54 PRACTICAL HISTOLOGY [VII 



Rub the inside of a watch-glass with glycerine, 

 removing excess so that the glycerine only remains as 

 a smear. If in the paraffin dish there is more than 

 about half a watch-glassful of paraffin, pour the excess 

 into another dish. Light a Bunsen burner, and have 

 ready a piece of wire or an old scalpel. Pour the 

 paraffin with the tissue into the watch-glass; warm 

 the wire in the Bunsen flame, and with it adjust the 

 tissue so that the face to be cut is towards the edge of 

 the watch-glass ; and if air-bubbles are present remove 

 them by means of the heated wire. If the paraffin 

 begins to set round the tissue, when an air-bubble still 

 remains attached to it, heat the wire and melt all the 

 paraffin around the tissue. 



Carefully take up the watch-glass and place it in 

 a shallow dish of cold water ; when the paraffin has set, 

 immerse the watch-glass cautiously in water; then 

 place the glass surface under a stream of water from a 

 tap. The more quickly the paraffin is cooled, the less 

 chance there is of crystals forming, and the easier it 

 will be to cut. 



Cut away the paraffin on each side of the tissue, 

 and remove the block with the imbedded tissue. Cut 

 the paraffin into a rectangular block, cutting away the 

 paraffin close up to the tissue on the face to be cut and 

 on the adjoining faces, but leaving 2 to 3 mm. of 

 paraffin on the face opposite to that to be cut. 



A piece of smooth glass is given you with a central 

 mass of paraffin fixed to it. Heat a scalpel in a 

 Bunsen burner and melt the central part of the paraffin, 

 on this place the paraffin end of the block with the 

 imbedded tissue. Pass the heated scalpel once or twice 



