SUPPORTING TISSUES FOE CUTTING. 19 



may be held in the vise of the microtome. The edge of the knife 

 should not be allowed to touch the cork. 



Fig. 11 shows a simple little instrument, very convenient for using 

 paraffin as a cement. A piece of stout copper or brass wire is bent 

 as indicated, pointed, and driven into an ordinary awl handle. 

 Paraffin wax possesses the very valuable property of remaining solid 

 at ordinary temperatures, not cracking in the cold of winter or 

 softening in summer. It is unaltered by most reagents, is easily 

 rendered fluid, and quickly solidifies. As a cement, it is invaluable 

 to the microscopical technologist. 



FIG. 12. MODE OF CEMENTING TISSUE TO A CORK SUPPORT WITH PARAFFIN. 



Fig. 12 indicates the method of cementing a piece of tissue to a 

 cork or other support. The tissue having been properly placed, the 

 wire tool is heated for a moment in the alcohol flame, and then 

 touched to a cake of paraffin. The paraffin is melted in the vicinity 

 of the hot wire, a drop adheres to the latter and is carried to the edge 

 of the tissue. In the cut the wire tool is seen in the position neces- 

 sary for cementing one edge. The wire being removed, the wax im- 

 mediately cools and becomes solid. The other sides are afterward 

 cemented in like manner. The whole is done in less time than is 

 necessary to the description of the process. 



