38 THE MICROSCOPIC PREPARATION. 



other by the end. The hone is placed on a table with one end directed 

 toward the person sharpening. If the knife is very dull, it is ground for 

 some time on the concave side only (all microtome knives are practically 

 plane on one side and concave on the other), with the knife at right 

 angles to the stone. It is carried from one end of the stone to the other, 

 edge foremost, giving it at the same time a diagonal movement, so that 

 with each sweep the entire edge is touched (see Fig. 8). In drawing 

 back the knife, the edge is slightly raised. The knife is ground on the 

 concave side until a fine thread (feather edge) appears along the entire 

 edge. It is then ground on both sides, care being taken to keep the knife 

 at right angles to the stone, to keep it flat, and to use practically no pres- 

 sure. It is a good plan to turn the knife on its back when the end of the 

 stone is reached. On the return stroke, the knife is again held at right 

 angles to the stone, the same diagonal sweep is used (see Fig. 8), so that the 

 whole edge of the knife is touched with each sweep. The grinding on 

 both sides is continued until the thread above mentioned has disappeared. 

 The knife should now be carefully cleaned and stropped, with the back of 

 the knife drawn foremost. The strop should be flat and rest on a firm 

 surface. 



Fig. 8. Diagram showing direction of the movements in honing. 



THE FURTHER TREATMENT OF THE SECTION. 



\. FIXATION TO THE SLIDE AND REMOVAL OF PARAFFIN, 



Sections obtained by means of the microtome undergo further treat- 

 ment either loose or, better, fixed to a slide or cover-glass, thus making 

 further manipulation much easier. 



The simplest, surest, and most convenient method of fixing par- 

 affin sections to the slide is by means of the glycerin-albumen of P. 

 Mayer (83.2). Egg-albumen is filtered and an equal volume of glycerin 



