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VOLUME 5 MARCH, 1919 
PROCEEDINGS 
OF THE. 
NUMBER 3 
National Academy 
OF Sciences 
OF THE 
UNITED STATES OF AMERICA 
EDITORIAL BOARD 
Raymond Pearl, Chairman 
C. G. Abbot, Acting.Home Secretary 
Edwin B. Wilson, Managing Editor 
George E. Hale, Foreign Secretary 
J. M. Clarke 
H. H. Donaldson 
E. B. Frost 
R. A. Harper 
LuDviG Hektoen 
H. S. Jennings 
Jacques Loeb 
Graham Lusk 
A. G. Mayor 
R. A. Millikan 
E. H. Moore 
A. A, NoYES 
W. A. NOYES 
E. L. Thorndike 
W. M. Wheeler 
Publication Office: Williams & Wilkins Company, Baltimore 
Editorial Office t^^Massachusetts Institute of Technology, Cambridge 
Home Office of the Academy: Washington, D. C. 
I 
Entered as second-class matter at the postoffice at Baltimore, Maryland, under the act of August 24, 1912, Acceptance for 
ratelof postage provided for in Section,. 1103, Act of October 3, 1917. Authorized on July 3, 1918. 
Price pgr annum^ $5.00 
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at special 
