PREFACE 



As you begin the study of biology you 

 begin a most exciting adventure, the 

 study of animals and plants — the living 

 things of the earth. You are one of these 

 living things, so you will learn much 

 about yourself. The study of living 

 things is not only exciting; it is impor- 

 tant to all mankind. Our knowledge of 

 biology has made it possible for us to 

 avoid many diseases, to provide more 

 and better food, and to understand our- 

 selves better. 



The study and teaching of biology is 

 the lifework of many people. They are 

 professional biologists. It is possible that 

 you will make the study of biology your 

 lifework. If so, you will find much in 

 this book to help you toward that goal. 

 In writing Adventures ivith Animals and 

 FlajJts, however, the authors had in 

 mind, principally, the much larger num- 

 ber of people who will not become pro- 

 fessional biologists. All of us need to 

 know many of the facts and principles 

 of biology in order to understand our- 

 selves and make the best use of many of 

 the things we see, hear about, and read 

 about. 



Whether or not you make biology 

 your lifework, you will want to know 

 how a professional biologist works and 

 thinks, how he discovers the facts and 

 principles that are so useful to all of us. 

 Biologists, and other scientists as well, 

 use a special method of discovering 



and testing facts and principles. It is 

 called the scientific method. As you 

 study this book, the scientific method 

 will be brought to your attention many 

 times. 



Hygiene, which is the science of main- 

 taining health and the prevention of dis- 

 ease, is based upon a knowledge of many 

 parts of biology. Throughout the book 

 you will find information that will be 

 useful to you in keeping healthy. 



We learn the facts and principles of 

 biology by three methods. One is by ob- 

 serving animals and plants, a\ riting down 

 what we observe, and comparing what 

 we see with what others have learned. 

 By a second method we also use observa- 

 tion, but we observe and interpret the 

 results of an experiment which was set 

 up to try to answer some question or 

 problem. A third method is to read what 

 others have learned bv the use of the 

 first two methods. In using- this book 

 you will make use of all three methods: 

 you will read, you will observe, and 

 you will experiment. Perhaps, if you are 

 a keen observer, or become one, you will 

 discover something no one else has ever 

 learned. 



In this book you will read about many 

 of the facts that biologists have learned 

 by observations and experiments; and 

 you will learn what conclusions or prin- 

 ciples have been stated to summarize or 

 explain the facts. You will frequently 



