iv PREFACE 



an introductory survey of the laws which apply to both ani- 

 mals and plants, and those principles which coordinate and 

 correlate them. It is hoped that it may have some influence 

 in developing the study of the fundamental principles of biology 

 as an introductory course, thus supplanting the old custom of 

 plunging the student at the outset more specifically into zoology 

 or botany. 



It is designed that this work shall be an elementary study 

 of biology, on a par with, and parallel to, elementary physics 

 and chemistry. Logically it should follow, rather than pre- 

 cede, these two sciences, although it may be taken simultane- 

 ously with them. Its place in a curriculum should, therefore, 

 be about the same as that of elementary physics and chemistry; 

 and as developed in the following pages, it belongs to the be- 

 ginning of college work. 



In preparing these pages, it has been recognized fully that 

 a certain amount of laboratory work is necessary in order that 

 the student may properly understand biological phenomena. 

 It is also appreciated that, with the present development of 

 the teaching of biology and the present equipment of many of 

 our institutions, it is frequently impossible to introduce any 

 extended laboratory work, on account both of insufficient equip- 

 ment and lack of time in the already crowded courses of study. 

 For this reason, the chapters have been arranged so that, where 

 necessary, they can be used without the accompanying labora- 

 tory demonstrations. Although this is an undesirable method 

 of studying biology, the author believes that the biological 

 principles covered in the following pages may be comprehended 

 in a fairly satisfactory manner, even though the student does 

 not have the opportunity of making the laboratory tests. It 

 is hardly necessary to state, however, that as much practical 

 laboratory work as possible should accompany the study of 

 the text. For this reason, outlines of the correlative laboratory 

 work have been added at the end of the chapters. In all cases 

 where laboratory work is possible, students should be required 



