Preface 7 



by means of which the student may readily acquire his necessary bio- 

 logical vocabulary; (b) methods for starting and caring for a balanced 

 aquarium which may be applied in the care of out-of-door pools; (c) 

 directions for collecting, preserving, and mounting insects, which may 

 be profitably continued long after a formal course in biology is com- 

 pleted; (d) a glossary which includes the derivation and definitions of 

 the important terms used in biology. 



The essentials of biology are so arranged as to permit an easier and 

 more effective mastery of the fundamentals. In brief, the book is 

 designed to "help the instructor help the student to help himself." 

 Zoological phases of the text may be emphasized more than the botani- 

 cal, or the latter may be reduced to a minimum to suit the type of 

 course. The author believes that beginning students in biology should 

 become familiar with both plant and animal fields because a majority 

 of them will not take specific courses in both fields. With the proper 

 foundation in both fields, those who desire may take specific courses in 

 either zoology or botany or both. The author is also of the opinion 

 that the principles of biology best can be learned by a rather careful 

 study of well-selected types of animals and plants. This conclusion is 

 the basis for the variety of animal and plant types considered. The 

 variety is sufficiently great as to permit the instructor to select those 

 which best fit the needs of the course as it is being offered. 



No attempt can be made in a work of this type to give due credit to 

 the many sources of information which through many years of common 

 use actually have become a part of the science. Cordial thanks are 

 extended to the authors, publishers, colleagues, and students who in 

 various ways have supplied the necessary materials and suggestions for 

 such a work as this. Special acknowledgments are made to Dr. E. T. 

 Bodenberg, Dr. C. G. Shatzer, Dr. C. A. Lawson, Dr. J. W. Barker, 

 Professor R. P. Thomas, and Professpr B. B. Young for their many help- 

 ful suggestions; and to Miss Adrien Jingozian for preparing Figs. 95, 

 95A, 96, and 132; to Dr. O. L. Inman, of the C. F. Kettering Founda- 

 tion for the Study of Chlorophyll and Photosynthesis, for his many help- 

 ful suggestions in Chapter XXXVIII; and to many others who directly 

 or indirectly have helped in various ways. 



William C. Beaver 



Wittenberg College 

 Springfield, Ohio 



