INTRODUCTION 21 



When a knife becomes dulled and stropping is no longer suffi- 

 cient to renew its edge, it should be honed. So few men learn 

 how properly to hone a knife that it has been questioned whether 

 students had better attempt it themselves or turn their scalpels 

 over to an instrument-maker to be honed. Still, as one needs also 

 to know how to keep a microtome-knife in repair, it is an advan- 

 tage to learn to do the honing one's self. A good oil-stone or Ar- 

 kansas stone is necessary. The knife, held obliquely, is drawn 

 to and fro with the edge in advance, the stroke extending from 

 the heel along the whole length to the toe of the blade. Ex- 

 perience under some one who is skilled is very desirable, that one 

 may know the exact angle of inclination to employ, and the point 

 when the blade has been sufficiently honed, for after a time a 

 continuance of the honing only does harm. Much skill and ex- 

 perience are required to get exactly the right thinness of edge. 

 It is to be borne in mind that dissecting knives ought not to be so 

 thin as a surgical knife, where quick penetration is all-important 

 and the knife is to be used only for a short period, for such 

 knives are quickly dulled. 



After repeated honing a knife may lose all its thin edge ; it 

 should then be ground. 



The student should avoid injuring his scalpels by cutting 

 against bone or the end of the forceps. It is well to keep one 

 coarse knife especially for cutting near the bone or through 

 calcified tissues. 



All instruments should be cleaned and rubbed thoroughly 

 dry before they are put away at the end of a day's work. If a 

 dissection has been completed and the instruments are to be 

 laid aside for some time, they should be boiled for ten minutes 

 in a one per cent, solution of sodium carbonate, thoroughly dried, 

 and lightly coated with clean vaseline. This sterilizes them com- 

 pletely and helps to prevent rust. 



USE OF INSTRUMENTS. 



Scalpel. One of the most important things for the student 

 to learn in technique is the use of the convex or belly-bladed 

 scalpel. This blade has a long cutting edge, and is employed for 

 making large cuts or for cutting large surfaces; it is unsuited 

 for small, careful cuts or for dissecting in angles or in the depth. 

 The convex scalpel is used chiefly in dissecting the skin, fascia, 

 and muscles, and in general where large incisions are to be 

 made and the work is relatively gross. In the dissection of 

 vessels and nerves, on the other hand, the larger belly-bladed 



UBARV 



