194 THE NA TUKE-STUD V REIVE IV [ 3 : 7 - ct., .907 



ner of presentation and not inherently in the subject-matter. 

 We need to avoid such desultory work in nature-study, or be 

 assured it will be temporarily abandoned. 



Some unifying element must be introduced or the course of 

 study becomes fragmented, resulting in a series of uncoordinate, 

 efforts that lose their cumulative effect. In a course aiming to 

 develop thought power this unifying factor would best be a series 

 of logically related ideas or a dominant concept. It is only by 

 some such unifying idea that the nature-study movement can 

 hope to achieve uniformity. The objects to be studied are so 

 varied, the world over, that there can be no course prescribed 

 with identical materials. A theme, however, may be worked out 

 uniformally and still use dissimilar objects. We must seek, then, 

 some unifying idea in nature -study sufficiently complex to insure 

 an increasing difficulty commensurate with the increasing power 

 of the pupils. 



Historically, scientific thought has been unified by the concept 

 of evolution. I can find no other idea that promises to so 

 thoroughly unify nature teaching. Not that the concept of evolu- 

 tion should be taught, or even suggested in the grades, but in the 

 selection of material and of the minor problems for study, we 

 should choose such as will store the mind of the pupil with the 

 facts, which, in his mature years, will enable him to think clearly 

 along the line of evolution — an idea that has come to affect 

 vitality the whole philosophy of life and that promises large 

 inspiration. Moreover, such a stimulating concept is rejuvenat- 

 ing to the teacher. It sends her afield with new interests, keen 

 to perceive again with childish delight the old, now new, environ- 

 ment. 



I am advocating in this no pedagogical heresy or even a new 

 idea. For we select the matter for study in the grades in other 

 lines in a totally analagous manner. We do not study all histoi v. 

 We ignore the Patagonians, the Icelanders, the Dahomies. 

 Attention is engrossed in fact by a geographically insignificant 

 region. We study the history of those people that have con- 

 tributed directly to the evolution of modern civilization. In 

 literature we do not read all authors. In fact we strive to elimi- 

 nate from the student's consideration the great bulk of printed 

 matter and confine his attention to those writers whose work has 

 contributed to the development of the world's thought and the 

 advance of the art of expression. The third principle may then 



