PREFACE Vll 



science teachers in secondary schools and colleges is leading 

 towards some golden mean between the old-time lecture and 

 demonstration method and the more recent laboratory work 

 for individual students. The authors have suggested for 

 demonstrations all practical work which experience shows is 

 ill-adapted for individual study by students with limited time 

 and training. See foot-note on page 10. 



. One of the authors has discussed the meaning of the move- 

 ment towards a course in introductory biology, instead of 

 separate courses in botany and zoology, in Chapter V of Part II 

 in Lloyd and Bigelow's " Teaching of Biology in the Secondary 

 School," and also in School Science and Mathematics for Octo- 

 ber, 1908; and the principles there stated have been held 

 fundamental while making this book of "Applied Biology." 

 See also the " Teachers' Manual." 



While it would be easily possible to select from this book 

 material for a very elementary course of biology in the first 

 year of some high schools, the authors have planned to issue 

 a smaller book especially arranged with reference to the 

 present peculiar conditions obtaining in high schools where 

 a course of biology comes in the first year. 



The authors acknowledge the useful suggestions and con- 

 structive criticisms which they have received from many 

 teachers of biology ; and especially are they grateful for the 

 help on numerous problems which have been discussed with 

 Professor H. M. Blchards and Professor C. C. Curtis, of 

 Columbia University, and with Miss Jean Broadhurst and 

 Miss Caroline Stackpole, of the Department of Biology in 

 Teachers College, Columbia University. Also, acknowledg- 

 ments are due publishers and authors who have granted per- 

 mission for the use of numerous illustrations from standard" 

 books. As far as sources were known to the authors, credit 

 for figures has been given in the legends. 



The authors cordially invite correspondence from teachers 



