ON STAINING FLUIDS, AND STAINING. 121 



Professor Rutherford's Microtome. 



This is Stirling's original well and screw- 

 microtome, plus an ice box arrangement. It is 

 used by filling the ice box with well-powdered and 

 mixed ice and bay salt in equal quantities. Whilst 

 freezing is going forward the well may be covered 

 with felt. One or several tissues can be cut at 

 once, either with a Rutherford's knife, or, what is 

 now found to be far better, a plane iron. By a 

 plane iron, we mean the iron taken out of a car- 

 penter's smoothing plane. These irons must be 2f 



inches broad, and are used either with or without a 

 covering of wood. When double-faced with wood, 

 the handling of them is more pleasant, but it does 

 not add to efficiency. The iron must be sharpened 

 on a very smooth hone, and then well stropped. 

 In sharpening, care must be taken to rub the entire 



