vi PREFACE 



a simple and untechnical text to cover this secondary 

 biology in its elementary phases. The book stands be- 

 tween the unorganized nature-study of the intermediate 

 grades and the formal science of the more advanced 

 courses. It is a difficult space to bridge, partly because 

 the subjects are so diverse, and partly because some 

 teachers do not yet understand the importance of im- 

 parting to beginners a general rather than a special 

 view point. 



Still another difficulty is the lack of uniformity in the 

 practice of different schools. It is not urged that it is 

 desirable to have uniformity in all respects, but the lack 

 of it makes it difficult to prepare a book that shall equally 

 meet all needs. It is hoped, however, that the present 

 book is fairly adaptable to a variety of conditions, and 

 with this thought in mind the following suggestions are 

 made as to its use : 



Being in three separate parts, the teacher may begin 

 with plants, or with animals, or with human physiology. 



If a one-year course is desired, the topics that are 

 printed in large type in Parts II and III may be used, 

 and a choice from the chapters in Part I. 



For three half-year courses, all the parts may be cov- 

 ered in full. 



If the course in biology begins in the fall (with the 

 school year), it may be well to study plant biology two 

 days in the week and animal biology three days until 

 midwinter; when outdoor material becomes scarce, human 

 biology may be followed five days in the week; in spring, 

 plants may be studied three days and animals two days. 



If the use of the book is begun at midyear, it will prob- 

 ably be better to follow the order in the book consecu- 

 tively. 



