vi 
CONTENTS 
Photic Orientation in Insects By S. 0. Mast 240 
A Preuminary Note on Tetramitus, a Stage in the Life Cyci.e oe a Copro- 
zoic Amoeba By Martha Bunting 294 
PHYSIOLOGY AND PATHOLOGY 
Structural Changes Associated with Factor Mutations and with Chromo- 
some Mutations in Datura By E.W. Sinnott and A. F. Blakeslee 17 
Characteristic Effects upon Growth, Oestrus and Ovulation Induced by 
THE Intraperitoneal Administration, of Fresh Anterior Hypophyseal 
Substance By H. M. Evans and J. A. Long 38 
A Study of the Effects of Cucurbita Pepo Seeds on Kidney Excretion 
By B. Masurovsky 39 
Preliminary Note on a Biometrical Study of the Relations of Certain 
Viscera in Tuberculosis By R. Pearl and A . L. Bacon 125 
Replantation of Entire Limbs without Suture of Vessels . . By W. S. Halsted 180 
The Relative Sensitivity of the Ear at Different Levels of Loudness 
By D. MacKenzie 188 
The Quantitative Influences of Certain Factors Involved in the Produc- 
tion OF Cyanosis By Christen Lundsgaard and Donald D. Van Slyke 280 
Bactericidal Properties of the Products of Radium Emanation 
By John Albert Marshall 317 
A Direct Method of Testing Color Vision In Lower Animals 
By W. F. Hamilton 350 
BIOLOGY 
Contribution to the Energetics of Evolution By A. J. Lotka 147 
Natural Selection as a Physical Principle By A. J. Lotka 151 
On the Influence of Density of Population upon the Rate of Reproduc- 
tion IN Drosophila By R. Pearl and S. L. Parker 212 
Animal Evolution By A. H. Clark 219 
The Correlation of Time Units and Climatic Changes in Peat Deposits of 
THE United States and Europe By A. P. Dachnowski 225 
