336 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fiq. 61. 



S 



position. Spring clips of some sort hold the razor firmly in place. For 

 the clips stout wire an eighth of an inch thick is good. Each wire may 

 he fastened to the hoard by double-pointed tacks. Near the bottom of 



the board, and in the centre, is the screw 

 S (fig. 61). A common screw will answer, 

 but a fine-threaded screw, passing through 

 a nut, is better. In either case, however, 

 a large disc may be soldered to the screw- 

 head for increased delicacy in operation. 

 The ' holder ' complete is now, by means 

 of a pair of hooks and eyes, to be made 

 attachable to the end of a box, so that 

 turning the screw gives a delicate move- 

 ment to the razor. The screw-point should 

 work against a small metal plate on the 

 box. Tension is secured with a rubber 

 band or spiral spring. Eeference to the 

 diagram (figs. 61, 62) will make the idea 

 clear. The ' holder ' should be so placed 

 that the razor- edge will be two or more 

 inches higher than the top of the box. 

 Now, when an adjustable object-holder 

 is provided, the microtome is completed. 

 To make the object-holder, a hoard some- 

 what shorter than the box, a block, and a 

 straight-grained stick about half an inch in cross-section, are necessary. 

 Fasten the block near one end of the board, nail the stick to the block 



Fig. 62. 



KNIFE HOLDER. 



(as indicated in the diagram), and the microtome is ready for service. 

 In use the paraffin block O is fastened to the end of the stick with 

 melted paraffin, and proper adjustments aro made with reference to the 



