EMBEDDING. 



45 



/ 



c d 



FIG. 30. Embedding Box. 



accelerate the cooling, as paraffin cooled rapidly is more homogeneous 

 and cuts better than when it is cooled slowly. In about half-an- 

 hour the paraffin has set, and can be removed from the mould. 



Embedding Boxes (fig. 30) may be used. These are readily 

 made from a rectangular 



piece of writing-paper B' C? d' D' 



folded to the size required. 

 The paper is first folded 

 along the lines aa' and bb' t 

 then along cc' and dd' t 

 always folding the paper 

 towards the same side. 

 The diagonals AA'-DD' 



are indented by means of a! * r *7 \Q>' 



the point of a lead pencil, 



or the paper is folded 



along these lines. These 



corners are then bent up 



between the fore-finger and thumb, and then bent round, so as to 



be applied to the sides AB and CD of the oblong, and are fixed 



there by turning down the flaps/''. 



Embedding in Paraffin. The f olio wingscheme shows the stages : 



(1.) Harden, either from the first or subsequent to other agents 



in absolute alcohol. 

 (2.) Xylol or turpentine (24 hours). 

 (3.) In warm paraffin fluid at 50 C. (1-12). 

 (4.) Embed and allow paraffin to cool. 

 (">.) Cut sections, and in some cases fix them on slide with 



a fixative (p. 60). 



(6.) Remove paraffin by turpentine or xylol. 

 (7.) Alcohol to remove xylol. 

 (8.) Add water and then stain, &c. 



3. Embedding in Celloidin. This method is specially valuable 

 where the parts of an organ when cut into sections are apt to fall 

 asunder. It is specially valuable in such as those of the ovary, 

 central nervous system, retina, &c. 



Celloidin is a form of mtro-cellulose or pyroxylin, or solidified 

 collodion, and is sold in two forms, one in tablets and the other in 

 cuttings. E. Schering's is the best, and the form sold in " cuttings " 

 is to be preferred. Do not let its solution dry, as it is then difficult 

 to redissolve it. 



This method was invented by Duval, who used collodion, and 

 improved by Schiefi'erdecker. Prepare the solutions of celloidin 

 by dissolving the latter in equal parts of absolute alcohol and 



