24 THE NATURE-STUDY REVIEW [i, i, jan. 1905 



and nature-study, should be brought under as few large headings 

 as possible, just as a good lecturer is under obligations to present 

 his thoughts under a few good points. . . . 



" In the second place, those subtopics should be selected in each 

 branch of study that are the best types of large groups, and that 

 thus give strategic positions in the field. . . . 



" In the third place, the leading questions that need to be 

 answered under each type, or other topic, need to be clearly con- 

 ceived in order to find a basis for selection of details. For in- 

 stance, I have an extension class of y6 primary teachers — much 

 above the average in ability — who agreed on 22 little points that 

 they desired to teach on the cat, as a topic in nature-study. But 

 until the principal questions that they had to answer in regard to 

 the cat were known, to which these many facts might be the 

 answers, their subject-matter was absolutely unorganized, and 

 they were unprepared to give the instruction. Now our main in- 

 terest in cats is as pets, and if we set out to learn ( i ) to what ex- 

 tent cats can provide for themselves, and therefore (2) to what 

 extent, and how, we should take care of them as our pets, we shall 

 cover all that is necessary about them. And when we desire only 

 the answers to these problems, we are given a standard that allows 

 the omission of the number of teeth, the color of the hair, the 

 length of the tail, and forty other facts that might consume time ; 

 in short, that lets us know when we are done with the cat. So, if 

 we set out to find out how grasshoppers sometimes prove injurious 

 to man, and what means may be used to destroy them, we must 

 discuss the food of the insect, his voracious appetite, his means of 

 locomotion and quickness, his enemies (including parasites), his 

 protection by mimicry^ and his stages of development; but we 

 shall have no time to consider whether or not he knows enough 

 to go under cover when it rains, provided he can find cover, or 

 the fact that he can eat apples, since he will never get many apples 

 to eat anyway. 



" Similarly, in geography, if we set out to learn what are the 

 main industries that have sprung up in the Western States, with 

 the causes, we shall need to consider the climate and topography, 

 as the principal key to the situation, and then the mining, lumber- 

 ing, agriculture, manufacturing, trade and manufacturing centers, 

 etc., but we shall have no excuse for bounding all the States, learn- 

 ing each capital and locating various capes, small towns, insignifi- 



