VII] SECTION CUTTING AND IMBEDDING 53 



drain off the salt solution. Treat another section in the same 

 way. 



Place a cover-glass on one of the sections and examine it. (A 

 drop of dilute methylene blue or Spiller's purple may be added 

 to another section, in 5 minutes the drop drained away, and a 

 cover-glass put on.) Let two or three drops of 95p.c. alcohol 

 fall on the other. Leave it for a quarter of an hour or longer, 

 then stain e.g. with hsematoxylin and mount in Canada balsam. 



b. Cut sections of e.g. a small lymphatic gland. Transfer 

 the sections to 30 p.c. alcohol. With a brush move them about 

 in the alcohol to remove some of the leucocytes. Stain and 

 mount. (Sections after unfolding in 30 p.c. alcohol may be 

 transferred flat on a lifter to any of the usual hardening agents.) 



5. Imbedding in Paraffin. Take the piece of 

 tissue given you, which has already been stained in 

 bulk 1 . Place it for J hour in 95 p.c. alcohol, and for 

 hour in absolute alcohol. Transfer it to a little 

 turpentine 2 in a watch-glass, cover up and place on a 

 warm bath at about 45 C. for 5 to 10 min. Place on 

 the warm bath a pair of forceps and a piece of blotting- 

 paper. Take up the tissue with the warm forceps, 

 drop it on the blotting-paper, and roll it over, wipe the 

 points of the forceps, take up the tissue and drop it 

 into one of the dishes of melted paraffin in the paraffin 

 bath. The paraffin used should have a melting point 

 of 45 to 52 C. Leave the tissue in the paraffin for 

 J hour to 3 hours according to its size. 



1 The piece of tissue should if practicable only be a few millimetres 

 thick. The larger the piece, the longer it should be left in the 

 alcohols. It is stained in bulk by leaving it for 1 to 3 days in acid 

 haematoxylin or alum carmine (cp. Less. vni. p. 61). 



2 When the student has become accustomed to imbedding, xylol 

 or cedar- wood oil should be used in place of turpentine (cp. Less. vi. 

 p. 43 and Notes at end of this Lesson). 



