CYTOLOGICAL METHODS 



257 



but an ordinary razor will not need this back. While honing 

 hold the knife in the position shown in Fig. 144, keeping the 

 back as well as edge against the stone, and while pushing the 

 knife edge foremost slide it at the same time from point to heel 

 as shown by the arrow. Then turn the other face of the knife 

 to the stone and repeat the stroke from point to heel toward the 

 other end of the stone, and so on until the thumb test above de- 



FiG. 144. — Sho-mring the manner of honing the section knife or razor. 



scribed is satisfactory. Do riot allow the stone to gum up; keep 

 plenty of oil upon it if it is an oil stone, or if a water stone keep 

 it well lathered with soap and water, and wipe the stone clean 

 after honing. Then strop the knife, drawing it over the leather 

 back foremost from heel to point (Fig. 145), reversing the face 

 for the back stroke, and keep this up until the knife readily 

 clips a hair. 



Cytological Methods. — Within comparatively recent times 

 methods have been worked out whereby the anatomy of cells 

 17 



