PREFACE TO FIRST EDITION 



If an attempt were made to include in a textbook much of the infor- 

 mation accumulated in the field of biology, the beginning student would 

 have difficulty in properly selecting the important parts as well as prop- 

 erly visualizing and retaining the fundamentals as he should. This 

 book is written with the hope that it will be of greater service to the 

 instructor and the student by presenting the more important biological 

 facts briefly enough to permit a complete comprehension of the subject 

 as a whole and also to serve as a skeleton to which such additional data 

 may be added as seem desirable. An attempt is made to systematize 

 and condense our biological knowledge so that it can be more easily 

 taught, visualized, and mastered. 



Particular attention is called to the following features: (1) Greater 

 emphasis is placed on the economic importance of animals and plants. 

 (2) A generalized discussion of the location and functions of the impor- 

 tant ductless (endocrine) glands, especially in man, is included. (3) A 

 comparative study of the ten systems of twenty-eight representative 

 animals, including man, is made in Chapters IX to XVIII. The method 

 of presentation permits the study to be made either on a comparative 

 basis or by studying the various systems of a particular animal by 

 selecting the proper parts of each of these chapters which deal with the 

 animal being studied. This method of presentation better illustrates the 

 general principles of the science as well as the unity and various rela- 

 tionships within the biological world and gives the student the oppor- 

 tunity of basing his conclusions and formulating his principles upon the 

 study of representative animals. (4) A comparative study of the vari- 

 ous structures and functions of fifteen representative plants is made in 

 Chapters XXIV to XXIX. These plants may be studied on a com- 

 parative basis, or the proper parts of each of these chapters may be used 

 in studying the plants in the usual manner. (5) A detailed reference 

 list of illustrations and drawings in other texts will be of service to the 

 student in his attempt to understand certain points. (6) The general 

 consideration of the phyla of animals and plants includes their general 

 characteristics, a brief but satisfactory classification, and a summary of 



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