CHAPTER 5 



Materials and Equipment 



This brief introductory chapter is intended only for those who have 

 never made a microscope slide and so are unacquainted with any of the 

 names of the pieces of equipment used in its production. As these names 

 will be used freely throughout the other chapters in this book, it is well 

 here, by reference to illustration and descriptions, to make sure that the 

 beginning student knows what the terms mean. 



Slides and Coverslips. The "microscope mount" consists essentially of 

 something intended for examination under the microscope, winch is held 

 between a "slide" and "coverslip." The slide is almost invariably a piece of 

 thin glass 3 in. by 1 in., although on rare occasions big series of sections are 

 mounted on 3- by 1%-in- or even 3- by 2-in. slides. It is a great mistake 

 to use slides that are too thin, for not only are they very easily broken, 

 but they also do not work well with the condensers of most modern micro- 

 scopes. A thickness of approximately 1 mm is the optimum, but slides as 

 thick as 1% mm are perfectly satisfactory. It is essential that the surface 

 of the slide be flat and that the glass of which it is composed be as 

 stable as possible for it will have to be passed through a great number of 

 reagents. These stable glass slides are usually called "noncorrosive," and 

 it is a great pity to use any other kind. 



Coverslips are circles, squares, or rectangles of thin glass; they are 

 rarely, particularly in the larger sizes, completely flat. They are made in 

 four thicknesses known as No. 0, No. 1, No. 2, and No. 3, each of which 

 has its own special use. No. coverslips, which are about 0.09 mm thick, 

 are very difficult to handle and should be used only on preparations that 

 are to be examined with an oil-immersion objective. They are rarely used 

 today since most people, even for immersion lenses, prefer a No. 1 cover- 

 slip, which averages about 0.15 mm in thickness. No. 1 coverslips are 

 easier to handle and to clean than are No. 0. No. 2 coverslips, which aver- 

 age about 0.20 mm in thickness, are generally used on wholemounts, 

 which are not customarily examined with the highest powers of the micro- 

 scope. They are sufficiently thick to be easy to clean without breakage 



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