Vol. LXIII. No. 1 a^o -J' MAY, 1903 



THE 



POPULAR SCIENCE 

 MONTHLY 



EDITED BY J. McKEEJf CATTELL 



CONTENTS 



The Classification of Fishes. President David Starr Jordan .... 5 



Stages of Vital Motion. O. F. Cook 14 



The Slavic Immiojrant. Dr. Allan McLaughlin 25 



Obituary Notice of a Lung-fish. Professor Bashford Dean .... 33 

 The Opportunity of the Smaller Museums of Natural History. Wil- 

 liam Orr 40 



College Entrance Examinations. Abraham Flexner 53 



A New Source of Heat: Radium. Dr. Henry Carrinqton Bolton . . 61 



The Decrease in the Size of American Families. Professor Edward L. 



Thorndike 64 



Helen Keller: A Psychological Autobiography. Professor Joseph 



Jastrow 71 



Discussion and Correspor.deuce : 



Professor Pearson on the Distribution of Fertility: Edwaed L. Thoendike . . 84 



Scientific Literature : 



Physiological Chemistry 85 



Progress of Science : 



William Harkness ; The American Society of Naturalists ; Race Senescence; The 

 Field Columbian Museum ; ^The Treatment of Typhoid Fever ; The British Ant- 

 arctic Expedition ; The New York Forest and Game Commission ; Scientific Items 86 



THE SCIENCE PRESS 



LANCASTER, PA. GARRISON, N. Y. 



NEW YORK : SuB-SiAnoN 84 

 Single Numbee, 30 Cents Yeaely Subscbiption, $3.00 



C«PTBieHT, 1903, BT THB SCISNCS PRESS 



