CHAPTER V 

 THE PARAFFIN METHOD: IMBEDDING AND SECTIONING 



1. From 70 per cent, alcohol take a small piece of intestine 

 (6 mm. long) fixed in Gilson, and also pieces of kidney and tongue, 

 and proceed according to the following schedule. Keep accurate 

 records on your cards. 



2. Ninety-five per cent, alcohol, 30 to 45 minutes. A longer 

 time will do no harm. 



3. Absolute alcohol, 45 minutes. Before transferring to 

 absolute, remove the excess of 95 per cent, alcohol from the 

 object by touching it with a piece of blotting paper or a clean 

 cloth. 



4. Xylol, 2 hours or until the object looks clear. It may be 

 left several hours. Rapidly remove all excess of xylol before 

 proceeding with step 5, but do not allow the tissue to become dry 

 or dull looking. 



5. Melted paraffin (melting-point about 53 C.), 2 hours. 

 The object may be left an hour or two longer, but it is best to 

 avoid as much as possible subjecting tissues to an elevated 

 temperature. Shift its position in the paraffin once or twice to 

 facilitate penetration of the latter. 



Cautions. ) Do not have the bath too hot. Cooked tissues 

 are worse than useless. 



6) To keep material clean, it is well to have a false bottom of 

 paper in the vessel containing paraffin. Make this by swinging a 

 strip of white paper into the cup so that the loop of the paper is 

 submerged in paraffin and the ends attached on either side to the 

 mouth of the cup. 



6. Prepare paper boxes according to the following instructions: 



A small rectangular block of wood or a stick with a flat end measuring 

 approximately 15x20 mm. is used. Cut a strip of stiff paper so that it 

 measures about 4x7 cm. Place the flat end of the block in the center of 

 the paper with its long diameter coinciding with the long diameter of the 



37 



