APPENDIX I 133 



sharpened. Some students will need to use a harder pencil 

 than others and each will need to experiment a little per- 

 haps. The teacher can advise in such matters. 



Eraser. A good soft rubber eraser will answer very well, 

 but students may consult their own tastes in this matter. 



Forceps. For handling small objects, even very slender 

 fingers are too large and clumsy, and the student should 

 possess a pair of small forceps for this purpose. Steel ones 

 are the best, but brass ones may be used. The tips of the 

 forceps should be fairly slender, and the points should be 

 roughened (not toothed) upon the inside so as to grasp the 

 object firmly. The " spring " of the forceps should be fairly 

 but not too strong. Too strong a spring tires the fingers 

 unnecessarily, while too weak a spring (so that the forceps 

 do not open promptly) renders them practically useless. 



Scalpel. A small scalpel is most useful for cutting small 

 objects. A penknife, provided the blades are kept sharp, 

 will do very well. A small razor with one side ground nearly 

 flat is perhaps even more useful at times than either the 

 penknife or scalpel. 



Pocket Lens. A pocket magnifying-glass mounted in 

 metal or hard rubber (or better a series of two or three 

 mounted lenses) is indispensable for the examination of 

 small parts. Almost any of the common ones in the market 

 will do. A simple dissecting microscope is, however, very 

 much more effective. Some of the cheaper ones will answer 

 very well, but the only really satisfactory one, is one possess- 

 ing besides a good stage (upon which the object may be 

 placed) and a good adjustable arm for carrying the lens, 

 also a mirror, adjustable to any angle. (Such a model as 

 the " Educational Dissecting Microscope " of the Bausch 

 and Lomb Optical Company of Rochester, N.Y.). 



Dissecting Needles. For use with the dissecting micro- 



