PREFACE 



THIS work is intended to serve as an introduction to the 

 study of botany and zoology. It has been for some time recog- 

 nized that there is a series of laws and principles which relate 

 both to animal and plant life, and another series of important 

 facts which refer to the relations of animals and plants to 

 each other. In helping to a comprehension of nature, these 

 interrelations are really of more significance than the detailed 

 study of certain animals and plants. But with the tendency 

 shown frequently in our educational system, to divide biology 

 into zoology and botany, there is danger that these fundamental 

 truths and interrelations be neglected, since a consideration of 

 them belongs strictly neither to zoology nor to botany. 



To students of the age of those in secondary schools, the 

 study of such concrete facts as the description of animals and 

 plants is most attractive; and for them, courses in elementary 

 botany and zoology are eminently appropriate. But to students 

 of the greater maturity of college grade, the study of the funda- 

 mental biological laws is more stimulating and better calculated 

 to develop the thinking powers. It is, therefore, the author's 

 belief that the proper way for older students to begin the 

 study of the great department of biology is to consider the 

 fundamental principles relating to both animals and plants, 

 before either of these groups is studied in detail. After the 

 student turns his attention more particularly to zoology or 

 botany, he is likely to be engrossed in the details of the life 

 and structure of animals and plants, and so almost inevi- 

 tably neglects the broader fundamental laws which should 

 correlate the phenomena of life as one science. Unless, there- 

 fore, the foundation principles of biology be studied as an 

 introductory course, it is very probable that they will be 

 neglected. For this reason, this text has been provided as 



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