FOREWORD ix 



Every biology teacher should also have access to the Science 

 News Letter, published by Science Service, School Science and 

 Mathematics, Turton and Warner, Chicago, and the General 

 Science Quarterly, W. G. Whitman, Salem, Mass., as all these pub- 

 lications contain much of value to the secondary school teacher of 

 science. 



The sincere thanks of the author are extended to all who by 

 advice and suggestions have helped make this book possible. 

 The following have read the manuscript in its entirety : Annah P. 

 Hazen, Head of the Department of Biology in the Eastern Dis- 

 trict High School, City of New York ; Leshe L. Hunt, Department 

 of Biology, Galesburg High School, Galesburg, 111. ; George W. 

 Hunter, III, Assistant in Biology, University of Illinois, Urbana, 

 111. ; Rosemary F. Mullen, Head of the Department of Biology, 

 Washington Irving High School, City of New York; Mary E. 

 Robb, Department of Biology, Hyde Park High School, Chicago, 

 111. ; Jesse M. Shaver, Department of Biology, Peabody College, 

 Nashville, Tenn. ; Professor A. C. Walton, Department of Biology, 

 Knox College; and Dr. Frank M. Wheat, Head of the Depart- 

 ment of Biology, George Washington High School, City of New 

 York. Dr. Henry B. Ward, Head of the Department of Zoology 

 of the University of Illinois, and Mr. Robert Sterling Yard, 

 Executive Secretary of the National Parks Association, have also 

 offered valuable suggestions on certain parts of the book. 



Thanks are due, also, to Professor E. B. Wilson, Mr. William 

 C. Barbour, Dr. John A. Sampson, W. C. Stevens, and Wilham 

 Beebe; to the United States Department of Agriculture; the 

 New York Aquarium; the Charity Organization Society; and 

 especially to the American Museum of Natural History, for per- 

 mission to copy and use certain photographs and cuts which have 

 been found useful in teaching. Dr. Frank M. Wheat made most 

 of the line drawings prepared for this book and has given many 

 valua,ble suggestions. 



