Introduction. xv 



working over will fill them with an interesting meaning, and the 

 work will cease to be drudgery and become a source of increasing 

 entertainment. 



BOOKS OF REFERENCE. 



1. The American Natural History, Hornaday. 



2. Riverside Natural History, Kingsley. 



3. A Manual for the Study of Insects, Comstock. 



4. Key to the Birds of North America, Coues. 



5. Manual of the Vertebrates, Jordan. 



6. A Naturalist's Rambles about Home, Abbott. 



7. Animal Life, Jordan and Kellogg. 



The first five of these should be used for reference. Each student ought to 

 read the last two. 



USE OF THE MICROSCOPE. 



General Rules. i. Do not touch lenses, nor allow them 

 to touch anything. 2. Keep the instrument away from dust. 

 3. If dust gets on a lens blow off as much as you can and 

 then wipe with chamois skin, or clean soft cloth, such as old 

 linen. Handle the microscope by the pillar below the stage. 



Setting up a Microscope. The eyepiece should slip easily 

 into place by its own weight. To attach an objective, first run 

 the tube up by the coarse adjustment, till the lower end of the 

 tube is two or three inches from the stage. Then hold the ob- 

 jective with the thumb and finger of one hand while the other 

 hand screws it to place. See that the threads catch fairly ; do 

 not use force or you may ruin the threads. Take care not to 

 touch the lens. 



Use of a Low-power Objective. Place on the stage a slide 

 holding a mounted preparation. Slip the ends of the slide 

 under the clips. Place the specimen over, the center of the 

 hole in the stage. Turn the mirror so that it throws light 

 through the hole upon the mounted object. Lower your head 

 to the level of the stage and watch while running the tube down 

 by the coarse adjustment ; stop when the objective is a quarter 

 of an inch from the glass slide. Take hold of the milled head 



