ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 



663 



fastened to it, and in which the tooth-wheel spindle moves, is formed of 

 two halves, on each of which, as in a forceps, a limit is affixed. A 

 -pring 'applied between these presses both parts sufficiently tight 



Fig. 156. 



together. A* pressure on the limb suffices to open the screw, and the 

 object-holder can then be pushed up and down. 



By the use of two screws in the knife-holder it is possible to set the 



Fig. 157. 



knife flat or oblique ; moreover, the knife moves on a slab rotatory 

 about an axis (figs. 155 and 156). The screw for clamping the knife- 

 rest moves on a block in a groove, whereby the adjustment of the clamp 



