224 NATURE STUDY. 



structure, because some knowledge of structure will be 

 necessary to understand life history, as in grasshopper 

 or crayfish, and because the life history, being merely 

 told to the children, will be hazy. What is hazy, the 

 weak link in the chain, should be left to the last and 

 made subordinate, so that later important steps will not 

 depend on it. 



We have studied plant or animal or stone as to : 



First. Its name and significance of name. 



Second. Its relation to natural environment. 



Third. Its habits and the functions of its parts (and 

 its life history?). 



Fourth. Its adaptation to function or its structure 

 (and life history ?). 



In the endeavor to farther unify our knowledge, the 

 object or phenomenon studied must now be compared 

 with others like and unlike it, so that what is like it 

 may be grouped with it, and what is unlike separated 

 from it. Thus in time the things we have studied are 

 not mere individuals, but types of classes, the grass- 

 hopper of hundreds of insects, the robin of scores of 

 birds, the buttercup or wild rose or lily-of-the-valley 

 of groups or families of plants ; and the experiments 

 we perform explain many phenomena, as the evapo- 

 ration and condensation of water from the tea-kettle 

 help the pupils to understand about the formation of 

 dew and rain and mist and fog and cloud. 



The purposes or objects of comparison or association, 

 and of classification or generalization, are: 



