THE SIMPLE MICROSCOPE 13 



to be prepared for examiaation under the higher 

 power of a compound microscope. 



From such simple dissection he may proceed by 

 easy stages to more elaborate work, not only in 

 botanical study, but in other lines. For example, 

 a beetle is a good subject for the beginner. Let it 

 be pirmed on to a flat piece of cork, say 2 inches 

 square, weighted with lead. Prehminary dissection 

 of wing-cases, wings, legs, antennae, etc., should be 

 effected in air under the lens ; but when the internal 

 anatomy is to be dealt with, the object, secured to 

 the weighted cork, should be sunk in a vessel of 

 hquid. If the dissection can be proceeded with 

 quickly, water wiE do ; but if the object is to remain 

 long in hquid, a 4 per cent, solution of formalin 

 will serve. The various organs and tissues require 

 dehcate handling ; scalpel, needles, forceps, syringe, 

 and camel-hair brush wiU be brought into use. 

 The viscera can be more readily separated in fluid 

 than in air, and their details are more apparent in 

 that medium. Each part as separated comes in 

 for examination under the compound microscope, 

 and, if desirable, can be mounted on a glass shp as 

 a permanent object. Moimting -nTll be discussed in 

 a later chapter. 



Watch-glasses are often used to contain objects 

 in fluid during dissection. In cases in which larger 

 vessels are required, small photographic developing 

 dishes, plain, shallow salt-cellars, porcelain oint- 

 ment boxes, or other vessels at hand, may suggest 

 themselves. Square slabs of glass with deep con- 

 cave cells and cover glasses are sold for the purpose 

 at low cost. 



