THE PRINCIPLES OF NATURE STUDY 49 



omitted; far from it! It means simply that all structure 

 must be interpreted as to function so far as possible. 

 'Activity is to be the dominant idea. For example, the 

 general structure of leaves ought to be observed, but only 

 as leading to interpretation of their exceedingly important 

 work. This dominating idea determines the structures 

 to be observed, and eliminates all dead work. The general 

 habits of trees ought to be observed in relation to their 

 scheme for the position of branches and the display of 

 foliage. The structure of bird feathers or of insect mouth 

 parts or of gastropod shells should be studied, but always 

 in terms of the part they play in the economy of the animal's 

 daily existence. 



This is not to be confused with the habit of assigning a 

 designed purpose, often more or less obscure and forced, 

 to every structure met. Warning has already been given 

 as to the dangers in wholesale claims of adaptations. 

 Where the structures observed have an obvious use that use 

 is to be brought out, always by the children rather than the 

 teacher, but the form of statement that things are thus 

 and so because of such a need of the organism is a form of 

 statement whose assumption is usually unwarranted by 

 the facts and is to be avoided. 



To show that plants as well as animals are busily at 

 work simple experiments are valuable and usually arouse 

 decided interest. Seeds are commonly germinated in the 

 schoolroom in connection with nature study. Pupils in 

 upper grades have been heard to complain that they "had 

 beans in every room." The loss of interest and time in 

 repetition has been pointed out, but the value and interest 

 of germination work are enhanced by the use of various seeds 



