Colors of 
the Brighter Stars in Four Globular Systems . . . By Harlow Shapley 525 
Physics. — ^The Effect of an Electric Field on the Likes of Lithium and 
Calcium , , , By Janet T. Howell 528 
Mathematics. — ^A Proof of White's Porism By A. B, Coble 530 
Petrology. — ^A Contribution to the Petrography of the Philippine Islands . 
By J. P. Iddings and E. W. Morley 531 
Physiology. — Salt Antagonism in Gelatine ByW.O. Fenn 534 
Physiology. — Similarity in the Behavior of Protoplasm and Gelatin . . . 
By W. 0. Fenn 539 
Mathematics. — On Certain Asymptotic Expressions^ in the Theory of Linear 
Differential Equations By W. E. Milne 5^3 
Mathematics.— On Newton's Method of Approximation . By Henry B. Fine 546 
