PREFACE 



THIS text is an attempt to present the fundamental facts of 

 elementary biology as clearly and briefly as a reasonable scientific 

 accuracy will allow. Three years' use in manuscript form has 

 dictated the topics included and the arrangement followed in order 

 that the book may be easily taught and readily understood. 



The course emphasizes the fact that biology is a unit science, 

 based on the fundamental idea of evolution rather than a forced 

 combination of portions 0f botany, zoology and hygiene. 



Emphasis has been placed upon a logical arrangement within 

 the chapters, so that it is easy for the pupil to study, outline, 

 and remember each lesson. 



A larger proportion of pages is devoted to outlines, tabulations, 

 and diagrams than in any other similar text. This means that 

 the pupil has less text matter to cover, and more help to assist 

 him in doing it. 



No laboratory work is included. Any laboratory manual can 

 be used with the text, however, as it covers much more than the 

 required ground. It is thought that a separate manual will allow 

 the teacher to emphasize in the laboratory, those subjects which 

 he considers most important. 



Experience has indicated that the "vocabularies" save the 

 pupil much time and confusion. Particular care has been taken 

 to keep the vocabulary of the text as simple as possible. Careful 

 explanations are made where this seems advisable. The definitions 

 in the text are not complete, but, for the sake of clearness, are 

 purposely limited to those meanings which fit the use in the chapter 

 concerned. 



In any science subject collateral reading is highly important. 

 To facilitate this, lists of references have been placed at the ends 

 of the chapters, covering such books as should be available in a 

 well-equipped school. This outside reading should be encouraged. 



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