REPORT OF THE SECRETARY IX 
NATIONAL ZOOLOGICAL PARK 
Director.—WILLIAM M. Mann. 
Assistant Director.—ERNEST P. WALKER. 
ASTROPHYSICAL OBSERVATORY 
Director.—CHARLES G. ABBOT. 
DIVISION OF ASTROPHYSICAL RESEARCH: Loyal B. Aldrich, assistant director; 
William H. Hoover, senior astrophysicist. 
DIVISION OF RADIATION AND ORGANISMS: Earl S. Johnston, assistant director; 
Edward D. McAlister, senior physicist; Leland B. Clark, engineer (precision 
instruments) ; Robert L. Weintraub, associate biochemist ;*Leonard Price, junior 
physicist (biophysics). 
