VI CONTENTS 



Maxwell, S. S. Labyrinth and equilibrium. I. A comparison 

 of the effect of removal of the otolith organs and of the 

 semicircular canals 123 



Harvey. E. Newton. Studies on bioluminescence. X. Car- 

 bon dioxide production during luminescence of Cypridina 

 hiciferin 133 



Harvey, E. Newton. Studies on bioluminescence. XI. Heat 



production during luminescence of Cypridina luciferin. ... 137 



CoHN, Edwin J., Gross, Joseph, and Johnson, Omer C. 

 The isoelectric points of the proteins in certain vegetable 

 juices 145 



Swingle, W. W. Iodine and the thyroid. IV. Quantitative 



experiments on iodine feeding and metamorphosis 161 



LoEB, Jacques. Influence of the concentration of electrolytes 

 on the electrification and the rate of diffusion of water 

 through collodion membranes 173 



No. 3, January 20, 1920. 



Moore, A. R. The action of strychnine and nicotine on the 



neuromuscular mechanism of Asterias 201 



Parmenter, Charles L. The chromosomes of parthenogenetic 

 frogs 205 



Harvey, E. Newton. Studies on bioluminescence. XII. The 

 action of acid and of light in the reduction of Cypridina 

 oxyluciferin 207 



McGuiRE, Grace, and Falk, K. George. Studies on enzyme 

 action. XVIII. The saccharogenic actions of potato 

 juice 215 



Hecht, Selig. The photochemical nature of the photosensory 



process 229 



Linhart, George A. The free energy of biological processes. 



Preliminary paper 247 



Harvey, R. B. Apparatus for measurement of oxidase and 



catalase activity 253 



LoEB, Jacques. Influence of a slight modification of the col- 

 lodion membrane on the sign of the electrification of water. 255 



