MOUNTING PARAFFIN SECTIONS 1 19 



with a knife, taking care to retain the rectangular 

 shape, and store the block in a pill-box. 



When several pieces of tissue have to be imbedded at 

 one time, shapes of stout copper, 10 cm., 5 cm., and 

 2.5 cm. square respectively, and 0.75 cm. deep (Fig. 74) 

 will be found extremely useful. 

 These placed upon plates of glass 

 replace the pair of L's in the above 

 process. When the paraffin has set 

 firmly the screw a should be loosened 

 to allow the two halves of the flange b 

 to separate slightly this facilitates FIG. 74. Paraffin 

 removal of the paraffin block. 



8. Cement the block on the carrier of a " paraffin" 

 microtome (the Minot, the Jung, or the Cambridge 

 Rocker) with a little melted paraffin. Greater security 

 is obtained if the paraffin around the base of the block is 

 melted by means of a hot metal or glass rod. 



9. Cut sections thin, and if possible in ribbands. 



Mounting Paraffin Sections. 



1. Place a large drop of 30 per cent, alcohol on the 

 centre of a slide (or cover-slip) and float the section 

 on to the surface of the drop, from a section lifter. 



2 . Hold the slide in the fingers of one hand and warm 

 cautiously over the flame of a Bunsen burner, touching 

 the under surface of the glass from time to time on the 

 back of the other hand. As soon as the slide feels 

 distinctly warm to the skin, the paraffin section will 

 flatten out and all wrinkles disappear. 



(The slide with the section floating on it may be 

 rested on the top of the paraffin bath for two or three 

 minutes, instead of warming over the flame as here 

 described.) 



3 . Cautiously tilt up the slide and blot off the excess 

 of spirit with blotting paper, leaving the section 

 attached to the centre of the slide. 



