VALENTIN'S KNIVES. 



183 



a piece with a pair of sharp scissors," or " cut a piece off 

 with a sharp scalpel," but all slides prepared in this manner 

 are mere fragments compared with the splendid sections of 

 Marsh, Cole, Wheeler, Norman, Ward, and others. 



FIG. 168. 



Fresh animal tissues, such as kidney or liver, are 

 frequently cut with Valentin's knife (Figs. 168 and 169). 



FIG. 169. 



This instrument is formed of two narrow blades lying 

 parallel to each other, their distance being regulated by 

 means of a fine screw. The knife is used immersed in 

 water ; it is drawn through the tissue to be cut, in a saw- 

 like fashion, the sections being afterwards disengaged by 

 shaking the blades gently in water. Dr. Maddox's form of 

 this knife is one with triple blades, so that a double section 

 might be cut, to show opposite but contiguous surfaces. It 

 is shown in Fig. 170. 



FIG. 170. 



Dr. Sylvester Marsh, who has written a small manualette 

 upon the subject of section-cutting, has devised a simple 

 but useful spoon for lifting thin sections. It is shown in 

 Fig. 171. 



After all, these methods of cutting are exceedingly 



