XVIII LIST OF CONTRIBUTORS 



McCoLLUM, Elmer Verner, ph.d., sc.d. 



Professor of Bio-Chemistry, Johns Hopkins University, School of Hygiene 

 and Public Health, Baltimore. 



MiLLiKAN, Robert A., ph.d., ll.d., sc.d. Nobel Prize, 1923. 



Director of Norman Bridge Laboratory of Physics, and Chairman of 

 Executive Council, Cahfornia Institute of Technology, Pasadena. 



Parker, George H., sc.d. 



Professor of Zoology and Director of the Zoological Laboratory, Harvard 

 University, Cambridge. 



Overstreet, Harry A., d.sc. (Oxon.) 



Head of the Department of Philosophy, College of the City of New 

 York; Lecturer in Philosophy at the New School for Social Research, 

 New York. 



Pearl, Raymond, ph.d., sc.d., ll.d. 



Directory of the Institute for Biological Research; Research Professor 

 of Biochemistry and Vital Statistics, School of Hygiene; Professor of 

 Biology, School of Medicine, Johns Hopkins University, Baltimore. 



Phelps, Earle B., b.s. 



Professor of Sanitary Science, College of Physicians and Surgeons, 

 Columbia University, New York. 



RoLLESTON, Sir Humphry, Bart., g.c.v.d., k.c.b., m.d. 



Physician-in-Ordinary to H. M. The King; Regius Professor of Physic, 

 Cambridge, England. 



Russell, Henry Norris, a.m., ph.d., Hon. d.sc. (Dartmouth), d.sc. 

 (Harvard) 



Charles A. Young Research Professor of Astronomy and Director of the 

 Princeton University Observatory, Princeton. 



Sherrington, Sir Charles S., m.d., o.m. 



Waynflete Professor of Physiology; Fellow of Magdalen College, Oxford. 



Wheeler, William Morton, ph.d., s.d., ll.d. 



Professor of Entomology, Harvard University, Associate Curator of 

 Entomology, Museum of Comparative Zoology, Cambridge. 



Wissler, Clark, ph.d., ll.d. 



Professor of Anthropology, Yale University, New Haven; Curator-in- 

 Chief, Division of Anthropology, American Museum of Natural History, 

 New York. 



Yerkes, Robert M., ph.d., Hon. sc.d., Hon. ll.d. 



Professor of Psychobiology, Yale University, New Haven. 



Zinsser, Hans, m.d. 



Professor of Bacteriology, Harvard University, Boston. 



