SECTION CUTTERS 



459 



iii water or, preferably, methylated spirit and water in equal parts. 

 An ordinary razor will answer for cutting. The motion given to 

 its edge should be a combination of drawhiy and press! />;/. " (It will 

 be generally found that 

 better sections are made 

 by working the kuifefroin 

 the operator than towards 

 him.) When one slice has 

 been thus taken off, it 

 should be removed from 

 the blade by dipping it into 

 spirit and water, or by the 

 use of a camel-hair brush ; 

 the milled head should be 

 again advanced, and an- 

 other section taken, and so 

 on. It is advantageous to 

 have the large milled head 

 graduated, and furnished 

 with a fixed index, so that 



FK,. :!s'.(. Simple microtome. 



this amount having been 



once determined, the screw shall be so turned as to always produce 

 the exact elevation required. "Where the substance of which it is 

 desired to obtain sections by this instrument is of too small a size or 

 of too soft a texture to be 

 held firmly in the manner 

 just described, it may be 

 placed between the two ver- 

 tical halves of a piece of carrot 

 of suitable size to be pressed 

 into the cylinder, and the 

 carrot with the object it 

 grasps is then to be sliced 

 in the manner already de- 

 scribed, the small section of 

 the latter being carefully 

 taken oft' the knife, or floated 

 away from it, on each occa- 

 sion, to pi-event it from being 

 lost among the lamella? of 

 carrot which are removed at 

 the same time. Vertical 

 sections of many leaves may 

 be successfully made in this 

 way, and if their texture be 

 so soft as to be injured by 

 the pressure of the carrot, 



they may lie placed between two half-cylinders of elder-pith, or be 

 imbedded in any of the ways employed with the more elaborate 

 microtomes about to be described. 



The modern art of section-cutting, as practised by the most 



FIG. 390. Microtome. 



