CLEARING 



117 



gently remove the slide from the water, taking care that any 

 folds in the section are floated out before the slide is finally 

 removed from the water. 



7. Drain away as much water as possible from the section. 

 Drop absolute alcohol on to the section from a drop bottle, to 

 dehydrate it. 



8. Double a piece of blotting paper and gently press it on the 

 section to dry it. 



9. Drop on xylol to clear the section. 



10. Place a large drop of xylol balsam on the section and care- 

 fully lower a cover-glass on to the balsam. 



PARAFFIN METHOD. 



1. Fixation. Place the pieces of tissue, resting on 

 cotton- wool, in a wide-mouthed glass bottle. Pour on 

 a sufficient quantity of the corrosive sublimate fixing 

 fluid; allow the tissue to remain therein for twelve to 

 twenty-four hours according to size. 



2. Pour off the fixing fluid and wash thoroughly in 

 running water for twenty minutes to half an hour to 

 remove the excess of corrosive sublimate. 



FIG. 72. L-shaped brass moulds. 



FIG. 73. Paraffin kettle. 



3. Hardening. Place the tissues in each of the fol- 

 lowing strengths of alcohol in turn for from twelve to 

 twenty-four hours: 50 per cent., 75 per cent., 90 per 

 cent., absolute. 



4. Dehydration is effected by transferring the tissues 

 to fresh absolute alcohol. 



5. Clearing. Half fill a wide-mouthed bottle with 



