PREFACE 



THE present tendency in secondary education is away 

 from the formal technical completion of separate subjects 

 and toward the developing of a workable training in the 

 activities that relate the pupil to his own life. In the 

 natural science field, the tendency is to attach less im- 

 portance to botany and zoology and physiology as such, 

 and to lay greater stress on the processes and adaptations 

 of life as expressed in plants and animals and men. This 

 tendency is a revolt against the laboratory method and 

 research method of the college as it has been impressed 

 into the common schools, for it is not uncommon for the 

 pupil to study botany without really knowing plants, or 

 physiology without knowing himself. Education that is 

 not applicable, that does not put the pupil into touch with 

 the living knowledge and the affairs of his time, may be 

 of less educative value than the learning of a trade in a 

 shop. We are coming to learn that the ideals and the 

 abilities should be developed out of the common surround- 

 ings and affairs of life rather than imposed on the pupil 

 as a matter of abstract, unrelated theory. 



One of the marks of this new tendency in education 

 is the introduction of unit -courses in biology in the sec- 

 ondary schools, in the place of the formal and often dry 

 and nearly meaningless isolated courses in botany, zoology, 

 and physiology. This result is one of the outcomes of the 

 recent nature-study discussions. 



The present volume is an effort to meet the need for 



